API: Provide websocket support

[jiekang]

Parent: #2380

Task

Provide websocket based API for the deployments page

Sub-Tasks

• Provide events API
• Provide pods API

[jiekang]

Sample Events data from k8s

{
	"metadata": {
		"name": "osio-prod-1.1533c1b153fafd6f",
		"namespace": "jkang-stage",
		"selfLink": "/api/v1/namespaces/jkang-stage/events/osio-prod-1.1533c1b153fafd6f",
		"uid": "a643f0b5-64e0-11e8-8d2f-02e52a0be43d",
		"resourceVersion": "1133031845",
		"creationTimestamp": "2018-05-31T14:41:05Z"
	},
	"involvedObject": {
		"kind": "DeploymentConfig",
		"namespace": "jkang-stage",
		"name": "osio-prod-1",
		"uid": "1b494f1a-5e29-11e8-a0e5-02d7377a4b17",
		"apiVersion": "apps.openshift.io",
		"resourceVersion": "1133031843"
	},
	"reason": "ReplicationControllerScaled",
	"message": "Scaled replication controller \"osio-prod-1-3\" from 2 to 1",
	"source": {
		"component": "deploymentconfig-controller"
	},
	"firstTimestamp": "2018-05-31T14:41:05Z",
	"lastTimestamp": "2018-05-31T14:41:05Z",
	"count": 1,
	"type": "Normal"
}

{
	"metadata": {
		"name": "osio-prod-1-3.1533c0a028f7976e",
		"namespace": "jkang-stage",
		"selfLink": "/api/v1/namespaces/jkang-stage/events/osio-prod-1-3.1533c0a028f7976e",
		"uid": "eaf47ee6-64dd-11e8-8c9e-0233cba325d9",
		"resourceVersion": "1133018536",
		"creationTimestamp": "2018-05-31T14:21:32Z"
	},
	"involvedObject": {
		"kind": "ReplicationController",
		"namespace": "jkang-stage",
		"name": "osio-prod-1-3",
		"uid": "d1a40fee-6422-11e8-8445-02e52a0be43d",
		"apiVersion": "v1",
		"resourceVersion": "1133018419"
	},
	"reason": "FailedCreate",
	"message": "(combined from similar events): Error creating: pods \"osio-prod-1-3-mtbrw\" is forbidden: exceeded quota: compute-resources, requested: limits.cpu=1,limits.memory=512Mi, used: limits.cpu=2,limits.memory=1Gi, limited: limits.cpu=2,limits.memory=1Gi",
	"source": {
		"component": "replication-controller"
	},
	"firstTimestamp": "2018-05-31T14:21:32Z",
	"lastTimestamp": "2018-05-31T14:21:40Z",
	"count": 3,
	"type": "Warning"
}

[jiekang]

Another sample:

{
	"metadata": {
		"name": "abc-123-1-bzmhz.1537c7865275bc9d",
		"namespace": "jkang-stage",
		"selfLink": "/api/v1/namespaces/jkang-stage/events/abc-123-1-bzmhz.1537c7865275bc9d",
		"uid": "04f86fc4-6f2d-11e8-bc5d-0233cba325d9",
		"resourceVersion": "1146081162",
		"creationTimestamp": "2018-06-13T17:12:58Z"
	},
	"involvedObject": {
		"kind": "Pod",
		"namespace": "jkang-stage",
		"name": "abc-123-1-bzmhz",
		"uid": "035d2fd8-6f2d-11e8-99de-02d7377a4b17",
		"apiVersion": "v1",
		"resourceVersion": "1146081121",
		"fieldPath": "spec.containers{vertx}"
	},
	"reason": "Pulled",
	"message": "Successfully pulled image \"docker-registry.default.svc:5000/jkang-stage/abc-123@sha256:4c1bb4adcdd3d462b1f3953ce947afc0c3afcd0dd810c007f4d3ed56220ac323\"",
	"source": {
		"component": "kubelet",
		"host": "ip-172-31-69-6.us-east-2.compute.internal"
	},
	"firstTimestamp": "2018-06-13T17:12:58Z",
	"lastTimestamp": "2018-06-13T17:12:58Z",
	"count": 1,
	"type": "Normal"
}

[jiekang]

Suggested reduced data object returned by deployments API

{
  involvedObject: {
    kind,
    namespace,
    name,
  },
  reason,
  message,
  count,
  type,
}

@andrewazores Thoughts? Do you think the information here will cover our needs? Are there any fields that could be dropped, or maybe added?

[andrewazores]

The timestamps might be useful at least for logging purposes, so I'd add those. Otherwise I think it's a good minimal set.

[jiekang]

For timestamps we have

metadata.creationTimestamp: CreationTimestamp is a timestamp representing the server time when this object was created.

firstTimestamp: The time at which the event was first recorded. (Time of server receipt is in TypeMeta.)
lastTimestamp: The time at which the most recent occurrence of this event was recorded.

Which were you thinking of? All three? Or maybe metadata.creationTimestamp is sufficient? Or just the first/last, hahah.

[andrewazores]

Hmm. Not really sure. Maybe creationTimestamp?

[jiekang]

Yeah if anything it can be changed pretty easily.

Sample transformed object:

{
	"involvedObject": {
		"kind": "ReplicationController",
		"namespace": "jkang-stage",
		"name": "abc-123-1",
		"uid": "0187287e-6f2d-11e8-bc5d-0233cba325d9",
		"apiVersion": "v1",
		"resourceVersion": "1146930893"
	},
	"reason": "FailedCreate",
	"message": "Error creating: pods \"abc-123-1-fn79z\" is forbidden: exceeded quota: compute-resources, requested: limits.cpu=1,limits.memory=512Mi, used: limits.cpu=2,limits.memory=1Gi, limited: limits.cpu=2,limits.memory=1Gi",
	"count": 1,
	"type": "Warning",
	"creationTimestamp": "2018-06-14T12:41:39Z"
}

[andrewazores]

That looks like it'll meet our needs.

[jiekang]

Feature has been merged. Closing.