Chapter 5. Knative Functions CLI commands 5.1. kn functions commands 5.1.1. Creating a function by using the Knative CLI You can specify the path, runtime, template, and image registry for a function as flags on the command line, or use the -c flag to start the interactive experience in the terminal. Prerequisites The OpenShift Serverless Operator and Knative Serving are installed on the cluster. You have installed the Knative ( kn ) CLI. Procedure Create a function project: USD kn func create -r <repository> -l <runtime> -t <template> <path> Accepted runtime values include quarkus , node , typescript , go , python , springboot , and rust . Accepted template values include http and cloudevents . Example command USD kn func create -l typescript -t cloudevents examplefunc Example output Created typescript function in /home/user/demo/examplefunc Alternatively, you can specify a repository that contains a custom template. Example command USD kn func create -r https://github.com/boson-project/templates/ -l node -t hello-world examplefunc Example output Created node function in /home/user/demo/examplefunc 5.1.2. Running a function locally You can use the kn func run command to run a function locally in the current directory or in the directory specified by the --path flag. If the function that you are running has never previously been built, or if the project files have been modified since the last time it was built, the kn func run command builds the function before running it by default. Example command to run a function in the current directory USD kn func run Example command to run a function in a directory specified as a path USD kn func run --path=<directory_path> You can also force a rebuild of an existing image before running the function, even if there have been no changes to the project files, by using the --build flag: Example run command using the build flag USD kn func run --build If you set the build flag as false, this disables building of the image, and runs the function using the previously built image: Example run command using the build flag USD kn func run --build=false You can use the help command to learn more about kn func run command options: Build help command USD kn func help run 5.1.3. Building a function Before you can run a function, you must build the function project. If you are using the kn func run command, the function is built automatically. However, you can use the kn func build command to build a function without running it, which can be useful for advanced users or debugging scenarios. The kn func build command creates an OCI container image that can be run locally on your computer or on an OpenShift Container Platform cluster. This command uses the function project name and the image registry name to construct a fully qualified image name for your function. 5.1.3.1. Image container types By default, kn func build creates a container image by using Red Hat Source-to-Image (S2I) technology. Example build command using Red Hat Source-to-Image (S2I) USD kn func build 5.1.3.2. Image registry types The OpenShift Container Registry is used by default as the image registry for storing function images. Example build command using OpenShift Container Registry USD kn func build Example output Building function image Function image has been built, image: registry.redhat.io/example/example-function:latest You can override using OpenShift Container Registry as the default image registry by using the --registry flag: Example build command overriding OpenShift Container Registry to use quay.io USD kn func build --registry quay.io/username Example output Building function image Function image has been built, image: quay.io/username/example-function:latest 5.1.3.3. Push flag You can add the --push flag to a kn func build command to automatically push the function image after it is successfully built: Example build command using OpenShift Container Registry USD kn func build --push 5.1.3.4. Help command You can use the help command to learn more about kn func build command options: Build help command USD kn func help build 5.1.4. Deploying a function You can deploy a function to your cluster as a Knative service by using the kn func deploy command. If the targeted function is already deployed, it is updated with a new container image that is pushed to a container image registry, and the Knative service is updated. Prerequisites The OpenShift Serverless Operator and Knative Serving are installed on the cluster. You have installed the Knative ( kn ) CLI. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You must have already created and initialized the function that you want to deploy. Procedure Deploy a function: USD kn func deploy [-n <namespace> -p <path> -i <image>] Example output Function deployed at: http://func.example.com If no namespace is specified, the function is deployed in the current namespace. The function is deployed from the current directory, unless a path is specified. The Knative service name is derived from the project name, and cannot be changed using this command. Note You can create a serverless function with a Git repository URL by using Import from Git or Create Serverless Function in the +Add view of the Developer perspective. 