cloud-event-proxy

The cloud-event-proxy project provides a mechanism for events from the K8s infrastructure to be delivered to CNFs with low-latency.
The initial event functionality focuses on the operation of the PTP synchronization protocol, but the mechanism can be extended for any infrastructure event that requires low-latency.
The mechanism is an integral part of k8s/OCP RAN deployments where the PTP protocol is used to provide timing synchronization for the RAN software elements

Contents

• Transport Protocol
  • HTTP Protocol
• Publishers
  • JSON Example
  • Go Example
• Subscriptions
  • JSON Example
  • GO Example
• Rest API
• Cloud Native Events
  • Event via sdk
  • Event via rest api
• Metrics
• Plugin

Event Transporter

Cloud event proxy currently support one type of transport protocol

1. HTTP Protocol

HTTP Protocol

Producer

CloudEvents HTTP Protocol will be enabled based on url in transport-host. If HTTP is identified then the publisher will start a publisher rest service, which is accessible outside the container via k8s service name. The Publisher service will have the ability to register consumer endpoints to publish events.

The transport URL is defined in the format of

- "--transport-host=$(TRANSPORT_PROTOCAL)://$(TRANSPORT_SERVICE).$(TRANSPORT_NAMESPACE).svc.cluster.local:$(TRANSPORT_PORT)"

HTTP producer example

 - name: cloud-event-sidecar
          image: quay.io/redhat-cne/cloud-event-proxy
          args:
            - "--metrics-addr=127.0.0.1:9091"
            - "--store-path=/store"
            - "--transport-host=http://ptp-event-publisher-service-NODE_NAME.openshift-ptp.svc.cluster.local:9043
            - "--api-port=9085"

The event producer uses a pubsubstore to store Subscriber information, including clientID, consumer service endpoint URI, resource ID etc. These are stored as one json file per registered subscriber. The pubsubstore needs to be mounted to a persistent volume in order to survive a pod reboot.

Example for configuring persistent storage

     spec:
      nodeSelector:
        node-role.kubernetes.io/worker: ""
      serviceAccountName: hw-event-proxy-sa
      containers:
        - name: cloud-event-sidecar
          volumeMounts:
            - name: pubsubstore
              mountPath: /store
      volumes:
        - name: pubsubstore
          persistentVolumeClaim:
            claimName: cloud-event-proxy-store-storage-class-http-events

Example PersistentVolumeClaim

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: cloud-event-proxy-store-storage-class-http-events
spec:
  storageClassName: storage-class-http-events
  resources:
    requests:
      storage: 10Mi
  accessModes:
  - ReadWriteOnce

Consumer

Consumer application will also set its own transport-host, which enabled cloud event proxy to run a service to listen to incoming events posted by the publisher. Consumer will also use http-event-publishers variable to request for registering publisher endpoints for consuming events.

HTTP consumer example

 - name: cloud-event-sidecar
          image: quay.io/redhat-cne/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"

Creating Publisher

Publisher JSON Example

Create Publisher Resource: JSON request

{
  "Resource": "/east-edge-10/vdu3/o-ran-sync/sync-group/sync-status/sync-state",
  "UriLocation": "http://localhost:9090/ack/event"
}

Create Publisher Resource: JSON response

{
  "Id": "789be75d-7ac3-472e-bbbc-6d62878aad4a",
  "Resource": "/east-edge-10/vdu3/o-ran-sync/sync-group/sync-status/sync-state",
  "UriLocation": "http://localhost:9090/ack/event" ,
  "EndpointUri ": "http://localhost:9085/api/ocloudNotifications/v1/publishers/{publisherid}"
}

Creating Publisher Golang Eexample

Creating publisher golang example with HTTP as transporter protocol

package main
import (
	v1pubsub "github.com/redhat-cne/sdk-go/v1/pubsub"
	"github.com/redhat-cne/sdk-go/pkg/types"
)
func main(){
  //channel for the transport handler subscribed to get and set events  
    eventInCh := make(chan *channel.DataChan, 10)
    pubSubInstance = v1pubsub.GetAPIInstance(".")
    endpointURL := &types.URI{URL: url.URL{Scheme: "http", Host: "localhost:9085", Path: fmt.Sprintf("%s%s", apiPath, "dummy")}}
    // create publisher 
    pub, err := pubSubInstance.CreatePublisher(v1pubsub.NewPubSub(endpointURL, "test/test", "1.0"))

}

Creating Subscriptions

Subscription JSON Example

Create Subscription Resource: JSON request

{
  "Resource": "/east-edge-10/vdu3/o-ran-sync/sync-group/sync-status/sync-state",
  "UriLocation”: “http://localhost:9090/event"
}

