Repository: kubernetes-csi/external-snapshotter
Pull request #435 (2020-12-02 22:42:19)

Cherry-pick: Add certwatcher to webhook server
Signed-off-by: Grant Griffiths <grant@portworx.com>

**What type of PR is this?**
/kind bug

**What this PR does / why we need it**:
Cherry-pick of #429 

**Which issue(s) this PR fixes**:
n/a

**Special notes for your reviewer**:
n/a

**Does this PR introduce a user-facing change?**:
```release-note
The validation-webhook server will now watch for changes to --tls-cert-file and --tls-private-key-file and update the server's TLS config accordingly.
```


k8s-ci-robot: [APPROVALNOTIFIER] This PR is **NOT APPROVED**

This pull-request has been approved by: *<a href="https://github.com/kubernetes-csi/external-snapshotter/pull/435#" title="Author self-approved">ggriffiths</a>*
To complete the [pull request process](https://git.k8s.io/community/contributors/guide/owners.md#the-code-review-process), please assign **lpabon** after the PR has been reviewed.
You can assign the PR to them by writing `/assign @lpabon` in a comment when ready.

The full list of commands accepted by this bot can be found [here](https://go.k8s.io/bot-commands?repo=kubernetes-csi%2Fexternal-snapshotter).

<details open>
Needs approval from an approver in each of these files:

- **[OWNERS](https://github.com/kubernetes-csi/external-snapshotter/blob/release-3.0/OWNERS)**

Approvers can indicate their approval by writing `/approve` in a comment
Approvers can cancel approval by writing `/approve cancel` in a comment
</details>
<!-- META={"approvers":["lpabon"]} -->
k8s-ci-robot: @ggriffiths: The following test **failed**, say `/retest` to rerun all failed tests:

Test name | Commit | Details | Rerun command
--- | --- | --- | ---
pull-kubernetes-csi-external-snapshotter-1-17-on-kubernetes-1-17 | e7e6e38e018db3c8f1c235160d638f8d3b72b716 | [link](https://prow.k8s.io/view/gs/kubernetes-jenkins/pr-logs/pull/kubernetes-csi_external-snapshotter/435/pull-kubernetes-csi-external-snapshotter-1-17-on-kubernetes-1-17/1334266681576394752) | `/test pull-kubernetes-csi-external-snapshotter-1-17-on-kubernetes-1-17`

[Full PR test history](https://prow.k8s.io/pr-history?org=kubernetes-csi&repo=external-snapshotter&pr=435). [Your PR dashboard](https://prow.k8s.io/pr?query=is%3Apr%20state%3Aopen%20author%3Aggriffiths). Please help us cut down on flakes by [linking to](https://git.k8s.io/community/contributors/devel/sig-testing/flaky-tests.md#filing-issues-for-flaky-tests) an [open issue](https://github.com/kubernetes-csi/external-snapshotter/issues?q=is:issue+is:open) when you hit one in your PR.

<details>

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md).  If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).
</details>
<!-- test report -->
k8s-ci-robot: @ggriffiths: The following tests **failed**, say `/retest` to rerun all failed tests:

Test name | Commit | Details | Rerun command
--- | --- | --- | ---
pull-kubernetes-csi-external-snapshotter-1-17-on-kubernetes-1-17 | e7e6e38e018db3c8f1c235160d638f8d3b72b716 | [link](https://prow.k8s.io/view/gs/kubernetes-jenkins/pr-logs/pull/kubernetes-csi_external-snapshotter/435/pull-kubernetes-csi-external-snapshotter-1-17-on-kubernetes-1-17/1334266681576394752) | `/test pull-kubernetes-csi-external-snapshotter-1-17-on-kubernetes-1-17`
pull-kubernetes-csi-external-snapshotter-1-19-on-kubernetes-1-19 | e7e6e38e018db3c8f1c235160d638f8d3b72b716 | [link](https://prow.k8s.io/view/gs/kubernetes-jenkins/pr-logs/pull/kubernetes-csi_external-snapshotter/435/pull-kubernetes-csi-external-snapshotter-1-19-on-kubernetes-1-19/1334266681626726400) | `/test pull-kubernetes-csi-external-snapshotter-1-19-on-kubernetes-1-19`

[Full PR test history](https://prow.k8s.io/pr-history?org=kubernetes-csi&repo=external-snapshotter&pr=435). [Your PR dashboard](https://prow.k8s.io/pr?query=is%3Apr%20state%3Aopen%20author%3Aggriffiths). Please help us cut down on flakes by [linking to](https://git.k8s.io/community/contributors/devel/sig-testing/flaky-tests.md#filing-issues-for-flaky-tests) an [open issue](https://github.com/kubernetes-csi/external-snapshotter/issues?q=is:issue+is:open) when you hit one in your PR.

<details>

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md).  If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).
</details>
<!-- test report -->
k8s-ci-robot: @ggriffiths: The following tests **failed**, say `/retest` to rerun all failed tests:

Test name | Commit | Details | Rerun command
--- | --- | --- | ---
pull-kubernetes-csi-external-snapshotter-1-17-on-kubernetes-1-17 | e7e6e38e018db3c8f1c235160d638f8d3b72b716 | [link](https://prow.k8s.io/view/gs/kubernetes-jenkins/pr-logs/pull/kubernetes-csi_external-snapshotter/435/pull-kubernetes-csi-external-snapshotter-1-17-on-kubernetes-1-17/1334266681576394752) | `/test pull-kubernetes-csi-external-snapshotter-1-17-on-kubernetes-1-17`
pull-kubernetes-csi-external-snapshotter-1-19-on-kubernetes-1-19 | e7e6e38e018db3c8f1c235160d638f8d3b72b716 | [link](https://prow.k8s.io/view/gs/kubernetes-jenkins/pr-logs/pull/kubernetes-csi_external-snapshotter/435/pull-kubernetes-csi-external-snapshotter-1-19-on-kubernetes-1-19/1334266681626726400) | `/test pull-kubernetes-csi-external-snapshotter-1-19-on-kubernetes-1-19`
pull-kubernetes-csi-external-snapshotter-1-18-on-kubernetes-1-18 | e7e6e38e018db3c8f1c235160d638f8d3b72b716 | [link](https://prow.k8s.io/view/gs/kubernetes-jenkins/pr-logs/pull/kubernetes-csi_external-snapshotter/435/pull-kubernetes-csi-external-snapshotter-1-18-on-kubernetes-1-18/1334266681597366272) | `/test pull-kubernetes-csi-external-snapshotter-1-18-on-kubernetes-1-18`

[Full PR test history](https://prow.k8s.io/pr-history?org=kubernetes-csi&repo=external-snapshotter&pr=435). [Your PR dashboard](https://prow.k8s.io/pr?query=is%3Apr%20state%3Aopen%20author%3Aggriffiths). Please help us cut down on flakes by [linking to](https://git.k8s.io/community/contributors/devel/sig-testing/flaky-tests.md#filing-issues-for-flaky-tests) an [open issue](https://github.com/kubernetes-csi/external-snapshotter/issues?q=is:issue+is:open) when you hit one in your PR.

<details>

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md).  If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).
</details>
<!-- test report -->
xing-yang: I think we probably need to backport some release-tools changes.  See the following errors:
```
INFO: Version 1.19.1, installing CRDs and snapshot controller
error: unable to read URL "https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/v3.0.2/config/crd/snapshot.storage.k8s.io_volumesnapshotclasses.yaml", server reported 404 Not Found, status code=404
error: unable to read URL "https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/v3.0.2/config/crd/snapshot.storage.k8s.io_volumesnapshots.yaml", server reported 404 Not Found, status code=404
error: unable to read URL "https://raw.githubusercontent.com/kubernetes-csi/external-snapshotter/v3.0.2/config/crd/snapshot.storage.k8s.io_volumesnapshotcontents.yaml", server reported 404 Not Found, status code=404
error: the server doesn't have a resource type "volumesnapshotclasses"
22:57:31 waiting for snapshot CRDs, attempt #0
error: the server doesn't have a resource type "volumesnapshotclasses"
22:57:33 waiting for snapshot CRDs, attempt #1
error: the server doesn't have a resource type "volumesnapshotclasses"
22:57:35 waiting for snapshot CRDs, attempt #2
```
xing-yang: I think we need these two:

https://github.com/kubernetes-csi/external-snapshotter/pull/430
https://github.com/kubernetes-csi/external-snapshotter/pull/426
ggriffiths: Opened separate PR with updated release tools:
https://github.com/kubernetes-csi/external-snapshotter/pull/436

Patch:
diff --git a/go.mod b/go.mod
index 7ac0241b2..09de7e58a 100644
--- a/go.mod
+++ b/go.mod
@@ -4,6 +4,7 @@ go 1.15
 
 require (
 	github.com/container-storage-interface/spec v1.2.0
+	github.com/fsnotify/fsnotify v1.4.9
 	github.com/golang/mock v1.4.3
 	github.com/golang/protobuf v1.4.2
 	github.com/google/gofuzz v1.1.0
diff --git a/pkg/validation-webhook/certwatcher.go b/pkg/validation-webhook/certwatcher.go
new file mode 100644
index 000000000..d79908df7
--- /dev/null
+++ b/pkg/validation-webhook/certwatcher.go
@@ -0,0 +1,164 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package webhook
+
+import (
+	"context"
+	"crypto/tls"
+	"sync"
+
+	"github.com/fsnotify/fsnotify"
+	"k8s.io/klog"
+)
+
+// This file originated from github.com/kubernetes-sigs/controller-runtime/pkg/webhook/internal/certwatcher.
+// We cannot import this package as it's an internal one. In addition, we cannot yet easily integrate
+// with controller-runtime/pkg/webhook directly, as it would require extensive rework:
+// https://github.com/kubernetes-csi/external-snapshotter/issues/422
+
+// CertWatcher watches certificate and key files for changes.  When either file
+// changes, it reads and parses both and calls an optional callback with the new
+// certificate.
+type CertWatcher struct {
+	sync.Mutex
+
+	currentCert *tls.Certificate
+	watcher     *fsnotify.Watcher
+
+	certPath string
+	keyPath  string
+}
+
+// NewCertWatcher returns a new CertWatcher watching the given certificate and key.
+func NewCertWatcher(certPath, keyPath string) (*CertWatcher, error) {
+	var err error
+
+	cw := &CertWatcher{
+		certPath: certPath,
+		keyPath:  keyPath,
+	}
+
+	// Initial read of certificate and key.
+	if err := cw.ReadCertificate(); err != nil {
+		return nil, err
+	}
+
+	cw.watcher, err = fsnotify.NewWatcher()
+	if err != nil {
+		return nil, err
+	}
+
+	return cw, nil
+}
+
+// GetCertificate fetches the currently loaded certificate, which may be nil.
+func (cw *CertWatcher) GetCertificate(_ *tls.ClientHelloInfo) (*tls.Certificate, error) {
+	cw.Lock()
+	defer cw.Unlock()
+	return cw.currentCert, nil
+}
+
+// Start starts the watch on the certificate and key files.
+func (cw *CertWatcher) Start(ctx context.Context) error {
+	files := []string{cw.certPath, cw.keyPath}
+
+	for _, f := range files {
+		if err := cw.watcher.Add(f); err != nil {
+			return err
+		}
+	}
+
+	go cw.Watch()
+
+	// Block until the context is done.
+	<-ctx.Done()
+
+	return cw.watcher.Close()
+}
+
+// Watch reads events from the watcher's channel and reacts to changes.
+func (cw *CertWatcher) Watch() {
+	for {
+		select {
+		case event, ok := <-cw.watcher.Events:
+			// Channel is closed.
+			if !ok {
+				return
+			}
+
+			cw.handleEvent(event)
+
+		case err, ok := <-cw.watcher.Errors:
+			// Channel is closed.
+			if !ok {
+				return
+			}
+
+			klog.Error(err, "certificate watch error")
+		}
+	}
+}
+
+// ReadCertificate reads the certificate and key files from disk, parses them,
+// and updates the current certificate on the watcher.  If a callback is set, it
+// is invoked with the new certificate.
+func (cw *CertWatcher) ReadCertificate() error {
+	cert, err := tls.LoadX509KeyPair(cw.certPath, cw.keyPath)
+	if err != nil {
+		return err
+	}
+
+	cw.Lock()
+	cw.currentCert = &cert
+	cw.Unlock()
+
+	klog.Info("Updated current TLS certificate")
+
+	return nil
+}
+
+func (cw *CertWatcher) handleEvent(event fsnotify.Event) {
+	// Only care about events which may modify the contents of the file.
+	if !(isWrite(event) || isRemove(event) || isCreate(event)) {
+		return
+	}
+
+	klog.V(1).Info("certificate event", "event", event)
+
+	// If the file was removed, re-add the watch.
+	if isRemove(event) {
+		if err := cw.watcher.Add(event.Name); err != nil {
+			klog.Error(err, "error re-watching file")
+		}
+	}
+
+	if err := cw.ReadCertificate(); err != nil {
+		klog.Error(err, "error re-reading certificate")
+	}
+}
+
+func isWrite(event fsnotify.Event) bool {
+	return event.Op&fsnotify.Write == fsnotify.Write
+}
+
+func isCreate(event fsnotify.Event) bool {
+	return event.Op&fsnotify.Create == fsnotify.Create
+}
+
+func isRemove(event fsnotify.Event) bool {
+	return event.Op&fsnotify.Remove == fsnotify.Remove
+}
diff --git a/pkg/validation-webhook/webhook.go b/pkg/validation-webhook/webhook.go
index 69d8b51f6..1e2b7d11a 100644
--- a/pkg/validation-webhook/webhook.go
+++ b/pkg/validation-webhook/webhook.go
@@ -17,6 +17,8 @@ limitations under the License.
 package webhook
 
 import (
+	"context"
+	"crypto/tls"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
@@ -175,21 +177,45 @@ func serveSnapshotRequest(w http.ResponseWriter, r *http.Request) {
 	serve(w, r, newDelegateToV1AdmitHandler(admitSnapshot))
 }
 
