Repository: serverless/serverless (JavaScript) — Bug Fix

Issue:
Breaking change introduced for Custom Authorizer Lambdas
# Bug Report
Merged PR https://github.com/serverless/serverless/commit/38f6ac125e54d927871b4e5f5b387e0d4c28a6a7 introduced breaking changes for lambda based custom authorizer.

## Description
Given I am running serverless v1.60.5
When I run `sls deploy`
Then the deploy fails because the "cloudformation-template-update-stack.json" file has an incorrect datatype in place for the FunctionName of the Authorizerr Function
    Error: `An error occurred: CustomAuthorizerLambdaPermissionApiGateway - Value of property FunctionName must be of type String.`

Source code that changed https://github.com/serverless/serverless/blob/38f6ac125e54d927871b4e5f5b387e0d4c28a6a7/lib/plugins/aws/package/compile/events/apiGateway/lib/permissions.js commit #38f6ac1

Resultant Cloudformation code showing that FunctionName isn't a String variable:
```
"CustomAuthorizerLambdaPermissionApiGateway": {
      "Type": "AWS::Lambda::Permission",
      "Properties": {
        "FunctionName": {
          "Fn::Join": [
            ":",
            [
              {
                "Fn::GetAtt": [
                  "CustomAuthorizerLambdaFunction",
                  "Arn"
                ]
              }
            ]
          ],
          "Fn::GetAtt": [
            "CustomAuthorizerLambdaFunction",
            "Arn"
          ]
        },
```


1. What did you do?
    Updated serverless from v1.59.3 to v1.60.5
1. What happened?
    Deploys started to fail because the CustomAuthorizer function could not be deployed
1. What should've happened?
    It should have delpoyed, like it previously had done for the past 18 months.
1. What's the content of your `serverless.yml` file?
Pasting in the relevant data:
```
frameworkVersion: ">=1.1.0 <2.0.0"

provider:
  name: aws
  runtime: python3.7
  stage: ${opt:stage,'dev'}
  region: eu-west-1
  tracing:
    lambda: true
    apiGateway: true
plugins:
  - serverless-python-requirements
  - serverless-stage-manager
  - serverless-prune-plugin

functions:
  customAuthorizer:
    handler: authorizer.auth
    events:
        - http:
            path: /auth
            method: GET
            cors: true

```
1. What's the output you get when you use the `SLS_DEBUG=*` environment variable (e.g. `SLS_DEBUG=* serverless deploy`)
  Serverless Error ---------------------------------------

  An error occurred: CustomAuthorizerLambdaPermissionApiGateway - Value of property FunctionName must be of type String.

  Get Support --------------------------------------------
     Docs:          docs.serverless.com
     Bugs:          github.com/serverless/serverless/issues
     Issues:        forum.serverless.com

  Your Environment Information ---------------------------
     Operating System:          darwin
     Node Version:              11.13.0
     Framework Version:         1.60.5
     Plugin Version:            3.2.7
     SDK Version:               2.2.1
     Components Core Version:   1.1.2
     Components CLI Version:    1.4.0

Similar or dependent issues:
The change to the relevant code was introduced as a result of the PR raised from issue:
- #7059
https://github.com/serverless/serverless/blob/38f6ac125e54d927871b4e5f5b387e0d4c28a6a7/lib/plugins/aws/package/compile/events/apiGateway/lib/permissions.js#L19-L29 


Discussion:
`Fn::Join` is a valid CloudFormation instruction, and this change is confirmed to work.

I'm guessing that some plugin relied on specific format of `FunctionName`, hence the error. Can you run same with `SLS_DEBUG=*` and check where exactly crash happens?

The `Fn::Join` is only joining `":"` and `[{"Fn::GetAtt": ["CustomAuthorizerLambdaFunction","Arn"]}]`

The `"Fn::GetAtt": ["CustomAuthorizerLambdaFunction","Arn"]` lies outside of the closing square bracket for `Fn::Join`

```
"Fn::Join": [
                ":", 
                [{"Fn::GetAtt": ["CustomAuthorizerLambdaFunction","Arn"]}]
            ],
"Fn::GetAtt": ["CustomAuthorizerLambdaFunction","Arn"]
```

That's where I thought the issue was coming from.


