docs/serving/samples/buildpack-function

Buildpack Sample Function

A sample function that demonstrates usage of Cloud Foundry buildpacks on Knative Serving, using the packs Docker images.

This deploys the riff square sample function for riff.

Prerequisites

Install Knative Serving

Running

This sample uses the Buildpack build template in the build-templates repo.

First, install the Buildpack build template from that repo:

kubectl apply -f buildpack.yaml

Then you can deploy this to Knative Serving from the root directory via:

# Replace the token string with a suitable registry
REPO="gcr.io/<your-project-here>"
perl -pi -e "s@DOCKER_REPO_OVERRIDE@$REPO@g" sample/buildpack-function/sample.yaml

kubectl apply -f sample/buildpack-function/sample.yaml

Once deployed, you will see that it first builds:

$ kubectl get revision -o yaml
apiVersion: v1
items:
- apiVersion: serving.knative.dev/v1alpha1
  kind: Revision
  ...
  status:
    conditions:
    - reason: Building
      status: "False"
      type: BuildComplete
...

Once the BuildComplete status becomes True the resources will start getting created.

To access this service via curl, we first need to determine its ingress address:

watch kubectl get svc knative-ingressgateway -n istio-system
NAME                     TYPE           CLUSTER-IP     EXTERNAL-IP      PORT(S)                                      AGE
knative-ingressgateway   LoadBalancer   10.23.247.74   35.203.155.229   80:32380/TCP,443:32390/TCP,32400:32400/TCP   2d

Once the EXTERNAL-IP gets assigned to the cluster, you can run:

# Put the Host name into an environment variable.
$ export SERVICE_HOST=`kubectl get route buildpack-function -o jsonpath="{.status.domain}"`

# Put the ingress IP into an environment variable.
$ export SERVICE_IP=`kubectl get svc knative-ingressgateway -n istio-system -o jsonpath="{.status.loadBalancer.ingress[*].ip}"`


# Curl the ingress IP "as-if" DNS were properly configured.
$ curl http://${SERVICE_IP}/ -H "Host: $SERVICE_HOST" -H "Content-Type: application/json" -d "33"
[response]

Cleaning up

To clean up the sample service:

kubectl delete -f sample/buildpack-function/sample.yaml