-func main(cmd *cobra.Command, args []string) {
+func startServer(ctx context.Context, tlsConfig *tls.Config, cw *CertWatcher) error {
+	go func() {
+		klog.Info("Starting certificate watcher")
+		if err := cw.Start(ctx); err != nil {
+			klog.Errorf("certificate watcher error: %v", err)
+		}
+	}()
+
 	fmt.Println("Starting webhook server")
-	config := Config{
-		CertFile: certFile,
-		KeyFile:  keyFile,
+	mux := http.NewServeMux()
+	mux.HandleFunc("/volumesnapshot", serveSnapshotRequest)
+	mux.HandleFunc("/readyz", func(w http.ResponseWriter, req *http.Request) { w.Write([]byte("ok")) })
+	srv := &http.Server{
+		Handler:   mux,
+		TLSConfig: tlsConfig,
 	}
 
-	http.HandleFunc("/volumesnapshot", serveSnapshotRequest)
-	http.HandleFunc("/readyz", func(w http.ResponseWriter, req *http.Request) { w.Write([]byte("ok")) })
-	server := &http.Server{
-		Addr:      fmt.Sprintf(":%d", port),
-		TLSConfig: configTLS(config),
+	// listener is always closed by srv.Serve
+	listener, err := tls.Listen("tcp", fmt.Sprintf(":%d", port), tlsConfig)
+	if err != nil {
+		return err
 	}
-	err := server.ListenAndServeTLS("", "")
+
+	return srv.Serve(listener)
+}
+
+func main(cmd *cobra.Command, args []string) {
+	// Create new cert watcher
+	ctx, cancel := context.WithCancel(cmd.Context())
+	defer cancel() // stops certwatcher
+	cw, err := NewCertWatcher(certFile, keyFile)
 	if err != nil {
-		panic(err)
+		klog.Fatalf("failed to initialize new cert watcher: %v", err)
+	}
+	tlsConfig := &tls.Config{
+		GetCertificate: cw.GetCertificate,
+	}
+
+	if err := startServer(ctx, tlsConfig, cw); err != nil {
+		klog.Fatalf("server stopped: %v", err)
 	}
 }
diff --git a/vendor/github.com/fsnotify/fsnotify/.editorconfig b/vendor/github.com/fsnotify/fsnotify/.editorconfig
new file mode 100644
index 000000000..fad895851
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/.editorconfig
@@ -0,0 +1,12 @@
+root = true
+
+[*.go]
+indent_style = tab
+indent_size = 4
+insert_final_newline = true
+
+[*.{yml,yaml}]
+indent_style = space
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
diff --git a/vendor/github.com/fsnotify/fsnotify/.gitattributes b/vendor/github.com/fsnotify/fsnotify/.gitattributes
new file mode 100644
index 000000000..32f1001be
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/.gitattributes
@@ -0,0 +1,1 @@
+go.sum linguist-generated
diff --git a/vendor/github.com/fsnotify/fsnotify/.gitignore b/vendor/github.com/fsnotify/fsnotify/.gitignore
new file mode 100644
index 000000000..4cd0cbaf4
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/.gitignore
@@ -0,0 +1,6 @@
+# Setup a Global .gitignore for OS and editor generated files:
+# https://help.github.com/articles/ignoring-files
+# git config --global core.excludesfile ~/.gitignore_global
+
+.vagrant
+*.sublime-project
diff --git a/vendor/github.com/fsnotify/fsnotify/.travis.yml b/vendor/github.com/fsnotify/fsnotify/.travis.yml
new file mode 100644
index 000000000..a9c30165c
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/.travis.yml
@@ -0,0 +1,36 @@
+sudo: false
+language: go
+
+go:
+  - "stable"
+  - "1.11.x"
+  - "1.10.x"
+  - "1.9.x"
+
+matrix:
+  include:
+    - go: "stable"
+      env: GOLINT=true
+  allow_failures:
+    - go: tip
+  fast_finish: true
+
+
+before_install:
+  - if [ ! -z "${GOLINT}" ]; then go get -u golang.org/x/lint/golint; fi
+
+script:
+  - go test --race ./...
+
+after_script:
+  - test -z "$(gofmt -s -l -w . | tee /dev/stderr)"
+  - if [ ! -z  "${GOLINT}" ]; then echo running golint; golint --set_exit_status  ./...; else echo skipping golint; fi
+  - go vet ./...
+
+os:
+  - linux
+  - osx
+  - windows
+
+notifications:
+  email: false
diff --git a/vendor/github.com/fsnotify/fsnotify/AUTHORS b/vendor/github.com/fsnotify/fsnotify/AUTHORS
new file mode 100644
index 000000000..5ab5d41c5
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/AUTHORS
@@ -0,0 +1,52 @@
+# Names should be added to this file as
+#	Name or Organization <email address>
+# The email address is not required for organizations.
+
+# You can update this list using the following command:
+#
+#   $ git shortlog -se | awk '{print $2 " " $3 " " $4}'
+
+# Please keep the list sorted.
+
+Aaron L <aaron@bettercoder.net>
+Adrien Bustany <adrien@bustany.org>
+Amit Krishnan <amit.krishnan@oracle.com>
+Anmol Sethi <me@anmol.io>
+Bjørn Erik Pedersen <bjorn.erik.pedersen@gmail.com>
+Bruno Bigras <bigras.bruno@gmail.com>
+Caleb Spare <cespare@gmail.com>
+Case Nelson <case@teammating.com>
+Chris Howey <chris@howey.me> <howeyc@gmail.com>
+Christoffer Buchholz <christoffer.buchholz@gmail.com>
+Daniel Wagner-Hall <dawagner@gmail.com>
+Dave Cheney <dave@cheney.net>
+Evan Phoenix <evan@fallingsnow.net>
+Francisco Souza <f@souza.cc>
+Hari haran <hariharan.uno@gmail.com>
+John C Barstow
+Kelvin Fo <vmirage@gmail.com>
+Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>
+Matt Layher <mdlayher@gmail.com>
+Nathan Youngman <git@nathany.com>
+Nickolai Zeldovich <nickolai@csail.mit.edu>
+Patrick <patrick@dropbox.com>
+Paul Hammond <paul@paulhammond.org>
+Pawel Knap <pawelknap88@gmail.com>
+Pieter Droogendijk <pieter@binky.org.uk>
+Pursuit92 <JoshChase@techpursuit.net>
+Riku Voipio <riku.voipio@linaro.org>
+Rob Figueiredo <robfig@gmail.com>
+Rodrigo Chiossi <rodrigochiossi@gmail.com>
+Slawek Ligus <root@ooz.ie>
+Soge Zhang <zhssoge@gmail.com>
+Tiffany Jernigan <tiffany.jernigan@intel.com>
+Tilak Sharma <tilaks@google.com>
+Tom Payne <twpayne@gmail.com>
+Travis Cline <travis.cline@gmail.com>
+Tudor Golubenco <tudor.g@gmail.com>
+Vahe Khachikyan <vahe@live.ca>
+Yukang <moorekang@gmail.com>
+bronze1man <bronze1man@gmail.com>
+debrando <denis.brandolini@gmail.com>
+henrikedwards <henrik.edwards@gmail.com>
+铁哥 <guotie.9@gmail.com>
diff --git a/vendor/github.com/fsnotify/fsnotify/CHANGELOG.md b/vendor/github.com/fsnotify/fsnotify/CHANGELOG.md
new file mode 100644
index 000000000..be4d7ea2c
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/CHANGELOG.md
@@ -0,0 +1,317 @@
+# Changelog
+
+## v1.4.7 / 2018-01-09
+
+* BSD/macOS: Fix possible deadlock on closing the watcher on kqueue (thanks @nhooyr and @glycerine)
+* Tests: Fix missing verb on format string (thanks @rchiossi)
+* Linux: Fix deadlock in Remove (thanks @aarondl)
+* Linux: Watch.Add improvements (avoid race, fix consistency, reduce garbage) (thanks @twpayne)
+* Docs: Moved FAQ into the README (thanks @vahe)
+* Linux: Properly handle inotify's IN_Q_OVERFLOW event (thanks @zeldovich)
+* Docs: replace references to OS X with macOS
+
+## v1.4.2 / 2016-10-10
+
+* Linux: use InotifyInit1 with IN_CLOEXEC to stop leaking a file descriptor to a child process when using fork/exec [#178](https://github.com/fsnotify/fsnotify/pull/178) (thanks @pattyshack)
+
+## v1.4.1 / 2016-10-04
+
+* Fix flaky inotify stress test on Linux [#177](https://github.com/fsnotify/fsnotify/pull/177) (thanks @pattyshack)
+
+## v1.4.0 / 2016-10-01
+
+* add a String() method to Event.Op [#165](https://github.com/fsnotify/fsnotify/pull/165) (thanks @oozie)
+
+## v1.3.1 / 2016-06-28
+
+* Windows: fix for double backslash when watching the root of a drive [#151](https://github.com/fsnotify/fsnotify/issues/151) (thanks @brunoqc)
+
+## v1.3.0 / 2016-04-19
+
+* Support linux/arm64 by [patching](https://go-review.googlesource.com/#/c/21971/) x/sys/unix and switching to to it from syscall (thanks @suihkulokki) [#135](https://github.com/fsnotify/fsnotify/pull/135)
+
+## v1.2.10 / 2016-03-02
+
+* Fix golint errors in windows.go [#121](https://github.com/fsnotify/fsnotify/pull/121) (thanks @tiffanyfj)
+
+## v1.2.9 / 2016-01-13
+
+kqueue: Fix logic for CREATE after REMOVE [#111](https://github.com/fsnotify/fsnotify/pull/111) (thanks @bep)
+
+## v1.2.8 / 2015-12-17
+
+* kqueue: fix race condition in Close [#105](https://github.com/fsnotify/fsnotify/pull/105) (thanks @djui for reporting the issue and @ppknap for writing a failing test)
+* inotify: fix race in test
+* enable race detection for continuous integration (Linux, Mac, Windows)
+
+## v1.2.5 / 2015-10-17
+
+* inotify: use epoll_create1 for arm64 support (requires Linux 2.6.27 or later) [#100](https://github.com/fsnotify/fsnotify/pull/100) (thanks @suihkulokki)
+* inotify: fix path leaks [#73](https://github.com/fsnotify/fsnotify/pull/73) (thanks @chamaken)
+* kqueue: watch for rename events on subdirectories [#83](https://github.com/fsnotify/fsnotify/pull/83) (thanks @guotie)
+* kqueue: avoid infinite loops from symlinks cycles [#101](https://github.com/fsnotify/fsnotify/pull/101) (thanks @illicitonion)
+
+## v1.2.1 / 2015-10-14
+
+* kqueue: don't watch named pipes [#98](https://github.com/fsnotify/fsnotify/pull/98) (thanks @evanphx)
+
+## v1.2.0 / 2015-02-08
+
+* inotify: use epoll to wake up readEvents [#66](https://github.com/fsnotify/fsnotify/pull/66) (thanks @PieterD)
+* inotify: closing watcher should now always shut down goroutine [#63](https://github.com/fsnotify/fsnotify/pull/63) (thanks @PieterD)
+* kqueue: close kqueue after removing watches, fixes [#59](https://github.com/fsnotify/fsnotify/issues/59)
+
+## v1.1.1 / 2015-02-05
+
+* inotify: Retry read on EINTR [#61](https://github.com/fsnotify/fsnotify/issues/61) (thanks @PieterD)
+
+## v1.1.0 / 2014-12-12
+
+* kqueue: rework internals [#43](https://github.com/fsnotify/fsnotify/pull/43)
+    * add low-level functions
+    * only need to store flags on directories
+    * less mutexes [#13](https://github.com/fsnotify/fsnotify/issues/13)
+    * done can be an unbuffered channel
+    * remove calls to os.NewSyscallError
+* More efficient string concatenation for Event.String() [#52](https://github.com/fsnotify/fsnotify/pull/52) (thanks @mdlayher)
+* kqueue: fix regression in  rework causing subdirectories to be watched [#48](https://github.com/fsnotify/fsnotify/issues/48)
+* kqueue: cleanup internal watch before sending remove event [#51](https://github.com/fsnotify/fsnotify/issues/51)
+
+## v1.0.4 / 2014-09-07
+
+* kqueue: add dragonfly to the build tags.
+* Rename source code files, rearrange code so exported APIs are at the top.
+* Add done channel to example code. [#37](https://github.com/fsnotify/fsnotify/pull/37) (thanks @chenyukang)
+
+## v1.0.3 / 2014-08-19
+
+* [Fix] Windows MOVED_TO now translates to Create like on BSD and Linux. [#36](https://github.com/fsnotify/fsnotify/issues/36)
+
+## v1.0.2 / 2014-08-17
+
+* [Fix] Missing create events on macOS. [#14](https://github.com/fsnotify/fsnotify/issues/14) (thanks @zhsso)
+* [Fix] Make ./path and path equivalent. (thanks @zhsso)
+
+## v1.0.0 / 2014-08-15
+
+* [API] Remove AddWatch on Windows, use Add.
+* Improve documentation for exported identifiers. [#30](https://github.com/fsnotify/fsnotify/issues/30)
+* Minor updates based on feedback from golint.
+
+## dev / 2014-07-09
+
+* Moved to [github.com/fsnotify/fsnotify](https://github.com/fsnotify/fsnotify).
+* Use os.NewSyscallError instead of returning errno (thanks @hariharan-uno)
+
+## dev / 2014-07-04
+
+* kqueue: fix incorrect mutex used in Close()
+* Update example to demonstrate usage of Op.
+
+## dev / 2014-06-28
+
+* [API] Don't set the Write Op for attribute notifications [#4](https://github.com/fsnotify/fsnotify/issues/4)
+* Fix for String() method on Event (thanks Alex Brainman)
+* Don't build on Plan 9 or Solaris (thanks @4ad)
+
+## dev / 2014-06-21
+
+* Events channel of type Event rather than *Event.
+* [internal] use syscall constants directly for inotify and kqueue.
+* [internal] kqueue: rename events to kevents and fileEvent to event.
+
+## dev / 2014-06-19
+
+* Go 1.3+ required on Windows (uses syscall.ERROR_MORE_DATA internally).
+* [internal] remove cookie from Event struct (unused).
+* [internal] Event struct has the same definition across every OS.
+* [internal] remove internal watch and removeWatch methods.
+
+## dev / 2014-06-12
+
+* [API] Renamed Watch() to Add() and RemoveWatch() to Remove().
+* [API] Pluralized channel names: Events and Errors.
+* [API] Renamed FileEvent struct to Event.
+* [API] Op constants replace methods like IsCreate().
+
+## dev / 2014-06-12
+
+* Fix data race on kevent buffer (thanks @tilaks) [#98](https://github.com/howeyc/fsnotify/pull/98)
+
+## dev / 2014-05-23
+
+* [API] Remove current implementation of WatchFlags.
+    * current implementation doesn't take advantage of OS for efficiency
+    * provides little benefit over filtering events as they are received, but has  extra bookkeeping and mutexes
+    * no tests for the current implementation
+    * not fully implemented on Windows [#93](https://github.com/howeyc/fsnotify/issues/93#issuecomment-39285195)
+
+## v0.9.3 / 2014-12-31
+
+* kqueue: cleanup internal watch before sending remove event [#51](https://github.com/fsnotify/fsnotify/issues/51)
+
+## v0.9.2 / 2014-08-17
+
+* [Backport] Fix missing create events on macOS. [#14](https://github.com/fsnotify/fsnotify/issues/14) (thanks @zhsso)
+
+## v0.9.1 / 2014-06-12
+