Here is the error output from a deploy:
```
Serverless: View the full error output: https://eu-west-1.console.aws.amazon.com/cloudformation/home?region=eu-west-1#/stack/detail?stackId=arn%3Aaws%3Acloudformation%3Aeu-west-1%3A389957958676%3Astack%2Fcmp-api-dev%2F47694580-7c9a-11e9-8bae-0a62311bc72a

  Serverless Error ---------------------------------------

  ServerlessError: An error occurred: CustomAuthorizerLambdaPermissionApiGateway - Value of property FunctionName must be of type String.
      at provider.request.then.data (/usr/local/lib/node_modules/serverless/lib/plugins/aws/lib/monitorStack.js:125:33)
  From previous event:
      at AwsDeploy.monitorStack (/usr/local/lib/node_modules/serverless/lib/plugins/aws/lib/monitorStack.js:28:12)
      at provider.request.then.cfData (/usr/local/lib/node_modules/serverless/lib/plugins/aws/lib/updateStack.js:103:28)
  From previous event:
      at AwsDeploy.update (/usr/local/lib/node_modules/serverless/lib/plugins/aws/lib/updateStack.js:103:8)
  From previous event:
      at AwsDeploy.BbPromise.bind.then (/usr/local/lib/node_modules/serverless/lib/plugins/aws/lib/updateStack.js:117:35)
  From previous event:
      at AwsDeploy.updateStack (/usr/local/lib/node_modules/serverless/lib/plugins/aws/lib/updateStack.js:113:33)
  From previous event:
      at AwsDeploy.BbPromise.bind.then (/usr/local/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:127:39)
  From previous event:
      at Object.aws:deploy:deploy:updateStack [as hook] (/usr/local/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:123:30)
      at BbPromise.reduce (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:490:55)
  From previous event:
      at PluginManager.invoke (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:490:22)
      at PluginManager.spawn (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:510:17)
      at AwsDeploy.BbPromise.bind.then (/usr/local/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:93:48)
  From previous event:
      at Object.deploy:deploy [as hook] (/usr/local/lib/node_modules/serverless/lib/plugins/aws/deploy/index.js:89:30)
      at BbPromise.reduce (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:490:55)
  From previous event:
      at PluginManager.invoke (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:490:22)
      at getHooks.reduce.then (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:525:24)
  From previous event:
      at PluginManager.run (/usr/local/lib/node_modules/serverless/lib/classes/PluginManager.js:525:8)
      at variables.populateService.then (/usr/local/lib/node_modules/serverless/lib/Serverless.js:133:33)
      at processImmediate (internal/timers.js:443:21)
      at process.topLevelDomainCallback (domain.js:136:23)
  From previous event:
      at Serverless.run (/usr/local/lib/node_modules/serverless/lib/Serverless.js:120:74)
      at serverless.init.then (/usr/local/lib/node_modules/serverless/bin/serverless.js:75:30)
      at /usr/local/lib/node_modules/serverless/node_modules/graceful-fs/graceful-fs.js:111:16
      at /usr/local/lib/node_modules/serverless/node_modules/graceful-fs/graceful-fs.js:45:10
      at FSReqCallback.args [as oncomplete] (fs.js:145:20)
  From previous event:
      at initializeErrorReporter.then (/usr/local/lib/node_modules/serverless/bin/serverless.js:75:8)
      at processImmediate (internal/timers.js:443:21)
      at process.topLevelDomainCallback (domain.js:136:23)
  From previous event:
      at Object.<anonymous> (/usr/local/lib/node_modules/serverless/bin/serverless.js:64:4)
      at Module._compile (internal/modules/cjs/loader.js:805:30)
      at Object.Module._extensions..js (internal/modules/cjs/loader.js:816:10)
      at Module.load (internal/modules/cjs/loader.js:672:32)
      at tryModuleLoad (internal/modules/cjs/loader.js:612:12)
      at Function.Module._load (internal/modules/cjs/loader.js:604:3)
      at Function.Module.runMain (internal/modules/cjs/loader.js:868:12)
      at internal/main/run_main_module.js:21:11

  Get Support --------------------------------------------
     Docs:          docs.serverless.com
     Bugs:          github.com/serverless/serverless/issues
     Issues:        forum.serverless.com

  Your Environment Information ---------------------------
     Operating System:          darwin
     Node Version:              11.13.0
     Framework Version:         1.60.5
     Plugin Version:            3.2.7
     SDK Version:               2.2.1
     Components Core Version:   1.1.2
     Components CLI Version:    1.4.0
```
P.S Thanks for the quick reply 👍 
@DrColza can you check what is the template as generated by framework without plugins involved.

