Chapter 20. Developing PTP events consumer applications

Example PTP events consumer server function in Go

func server() {
  http.HandleFunc("/event", getEvent)
  http.ListenAndServe("localhost:8989", nil)
}

func getEvent(w http.ResponseWriter, req *http.Request) {
  defer req.Body.Close()
  bodyBytes, err := io.ReadAll(req.Body)
  if err != nil {
    log.Errorf("error reading event %v", err)
  }
  e := string(bodyBytes)
  if e != "" {
    processEvent(bodyBytes)
    log.Infof("received event %s", string(bodyBytes))
  } else {
    w.WriteHeader(http.StatusNoContent)
  }
}

Example PTP events createSubscription function in Go

import (
"github.com/redhat-cne/sdk-go/pkg/pubsub"
"github.com/redhat-cne/sdk-go/pkg/types"
v1pubsub "github.com/redhat-cne/sdk-go/v1/pubsub"
)

// Subscribe to PTP events using REST API
s1,_:=createsubscription("/cluster/node/<node_name>/sync/sync-status/os-clock-sync-state") 1
s2,_:=createsubscription("/cluster/node/<node_name>/sync/ptp-status/ptp-clock-class-change")
s3,_:=createsubscription("/cluster/node/<node_name>/sync/ptp-status/lock-state")

// Create PTP event subscriptions POST
func createSubscription(resourceAddress string) (sub pubsub.PubSub, err error) {
  var status int
      apiPath:= "/api/ocloudNotifications/v1/"
      localAPIAddr:=localhost:8989 // vDU service API address
      apiAddr:= "localhost:8089" // event framework API address

  subURL := &types.URI{URL: url.URL{Scheme: "http",
    Host: apiAddr
    Path: fmt.Sprintf("%s%s", apiPath, "subscriptions")}}
  endpointURL := &types.URI{URL: url.URL{Scheme: "http",
    Host: localAPIAddr,
    Path: "event"}}

  sub = v1pubsub.NewPubSub(endpointURL, resourceAddress)
  var subB []byte

  if subB, err = json.Marshal(&sub); err == nil {
    rc := restclient.New()
    if status, subB = rc.PostWithReturn(subURL, subB); status != http.StatusCreated {
      err = fmt.Errorf("error in subscription creation api at %s, returned status %d", subURL, status)
    } else {
      err = json.Unmarshal(subB, &sub)
    }
  } else {
    err = fmt.Errorf("failed to marshal subscription for %s", resourceAddress)
  }
  return
}

Example PTP events consumer getCurrentState function in Go

//Get PTP event state for the resource
func getCurrentState(resource string) {
  //Create publisher
  url := &types.URI{URL: url.URL{Scheme: "http",
    Host: localhost:8989,
    Path: fmt.SPrintf("/api/ocloudNotifications/v1/%s/CurrentState",resource}}
  rc := restclient.New()
  status, event := rc.Get(url)
  if status != http.StatusOK {
    log.Errorf("CurrentState:error %d from url %s, %s", status, url.String(), event)
  } else {
    log.Debugf("Got CurrentState: %s ", event)
  }
}

Reference cloud-event-proxy deployment with HTTP transport

apiVersion: apps/v1
kind: Deployment
metadata:
  name: event-consumer-deployment
  namespace: <namespace>
  labels:
    app: consumer
spec:
  replicas: 1
  selector:
    matchLabels:
      app: consumer
  template:
    metadata:
      labels:
        app: consumer
    spec:
      serviceAccountName: sidecar-consumer-sa
      containers:
        - name: event-subscriber
          image: event-subscriber-app
        - name: cloud-event-proxy-as-sidecar
          image: openshift4/ose-cloud-event-proxy
          args:
            - "--metrics-addr=127.0.0.1:9091"
            - "--store-path=/store"
            - "--transport-host=consumer-events-subscription-service.cloud-events.svc.cluster.local:9043"
            - "--http-event-publishers=ptp-event-publisher-service-NODE_NAME.openshift-ptp.svc.cluster.local:9043"
            - "--api-port=8089"
          env:
            - name: NODE_NAME
              valueFrom:
                fieldRef:
                  fieldPath: spec.nodeName
            - name: NODE_IP
              valueFrom:
                fieldRef:
                  fieldPath: status.hostIP
              volumeMounts:
                - name: pubsubstore
                  mountPath: /store
          ports:
            - name: metrics-port
              containerPort: 9091
            - name: sub-port
              containerPort: 9043
          volumes:
            - name: pubsubstore
              emptyDir: {}

Reference cloud-event-proxy deployment with AMQ transport

apiVersion: apps/v1
kind: Deployment
metadata:
  name: cloud-event-proxy-sidecar
  namespace: cloud-events
  labels:
    app: cloud-event-proxy
spec:
  selector:
    matchLabels:
      app: cloud-event-proxy
  template:
    metadata:
      labels:
        app: cloud-event-proxy
    spec:
      nodeSelector:
        node-role.kubernetes.io/worker: ""
      containers:
        - name: cloud-event-sidecar
          image: openshift4/ose-cloud-event-proxy
          args:
            - "--metrics-addr=127.0.0.1:9091"
            - "--store-path=/store"
            - "--transport-host=amqp://router.router.svc.cluster.local"
            - "--api-port=8089"
          env:
            - name: <node_name>
              valueFrom:
                fieldRef:
                  fieldPath: spec.nodeName
            - name: <node_ip>
              valueFrom:
                fieldRef:
                  fieldPath: status.hostIP
          volumeMounts:
            - name: pubsubstore
              mountPath: /store
          ports:
            - name: metrics-port
              containerPort: 9091
            - name: sub-port
              containerPort: 9043
          volumes:
            - name: pubsubstore
              emptyDir: {}

Reference cloud-event-proxy subscriber service

apiVersion: v1
kind: Service
metadata:
  annotations:
    prometheus.io/scrape: "true"
    service.alpha.openshift.io/serving-cert-secret-name: sidecar-consumer-secret
  name: consumer-events-subscription-service
  namespace: cloud-events
  labels:
    app: consumer-service
spec:
  ports:
    - name: sub-port
      port: 9043
  selector:
    app: consumer
  clusterIP: None
  sessionAffinity: None
  type: ClusterIP

Example lock-state API response

{
  "id": "c1ac3aa5-1195-4786-84f8-da0ea4462921",
  "type": "event.sync.ptp-status.ptp-state-change",
  "source": "/cluster/node/compute-1.example.com/sync/ptp-status/lock-state",
  "dataContentType": "application/json",
  "time": "2023-01-10T02:41:57.094981478Z",
  "data": {
    "version": "v1",
    "values": [
      {
        "resource": "/cluster/node/compute-1.example.com/ens5fx/master",
        "dataType": "notification",
        "valueType": "enumeration",
        "value": "LOCKED"
      },
      {
        "resource": "/cluster/node/compute-1.example.com/ens5fx/master",
        "dataType": "metric",
        "valueType": "decimal64.3",
        "value": "29"
      }
    ]
  }
}