+* Fix data race on kevent buffer (thanks @tilaks) [#98](https://github.com/howeyc/fsnotify/pull/98)
+
+## v0.9.0 / 2014-01-17
+
+* IsAttrib() for events that only concern a file's metadata [#79][] (thanks @abustany)
+* [Fix] kqueue: fix deadlock [#77][] (thanks @cespare)
+* [NOTICE] Development has moved to `code.google.com/p/go.exp/fsnotify` in preparation for inclusion in the Go standard library.
+
+## v0.8.12 / 2013-11-13
+
+* [API] Remove FD_SET and friends from Linux adapter
+
+## v0.8.11 / 2013-11-02
+
+* [Doc] Add Changelog [#72][] (thanks @nathany)
+* [Doc] Spotlight and double modify events on macOS [#62][] (reported by @paulhammond)
+
+## v0.8.10 / 2013-10-19
+
+* [Fix] kqueue: remove file watches when parent directory is removed [#71][] (reported by @mdwhatcott)
+* [Fix] kqueue: race between Close and readEvents [#70][] (reported by @bernerdschaefer)
+* [Doc] specify OS-specific limits in README (thanks @debrando)
+
+## v0.8.9 / 2013-09-08
+
+* [Doc] Contributing (thanks @nathany)
+* [Doc] update package path in example code [#63][] (thanks @paulhammond)
+* [Doc] GoCI badge in README (Linux only) [#60][]
+* [Doc] Cross-platform testing with Vagrant  [#59][] (thanks @nathany)
+
+## v0.8.8 / 2013-06-17
+
+* [Fix] Windows: handle `ERROR_MORE_DATA` on Windows [#49][] (thanks @jbowtie)
+
+## v0.8.7 / 2013-06-03
+
+* [API] Make syscall flags internal
+* [Fix] inotify: ignore event changes
+* [Fix] race in symlink test [#45][] (reported by @srid)
+* [Fix] tests on Windows
+* lower case error messages
+
+## v0.8.6 / 2013-05-23
+
+* kqueue: Use EVT_ONLY flag on Darwin
+* [Doc] Update README with full example
+
+## v0.8.5 / 2013-05-09
+
+* [Fix] inotify: allow monitoring of "broken" symlinks (thanks @tsg)
+
+## v0.8.4 / 2013-04-07
+
+* [Fix] kqueue: watch all file events [#40][] (thanks @ChrisBuchholz)
+
+## v0.8.3 / 2013-03-13
+
+* [Fix] inoitfy/kqueue memory leak [#36][] (reported by @nbkolchin)
+* [Fix] kqueue: use fsnFlags for watching a directory [#33][] (reported by @nbkolchin)
+
+## v0.8.2 / 2013-02-07
+
+* [Doc] add Authors
+* [Fix] fix data races for map access [#29][] (thanks @fsouza)
+
+## v0.8.1 / 2013-01-09
+
+* [Fix] Windows path separators
+* [Doc] BSD License
+
+## v0.8.0 / 2012-11-09
+
+* kqueue: directory watching improvements (thanks @vmirage)
+* inotify: add `IN_MOVED_TO` [#25][] (requested by @cpisto)
+* [Fix] kqueue: deleting watched directory [#24][] (reported by @jakerr)
+
+## v0.7.4 / 2012-10-09
+
+* [Fix] inotify: fixes from https://codereview.appspot.com/5418045/ (ugorji)
+* [Fix] kqueue: preserve watch flags when watching for delete [#21][] (reported by @robfig)
+* [Fix] kqueue: watch the directory even if it isn't a new watch (thanks @robfig)
+* [Fix] kqueue: modify after recreation of file
+
+## v0.7.3 / 2012-09-27
+
+* [Fix] kqueue: watch with an existing folder inside the watched folder (thanks @vmirage)
+* [Fix] kqueue: no longer get duplicate CREATE events
+
+## v0.7.2 / 2012-09-01
+
+* kqueue: events for created directories
+
+## v0.7.1 / 2012-07-14
+
+* [Fix] for renaming files
+
+## v0.7.0 / 2012-07-02
+
+* [Feature] FSNotify flags
+* [Fix] inotify: Added file name back to event path
+
+## v0.6.0 / 2012-06-06
+
+* kqueue: watch files after directory created (thanks @tmc)
+
+## v0.5.1 / 2012-05-22
+
+* [Fix] inotify: remove all watches before Close()
+
+## v0.5.0 / 2012-05-03
+
+* [API] kqueue: return errors during watch instead of sending over channel
+* kqueue: match symlink behavior on Linux
+* inotify: add `DELETE_SELF` (requested by @taralx)
+* [Fix] kqueue: handle EINTR (reported by @robfig)
+* [Doc] Godoc example [#1][] (thanks @davecheney)
+
+## v0.4.0 / 2012-03-30
+
+* Go 1 released: build with go tool
+* [Feature] Windows support using winfsnotify
+* Windows does not have attribute change notifications
+* Roll attribute notifications into IsModify
+
+## v0.3.0 / 2012-02-19
+
+* kqueue: add files when watch directory
+
+## v0.2.0 / 2011-12-30
+
+* update to latest Go weekly code
+
+## v0.1.0 / 2011-10-19
+
+* kqueue: add watch on file creation to match inotify
+* kqueue: create file event
+* inotify: ignore `IN_IGNORED` events
+* event String()
+* linux: common FileEvent functions
+* initial commit
+
+[#79]: https://github.com/howeyc/fsnotify/pull/79
+[#77]: https://github.com/howeyc/fsnotify/pull/77
+[#72]: https://github.com/howeyc/fsnotify/issues/72
+[#71]: https://github.com/howeyc/fsnotify/issues/71
+[#70]: https://github.com/howeyc/fsnotify/issues/70
+[#63]: https://github.com/howeyc/fsnotify/issues/63
+[#62]: https://github.com/howeyc/fsnotify/issues/62
+[#60]: https://github.com/howeyc/fsnotify/issues/60
+[#59]: https://github.com/howeyc/fsnotify/issues/59
+[#49]: https://github.com/howeyc/fsnotify/issues/49
+[#45]: https://github.com/howeyc/fsnotify/issues/45
+[#40]: https://github.com/howeyc/fsnotify/issues/40
+[#36]: https://github.com/howeyc/fsnotify/issues/36
+[#33]: https://github.com/howeyc/fsnotify/issues/33
+[#29]: https://github.com/howeyc/fsnotify/issues/29
+[#25]: https://github.com/howeyc/fsnotify/issues/25
+[#24]: https://github.com/howeyc/fsnotify/issues/24
+[#21]: https://github.com/howeyc/fsnotify/issues/21
diff --git a/vendor/github.com/fsnotify/fsnotify/CONTRIBUTING.md b/vendor/github.com/fsnotify/fsnotify/CONTRIBUTING.md
new file mode 100644
index 000000000..828a60b24
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/CONTRIBUTING.md
@@ -0,0 +1,77 @@
+# Contributing
+
+## Issues
+
+* Request features and report bugs using the [GitHub Issue Tracker](https://github.com/fsnotify/fsnotify/issues).
+* Please indicate the platform you are using fsnotify on.
+* A code example to reproduce the problem is appreciated.
+
+## Pull Requests
+
+### Contributor License Agreement
+
+fsnotify is derived from code in the [golang.org/x/exp](https://godoc.org/golang.org/x/exp) package and it may be included [in the standard library](https://github.com/fsnotify/fsnotify/issues/1) in the future. Therefore fsnotify carries the same [LICENSE](https://github.com/fsnotify/fsnotify/blob/master/LICENSE) as Go. Contributors retain their copyright, so you need to fill out a short form before we can accept your contribution: [Google Individual Contributor License Agreement](https://developers.google.com/open-source/cla/individual).
+
+Please indicate that you have signed the CLA in your pull request.
+
+### How fsnotify is Developed
+
+* Development is done on feature branches.
+* Tests are run on BSD, Linux, macOS and Windows.
+* Pull requests are reviewed and [applied to master][am] using [hub][].
+  * Maintainers may modify or squash commits rather than asking contributors to.
+* To issue a new release, the maintainers will:
+  * Update the CHANGELOG
+  * Tag a version, which will become available through gopkg.in.
+ 
+### How to Fork
+
+For smooth sailing, always use the original import path. Installing with `go get` makes this easy. 
+
+1. Install from GitHub (`go get -u github.com/fsnotify/fsnotify`)
+2. Create your feature branch (`git checkout -b my-new-feature`)
+3. Ensure everything works and the tests pass (see below)
+4. Commit your changes (`git commit -am 'Add some feature'`)
+
+Contribute upstream:
+
+1. Fork fsnotify on GitHub
+2. Add your remote (`git remote add fork git@github.com:mycompany/repo.git`)
+3. Push to the branch (`git push fork my-new-feature`)
+4. Create a new Pull Request on GitHub
+
+This workflow is [thoroughly explained by Katrina Owen](https://splice.com/blog/contributing-open-source-git-repositories-go/).
+
+### Testing
+
+fsnotify uses build tags to compile different code on Linux, BSD, macOS, and Windows.
+
+Before doing a pull request, please do your best to test your changes on multiple platforms, and list which platforms you were able/unable to test on.
+
+To aid in cross-platform testing there is a Vagrantfile for Linux and BSD.
+
+* Install [Vagrant](http://www.vagrantup.com/) and [VirtualBox](https://www.virtualbox.org/)
+* Setup [Vagrant Gopher](https://github.com/nathany/vagrant-gopher) in your `src` folder.
+* Run `vagrant up` from the project folder. You can also setup just one box with `vagrant up linux` or `vagrant up bsd` (note: the BSD box doesn't support Windows hosts at this time, and NFS may prompt for your host OS password)
+* Once setup, you can run the test suite on a given OS with a single command `vagrant ssh linux -c 'cd fsnotify/fsnotify; go test'`.
+* When you're done, you will want to halt or destroy the Vagrant boxes.
+
+Notice: fsnotify file system events won't trigger in shared folders. The tests get around this limitation by using the /tmp directory.
+
+Right now there is no equivalent solution for Windows and macOS, but there are Windows VMs [freely available from Microsoft](http://www.modern.ie/en-us/virtualization-tools#downloads).
+
+### Maintainers
+
+Help maintaining fsnotify is welcome. To be a maintainer:
+
+* Submit a pull request and sign the CLA as above.
+* You must be able to run the test suite on Mac, Windows, Linux and BSD.
+
+To keep master clean, the fsnotify project uses the "apply mail" workflow outlined in Nathaniel Talbott's post ["Merge pull request" Considered Harmful][am]. This requires installing [hub][].
+
+All code changes should be internal pull requests.
+
+Releases are tagged using [Semantic Versioning](http://semver.org/).
+
+[hub]: https://github.com/github/hub
+[am]: http://blog.spreedly.com/2014/06/24/merge-pull-request-considered-harmful/#.VGa5yZPF_Zs
diff --git a/vendor/github.com/fsnotify/fsnotify/LICENSE b/vendor/github.com/fsnotify/fsnotify/LICENSE
new file mode 100644
index 000000000..e180c8fb0
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/LICENSE
@@ -0,0 +1,28 @@
+Copyright (c) 2012 The Go Authors. All rights reserved.
+Copyright (c) 2012-2019 fsnotify Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/github.com/fsnotify/fsnotify/README.md b/vendor/github.com/fsnotify/fsnotify/README.md
new file mode 100644
index 000000000..b2629e522
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/README.md
@@ -0,0 +1,130 @@
+# File system notifications for Go
+
+[![GoDoc](https://godoc.org/github.com/fsnotify/fsnotify?status.svg)](https://godoc.org/github.com/fsnotify/fsnotify) [![Go Report Card](https://goreportcard.com/badge/github.com/fsnotify/fsnotify)](https://goreportcard.com/report/github.com/fsnotify/fsnotify)
+
+fsnotify utilizes [golang.org/x/sys](https://godoc.org/golang.org/x/sys) rather than `syscall` from the standard library. Ensure you have the latest version installed by running:
+
+```console
+go get -u golang.org/x/sys/...
+```
+
+Cross platform: Windows, Linux, BSD and macOS.
+
+| Adapter               | OS                               | Status                                                                                                                          |
+| --------------------- | -------------------------------- | ------------------------------------------------------------------------------------------------------------------------------- |
+| inotify               | Linux 2.6.27 or later, Android\* | Supported [![Build Status](https://travis-ci.org/fsnotify/fsnotify.svg?branch=master)](https://travis-ci.org/fsnotify/fsnotify) |
+| kqueue                | BSD, macOS, iOS\*                | Supported [![Build Status](https://travis-ci.org/fsnotify/fsnotify.svg?branch=master)](https://travis-ci.org/fsnotify/fsnotify) |
+| ReadDirectoryChangesW | Windows                          | Supported [![Build Status](https://travis-ci.org/fsnotify/fsnotify.svg?branch=master)](https://travis-ci.org/fsnotify/fsnotify) |
+| FSEvents              | macOS                            | [Planned](https://github.com/fsnotify/fsnotify/issues/11)                                                                       |
+| FEN                   | Solaris 11                       | [In Progress](https://github.com/fsnotify/fsnotify/issues/12)                                                                   |
+| fanotify              | Linux 2.6.37+                    | [Planned](https://github.com/fsnotify/fsnotify/issues/114)                                                                      |
+| USN Journals          | Windows                          | [Maybe](https://github.com/fsnotify/fsnotify/issues/53)                                                                         |
+| Polling               | *All*                            | [Maybe](https://github.com/fsnotify/fsnotify/issues/9)                                                                          |
+
+\* Android and iOS are untested.
+
+Please see [the documentation](https://godoc.org/github.com/fsnotify/fsnotify) and consult the [FAQ](#faq) for usage information.
+
+## API stability
+
+fsnotify is a fork of [howeyc/fsnotify](https://godoc.org/github.com/howeyc/fsnotify) with a new API as of v1.0. The API is based on [this design document](http://goo.gl/MrYxyA). 
+