5.1.5. Listing existing functions You can list existing functions by using kn func list . If you want to list functions that have been deployed as Knative services, you can also use kn service list . Procedure List existing functions: USD kn func list [-n <namespace> -p <path>] Example output NAME NAMESPACE RUNTIME URL READY example-function default node http://example-function.default.apps.ci-ln-g9f36hb-d5d6b.origin-ci-int-aws.dev.rhcloud.com True List functions deployed as Knative services: USD kn service list -n <namespace> Example output NAME URL LATEST AGE CONDITIONS READY REASON example-function http://example-function.default.apps.ci-ln-g9f36hb-d5d6b.origin-ci-int-aws.dev.rhcloud.com example-function-gzl4c 16m 3 OK / 3 True 5.1.6. Describing a function The kn func info command prints information about a deployed function, such as the function name, image, namespace, Knative service information, route information, and event subscriptions. Procedure Describe a function: USD kn func info [-f <format> -n <namespace> -p <path>] Example command USD kn func info -p function/example-function Example output Function name: example-function Function is built in image: docker.io/user/example-function:latest Function is deployed as Knative Service: example-function Function is deployed in namespace: default Routes: http://example-function.default.apps.ci-ln-g9f36hb-d5d6b.origin-ci-int-aws.dev.rhcloud.com 5.1.7. Invoking a deployed function with a test event You can use the kn func invoke CLI command to send a test request to invoke a function either locally or on your OpenShift Container Platform cluster. You can use this command to test that a function is working and able to receive events correctly. Invoking a function locally is useful for a quick test during function development. Invoking a function on the cluster is useful for testing that is closer to the production environment. Prerequisites The OpenShift Serverless Operator and Knative Serving are installed on the cluster. You have installed the Knative ( kn ) CLI. You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform. You must have already deployed the function that you want to invoke. Procedure Invoke a function: USD kn func invoke The kn func invoke command only works when there is either a local container image currently running, or when there is a function deployed in the cluster. The kn func invoke command executes on the local directory by default, and assumes that this directory is a function project. 5.1.7.1. kn func invoke optional parameters You can specify optional parameters for the request by using the following kn func invoke CLI command flags. Flags Description -t , --target Specifies the target instance of the invoked function, for example, local or remote or https://staging.example.com/ . The default target is local . -f , --format Specifies the format of the message, for example, cloudevent or http . --id Specifies a unique string identifier for the request. -n , --namespace Specifies the namespace on the cluster. --source Specifies sender name for the request. This corresponds to the CloudEvent source attribute. --type Specifies the type of request, for example, boson.fn . This corresponds to the CloudEvent type attribute. --data Specifies content for the request. For CloudEvent requests, this is the CloudEvent data attribute. --file Specifies path to a local file containing data to be sent. --content-type Specifies the MIME content type for the request. -p , --path Specifies path to the project directory. -c , --confirm Enables prompting to interactively confirm all options. -v , --verbose Enables printing verbose output. -h , --help Prints information on usage of kn func invoke . 5.1.7.1.1. Main parameters The following parameters define the main properties of the kn func invoke command: Event target ( -t , --target ) The target instance of the invoked function. Accepts the local value for a locally deployed function, the remote value for a remotely deployed function, or a URL for a function deployed to an arbitrary endpoint. If a target is not specified, it defaults to local . Event message format ( -f , --format ) The message format for the event, such as http or cloudevent . This defaults to the format of the template that was used when creating the function. Event type ( --type ) The type of event that is sent. You can find information about the type parameter that is set in the documentation for each event producer. For example, the API server source might set the type parameter of produced events as dev.knative.apiserver.resource.update . Event source ( --source ) The unique event source that produced the event. This might be a URI for the event source, for example https://10.96.0.1/ , or the name of the event source. Event ID ( --id ) A random, unique ID that is created by the event producer. Event data ( --data ) Allows you to specify a data value for the event sent by the kn func invoke command. For example, you can specify a --data value such as "Hello World" so that the event contains this data string. By default, no data is included in the events created by kn func invoke . Note Functions that have been deployed to a cluster can respond to events from an existing event source that provides values for properties such as source and type . These events often have a data value in JSON format, which captures the domain specific context of the event. By using the CLI flags noted in this document, developers can simulate those events for local testing. You can also send event data using the --file flag to provide a local file containing data for the event. In this case, specify the content type using --content-type . Data content type ( --content-type ) If you are using the --data flag to add data for events, you can use the --content-type flag to specify what type of data is carried by the event. In the example, the data is plain text, so you might specify kn func invoke --data "Hello world!" --content-type "text/plain" . 