I  believe framework produces a valid template and it's one of the plugins which you rely on that introduces breaking changes to it
Given I comment out the plugins section in `serverless.yml`
When I run `sls package --stage dev`
Then I get the following JSON in `cloudformation-template-update-stack.json`

```
"CustomAuthorizerLambdaPermissionApiGateway": {
      "Type": "AWS::Lambda::Permission",
      "Properties": {
        "FunctionName": {
          "Fn::Join": [
            ":",
            [
              {
                "Fn::GetAtt": [
                  "CustomAuthorizerLambdaFunction",
                  "Arn"
                ]
              }
            ]
          ],
          "Fn::GetAtt": [
            "CustomAuthorizerLambdaFunction",
            "Arn"
          ]
        },
```

When I run the same scenario in v1.59.3 
Then I get the follwoing JSON:

```
"CustomAuthorizerLambdaPermissionApiGateway": {
      "Type": "AWS::Lambda::Permission",
      "Properties": {
        "FunctionName": {
          "Fn::GetAtt": [
            "CustomAuthorizerLambdaFunction",
            "Arn"
          ]
        },
```
@DrColza I'm not able to reproduce that. I've created very similar service as yours:
https://github.com/medikoo/test-serverless/blob/7189-case/serverless.yml

And it deploys successfully with v1.60.5, also we can see that `AWS::Lambda::Permission` resource is generated as expected: https://github.com/medikoo/test-serverless/blob/f0874b530b82f916307b771ee18636c29fa349d1/.serverless/cloudformation-template-update-stack.json#L342-L354

The only difference is that it's for `node12.x` runtime. Still I've switched to Python, tested packaging, and shape of `AWS::Lambda::Permission` was not affected.

If you're positive you get that without any plugins involved, can you update this test case, so i can reproduce issue on my side (?)