+All [releases](https://github.com/fsnotify/fsnotify/releases) are tagged based on [Semantic Versioning](http://semver.org/). Further API changes are [planned](https://github.com/fsnotify/fsnotify/milestones), and will be tagged with a new major revision number.
+
+Go 1.6 supports dependencies located in the `vendor/` folder. Unless you are creating a library, it is recommended that you copy fsnotify into `vendor/github.com/fsnotify/fsnotify` within your project, and likewise for `golang.org/x/sys`.
+
+## Usage
+
+```go
+package main
+
+import (
+	"log"
+
+	"github.com/fsnotify/fsnotify"
+)
+
+func main() {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer watcher.Close()
+
+	done := make(chan bool)
+	go func() {
+		for {
+			select {
+			case event, ok := <-watcher.Events:
+				if !ok {
+					return
+				}
+				log.Println("event:", event)
+				if event.Op&fsnotify.Write == fsnotify.Write {
+					log.Println("modified file:", event.Name)
+				}
+			case err, ok := <-watcher.Errors:
+				if !ok {
+					return
+				}
+				log.Println("error:", err)
+			}
+		}
+	}()
+
+	err = watcher.Add("/tmp/foo")
+	if err != nil {
+		log.Fatal(err)
+	}
+	<-done
+}
+```
+
+## Contributing
+
+Please refer to [CONTRIBUTING][] before opening an issue or pull request.
+
+## Example
+
+See [example_test.go](https://github.com/fsnotify/fsnotify/blob/master/example_test.go).
+
+## FAQ
+
+**When a file is moved to another directory is it still being watched?**
+
+No (it shouldn't be, unless you are watching where it was moved to).
+
+**When I watch a directory, are all subdirectories watched as well?**
+
+No, you must add watches for any directory you want to watch (a recursive watcher is on the roadmap [#18][]).
+
+**Do I have to watch the Error and Event channels in a separate goroutine?**
+
+As of now, yes. Looking into making this single-thread friendly (see [howeyc #7][#7])
+
+**Why am I receiving multiple events for the same file on OS X?**
+
+Spotlight indexing on OS X can result in multiple events (see [howeyc #62][#62]). A temporary workaround is to add your folder(s) to the *Spotlight Privacy settings* until we have a native FSEvents implementation (see [#11][]).
+
+**How many files can be watched at once?**
+
+There are OS-specific limits as to how many watches can be created:
+* Linux: /proc/sys/fs/inotify/max_user_watches contains the limit, reaching this limit results in a "no space left on device" error.
+* BSD / OSX: sysctl variables "kern.maxfiles" and "kern.maxfilesperproc", reaching these limits results in a "too many open files" error.
+
+**Why don't notifications work with NFS filesystems or filesystem in userspace (FUSE)?**
+
+fsnotify requires support from underlying OS to work. The current NFS protocol does not provide network level support for file notifications.
+
+[#62]: https://github.com/howeyc/fsnotify/issues/62
+[#18]: https://github.com/fsnotify/fsnotify/issues/18
+[#11]: https://github.com/fsnotify/fsnotify/issues/11
+[#7]: https://github.com/howeyc/fsnotify/issues/7
+
+[contributing]: https://github.com/fsnotify/fsnotify/blob/master/CONTRIBUTING.md
+
+## Related Projects
+
+* [notify](https://github.com/rjeczalik/notify)
+* [fsevents](https://github.com/fsnotify/fsevents)
+
diff --git a/vendor/github.com/fsnotify/fsnotify/fen.go b/vendor/github.com/fsnotify/fsnotify/fen.go
new file mode 100644
index 000000000..ced39cb88
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/fen.go
@@ -0,0 +1,37 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build solaris
+
+package fsnotify
+
+import (
+	"errors"
+)
+
+// Watcher watches a set of files, delivering events to a channel.
+type Watcher struct {
+	Events chan Event
+	Errors chan error
+}
+
+// NewWatcher establishes a new watcher with the underlying OS and begins waiting for events.
+func NewWatcher() (*Watcher, error) {
+	return nil, errors.New("FEN based watcher not yet supported for fsnotify\n")
+}
+
+// Close removes all watches and closes the events channel.
+func (w *Watcher) Close() error {
+	return nil
+}
+
+// Add starts watching the named file or directory (non-recursively).
+func (w *Watcher) Add(name string) error {
+	return nil
+}
+
+// Remove stops watching the the named file or directory (non-recursively).
+func (w *Watcher) Remove(name string) error {
+	return nil
+}
diff --git a/vendor/github.com/fsnotify/fsnotify/fsnotify.go b/vendor/github.com/fsnotify/fsnotify/fsnotify.go
new file mode 100644
index 000000000..89cab046d
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/fsnotify.go
@@ -0,0 +1,68 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !plan9
+
+// Package fsnotify provides a platform-independent interface for file system notifications.
+package fsnotify
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+)
+
+// Event represents a single file system notification.
+type Event struct {
+	Name string // Relative path to the file or directory.
+	Op   Op     // File operation that triggered the event.
+}
+
+// Op describes a set of file operations.
+type Op uint32
+
+// These are the generalized file operations that can trigger a notification.
+const (
+	Create Op = 1 << iota
+	Write
+	Remove
+	Rename
+	Chmod
+)
+
+func (op Op) String() string {
+	// Use a buffer for efficient string concatenation
+	var buffer bytes.Buffer
+
+	if op&Create == Create {
+		buffer.WriteString("|CREATE")
+	}
+	if op&Remove == Remove {
+		buffer.WriteString("|REMOVE")
+	}
+	if op&Write == Write {
+		buffer.WriteString("|WRITE")
+	}
+	if op&Rename == Rename {
+		buffer.WriteString("|RENAME")
+	}
+	if op&Chmod == Chmod {
+		buffer.WriteString("|CHMOD")
+	}
+	if buffer.Len() == 0 {
+		return ""
+	}
+	return buffer.String()[1:] // Strip leading pipe
+}
+
+// String returns a string representation of the event in the form
+// "file: REMOVE|WRITE|..."
+func (e Event) String() string {
+	return fmt.Sprintf("%q: %s", e.Name, e.Op.String())
+}
+
+// Common errors that can be reported by a watcher
+var (
+	ErrEventOverflow = errors.New("fsnotify queue overflow")
+)
diff --git a/vendor/github.com/fsnotify/fsnotify/go.mod b/vendor/github.com/fsnotify/fsnotify/go.mod
new file mode 100644
index 000000000..ff11e13f2
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/go.mod
@@ -0,0 +1,5 @@
+module github.com/fsnotify/fsnotify
+
+go 1.13
+
+require golang.org/x/sys v0.0.0-20191005200804-aed5e4c7ecf9
diff --git a/vendor/github.com/fsnotify/fsnotify/go.sum b/vendor/github.com/fsnotify/fsnotify/go.sum
new file mode 100644
index 000000000..f60af9855
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/go.sum
@@ -0,0 +1,2 @@
+golang.org/x/sys v0.0.0-20191005200804-aed5e4c7ecf9 h1:L2auWcuQIvxz9xSEqzESnV/QN/gNRXNApHi3fYwl2w0=
+golang.org/x/sys v0.0.0-20191005200804-aed5e4c7ecf9/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
diff --git a/vendor/github.com/fsnotify/fsnotify/inotify.go b/vendor/github.com/fsnotify/fsnotify/inotify.go
new file mode 100644
index 000000000..d9fd1b88a
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/inotify.go
@@ -0,0 +1,337 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux
+
+package fsnotify
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+// Watcher watches a set of files, delivering events to a channel.
+type Watcher struct {
+	Events   chan Event
+	Errors   chan error
+	mu       sync.Mutex // Map access
+	fd       int
+	poller   *fdPoller
+	watches  map[string]*watch // Map of inotify watches (key: path)
+	paths    map[int]string    // Map of watched paths (key: watch descriptor)
+	done     chan struct{}     // Channel for sending a "quit message" to the reader goroutine
+	doneResp chan struct{}     // Channel to respond to Close
+}
+
+// NewWatcher establishes a new watcher with the underlying OS and begins waiting for events.
+func NewWatcher() (*Watcher, error) {
+	// Create inotify fd
+	fd, errno := unix.InotifyInit1(unix.IN_CLOEXEC)
+	if fd == -1 {
+		return nil, errno
+	}
+	// Create epoll
+	poller, err := newFdPoller(fd)
+	if err != nil {
+		unix.Close(fd)
+		return nil, err
+	}
+	w := &Watcher{
+		fd:       fd,
+		poller:   poller,
+		watches:  make(map[string]*watch),
+		paths:    make(map[int]string),
+		Events:   make(chan Event),
+		Errors:   make(chan error),
+		done:     make(chan struct{}),
+		doneResp: make(chan struct{}),
+	}
+
+	go w.readEvents()
+	return w, nil
+}
+
+func (w *Watcher) isClosed() bool {
+	select {
+	case <-w.done:
+		return true
+	default:
+		return false
+	}
+}
+
+// Close removes all watches and closes the events channel.
+func (w *Watcher) Close() error {
+	if w.isClosed() {
+		return nil
+	}
+
+	// Send 'close' signal to goroutine, and set the Watcher to closed.
+	close(w.done)
+
+	// Wake up goroutine
+	w.poller.wake()
+
+	// Wait for goroutine to close
+	<-w.doneResp
+
+	return nil
+}
+
+// Add starts watching the named file or directory (non-recursively).
+func (w *Watcher) Add(name string) error {
+	name = filepath.Clean(name)
+	if w.isClosed() {
+		return errors.New("inotify instance already closed")
+	}
+
+	const agnosticEvents = unix.IN_MOVED_TO | unix.IN_MOVED_FROM |
+		unix.IN_CREATE | unix.IN_ATTRIB | unix.IN_MODIFY |
+		unix.IN_MOVE_SELF | unix.IN_DELETE | unix.IN_DELETE_SELF
+
+	var flags uint32 = agnosticEvents
+
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	watchEntry := w.watches[name]
+	if watchEntry != nil {
+		flags |= watchEntry.flags | unix.IN_MASK_ADD
+	}
+	wd, errno := unix.InotifyAddWatch(w.fd, name, flags)
+	if wd == -1 {
+		return errno
+	}
+
+	if watchEntry == nil {
+		w.watches[name] = &watch{wd: uint32(wd), flags: flags}
+		w.paths[wd] = name
+	} else {
+		watchEntry.wd = uint32(wd)
+		watchEntry.flags = flags
+	}
+
+	return nil
+}
+
+// Remove stops watching the named file or directory (non-recursively).
+func (w *Watcher) Remove(name string) error {
+	name = filepath.Clean(name)
+
+	// Fetch the watch.
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	watch, ok := w.watches[name]
+
+	// Remove it from inotify.
+	if !ok {
+		return fmt.Errorf("can't remove non-existent inotify watch for: %s", name)
+	}
+
+	// We successfully removed the watch if InotifyRmWatch doesn't return an
+	// error, we need to clean up our internal state to ensure it matches
+	// inotify's kernel state.
+	delete(w.paths, int(watch.wd))
+	delete(w.watches, name)
+
+	// inotify_rm_watch will return EINVAL if the file has been deleted;
+	// the inotify will already have been removed.
+	// watches and pathes are deleted in ignoreLinux() implicitly and asynchronously
+	// by calling inotify_rm_watch() below. e.g. readEvents() goroutine receives IN_IGNORE
+	// so that EINVAL means that the wd is being rm_watch()ed or its file removed
+	// by another thread and we have not received IN_IGNORE event.
+	success, errno := unix.InotifyRmWatch(w.fd, watch.wd)
+	if success == -1 {
+		// TODO: Perhaps it's not helpful to return an error here in every case.
+		// the only two possible errors are:
+		// EBADF, which happens when w.fd is not a valid file descriptor of any kind.
+		// EINVAL, which is when fd is not an inotify descriptor or wd is not a valid watch descriptor.
+		// Watch descriptors are invalidated when they are removed explicitly or implicitly;
+		// explicitly by inotify_rm_watch, implicitly when the file they are watching is deleted.
+		return errno
+	}
+
+	return nil
+}
+
+type watch struct {
+	wd    uint32 // Watch descriptor (as returned by the inotify_add_watch() syscall)
+	flags uint32 // inotify flags of this watch (see inotify(7) for the list of valid flags)
+}
+
+// readEvents reads from the inotify file descriptor, converts the
+// received events into Event objects and sends them via the Events channel
+func (w *Watcher) readEvents() {
+	var (
+		buf   [unix.SizeofInotifyEvent * 4096]byte // Buffer for a maximum of 4096 raw events
+		n     int                                  // Number of bytes read with read()
+		errno error                                // Syscall errno
+		ok    bool                                 // For poller.wait
+	)
+
+	defer close(w.doneResp)
+	defer close(w.Errors)
+	defer close(w.Events)
+	defer unix.Close(w.fd)
+	defer w.poller.close()
+
+	for {
+		// See if we have been closed.
+		if w.isClosed() {
+			return
+		}
+
+		ok, errno = w.poller.wait()
+		if errno != nil {
+			select {
+			case w.Errors <- errno:
+			case <-w.done:
+				return
+			}
+			continue
+		}
+
+		if !ok {
+			continue
+		}
+
+		n, errno = unix.Read(w.fd, buf[:])
+		// If a signal interrupted execution, see if we've been asked to close, and try again.
+		// http://man7.org/linux/man-pages/man7/signal.7.html :
+		// "Before Linux 3.8, reads from an inotify(7) file descriptor were not restartable"
+		if errno == unix.EINTR {
+			continue
+		}
+
+		// unix.Read might have been woken up by Close. If so, we're done.
+		if w.isClosed() {
+			return
+		}
+
+		if n < unix.SizeofInotifyEvent {
+			var err error
+			if n == 0 {