5.1.7.1.2. Example commands This is the general invocation of the kn func invoke command: USD kn func invoke --type <event_type> --source <event_source> --data <event_data> --content-type <content_type> --id <event_ID> --format <format> --namespace <namespace> For example, to send a "Hello world!" event, you can run: USD kn func invoke --type ping --source example-ping --data "Hello world!" --content-type "text/plain" --id example-ID --format http --namespace my-ns 5.1.7.1.2.1. Specifying the file with data To specify the file on disk that contains the event data, use the --file and --content-type flags: USD kn func invoke --file <path> --content-type <content-type> For example, to send JSON data stored in the test.json file, use this command: USD kn func invoke --file ./test.json --content-type application/json 5.1.7.1.2.2. Specifying the function project You can specify a path to the function project by using the --path flag: USD kn func invoke --path <path_to_function> For example, to use the function project located in the ./example/example-function directory, use this command: USD kn func invoke --path ./example/example-function 5.1.7.1.2.3. Specifying where the target function is deployed By default, kn func invoke targets the local deployment of the function: USD kn func invoke To use a different deployment, use the --target flag: USD kn func invoke --target <target> For example, to use the function deployed on the cluster, use the --target remote flag: USD kn func invoke --target remote To use the function deployed at an arbitrary URL, use the --target <URL> flag: USD kn func invoke --target "https://my-event-broker.example.com" You can explicitly target the local deployment. In this case, if the function is not running locally, the command fails: USD kn func invoke --target local 5.1.8. Deleting a function You can delete a function by using the kn func delete command. This is useful when a function is no longer required, and can help to save resources on your cluster. Procedure Delete a function: USD kn func delete [<function_name> -n <namespace> -p <path>] If the name or path of the function to delete is not specified, the current directory is searched for a func.yaml file that is used to determine the function to delete. If the namespace is not specified, it defaults to the namespace value in the func.yaml file.

Commands:
kn func create -r <repository> -l <runtime> -t <template> <path>
kn func create -l typescript -t cloudevents examplefunc
Created typescript function in /home/user/demo/examplefunc
kn func create -r https://github.com/boson-project/templates/ -l node -t hello-world examplefunc
Created node function in /home/user/demo/examplefunc
kn func run
kn func run --path=<directory_path>
kn func run --build
kn func run --build=false
kn func help run
kn func build
kn func build
Building function image Function image has been built, image: registry.redhat.io/example/example-function:latest
kn func build --registry quay.io/username
Building function image Function image has been built, image: quay.io/username/example-function:latest
kn func build --push
kn func help build
kn func deploy [-n <namespace> -p <path> -i <image>]
Function deployed at: http://func.example.com
kn func list [-n <namespace> -p <path>]
NAME NAMESPACE RUNTIME URL READY example-function default node http://example-function.default.apps.ci-ln-g9f36hb-d5d6b.origin-ci-int-aws.dev.rhcloud.com True
kn service list -n <namespace>
NAME URL LATEST AGE CONDITIONS READY REASON example-function http://example-function.default.apps.ci-ln-g9f36hb-d5d6b.origin-ci-int-aws.dev.rhcloud.com example-function-gzl4c 16m 3 OK / 3 True
kn func info [-f <format> -n <namespace> -p <path>]
kn func info -p function/example-function
Function name: example-function Function is built in image: docker.io/user/example-function:latest Function is deployed as Knative Service: example-function Function is deployed in namespace: default Routes: http://example-function.default.apps.ci-ln-g9f36hb-d5d6b.origin-ci-int-aws.dev.rhcloud.com
kn func invoke
kn func invoke --type <event_type> --source <event_source> --data <event_data> --content-type <content_type> --id <event_ID> --format <format> --namespace <namespace>
kn func invoke --type ping --source example-ping --data "Hello world!" --content-type "text/plain" --id example-ID --format http --namespace my-ns
kn func invoke --file <path> --content-type <content-type>
kn func invoke --file ./test.json --content-type application/json
kn func invoke --path <path_to_function>
kn func invoke --path ./example/example-function
kn func invoke
kn func invoke --target <target>
kn func invoke --target remote
kn func invoke --target "https://my-event-broker.example.com"
kn func invoke --target local
kn func delete [<function_name> -n <namespace> -p <path>]