Hi @medikoo 

I can replicate it with this (in Nodejs) 1.60.5

```service: test-7189

provider:
  name: aws
  runtime: nodejs12.x
  region: us-east-1
  stage: dev
  tracing:
    lambda: true
    apiGateway: true

functions:
  customAuthorizer:
    handler: index.auth
    events:
      - http:
          path: /auth
          method: GET
          cors: true

  function:
    handler: index.handler
    events:
      - http:
          path: foo
          method: GET
          cors: true
          authorizer: customAuthorizer
```

```"CustomAuthorizerLambdaPermissionApiGateway": {
      "Type": "AWS::Lambda::Permission",
      "Properties": {
        "FunctionName": {
          "Fn::Join": [
            ":",
            [
              {
                "Fn::GetAtt": [
                  "CustomAuthorizerLambdaFunction",
                  "Arn"
                ]
              }
            ]
          ],
          "Fn::GetAtt": [
            "CustomAuthorizerLambdaFunction",
            "Arn"
          ]
        },```

Resolving patch:
diff --git a/lib/plugins/aws/package/compile/events/apiGateway/lib/permissions.js b/lib/plugins/aws/package/compile/events/apiGateway/lib/permissions.js
index 1b3b28b4dc4..e331be1d40e 100644
--- a/lib/plugins/aws/package/compile/events/apiGateway/lib/permissions.js
+++ b/lib/plugins/aws/package/compile/events/apiGateway/lib/permissions.js
@@ -1,32 +1,25 @@
 'use strict';
 
-const _ = require('lodash');
 const BbPromise = require('bluebird');
 const awsArnRegExs = require('../../../../../utils/arnRegularExpressions');
 
 module.exports = {
   compilePermissions() {
+    const cfResources = this.serverless.service.provider.compiledCloudFormationTemplate.Resources;
     this.permissionMapping.forEach(
       ({ lambdaLogicalId, lambdaAliasName, lambdaAliasLogicalId, event }) => {
         const lambdaPermissionLogicalId = this.provider.naming.getLambdaApiGatewayPermissionLogicalId(
           event.functionName
         );
 
-        _.merge(this.serverless.service.provider.compiledCloudFormationTemplate.Resources, {
+        const functionArnGetter = { 'Fn::GetAtt': [lambdaLogicalId, 'Arn'] };
+        Object.assign(cfResources, {
           [lambdaPermissionLogicalId]: {
             Type: 'AWS::Lambda::Permission',
             Properties: {
-              FunctionName: {
-                'Fn::Join': [
-                  ':',
-                  [
-                    {
-                      'Fn::GetAtt': [lambdaLogicalId, 'Arn'],
-                    },
-                    ...(lambdaAliasName ? [lambdaAliasName] : []),
-                  ],
-                ],
-              },
+              FunctionName: lambdaAliasName
+                ? { 'Fn::Join': [':', [functionArnGetter, lambdaAliasName]] }
+                : functionArnGetter,
               Action: 'lambda:InvokeFunction',
               Principal: 'apigateway.amazonaws.com',
               SourceArn: {
@@ -63,7 +56,8 @@ module.exports = {
             return;
           }
 
-          _.merge(this.serverless.service.provider.compiledCloudFormationTemplate.Resources, {
+          if (cfResources[authorizerPermissionLogicalId]) return;
+          Object.assign(cfResources, {
             [authorizerPermissionLogicalId]: {
               Type: 'AWS::Lambda::Permission',
               Properties: {


Test patch:
diff --git a/lib/plugins/aws/package/compile/events/apiGateway/lib/permissions.test.js b/lib/plugins/aws/package/compile/events/apiGateway/lib/permissions.test.js
index 5cb70c0d45e..c1edd41ac91 100644
--- a/lib/plugins/aws/package/compile/events/apiGateway/lib/permissions.test.js
+++ b/lib/plugins/aws/package/compile/events/apiGateway/lib/permissions.test.js
@@ -46,9 +46,7 @@ describe('#awsCompilePermissions()', () => {
     return awsCompileApigEvents.compilePermissions().then(() => {
       expect(
         awsCompileApigEvents.serverless.service.provider.compiledCloudFormationTemplate.Resources
-          .FirstLambdaPermissionApiGateway.Properties.FunctionName['Fn::Join'][1][0][
-          'Fn::GetAtt'
-        ][0]
+          .FirstLambdaPermissionApiGateway.Properties.FunctionName['Fn::GetAtt'][0]
       ).to.equal('FirstLambdaFunction');
 
       const deepObj = {
@@ -106,9 +104,7 @@ describe('#awsCompilePermissions()', () => {
     return awsCompileApigEvents.compilePermissions().then(() => {
       expect(
         awsCompileApigEvents.serverless.service.provider.compiledCloudFormationTemplate.Resources
-          .FirstLambdaPermissionApiGateway.Properties.FunctionName['Fn::Join'][1][0][
-          'Fn::GetAtt'
-        ][0]
+          .FirstLambdaPermissionApiGateway.Properties.FunctionName['Fn::GetAtt'][0]
       ).to.equal('FirstLambdaFunction');
 
       const deepObj = {
@@ -188,6 +184,67 @@ describe('#awsCompilePermissions()', () => {
     ];
     awsCompileApigEvents.apiGatewayRestApiLogicalId = 'ApiGatewayRestApi';
     awsCompileApigEvents.permissionMapping = [
+      {
+        lambdaLogicalId: 'AuthorizerLambdaFunction',
+        event: {
+          http: {
+            path: 'foo/bar',
+            method: 'post',
+          },
+          functionName: 'authorizer',
+        },
+      },
+      {
+        lambdaLogicalId: 'FirstLambdaFunction',
+        resourceName: 'FooBar',
+        event: {
+          http: {
+            authorizer: {
+              name: 'authorizer',
+              arn: { 'Fn::GetAtt': ['AuthorizerLambdaFunction', 'Arn'] },
+            },
+            path: 'foo/bar',
+            method: 'post',
+          },
+          functionName: 'First',
+        },
+      },
+    ];
+    return awsCompileApigEvents.compilePermissions().then(() => {
+      expect(
+        awsCompileApigEvents.serverless.service.provider.compiledCloudFormationTemplate.Resources
+          .AuthorizerLambdaPermissionApiGateway.Properties.FunctionName
+      ).to.deep.equal({ 'Fn::GetAtt': ['AuthorizerLambdaFunction', 'Arn'] });
+    });
+  });
+
+  it('should create permission resources for aliased authorizers', () => {
+    awsCompileApigEvents.validated.events = [
+      {
+        functionName: 'First',
+        http: {
+          authorizer: {
+            name: 'authorizer',
+            arn: { 'Fn::GetAtt': ['AuthorizerLambdaFunction', 'Arn'] },
+          },
+          path: 'foo/bar',
+          method: 'post',
+        },
+      },
+    ];
+    awsCompileApigEvents.apiGatewayRestApiLogicalId = 'ApiGatewayRestApi';
+    awsCompileApigEvents.permissionMapping = [
+      {
+        lambdaLogicalId: 'AuthorizerLambdaFunction',
+        lambdaAliasName: 'provisioned',
+        event: {
+          http: {
+            path: 'foo/bar',
+            method: 'post',
+          },
+          functionName: 'authorizer',
+        },
+      },
       {
         lambdaLogicalId: 'FirstLambdaFunction',
         resourceName: 'FooBar',
@@ -207,8 +264,10 @@ describe('#awsCompilePermissions()', () => {
     return awsCompileApigEvents.compilePermissions().then(() => {
       expect(
         awsCompileApigEvents.serverless.service.provider.compiledCloudFormationTemplate.Resources
-          .AuthorizerLambdaPermissionApiGateway.Properties.FunctionName['Fn::GetAtt'][0]
-      ).to.equal('AuthorizerLambdaFunction');
+          .AuthorizerLambdaPermissionApiGateway.Properties.FunctionName
+      ).to.deep.equal({
+        'Fn::Join': [':', [{ 'Fn::GetAtt': ['AuthorizerLambdaFunction', 'Arn'] }, 'provisioned']],
+      });
     });
   });