+				// If EOF is received. This should really never happen.
+				err = io.EOF
+			} else if n < 0 {
+				// If an error occurred while reading.
+				err = errno
+			} else {
+				// Read was too short.
+				err = errors.New("notify: short read in readEvents()")
+			}
+			select {
+			case w.Errors <- err:
+			case <-w.done:
+				return
+			}
+			continue
+		}
+
+		var offset uint32
+		// We don't know how many events we just read into the buffer
+		// While the offset points to at least one whole event...
+		for offset <= uint32(n-unix.SizeofInotifyEvent) {
+			// Point "raw" to the event in the buffer
+			raw := (*unix.InotifyEvent)(unsafe.Pointer(&buf[offset]))
+
+			mask := uint32(raw.Mask)
+			nameLen := uint32(raw.Len)
+
+			if mask&unix.IN_Q_OVERFLOW != 0 {
+				select {
+				case w.Errors <- ErrEventOverflow:
+				case <-w.done:
+					return
+				}
+			}
+
+			// If the event happened to the watched directory or the watched file, the kernel
+			// doesn't append the filename to the event, but we would like to always fill the
+			// the "Name" field with a valid filename. We retrieve the path of the watch from
+			// the "paths" map.
+			w.mu.Lock()
+			name, ok := w.paths[int(raw.Wd)]
+			// IN_DELETE_SELF occurs when the file/directory being watched is removed.
+			// This is a sign to clean up the maps, otherwise we are no longer in sync
+			// with the inotify kernel state which has already deleted the watch
+			// automatically.
+			if ok && mask&unix.IN_DELETE_SELF == unix.IN_DELETE_SELF {
+				delete(w.paths, int(raw.Wd))
+				delete(w.watches, name)
+			}
+			w.mu.Unlock()
+
+			if nameLen > 0 {
+				// Point "bytes" at the first byte of the filename
+				bytes := (*[unix.PathMax]byte)(unsafe.Pointer(&buf[offset+unix.SizeofInotifyEvent]))
+				// The filename is padded with NULL bytes. TrimRight() gets rid of those.
+				name += "/" + strings.TrimRight(string(bytes[0:nameLen]), "\000")
+			}
+
+			event := newEvent(name, mask)
+
+			// Send the events that are not ignored on the events channel
+			if !event.ignoreLinux(mask) {
+				select {
+				case w.Events <- event:
+				case <-w.done:
+					return
+				}
+			}
+
+			// Move to the next event in the buffer
+			offset += unix.SizeofInotifyEvent + nameLen
+		}
+	}
+}
+
+// Certain types of events can be "ignored" and not sent over the Events
+// channel. Such as events marked ignore by the kernel, or MODIFY events
+// against files that do not exist.
+func (e *Event) ignoreLinux(mask uint32) bool {
+	// Ignore anything the inotify API says to ignore
+	if mask&unix.IN_IGNORED == unix.IN_IGNORED {
+		return true
+	}
+
+	// If the event is not a DELETE or RENAME, the file must exist.
+	// Otherwise the event is ignored.
+	// *Note*: this was put in place because it was seen that a MODIFY
+	// event was sent after the DELETE. This ignores that MODIFY and
+	// assumes a DELETE will come or has come if the file doesn't exist.
+	if !(e.Op&Remove == Remove || e.Op&Rename == Rename) {
+		_, statErr := os.Lstat(e.Name)
+		return os.IsNotExist(statErr)
+	}
+	return false
+}
+
+// newEvent returns an platform-independent Event based on an inotify mask.
+func newEvent(name string, mask uint32) Event {
+	e := Event{Name: name}
+	if mask&unix.IN_CREATE == unix.IN_CREATE || mask&unix.IN_MOVED_TO == unix.IN_MOVED_TO {
+		e.Op |= Create
+	}
+	if mask&unix.IN_DELETE_SELF == unix.IN_DELETE_SELF || mask&unix.IN_DELETE == unix.IN_DELETE {
+		e.Op |= Remove
+	}
+	if mask&unix.IN_MODIFY == unix.IN_MODIFY {
+		e.Op |= Write
+	}
+	if mask&unix.IN_MOVE_SELF == unix.IN_MOVE_SELF || mask&unix.IN_MOVED_FROM == unix.IN_MOVED_FROM {
+		e.Op |= Rename
+	}
+	if mask&unix.IN_ATTRIB == unix.IN_ATTRIB {
+		e.Op |= Chmod
+	}
+	return e
+}
diff --git a/vendor/github.com/fsnotify/fsnotify/inotify_poller.go b/vendor/github.com/fsnotify/fsnotify/inotify_poller.go
new file mode 100644
index 000000000..b33f2b4d4
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/inotify_poller.go
@@ -0,0 +1,187 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux
+
+package fsnotify
+
+import (
+	"errors"
+
+	"golang.org/x/sys/unix"
+)
+
+type fdPoller struct {
+	fd   int    // File descriptor (as returned by the inotify_init() syscall)
+	epfd int    // Epoll file descriptor
+	pipe [2]int // Pipe for waking up
+}
+
+func emptyPoller(fd int) *fdPoller {
+	poller := new(fdPoller)
+	poller.fd = fd
+	poller.epfd = -1
+	poller.pipe[0] = -1
+	poller.pipe[1] = -1
+	return poller
+}
+
+// Create a new inotify poller.
+// This creates an inotify handler, and an epoll handler.
+func newFdPoller(fd int) (*fdPoller, error) {
+	var errno error
+	poller := emptyPoller(fd)
+	defer func() {
+		if errno != nil {
+			poller.close()
+		}
+	}()
+	poller.fd = fd
+
+	// Create epoll fd
+	poller.epfd, errno = unix.EpollCreate1(unix.EPOLL_CLOEXEC)
+	if poller.epfd == -1 {
+		return nil, errno
+	}
+	// Create pipe; pipe[0] is the read end, pipe[1] the write end.
+	errno = unix.Pipe2(poller.pipe[:], unix.O_NONBLOCK|unix.O_CLOEXEC)
+	if errno != nil {
+		return nil, errno
+	}
+
+	// Register inotify fd with epoll
+	event := unix.EpollEvent{
+		Fd:     int32(poller.fd),
+		Events: unix.EPOLLIN,
+	}
+	errno = unix.EpollCtl(poller.epfd, unix.EPOLL_CTL_ADD, poller.fd, &event)
+	if errno != nil {
+		return nil, errno
+	}
+
+	// Register pipe fd with epoll
+	event = unix.EpollEvent{
+		Fd:     int32(poller.pipe[0]),
+		Events: unix.EPOLLIN,
+	}
+	errno = unix.EpollCtl(poller.epfd, unix.EPOLL_CTL_ADD, poller.pipe[0], &event)
+	if errno != nil {
+		return nil, errno
+	}
+
+	return poller, nil
+}
+
+// Wait using epoll.
+// Returns true if something is ready to be read,
+// false if there is not.
+func (poller *fdPoller) wait() (bool, error) {
+	// 3 possible events per fd, and 2 fds, makes a maximum of 6 events.
+	// I don't know whether epoll_wait returns the number of events returned,
+	// or the total number of events ready.
+	// I decided to catch both by making the buffer one larger than the maximum.
+	events := make([]unix.EpollEvent, 7)
+	for {
+		n, errno := unix.EpollWait(poller.epfd, events, -1)
+		if n == -1 {
+			if errno == unix.EINTR {
+				continue
+			}
+			return false, errno
+		}
+		if n == 0 {
+			// If there are no events, try again.
+			continue
+		}
+		if n > 6 {
+			// This should never happen. More events were returned than should be possible.
+			return false, errors.New("epoll_wait returned more events than I know what to do with")
+		}
+		ready := events[:n]
+		epollhup := false
+		epollerr := false
+		epollin := false
+		for _, event := range ready {
+			if event.Fd == int32(poller.fd) {
+				if event.Events&unix.EPOLLHUP != 0 {
+					// This should not happen, but if it does, treat it as a wakeup.
+					epollhup = true
+				}
+				if event.Events&unix.EPOLLERR != 0 {
+					// If an error is waiting on the file descriptor, we should pretend
+					// something is ready to read, and let unix.Read pick up the error.
+					epollerr = true
+				}
+				if event.Events&unix.EPOLLIN != 0 {
+					// There is data to read.
+					epollin = true
+				}
+			}
+			if event.Fd == int32(poller.pipe[0]) {
+				if event.Events&unix.EPOLLHUP != 0 {
+					// Write pipe descriptor was closed, by us. This means we're closing down the
+					// watcher, and we should wake up.
+				}
+				if event.Events&unix.EPOLLERR != 0 {
+					// If an error is waiting on the pipe file descriptor.
+					// This is an absolute mystery, and should never ever happen.
+					return false, errors.New("Error on the pipe descriptor.")
+				}
+				if event.Events&unix.EPOLLIN != 0 {
+					// This is a regular wakeup, so we have to clear the buffer.
+					err := poller.clearWake()
+					if err != nil {
+						return false, err
+					}
+				}
+			}
+		}
+
+		if epollhup || epollerr || epollin {
+			return true, nil
+		}
+		return false, nil
+	}
+}
+
+// Close the write end of the poller.
+func (poller *fdPoller) wake() error {
+	buf := make([]byte, 1)
+	n, errno := unix.Write(poller.pipe[1], buf)
+	if n == -1 {
+		if errno == unix.EAGAIN {
+			// Buffer is full, poller will wake.
+			return nil
+		}
+		return errno
+	}
+	return nil
+}
+
+func (poller *fdPoller) clearWake() error {
+	// You have to be woken up a LOT in order to get to 100!
+	buf := make([]byte, 100)
+	n, errno := unix.Read(poller.pipe[0], buf)
+	if n == -1 {
+		if errno == unix.EAGAIN {
+			// Buffer is empty, someone else cleared our wake.
+			return nil
+		}
+		return errno
+	}
+	return nil
+}
+
+// Close all poller file descriptors, but not the one passed to it.
+func (poller *fdPoller) close() {
+	if poller.pipe[1] != -1 {
+		unix.Close(poller.pipe[1])
+	}
+	if poller.pipe[0] != -1 {
+		unix.Close(poller.pipe[0])
+	}
+	if poller.epfd != -1 {
+		unix.Close(poller.epfd)
+	}
+}
diff --git a/vendor/github.com/fsnotify/fsnotify/kqueue.go b/vendor/github.com/fsnotify/fsnotify/kqueue.go
new file mode 100644
index 000000000..86e76a3d6
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/kqueue.go
@@ -0,0 +1,521 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build freebsd openbsd netbsd dragonfly darwin
+
+package fsnotify
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+// Watcher watches a set of files, delivering events to a channel.
+type Watcher struct {
+	Events chan Event
+	Errors chan error
+	done   chan struct{} // Channel for sending a "quit message" to the reader goroutine
+
+	kq int // File descriptor (as returned by the kqueue() syscall).
+
+	mu              sync.Mutex        // Protects access to watcher data
+	watches         map[string]int    // Map of watched file descriptors (key: path).
+	externalWatches map[string]bool   // Map of watches added by user of the library.
+	dirFlags        map[string]uint32 // Map of watched directories to fflags used in kqueue.
+	paths           map[int]pathInfo  // Map file descriptors to path names for processing kqueue events.
+	fileExists      map[string]bool   // Keep track of if we know this file exists (to stop duplicate create events).
+	isClosed        bool              // Set to true when Close() is first called
+}
+
+type pathInfo struct {
+	name  string
+	isDir bool
+}
+
+// NewWatcher establishes a new watcher with the underlying OS and begins waiting for events.
+func NewWatcher() (*Watcher, error) {
+	kq, err := kqueue()
+	if err != nil {
+		return nil, err
+	}
+
+	w := &Watcher{
+		kq:              kq,
+		watches:         make(map[string]int),
+		dirFlags:        make(map[string]uint32),
+		paths:           make(map[int]pathInfo),
+		fileExists:      make(map[string]bool),
+		externalWatches: make(map[string]bool),
+		Events:          make(chan Event),
+		Errors:          make(chan error),
+		done:            make(chan struct{}),
+	}
+
+	go w.readEvents()
+	return w, nil
+}
+
+// Close removes all watches and closes the events channel.
+func (w *Watcher) Close() error {
+	w.mu.Lock()
+	if w.isClosed {
+		w.mu.Unlock()
+		return nil
+	}
+	w.isClosed = true
+
+	// copy paths to remove while locked
+	var pathsToRemove = make([]string, 0, len(w.watches))
+	for name := range w.watches {
+		pathsToRemove = append(pathsToRemove, name)
+	}
+	w.mu.Unlock()
+	// unlock before calling Remove, which also locks
+
+	for _, name := range pathsToRemove {
+		w.Remove(name)
+	}
+
+	// send a "quit" message to the reader goroutine
+	close(w.done)
+
+	return nil
+}
+
+// Add starts watching the named file or directory (non-recursively).
+func (w *Watcher) Add(name string) error {
+	w.mu.Lock()
+	w.externalWatches[name] = true
+	w.mu.Unlock()
+	_, err := w.addWatch(name, noteAllEvents)
+	return err
+}
+
+// Remove stops watching the the named file or directory (non-recursively).
+func (w *Watcher) Remove(name string) error {
+	name = filepath.Clean(name)
+	w.mu.Lock()
+	watchfd, ok := w.watches[name]
+	w.mu.Unlock()
+	if !ok {
+		return fmt.Errorf("can't remove non-existent kevent watch for: %s", name)
+	}
+
+	const registerRemove = unix.EV_DELETE
+	if err := register(w.kq, []int{watchfd}, registerRemove, 0); err != nil {
+		return err
+	}
+
+	unix.Close(watchfd)
+
+	w.mu.Lock()
+	isDir := w.paths[watchfd].isDir
+	delete(w.watches, name)
+	delete(w.paths, watchfd)
+	delete(w.dirFlags, name)
+	w.mu.Unlock()
+
+	// Find all watched paths that are in this directory that are not external.
+	if isDir {
+		var pathsToRemove []string
+		w.mu.Lock()
+		for _, path := range w.paths {
+			wdir, _ := filepath.Split(path.name)
+			if filepath.Clean(wdir) == name {
+				if !w.externalWatches[path.name] {
+					pathsToRemove = append(pathsToRemove, path.name)
+				}
+			}
+		}
+		w.mu.Unlock()
+		for _, name := range pathsToRemove {
+			// Since these are internal, not much sense in propagating error
+			// to the user, as that will just confuse them with an error about
+			// a path they did not explicitly watch themselves.
+			w.Remove(name)
+		}
+	}
+
+	return nil
+}
+
+// Watch all events (except NOTE_EXTEND, NOTE_LINK, NOTE_REVOKE)
