11.5. Using sink binding

Procedure

1. To check that sink binding is set up correctly, create a Knative event display service, or event sink, that dumps incoming messages to its log:

   $ kn service create event-display --image quay.io/openshift-knative/knative-eventing-sources-event-display:latest

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2. Create a SinkBinding object that directs events to the service:

   $ kn source binding create bind-heartbeat --subject Job:batch/v1:app=heartbeat-cron --sink ksvc:event-display

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3. Create a CronJob.

   1. Create a file named heartbeats-cronjob.yaml and copy the following sample code into it:

      apiVersion: batch/v1beta1
      kind: CronJob
      metadata:
        name: heartbeat-cron
      spec:
      spec:
        # Run every minute
        schedule: "* * * * *"
        jobTemplate:
          metadata:
            labels:
              app: heartbeat-cron
              bindings.knative.dev/include: "true"
          spec:
            template:
              spec:
                restartPolicy: Never
                containers:
                  - name: single-heartbeat
                    image: quay.io/openshift-knative/knative-eventing-sources-heartbeats:latest
                    args:
                      - --period=1
                    env:
                      - name: ONE_SHOT
                        value: "true"
                      - name: POD_NAME
                        valueFrom:
                          fieldRef:
                            fieldPath: metadata.name
                      - name: POD_NAMESPACE
                        valueFrom:
                          fieldRef:
                            fieldPath: metadata.namespace

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      重要

      To use sink binding, you must manually add a bindings.knative.dev/include=true label to your Knative resources.

      For example, to add this label to a CronJob object, add the following lines to the Job resource YAML definition:

        jobTemplate:
          metadata:
            labels:
              app: heartbeat-cron
              bindings.knative.dev/include: "true"

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   2. After you have created the heartbeats-cronjob.yaml file, apply it:

      $ oc apply --filename heartbeats-cronjob.yaml

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4. Check that the controller is mapped correctly by entering the following command and inspecting the output:

   $ kn source binding describe bind-heartbeat

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   Example output

   Name:         bind-heartbeat
   Namespace:    demo-2
   Annotations:  sources.knative.dev/creator=minikube-user, sources.knative.dev/lastModifier=minikub ...
   Age:          2m
   Subject:
     Resource:   job (batch/v1)
     Selector:
       app:      heartbeat-cron
   Sink:
     Name:       event-display
     Resource:   Service (serving.knative.dev/v1)
   
   Conditions:
     OK TYPE     AGE REASON
     ++ Ready     2m

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Procedure

1. To check that sink binding is set up correctly, create a Knative event display service, or event sink, that dumps incoming messages to its log.

   1. Copy the following sample YAML into a file named service.yaml:

      apiVersion: serving.knative.dev/v1
      kind: Service
      metadata:
        name: event-display
      spec:
        template:
          spec:
            containers:
              - image: quay.io/openshift-knative/knative-eventing-sources-event-display:latest

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   2. After you have created the service.yaml file, apply it:

      $ oc apply -f service.yaml

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2. Create a SinkBinding object that directs events to the service.

   1. Create a file named sinkbinding.yaml and copy the following sample code into it:

      apiVersion: sources.knative.dev/v1alpha1
      kind: SinkBinding
      metadata:
        name: bind-heartbeat
      spec:
        subject:
          apiVersion: batch/v1
          kind: Job 

      1

      
          selector:
            matchLabels:
              app: heartbeat-cron
      
        sink:
          ref:
            apiVersion: serving.knative.dev/v1
            kind: Service
            name: event-display

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      1

      In this example, any Job with the label app: heartbeat-cron will be bound to the event sink.

   2. After you have created the sinkbinding.yaml file, apply it:

      $ oc apply -f sinkbinding.yaml

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3. Create a CronJob object.

   1. Create a file named heartbeats-cronjob.yaml and copy the following sample code into it:

      apiVersion: batch/v1beta1
      kind: CronJob
      metadata:
        name: heartbeat-cron
      spec:
      spec:
        # Run every minute
        schedule: "* * * * *"
        jobTemplate:
          metadata:
            labels:
              app: heartbeat-cron
              bindings.knative.dev/include: "true"
          spec:
            template:
              spec:
                restartPolicy: Never
                containers:
                  - name: single-heartbeat
                    image: quay.io/openshift-knative/knative-eventing-sources-heartbeats:latest
                    args:
                      - --period=1
                    env:
                      - name: ONE_SHOT
                        value: "true"
                      - name: POD_NAME
                        valueFrom:
                          fieldRef:
                            fieldPath: metadata.name
                      - name: POD_NAMESPACE
                        valueFrom:
                          fieldRef:
                            fieldPath: metadata.namespace

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      重要

      To use sink binding, you must manually add a bindings.knative.dev/include=true label to your Knative resources.

      For example, to add this label to a cron job instance, add the following lines to the Job resource YAML definition:

        jobTemplate:
          metadata:
            labels:
              app: heartbeat-cron
              bindings.knative.dev/include: "true"

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   2. After you have created the heartbeats-cronjob.yaml file, apply it:

      $ oc apply -f heartbeats-cronjob.yaml

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4. Check that the controller is mapped correctly by entering the following command and inspecting the output:

   $ oc get sinkbindings.sources.knative.dev bind-heartbeat -oyaml

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   Example output

   spec:
     sink:
       ref:
         apiVersion: serving.knative.dev/v1
         kind: Service
         name: event-display
         namespace: default
     subject:
       apiVersion: batch/v1
       kind: Job
       namespace: default
       selector:
         matchLabels:
           app: heartbeat-cron

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1. View the message dumper function logs:

   $ oc get pods

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   $ oc logs $(oc get pod -o name | grep event-display) -c user-container

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   Example output

   ☁️  cloudevents.Event
   Validation: valid
   Context Attributes,
     specversion: 1.0
     type: dev.knative.eventing.samples.heartbeat
     source: https://knative.dev/eventing-contrib/cmd/heartbeats/#event-test/mypod
     id: 2b72d7bf-c38f-4a98-a433-608fbcdd2596
     time: 2019-10-18T15:23:20.809775386Z
     contenttype: application/json
   Extensions,
     beats: true
     heart: yes
     the: 42
   Data,
     {
       "id": 1,
       "label": ""
     }

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