chapter-5-spring-cloud-events

chapter-5-spring-cloud-events project

This sample project contains a single function based on Spring Cloud Function: functions.CloudFunctionApplication.uppercase(), which returns the uppercase of the data passed via CloudEvents.

Local execution

Make sure that Java 11 SDK is installed.

To start server locally run ./mvnw spring-boot:run. The command starts http server and automatically watches for changes of source code. If source code changes the change will be propagated to running server. It also opens debugging port 5005 so a debugger can be attached if needed.

To run tests locally run ./mvnw test.

The func CLI

The func CLI is a new open source client library and command-line interface tool for the development of platform-agnostic functions on any Kubernetes cluster. Install the func tool on your OS (e.g. Linux, macOS, and Windows). Then make sure to log in to a Kubernetes cluster where you need to deploy the function.

It's recommended to set FUNC_REGISTRY environment variable.

# replace ~/.bashrc by your shell rc file
# replace docker.io/johndoe with your registry
export FUNC_REGISTRY=docker.io/johndoe
echo "export FUNC_REGISTRY=docker.io/johndoe" >> ~/.bashrc

Building

This command builds an OCI image for the function.

func build -v                # build jar

Running

This command runs the func locally in a container using the image created above.

func run

Deploying

This command will build and deploy the function into cluster.

func deploy -v # also triggers build

Function invocation

For the examples below, please be sure to set the URL variable to the route of your function.

You get the route by following command.

func describe

Note the value of Routes: from the output, set $URL to its value.

TIP:

If you use kn then you can set the url by:

# kn service describe <function name> and show route url
export URL=$(kn service describe $(basename $PWD) -ourl)

cURL

URL=http://localhost:8080/
curl -v ${URL} \
  -H "Content-Type:application/json" \
  -H "Ce-Id:1" \
  -H "Ce-Source:cloud-event-example" \
  -H "Ce-Type:dev.knative.example" \
  -H "Ce-Specversion:1.0" \
  -d "{\"input\": \"hello\"}\""

HTTPie

URL=http://localhost:8080/
http -v ${URL} \
  Content-Type:application/json \
  Ce-Id:1 \
  Ce-Source:cloud-event-example \
  Ce-Type:dev.knative.example \
  Ce-Specversion:1.0 \
  input=hello

Then, you should see the similar output below:

{
    "error": null,
    "input": "hello",
    "operation": null,
    "output": "HELLO"
}

Cleanup

To remove the deployed function from your cluster, run:

func delete