+const noteAllEvents = unix.NOTE_DELETE | unix.NOTE_WRITE | unix.NOTE_ATTRIB | unix.NOTE_RENAME
+
+// keventWaitTime to block on each read from kevent
+var keventWaitTime = durationToTimespec(100 * time.Millisecond)
+
+// addWatch adds name to the watched file set.
+// The flags are interpreted as described in kevent(2).
+// Returns the real path to the file which was added, if any, which may be different from the one passed in the case of symlinks.
+func (w *Watcher) addWatch(name string, flags uint32) (string, error) {
+	var isDir bool
+	// Make ./name and name equivalent
+	name = filepath.Clean(name)
+
+	w.mu.Lock()
+	if w.isClosed {
+		w.mu.Unlock()
+		return "", errors.New("kevent instance already closed")
+	}
+	watchfd, alreadyWatching := w.watches[name]
+	// We already have a watch, but we can still override flags.
+	if alreadyWatching {
+		isDir = w.paths[watchfd].isDir
+	}
+	w.mu.Unlock()
+
+	if !alreadyWatching {
+		fi, err := os.Lstat(name)
+		if err != nil {
+			return "", err
+		}
+
+		// Don't watch sockets.
+		if fi.Mode()&os.ModeSocket == os.ModeSocket {
+			return "", nil
+		}
+
+		// Don't watch named pipes.
+		if fi.Mode()&os.ModeNamedPipe == os.ModeNamedPipe {
+			return "", nil
+		}
+
+		// Follow Symlinks
+		// Unfortunately, Linux can add bogus symlinks to watch list without
+		// issue, and Windows can't do symlinks period (AFAIK). To  maintain
+		// consistency, we will act like everything is fine. There will simply
+		// be no file events for broken symlinks.
+		// Hence the returns of nil on errors.
+		if fi.Mode()&os.ModeSymlink == os.ModeSymlink {
+			name, err = filepath.EvalSymlinks(name)
+			if err != nil {
+				return "", nil
+			}
+
+			w.mu.Lock()
+			_, alreadyWatching = w.watches[name]
+			w.mu.Unlock()
+
+			if alreadyWatching {
+				return name, nil
+			}
+
+			fi, err = os.Lstat(name)
+			if err != nil {
+				return "", nil
+			}
+		}
+
+		watchfd, err = unix.Open(name, openMode, 0700)
+		if watchfd == -1 {
+			return "", err
+		}
+
+		isDir = fi.IsDir()
+	}
+
+	const registerAdd = unix.EV_ADD | unix.EV_CLEAR | unix.EV_ENABLE
+	if err := register(w.kq, []int{watchfd}, registerAdd, flags); err != nil {
+		unix.Close(watchfd)
+		return "", err
+	}
+
+	if !alreadyWatching {
+		w.mu.Lock()
+		w.watches[name] = watchfd
+		w.paths[watchfd] = pathInfo{name: name, isDir: isDir}
+		w.mu.Unlock()
+	}
+
+	if isDir {
+		// Watch the directory if it has not been watched before,
+		// or if it was watched before, but perhaps only a NOTE_DELETE (watchDirectoryFiles)
+		w.mu.Lock()
+
+		watchDir := (flags&unix.NOTE_WRITE) == unix.NOTE_WRITE &&
+			(!alreadyWatching || (w.dirFlags[name]&unix.NOTE_WRITE) != unix.NOTE_WRITE)
+		// Store flags so this watch can be updated later
+		w.dirFlags[name] = flags
+		w.mu.Unlock()
+
+		if watchDir {
+			if err := w.watchDirectoryFiles(name); err != nil {
+				return "", err
+			}
+		}
+	}
+	return name, nil
+}
+
+// readEvents reads from kqueue and converts the received kevents into
+// Event values that it sends down the Events channel.
+func (w *Watcher) readEvents() {
+	eventBuffer := make([]unix.Kevent_t, 10)
+
+loop:
+	for {
+		// See if there is a message on the "done" channel
+		select {
+		case <-w.done:
+			break loop
+		default:
+		}
+
+		// Get new events
+		kevents, err := read(w.kq, eventBuffer, &keventWaitTime)
+		// EINTR is okay, the syscall was interrupted before timeout expired.
+		if err != nil && err != unix.EINTR {
+			select {
+			case w.Errors <- err:
+			case <-w.done:
+				break loop
+			}
+			continue
+		}
+
+		// Flush the events we received to the Events channel
+		for len(kevents) > 0 {
+			kevent := &kevents[0]
+			watchfd := int(kevent.Ident)
+			mask := uint32(kevent.Fflags)
+			w.mu.Lock()
+			path := w.paths[watchfd]
+			w.mu.Unlock()
+			event := newEvent(path.name, mask)
+
+			if path.isDir && !(event.Op&Remove == Remove) {
+				// Double check to make sure the directory exists. This can happen when
+				// we do a rm -fr on a recursively watched folders and we receive a
+				// modification event first but the folder has been deleted and later
+				// receive the delete event
+				if _, err := os.Lstat(event.Name); os.IsNotExist(err) {
+					// mark is as delete event
+					event.Op |= Remove
+				}
+			}
+
+			if event.Op&Rename == Rename || event.Op&Remove == Remove {
+				w.Remove(event.Name)
+				w.mu.Lock()
+				delete(w.fileExists, event.Name)
+				w.mu.Unlock()
+			}
+
+			if path.isDir && event.Op&Write == Write && !(event.Op&Remove == Remove) {
+				w.sendDirectoryChangeEvents(event.Name)
+			} else {
+				// Send the event on the Events channel.
+				select {
+				case w.Events <- event:
+				case <-w.done:
+					break loop
+				}
+			}
+
+			if event.Op&Remove == Remove {
+				// Look for a file that may have overwritten this.
+				// For example, mv f1 f2 will delete f2, then create f2.
+				if path.isDir {
+					fileDir := filepath.Clean(event.Name)
+					w.mu.Lock()
+					_, found := w.watches[fileDir]
+					w.mu.Unlock()
+					if found {
+						// make sure the directory exists before we watch for changes. When we
+						// do a recursive watch and perform rm -fr, the parent directory might
+						// have gone missing, ignore the missing directory and let the
+						// upcoming delete event remove the watch from the parent directory.
+						if _, err := os.Lstat(fileDir); err == nil {
+							w.sendDirectoryChangeEvents(fileDir)
+						}
+					}
+				} else {
+					filePath := filepath.Clean(event.Name)
+					if fileInfo, err := os.Lstat(filePath); err == nil {
+						w.sendFileCreatedEventIfNew(filePath, fileInfo)
+					}
+				}
+			}
+
+			// Move to next event
+			kevents = kevents[1:]
+		}
+	}
+
+	// cleanup
+	err := unix.Close(w.kq)
+	if err != nil {
+		// only way the previous loop breaks is if w.done was closed so we need to async send to w.Errors.
+		select {
+		case w.Errors <- err:
+		default:
+		}
+	}
+	close(w.Events)
+	close(w.Errors)
+}
+
+// newEvent returns an platform-independent Event based on kqueue Fflags.
+func newEvent(name string, mask uint32) Event {
+	e := Event{Name: name}
+	if mask&unix.NOTE_DELETE == unix.NOTE_DELETE {
+		e.Op |= Remove
+	}
+	if mask&unix.NOTE_WRITE == unix.NOTE_WRITE {
+		e.Op |= Write
+	}
+	if mask&unix.NOTE_RENAME == unix.NOTE_RENAME {
+		e.Op |= Rename
+	}
+	if mask&unix.NOTE_ATTRIB == unix.NOTE_ATTRIB {
+		e.Op |= Chmod
+	}
+	return e
+}
+
+func newCreateEvent(name string) Event {
+	return Event{Name: name, Op: Create}
+}
+
+// watchDirectoryFiles to mimic inotify when adding a watch on a directory
+func (w *Watcher) watchDirectoryFiles(dirPath string) error {
+	// Get all files
+	files, err := ioutil.ReadDir(dirPath)
+	if err != nil {
+		return err
+	}
+
+	for _, fileInfo := range files {
+		filePath := filepath.Join(dirPath, fileInfo.Name())
+		filePath, err = w.internalWatch(filePath, fileInfo)
+		if err != nil {
+			return err
+		}
+
+		w.mu.Lock()
+		w.fileExists[filePath] = true
+		w.mu.Unlock()
+	}
+
+	return nil
+}
+
+// sendDirectoryEvents searches the directory for newly created files
+// and sends them over the event channel. This functionality is to have
+// the BSD version of fsnotify match Linux inotify which provides a
+// create event for files created in a watched directory.
+func (w *Watcher) sendDirectoryChangeEvents(dirPath string) {
+	// Get all files
+	files, err := ioutil.ReadDir(dirPath)
+	if err != nil {
+		select {
+		case w.Errors <- err:
+		case <-w.done:
+			return
+		}
+	}
+
+	// Search for new files
+	for _, fileInfo := range files {
+		filePath := filepath.Join(dirPath, fileInfo.Name())
+		err := w.sendFileCreatedEventIfNew(filePath, fileInfo)
+
+		if err != nil {
+			return
+		}
+	}
+}
+
+// sendFileCreatedEvent sends a create event if the file isn't already being tracked.
+func (w *Watcher) sendFileCreatedEventIfNew(filePath string, fileInfo os.FileInfo) (err error) {
+	w.mu.Lock()
+	_, doesExist := w.fileExists[filePath]
+	w.mu.Unlock()
+	if !doesExist {
+		// Send create event
+		select {
+		case w.Events <- newCreateEvent(filePath):
+		case <-w.done:
+			return
+		}
+	}
+
+	// like watchDirectoryFiles (but without doing another ReadDir)
+	filePath, err = w.internalWatch(filePath, fileInfo)
+	if err != nil {
+		return err
+	}
+
+	w.mu.Lock()
+	w.fileExists[filePath] = true
+	w.mu.Unlock()
+
+	return nil
+}
+
+func (w *Watcher) internalWatch(name string, fileInfo os.FileInfo) (string, error) {
+	if fileInfo.IsDir() {
+		// mimic Linux providing delete events for subdirectories
+		// but preserve the flags used if currently watching subdirectory
+		w.mu.Lock()
+		flags := w.dirFlags[name]
+		w.mu.Unlock()
+
+		flags |= unix.NOTE_DELETE | unix.NOTE_RENAME
+		return w.addWatch(name, flags)
+	}
+
+	// watch file to mimic Linux inotify
+	return w.addWatch(name, noteAllEvents)
+}
+
+// kqueue creates a new kernel event queue and returns a descriptor.
+func kqueue() (kq int, err error) {
+	kq, err = unix.Kqueue()
+	if kq == -1 {
+		return kq, err
+	}
+	return kq, nil
+}
+
+// register events with the queue
+func register(kq int, fds []int, flags int, fflags uint32) error {
+	changes := make([]unix.Kevent_t, len(fds))
+
+	for i, fd := range fds {
+		// SetKevent converts int to the platform-specific types:
+		unix.SetKevent(&changes[i], fd, unix.EVFILT_VNODE, flags)
+		changes[i].Fflags = fflags
+	}
+
+	// register the events
+	success, err := unix.Kevent(kq, changes, nil, nil)
+	if success == -1 {
+		return err
+	}
+	return nil
+}
+
+// read retrieves pending events, or waits until an event occurs.
+// A timeout of nil blocks indefinitely, while 0 polls the queue.
+func read(kq int, events []unix.Kevent_t, timeout *unix.Timespec) ([]unix.Kevent_t, error) {
+	n, err := unix.Kevent(kq, nil, events, timeout)
+	if err != nil {
+		return nil, err
+	}
+	return events[0:n], nil
+}
+
+// durationToTimespec prepares a timeout value
+func durationToTimespec(d time.Duration) unix.Timespec {
+	return unix.NsecToTimespec(d.Nanoseconds())
+}
diff --git a/vendor/github.com/fsnotify/fsnotify/open_mode_bsd.go b/vendor/github.com/fsnotify/fsnotify/open_mode_bsd.go
new file mode 100644
index 000000000..2306c4620
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/open_mode_bsd.go
@@ -0,0 +1,11 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build freebsd openbsd netbsd dragonfly
+
+package fsnotify
+
+import "golang.org/x/sys/unix"
+
+const openMode = unix.O_NONBLOCK | unix.O_RDONLY | unix.O_CLOEXEC
diff --git a/vendor/github.com/fsnotify/fsnotify/open_mode_darwin.go b/vendor/github.com/fsnotify/fsnotify/open_mode_darwin.go
new file mode 100644
index 000000000..870c4d6d1
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/open_mode_darwin.go
@@ -0,0 +1,12 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin
+
+package fsnotify
+
+import "golang.org/x/sys/unix"
+
+// note: this constant is not defined on BSD
+const openMode = unix.O_EVTONLY | unix.O_CLOEXEC
diff --git a/vendor/github.com/fsnotify/fsnotify/windows.go b/vendor/github.com/fsnotify/fsnotify/windows.go
new file mode 100644
index 000000000..09436f31d
--- /dev/null
+++ b/vendor/github.com/fsnotify/fsnotify/windows.go
@@ -0,0 +1,561 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build windows
+
+package fsnotify
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"sync"
+	"syscall"
+	"unsafe"
+)
+
+// Watcher watches a set of files, delivering events to a channel.
+type Watcher struct {
+	Events   chan Event
+	Errors   chan error
+	isClosed bool           // Set to true when Close() is first called
+	mu       sync.Mutex     // Map access
+	port     syscall.Handle // Handle to completion port
+	watches  watchMap       // Map of watches (key: i-number)
+	input    chan *input    // Inputs to the reader are sent on this channel
+	quit     chan chan<- error
+}
+
+// NewWatcher establishes a new watcher with the underlying OS and begins waiting for events.
+func NewWatcher() (*Watcher, error) {
+	port, e := syscall.CreateIoCompletionPort(syscall.InvalidHandle, 0, 0, 0)
+	if e != nil {
+		return nil, os.NewSyscallError("CreateIoCompletionPort", e)
+	}
+	w := &Watcher{
+		port:    port,
+		watches: make(watchMap),
+		input:   make(chan *input, 1),
+		Events:  make(chan Event, 50),
+		Errors:  make(chan error),
+		quit:    make(chan chan<- error, 1),
+	}
+	go w.readEvents()
+	return w, nil
+}
+
+// Close removes all watches and closes the events channel.
+func (w *Watcher) Close() error {
+	if w.isClosed {
+		return nil
+	}
+	w.isClosed = true
+
+	// Send "quit" message to the reader goroutine
+	ch := make(chan error)
+	w.quit <- ch
+	if err := w.wakeupReader(); err != nil {
+		return err
+	}
+	return <-ch
+}
+
+// Add starts watching the named file or directory (non-recursively).
+func (w *Watcher) Add(name string) error {
+	if w.isClosed {
+		return errors.New("watcher already closed")
+	}
+	in := &input{
+		op:    opAddWatch,
