Chapter 5. Knative Functions CLI commands
5.1. kn functions commands
5.1.1. Creating functions
Before you can build and deploy a function, you must create it by using the Knative (kn
) CLI. You can specify the path, runtime, template, and image registry 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:
$ kn func create -r <repository> -l <runtime> -t <template> <path>
-
Accepted runtime values include
quarkus
,node
,typescript
,go
,python
,springboot
, andrust
. Accepted template values include
http
andcloudevents
.Example command
$ 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
$ 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
-
Accepted runtime values include
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
$ kn func run
Example command to run a function in a directory specified as a path
$ 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
$ 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
$ kn func run --build=false
You can use the help command to learn more about kn func run
command options:
Build help command
$ kn func help run
5.1.3. Building functions
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)
$ 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
$ 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
$ 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
$ 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
$ kn func help build
5.1.4. Deploying functions
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:
$ 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.
-
If no
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:
$ 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:
$ 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:
$ kn func info [-f <format> -n <namespace> -p <path>]
Example command
$ 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:
$ 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.
-
The
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 |
---|---|
|
Specifies the target instance of the invoked function, for example, |
|
Specifies the format of the message, for example, |
| Specifies a unique string identifier for the request. |
| Specifies the namespace on the cluster. |
|
Specifies sender name for the request. This corresponds to the CloudEvent |
|
Specifies the type of request, for example, |
|
Specifies content for the request. For CloudEvent requests, this is the CloudEvent |
| Specifies path to a local file containing data to be sent. |
| Specifies the MIME content type for the request. |
| Specifies path to the project directory. |
| Enables prompting to interactively confirm all options. |
| Enables printing verbose output. |
|
Prints information on usage of |
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, theremote
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 tolocal
. - Event message format (
-f
,--format
) -
The message format for the event, such as
http
orcloudevent
. 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 thetype
parameter of produced events asdev.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 thekn 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 bykn func invoke
.NoteFunctions that have been deployed to a cluster can respond to events from an existing event source that provides values for properties such as
source
andtype
. These events often have adata
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 previous example, the data is plain text, so you might specifykn 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:
$ 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:
$ 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:
$ kn func invoke --file <path> --content-type <content-type>
For example, to send JSON data stored in the test.json
file, use this command:
$ 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:
$ kn func invoke --path <path_to_function>
For example, to use the function project located in the ./example/example-function
directory, use this command:
$ 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:
$ kn func invoke
To use a different deployment, use the --target
flag:
$ kn func invoke --target <target>
For example, to use the function deployed on the cluster, use the --target remote
flag:
$ kn func invoke --target remote
To use the function deployed at an arbitrary URL, use the --target <URL>
flag:
$ 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:
$ 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:
$ 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 thefunc.yaml
file.
-
If the name or path of the function to delete is not specified, the current directory is searched for a