Example Create Subscription Resource: JSON response

{
  "Id": "789be75d-7ac3-472e-bbbc-6d62878aad4a",
  "Resource": "/east-edge-10/vdu3/o-ran-sync/sync-group/sync-status/sync-state",
  "UriLocation": "http://localhost:9090/ack/event",
  "EndpointUri": "http://localhost:8089/api/ocloudNotifications/v1/subscriptions/{subscriptionid}"
}

Creating Subscription Golang Example

Creating subscription golang example with HTTP as transporter protocol

package main
import (
	v1pubsub "github.com/redhat-cne/sdk-go/v1/pubsub"
	"github.com/redhat-cne/sdk-go/pkg/types"
)
func main(){
    //channel for the transport handler subscribed to get and set events  
    eventInCh := make(chan *channel.DataChan, 10)
    
    pubSubInstance = v1pubsub.GetAPIInstance(".")
    endpointURL := &types.URI{URL: url.URL{Scheme: "http", Host: "localhost:8089", Path: fmt.Sprintf("%s%s", apiPath, "dummy")}}
    // create subscription 
    pub, err := pubSubInstance.CreateSubscription(v1pubsub.NewPubSub(endpointURL, "test/test", "1.0"))
    
}

Rest-API

Rest-API to create a Publisher and Subscription

Cloud-Event-Proxy container running with rest api plugin will be running a webservice and exposing following end points.

POST /api/ocloudNotifications/v1/subscriptions
POST /api/ocloudNotifications/v1/publishers
GET /api/ocloudNotifications/v1/subscriptions
GET /api/ocloudNotifications/v1/publishers
GET /api/ocloudNotifications/v1/subscriptions/$subscriptionid
GET /api/ocloudNotifications/v1/publishers/$publisherid
GET /api/ocloudNotifications/v1/health
POST /api/ocloudNotifications/v1/log
POST /api/ocloudNotifications/v1/create/event

Cloud Native Events

The following example shows a Cloud Native Events serialized as JSON: (Following json should be validated with Cloud native events' event_spec.json schema)

{
    "id": "5ce55d17-9234-4fee-a589-d0f10cb32b8e",
    "type": "event.synchronization-state-chang",
    "time": "2021-02-05T17:31:00Z",
    "data": {
    "version": "v1.0",
    "values": [{
        "resource": "/cluster/node/ptp", 
        "dataType": "notification",
        "valueType": "enumeration",
        "value": "ACQUIRING-SYNC"
    }, {

        "resource": "/cluster/node/clock",
        "dataType": "metric",
        "valueType": "decimal64.3",
        "value": 100.3
    }]
    }
}

Event can be created via rest-api or calling sdk methods To produce or consume an event, the producer and consumer should have created publisher and subscription objects and should have access to the id of the publisher/subscription data objects.

import (
   v1event "github.com/redhat-cne/sdk-go/v1/event"
   cneevent "github.com/redhat-cne/sdk-go/pkg/event"
   cneevent "github.com/redhat-cne/sdk-go/pkg/event/ptp"
)

// create an event
event := v1event.CloudNativeEvent()
event.SetID(pub.ID)
event.Type = string(ptp.PtpStateChange)
event.SetTime(types.Timestamp{Time: time.Now().UTC()}.Time)
event.SetDataContentType(cneevent.ApplicationJSON)
data := cneevent.Data{
Version: "v1",
Values: []cneevent.DataValue{
	    {
        Resource:  "/cluster/node/ptp",
        DataType:  cneevent.NOTIFICATION,
        ValueType: cneevent.ENUMERATION,
        Value:     cneevent.GNSS_ACQUIRING_SYNC,
        },
    },
}
data.SetVersion("v1") 
event.SetData(data)

Publisher event create via go-sdk

cloudEvent, _ := v1event.CreateCloudEvents(event, pub)
//send event to transport (rest API does this action by default)
v1event.SendNewEventToDataChannel(eventInCh, pub.Resource, cloudEvent)

Publisher event create via rest-api

//POST /api/ocloudNotifications/v1/create/event
if pub,err:=pubSubInstance.GetPublisher(publisherID);err==nil {
    url = fmt.SPrintf("%s%s", server.HostPath, "create/event")
    restClient.PostEvent(pub.EndPointURI.String(), event)
}

Metrics

sdk-go metrics

Cloud native events sdk-go comes with following metrics collectors .

1. Number of events received by the transport
2. Number of events published by the transport.
3. Number of connection resets.
4. Number of sender created
5. Number of receiver created

rest-api metrics

Cloud native events rest API comes with following metrics collectors .

1. Number of events published by the rest api.
2. Number of active subscriptions.
3. Number of active publishers.

cloud-event-proxy metrics

1. Number of events produced.
2. Number of events received.

Metrics details

Plugin

Plugin details