+		path:  filepath.Clean(name),
+		flags: sysFSALLEVENTS,
+		reply: make(chan error),
+	}
+	w.input <- in
+	if err := w.wakeupReader(); err != nil {
+		return err
+	}
+	return <-in.reply
+}
+
+// Remove stops watching the the named file or directory (non-recursively).
+func (w *Watcher) Remove(name string) error {
+	in := &input{
+		op:    opRemoveWatch,
+		path:  filepath.Clean(name),
+		reply: make(chan error),
+	}
+	w.input <- in
+	if err := w.wakeupReader(); err != nil {
+		return err
+	}
+	return <-in.reply
+}
+
+const (
+	// Options for AddWatch
+	sysFSONESHOT = 0x80000000
+	sysFSONLYDIR = 0x1000000
+
+	// Events
+	sysFSACCESS     = 0x1
+	sysFSALLEVENTS  = 0xfff
+	sysFSATTRIB     = 0x4
+	sysFSCLOSE      = 0x18
+	sysFSCREATE     = 0x100
+	sysFSDELETE     = 0x200
+	sysFSDELETESELF = 0x400
+	sysFSMODIFY     = 0x2
+	sysFSMOVE       = 0xc0
+	sysFSMOVEDFROM  = 0x40
+	sysFSMOVEDTO    = 0x80
+	sysFSMOVESELF   = 0x800
+
+	// Special events
+	sysFSIGNORED   = 0x8000
+	sysFSQOVERFLOW = 0x4000
+)
+
+func newEvent(name string, mask uint32) Event {
+	e := Event{Name: name}
+	if mask&sysFSCREATE == sysFSCREATE || mask&sysFSMOVEDTO == sysFSMOVEDTO {
+		e.Op |= Create
+	}
+	if mask&sysFSDELETE == sysFSDELETE || mask&sysFSDELETESELF == sysFSDELETESELF {
+		e.Op |= Remove
+	}
+	if mask&sysFSMODIFY == sysFSMODIFY {
+		e.Op |= Write
+	}
+	if mask&sysFSMOVE == sysFSMOVE || mask&sysFSMOVESELF == sysFSMOVESELF || mask&sysFSMOVEDFROM == sysFSMOVEDFROM {
+		e.Op |= Rename
+	}
+	if mask&sysFSATTRIB == sysFSATTRIB {
+		e.Op |= Chmod
+	}
+	return e
+}
+
+const (
+	opAddWatch = iota
+	opRemoveWatch
+)
+
+const (
+	provisional uint64 = 1 << (32 + iota)
+)
+
+type input struct {
+	op    int
+	path  string
+	flags uint32
+	reply chan error
+}
+
+type inode struct {
+	handle syscall.Handle
+	volume uint32
+	index  uint64
+}
+
+type watch struct {
+	ov     syscall.Overlapped
+	ino    *inode            // i-number
+	path   string            // Directory path
+	mask   uint64            // Directory itself is being watched with these notify flags
+	names  map[string]uint64 // Map of names being watched and their notify flags
+	rename string            // Remembers the old name while renaming a file
+	buf    [4096]byte
+}
+
+type indexMap map[uint64]*watch
+type watchMap map[uint32]indexMap
+
+func (w *Watcher) wakeupReader() error {
+	e := syscall.PostQueuedCompletionStatus(w.port, 0, 0, nil)
+	if e != nil {
+		return os.NewSyscallError("PostQueuedCompletionStatus", e)
+	}
+	return nil
+}
+
+func getDir(pathname string) (dir string, err error) {
+	attr, e := syscall.GetFileAttributes(syscall.StringToUTF16Ptr(pathname))
+	if e != nil {
+		return "", os.NewSyscallError("GetFileAttributes", e)
+	}
+	if attr&syscall.FILE_ATTRIBUTE_DIRECTORY != 0 {
+		dir = pathname
+	} else {
+		dir, _ = filepath.Split(pathname)
+		dir = filepath.Clean(dir)
+	}
+	return
+}
+
+func getIno(path string) (ino *inode, err error) {
+	h, e := syscall.CreateFile(syscall.StringToUTF16Ptr(path),
+		syscall.FILE_LIST_DIRECTORY,
+		syscall.FILE_SHARE_READ|syscall.FILE_SHARE_WRITE|syscall.FILE_SHARE_DELETE,
+		nil, syscall.OPEN_EXISTING,
+		syscall.FILE_FLAG_BACKUP_SEMANTICS|syscall.FILE_FLAG_OVERLAPPED, 0)
+	if e != nil {
+		return nil, os.NewSyscallError("CreateFile", e)
+	}
+	var fi syscall.ByHandleFileInformation
+	if e = syscall.GetFileInformationByHandle(h, &fi); e != nil {
+		syscall.CloseHandle(h)
+		return nil, os.NewSyscallError("GetFileInformationByHandle", e)
+	}
+	ino = &inode{
+		handle: h,
+		volume: fi.VolumeSerialNumber,
+		index:  uint64(fi.FileIndexHigh)<<32 | uint64(fi.FileIndexLow),
+	}
+	return ino, nil
+}
+
+// Must run within the I/O thread.
+func (m watchMap) get(ino *inode) *watch {
+	if i := m[ino.volume]; i != nil {
+		return i[ino.index]
+	}
+	return nil
+}
+
+// Must run within the I/O thread.
+func (m watchMap) set(ino *inode, watch *watch) {
+	i := m[ino.volume]
+	if i == nil {
+		i = make(indexMap)
+		m[ino.volume] = i
+	}
+	i[ino.index] = watch
+}
+
+// Must run within the I/O thread.
+func (w *Watcher) addWatch(pathname string, flags uint64) error {
+	dir, err := getDir(pathname)
+	if err != nil {
+		return err
+	}
+	if flags&sysFSONLYDIR != 0 && pathname != dir {
+		return nil
+	}
+	ino, err := getIno(dir)
+	if err != nil {
+		return err
+	}
+	w.mu.Lock()
+	watchEntry := w.watches.get(ino)
+	w.mu.Unlock()
+	if watchEntry == nil {
+		if _, e := syscall.CreateIoCompletionPort(ino.handle, w.port, 0, 0); e != nil {
+			syscall.CloseHandle(ino.handle)
+			return os.NewSyscallError("CreateIoCompletionPort", e)
+		}
+		watchEntry = &watch{
+			ino:   ino,
+			path:  dir,
+			names: make(map[string]uint64),
+		}
+		w.mu.Lock()
+		w.watches.set(ino, watchEntry)
+		w.mu.Unlock()
+		flags |= provisional
+	} else {
+		syscall.CloseHandle(ino.handle)
+	}
+	if pathname == dir {
+		watchEntry.mask |= flags
+	} else {
+		watchEntry.names[filepath.Base(pathname)] |= flags
+	}
+	if err = w.startRead(watchEntry); err != nil {
+		return err
+	}
+	if pathname == dir {
+		watchEntry.mask &= ^provisional
+	} else {
+		watchEntry.names[filepath.Base(pathname)] &= ^provisional
+	}
+	return nil
+}
+
+// Must run within the I/O thread.
+func (w *Watcher) remWatch(pathname string) error {
+	dir, err := getDir(pathname)
+	if err != nil {
+		return err
+	}
+	ino, err := getIno(dir)
+	if err != nil {
+		return err
+	}
+	w.mu.Lock()
+	watch := w.watches.get(ino)
+	w.mu.Unlock()
+	if watch == nil {
+		return fmt.Errorf("can't remove non-existent watch for: %s", pathname)
+	}
+	if pathname == dir {
+		w.sendEvent(watch.path, watch.mask&sysFSIGNORED)
+		watch.mask = 0
+	} else {
+		name := filepath.Base(pathname)
+		w.sendEvent(filepath.Join(watch.path, name), watch.names[name]&sysFSIGNORED)
+		delete(watch.names, name)
+	}
+	return w.startRead(watch)
+}
+
+// Must run within the I/O thread.
+func (w *Watcher) deleteWatch(watch *watch) {
+	for name, mask := range watch.names {
+		if mask&provisional == 0 {
+			w.sendEvent(filepath.Join(watch.path, name), mask&sysFSIGNORED)
+		}
+		delete(watch.names, name)
+	}
+	if watch.mask != 0 {
+		if watch.mask&provisional == 0 {
+			w.sendEvent(watch.path, watch.mask&sysFSIGNORED)
+		}
+		watch.mask = 0
+	}
+}
+
+// Must run within the I/O thread.
+func (w *Watcher) startRead(watch *watch) error {
+	if e := syscall.CancelIo(watch.ino.handle); e != nil {
+		w.Errors <- os.NewSyscallError("CancelIo", e)
+		w.deleteWatch(watch)
+	}
+	mask := toWindowsFlags(watch.mask)
+	for _, m := range watch.names {
+		mask |= toWindowsFlags(m)
+	}
+	if mask == 0 {
+		if e := syscall.CloseHandle(watch.ino.handle); e != nil {
+			w.Errors <- os.NewSyscallError("CloseHandle", e)
+		}
+		w.mu.Lock()
+		delete(w.watches[watch.ino.volume], watch.ino.index)
+		w.mu.Unlock()
+		return nil
+	}
+	e := syscall.ReadDirectoryChanges(watch.ino.handle, &watch.buf[0],
+		uint32(unsafe.Sizeof(watch.buf)), false, mask, nil, &watch.ov, 0)
+	if e != nil {
+		err := os.NewSyscallError("ReadDirectoryChanges", e)
+		if e == syscall.ERROR_ACCESS_DENIED && watch.mask&provisional == 0 {
+			// Watched directory was probably removed
+			if w.sendEvent(watch.path, watch.mask&sysFSDELETESELF) {
+				if watch.mask&sysFSONESHOT != 0 {
+					watch.mask = 0
+				}
+			}
+			err = nil
+		}
+		w.deleteWatch(watch)
+		w.startRead(watch)
+		return err
+	}
+	return nil
+}
+
+// readEvents reads from the I/O completion port, converts the
+// received events into Event objects and sends them via the Events channel.
+// Entry point to the I/O thread.
+func (w *Watcher) readEvents() {
+	var (
+		n, key uint32
+		ov     *syscall.Overlapped
+	)
+	runtime.LockOSThread()
+
+	for {
+		e := syscall.GetQueuedCompletionStatus(w.port, &n, &key, &ov, syscall.INFINITE)
+		watch := (*watch)(unsafe.Pointer(ov))
+
+		if watch == nil {
+			select {
+			case ch := <-w.quit:
+				w.mu.Lock()
+				var indexes []indexMap
+				for _, index := range w.watches {
+					indexes = append(indexes, index)
+				}
+				w.mu.Unlock()
+				for _, index := range indexes {
+					for _, watch := range index {
+						w.deleteWatch(watch)
+						w.startRead(watch)
+					}
+				}
+				var err error
+				if e := syscall.CloseHandle(w.port); e != nil {
+					err = os.NewSyscallError("CloseHandle", e)
+				}
+				close(w.Events)
+				close(w.Errors)
+				ch <- err
+				return
+			case in := <-w.input:
+				switch in.op {
+				case opAddWatch:
+					in.reply <- w.addWatch(in.path, uint64(in.flags))
+				case opRemoveWatch:
+					in.reply <- w.remWatch(in.path)
+				}
+			default:
+			}
+			continue
+		}
+
+		switch e {
+		case syscall.ERROR_MORE_DATA:
+			if watch == nil {
+				w.Errors <- errors.New("ERROR_MORE_DATA has unexpectedly null lpOverlapped buffer")
+			} else {
+				// The i/o succeeded but the buffer is full.
+				// In theory we should be building up a full packet.
+				// In practice we can get away with just carrying on.
+				n = uint32(unsafe.Sizeof(watch.buf))
+			}
+		case syscall.ERROR_ACCESS_DENIED:
+			// Watched directory was probably removed
+			w.sendEvent(watch.path, watch.mask&sysFSDELETESELF)
+			w.deleteWatch(watch)
+			w.startRead(watch)
+			continue
+		case syscall.ERROR_OPERATION_ABORTED:
+			// CancelIo was called on this handle
+			continue
+		default:
+			w.Errors <- os.NewSyscallError("GetQueuedCompletionPort", e)
+			continue
+		case nil:
+		}
+
+		var offset uint32
+		for {
+			if n == 0 {
+				w.Events <- newEvent("", sysFSQOVERFLOW)
+				w.Errors <- errors.New("short read in readEvents()")
+				break
+			}
+
+			// Point "raw" to the event in the buffer
+			raw := (*syscall.FileNotifyInformation)(unsafe.Pointer(&watch.buf[offset]))
+			buf := (*[syscall.MAX_PATH]uint16)(unsafe.Pointer(&raw.FileName))
+			name := syscall.UTF16ToString(buf[:raw.FileNameLength/2])
+			fullname := filepath.Join(watch.path, name)
+
+			var mask uint64
+			switch raw.Action {
+			case syscall.FILE_ACTION_REMOVED:
+				mask = sysFSDELETESELF
+			case syscall.FILE_ACTION_MODIFIED:
+				mask = sysFSMODIFY
+			case syscall.FILE_ACTION_RENAMED_OLD_NAME:
+				watch.rename = name
+			case syscall.FILE_ACTION_RENAMED_NEW_NAME:
+				if watch.names[watch.rename] != 0 {
+					watch.names[name] |= watch.names[watch.rename]
+					delete(watch.names, watch.rename)
+					mask = sysFSMOVESELF
+				}
+			}
+
+			sendNameEvent := func() {
+				if w.sendEvent(fullname, watch.names[name]&mask) {
+					if watch.names[name]&sysFSONESHOT != 0 {
+						delete(watch.names, name)
+					}
+				}
+			}
+			if raw.Action != syscall.FILE_ACTION_RENAMED_NEW_NAME {
+				sendNameEvent()
+			}
+			if raw.Action == syscall.FILE_ACTION_REMOVED {
+				w.sendEvent(fullname, watch.names[name]&sysFSIGNORED)
+				delete(watch.names, name)
+			}
+			if w.sendEvent(fullname, watch.mask&toFSnotifyFlags(raw.Action)) {
+				if watch.mask&sysFSONESHOT != 0 {
+					watch.mask = 0
+				}
+			}
+			if raw.Action == syscall.FILE_ACTION_RENAMED_NEW_NAME {
+				fullname = filepath.Join(watch.path, watch.rename)
+				sendNameEvent()
+			}
+
+			// Move to the next event in the buffer
+			if raw.NextEntryOffset == 0 {
+				break
+			}
+			offset += raw.NextEntryOffset
+
+			// Error!
+			if offset >= n {
+				w.Errors <- errors.New("Windows system assumed buffer larger than it is, events have likely been missed.")
+				break
+			}
+		}
+
+		if err := w.startRead(watch); err != nil {
+			w.Errors <- err
+		}
+	}
+}
+
+func (w *Watcher) sendEvent(name string, mask uint64) bool {
+	if mask == 0 {
+		return false
+	}
+	event := newEvent(name, uint32(mask))
+	select {
+	case ch := <-w.quit:
+		w.quit <- ch
+	case w.Events <- event:
+	}
+	return true
+}
+
+func toWindowsFlags(mask uint64) uint32 {
+	var m uint32
+	if mask&sysFSACCESS != 0 {
+		m |= syscall.FILE_NOTIFY_CHANGE_LAST_ACCESS
+	}
+	if mask&sysFSMODIFY != 0 {
+		m |= syscall.FILE_NOTIFY_CHANGE_LAST_WRITE
+	}
+	if mask&sysFSATTRIB != 0 {
+		m |= syscall.FILE_NOTIFY_CHANGE_ATTRIBUTES
+	}
+	if mask&(sysFSMOVE|sysFSCREATE|sysFSDELETE) != 0 {
+		m |= syscall.FILE_NOTIFY_CHANGE_FILE_NAME | syscall.FILE_NOTIFY_CHANGE_DIR_NAME
+	}
+	return m
+}
+
+func toFSnotifyFlags(action uint32) uint64 {
+	switch action {
+	case syscall.FILE_ACTION_ADDED:
+		return sysFSCREATE
+	case syscall.FILE_ACTION_REMOVED:
+		return sysFSDELETE
+	case syscall.FILE_ACTION_MODIFIED:
+		return sysFSMODIFY
+	case syscall.FILE_ACTION_RENAMED_OLD_NAME:
+		return sysFSMOVEDFROM
+	case syscall.FILE_ACTION_RENAMED_NEW_NAME:
+		return sysFSMOVEDTO
+	}
+	return 0
+}
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 2766d6359..22d6723be 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -11,6 +11,9 @@ github.com/container-storage-interface/spec/lib/go/csi
 github.com/davecgh/go-spew/spew
 # github.com/evanphx/json-patch v4.9.0+incompatible
 github.com/evanphx/json-patch
+# github.com/fsnotify/fsnotify v1.4.9
+## explicit
+github.com/fsnotify/fsnotify
 # github.com/go-logr/logr v0.2.0
 github.com/go-logr/logr
 # github.com/gogo/protobuf v1.3.1


