hello-world-go

Sample Function Go

Prerequisites

OpenFunction

You can refer to the Installation Guide to setup OpenFunction.

Run it locally

Build the function locally

pack build func-helloworld-go --builder openfunction/builder-go:v2.3.0-1.16 --env FUNC_NAME="HelloWorld"  --env FUNC_CLEAR_SOURCE=true

Run the function

docker run --rm --env="FUNC_CONTEXT={\"name\":\"HelloWorld\",\"version\":\"v1.0.0\",\"port\":\"8080\",\"runtime\":\"Knative\"}" --env="CONTEXT_MODE=self-host" --name func-helloworld-go -p 8080:8080 func-helloworld-go

Send a request

curl http://localhost:8080/OpenFunction
# Hello, OpenFunction!

Deployment

1. Create secret

Generate a secret to access your container registry, such as one on Docker Hub or Quay.io. You can create this secret by editing the REGISTRY_SERVER, REGISTRY_USER and REGISTRY_PASSWORD fields in following command, and then run it.

REGISTRY_SERVER=https://index.docker.io/v1/ REGISTRY_USER=<your_registry_user> REGISTRY_PASSWORD=<your_registry_password>
kubectl create secret docker-registry push-secret \
    --docker-server=$REGISTRY_SERVER \
    --docker-username=$REGISTRY_USER \
    --docker-password=$REGISTRY_PASSWORD

2. Create function

   For sample function below, modify the spec.image field in function-sample.yaml to your own container registry address:

   apiVersion: core.openfunction.io/v1beta1
   kind: Function
   metadata:
     name: function-sample
   spec:
     image: "<your registry name>/sample-go-func:v1"

   Use the following command to create this Function:

   kubectl apply -f function-sample.yaml

3. Access function

   You can observe the process of a function with the following command:

   kubectl get functions.core.openfunction.io
   
   NAME              BUILDSTATE   SERVINGSTATE   BUILDER         SERVING         URL                                              AGE
   function-sample   Succeeded    Running        builder-jgnzp   serving-q6wdp   http://openfunction.io/default/function-sample   22m

   The URL is the address provided by the OpenFunction Domain that can be accessed. To access the function via this URL address, you need to make sure that DNS can resolve this address.

   You can use the following command to create a pod in the cluster and access the function from the pod:

   kubectl run curl --image=radial/busyboxplus:curl -i --tty

   Access the function via URL:

   [ root@curl:/ ]$ curl http://openfunction.io.svc.cluster.local/default/function-sample/World
   Hello, World!
   
   [ root@curl:/ ]$ curl http://openfunction.io.svc.cluster.local/default/function-sample/OpenFunction
   Hello, OpenFunction!

   There is also an alternative way to trigger the function via the access address provided by the Knative Services:

   kubectl get ksvc
    
   NAME                       URL                                                            LATESTCREATED                   LATESTREADY                     READY   REASON
   serving-q6wdp-ksvc-wk6mv   http://serving-q6wdp-ksvc-wk6mv.default.<external-ip>.sslip.io   serving-q6wdp-ksvc-wk6mv-v100   serving-q6wdp-ksvc-wk6mv-v100   True

   Or get the service address directly with the following command:

   where<external-ip>indicates the external address of your gateway service.

   You can do a simple configuration to use the node ip as the <external-ip> as follows (Assuming you are using Kourier as network layer of Knative). Where 1.2.3.4 can be replaced by your node ip.

   kubectl patch svc -n kourier-system kourier \
     -p '{"spec": {"type": "LoadBalancer", "externalIPs": ["1.2.3.4"]}}'
   
   kubectl patch configmap/config-domain -n knative-serving \
     --type merge --patch '{"data":{"1.2.3.4.sslip.io":""}}'

   kubectl get ksvc serving-q6wdp-ksvc-wk6mv -o jsonpath={.status.url}
    
   http://serving-q6wdp-ksvc-wk6mv.default.<external-ip>.sslip.io

   Access the above service address via commands such as curl:

   curl http://serving-q6wdp-ksvc-wk6mv.default.<external-ip>.sslip.io/World
    
   Hello, World!
   
   curl http://serving-q6wdp-ksvc-wk6mv.default.<external-ip>.sslip.io/OpenFunction
    
   Hello, OpenFunction!