Test patch:
diff --git a/pkg/validation-webhook/webhook_test.go b/pkg/validation-webhook/webhook_test.go
new file mode 100644
index 000000000..1c325a5b4
--- /dev/null
+++ b/pkg/validation-webhook/webhook_test.go
@@ -0,0 +1,169 @@
+package webhook
+
+import (
+	"context"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/tls"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+	"fmt"
+	"math/big"
+	"net"
+	"os"
+	"testing"
+	"time"
+)
+
+func TestWebhookCertReload(t *testing.T) {
+	// Initialize test space
+	tmpDir := os.TempDir() + "/webhook-cert-tests"
+	certFile = tmpDir + "/tls.crt"
+	keyFile = tmpDir + "/tls.key"
+	port = 30443
+	err := os.Mkdir(tmpDir, 0777)
+	if err != nil && err != os.ErrExist {
+		t.Errorf("unexpected error occurred while creating tmp dir: %v", err)
+	}
+	defer func() {
+		err := os.RemoveAll(tmpDir)
+		if err != nil {
+			t.Errorf("unexpected error occurred while deleting certs: %v", err)
+		}
+	}()
+	generateTestCertKeyPair(t, certFile, keyFile)
+
+	// Start test server
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	cw, err := NewCertWatcher(certFile, keyFile)
+	if err != nil {
+		t.Errorf("failed to initialize new cert watcher: %v", err)
+	}
+	tlsConfig := &tls.Config{
+		GetCertificate: cw.GetCertificate,
+	}
+	go func() {
+		if err := startServer(ctx, tlsConfig, cw); err != nil {
+			panic(err)
+		}
+	}()
+	time.Sleep(250 * time.Millisecond) // Give some time for watcher to start
+
+	// TC: Original cert should not change with no file changes
+	originalCert, err := tlsConfig.GetCertificate(nil)
+	if err != nil {
+		t.Errorf("unexpected error occurred while getting cert: %v", err)
+	}
+	originalCertStr := string(originalCert.Certificate[0])
+	originalKey := originalCert.PrivateKey.(*rsa.PrivateKey)
+
+	newCert, err := tlsConfig.GetCertificate(nil) // get certificate again
+	if err != nil {
+		t.Errorf("unexpected error occurred while getting  newcert: %v", err)
+	}
+	if string(newCert.Certificate[0]) != originalCertStr {
+		t.Error("new cert was updated when it should not have been")
+	}
+	newKey := newCert.PrivateKey.(*rsa.PrivateKey)
+	if !newKey.Equal(originalKey) {
+		t.Error("new key was updated when it should not have been")
+	}
+
+	// TC: Certificate should consistently change with a file change
+	for i := 0; i < 5; i++ {
+		// Generate new key/cert
+		generateTestCertKeyPair(t, certFile, keyFile)
+
+		// Wait for certwatcher to update
+		time.Sleep(250 * time.Millisecond)
+		newCert, err = tlsConfig.GetCertificate(nil)
+		if err != nil {
+			t.Errorf("unexpected error occurred while getting  newcert: %v", err)
+		}
+		if string(newCert.Certificate[0]) == originalCertStr {
+			t.Errorf("new cert was not updated")
+		}
+
+		newKey = newCert.PrivateKey.(*rsa.PrivateKey)
+		if newKey.Equal(originalKey) {
+			t.Error("new key was not updated")
+		}
+
+		originalCertStr = string(newCert.Certificate[0])
+		originalKey = newKey
+	}
+}
+
+// generateTestCertKeyPair generates a new random test key/crt and writes it to tmpDir
+// based on https://golang.org/src/crypto/tls/generate_cert.go
+func generateTestCertKeyPair(t *testing.T, certPath, keyPath string) error {
+	notBefore := time.Now()
+	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
+	serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
+	if err != nil {
+		return fmt.Errorf("Failed to generate serial number: %v", err)
+	}
+
+	var priv interface{}
+	priv, err = rsa.GenerateKey(rand.Reader, 4096)
+	if err != nil {
+		return fmt.Errorf("Failed to generate key: %v", err)
+	}
+	keyUsage := x509.KeyUsageDigitalSignature
+	if _, isRSA := priv.(*rsa.PrivateKey); isRSA {
+		keyUsage |= x509.KeyUsageKeyEncipherment
+	}
+	randomOrganizationStr := time.Now().String()
+	template := x509.Certificate{
+		SerialNumber: serialNumber,
+		Subject: pkix.Name{
+			Organization: []string{randomOrganizationStr},
+		},
+		NotBefore: notBefore,
+		NotAfter:  time.Now().Add(1 * time.Hour),
+
+		KeyUsage:              keyUsage,
+		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
+		BasicConstraintsValid: true,
+		IPAddresses:           []net.IP{net.ParseIP("127.0.0.1")},
+		DNSNames:              []string{"127.0.0.1"},
+	}
+
+	rk := priv.(*rsa.PrivateKey)
+	derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, &rk.PublicKey, priv)
+	if err != nil {
+		return fmt.Errorf("Failed to create certificate: %v", err)
+	}
+
+	certOut, err := os.Create(certPath)
+	if err != nil {
+		return fmt.Errorf("Failed to open tls.crt for writing: %v", err)
+	}
+	if err := pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}); err != nil {
+		return fmt.Errorf("Failed to write data to tls.crt: %v", err)
+	}
+	if err := certOut.Close(); err != nil {
+		return fmt.Errorf("Error closing tls.crt: %v", err)
+	}
+	fmt.Printf("wrote new cert: %s\n", certPath)
+
+	keyOut, err := os.OpenFile(keyPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		return fmt.Errorf("Failed to open tls.key for writing: %v", err)
+	}
+	privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
+	if err != nil {
+		return fmt.Errorf("Unable to marshal private key: %v", err)
+	}
+	if err := pem.Encode(keyOut, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes}); err != nil {
+		return fmt.Errorf("Failed to write data to tls.key: %v", err)
+	}
+	if err := keyOut.Close(); err != nil {
+		return fmt.Errorf("Error closing tls.key: %v", err)
+	}
+	fmt.Printf("wrote new key: %s\n", keyPath)
+
+	return nil
+}