Merge pull request #834 from nicksardo/gce-websocket-example

[GCLB] Add websocket example

controllers/gce/examples/websocket/Dockerfile

@@ -0,0 +1,5 @@
+FROM alpine:3.5
+
+COPY wsserver /wsserver
+
+CMD ["/wsserver"]

controllers/gce/examples/websocket/README.md

@@ -0,0 +1,109 @@
+# Simple Websocket Example
+
+Any websocket server will suffice; however, for the purpose of demonstration, we'll use the gorilla/websocket package in a Go process.
+
+### Build
+```shell
+➜ CGO_ENABLED=0 go build -o wsserver
+```
+
+### Containerize
+```shell
+➜ docker build -t nicksardo/websocketexample .
+Sending build context to Docker daemon 6.134 MB
+Step 1 : FROM alpine:3.5
+ ---> 4a415e366388
+Step 2 : COPY wsserver /wsserver
+ ---> 8002887d752d
+Removing intermediate container 7772a3e76155
+Step 3 : CMD /wsserver
+ ---> Running in 27c8ff226267
+ ---> eecd0574e5d1
+Removing intermediate container 27c8ff226267
+Successfully built eecd0574e5d1
+
+➜ docker push nicksardo/websocketexample:latest
+...
+```
+
+### Deploy
+Either update the image in the `Deployment` to your newly created image or continue using `nicksardo/websocketexample.`
+```shell
+➜ vi deployment.yaml
+# Change image to your own
+```
+
+```shell
+➜ kubectl create -f deployment.yaml
+deployment "ws-example" created
+service "ws-example-svc" created
+ingress "ws-example-ing" created
+
+```
+
+### Test
+Retrieve the ingress external IP:
+```shell
+➜ kubectl get ing/ws-example-ing
+NAME             HOSTS     ADDRESS          PORTS     AGE
+ws-example-ing   *         xxx.xxx.xxx.xxx   80        3m
+```
+
+Wait for the loadbalancer to be created and functioning. When you receive a successful response, you can proceed.
+```
+➜ curl http://xxx.xxx.xxx.xxx
+Websocket example. Connect to /ws%   
+```
+
+The binary we deployed does not have any html/javascript to demonstrate thwe websocket, so we'll use websocket.org's client.
+
+Visit http://www.websocket.org/echo.html. It's important to use `HTTP` instead of `HTTPS` since we assembled an `HTTP` load balancer. Browsers may prevent `HTTP` websocket connections as a security feature.
+Set the `Location` to
+```
+ws://xxx.xxx.xxx.xxx/ws
+```
+Click 'Connect' and you should see messages received from server:  
+![Log screenshot](http://i.imgur.com/hlwwa0G.png)
+
+
+### Change backend timeout
+
+At this point, the websocket connection will be destroyed by the HTTP(S) Load Balancer after 30 seconds, which is the default timeout. Note: this timeout is not an idle timeout - it's a timeout on the connection lifetime.
+
+Currently, the GCE ingress controller does not provide a way to set this timeout via Ingress specification. You'll need to change this value either through the GCP Cloud Console or through gcloud CLI.
+
+
+```shell
+➜  kubectl describe ingress/ws-example-ing   
+Name:			ws-example-ing
+Namespace:		default
+Address:		xxxxxxxxxxxx
+Default backend:	ws-example-svc:80 (10.48.10.12:8080,10.48.5.14:8080,10.48.7.11:8080)
+Rules:
+  Host	Path	Backends
+  ----	----	--------
+  *	* 	ws-example-svc:80 (10.48.10.12:8080,10.48.5.14:8080,10.48.7.11:8080)
+Annotations:
+  target-proxy:		k8s-tp-default-ws-example-ing--52aa8ae8221ffa9c
+  url-map:		k8s-um-default-ws-example-ing--52aa8ae8221ffa9c
+  backends:		{"k8s-be-31127--52aa8ae8221ffa9c":"HEALTHY"}
+  forwarding-rule:	k8s-fw-default-ws-example-ing--52aa8ae8221ffa9c
+Events:
+  FirstSeen	LastSeen	Count	From			SubObjectPath	Type		Reason	Message
+  ---------	--------	-----	----			-------------	--------	------	-------
+  12m		12m		1	loadbalancer-controller			Normal		ADD	default/ws-example-ing
+  11m		11m		1	loadbalancer-controller			Normal		CREATE	ip: xxxxxxxxxxxx
+  11m		9m		5	loadbalancer-controller			Normal		Service	default backend set to ws-example-svc:31127
+```
+
+Retrieve the name of the backend service from within the annotation section.
+
+Update the timeout field for every backend that needs a higher timeout.
+
+```shell
+➜ export BACKEND=k8s-be-31127--52aa8ae8221ffa9c
+➜ gcloud compute backend-services update $BACKEND --global --timeout=86400 # seconds
+Updated [https://www.googleapis.com/compute/v1/projects/xxxxxxxxx/global/backendServices/k8s-be-31127--52aa8ae8221ffa9c].
+```
+
+Wait up to twenty minutes for this change to propagate.

controllers/gce/examples/websocket/deployment.yaml

@@ -0,0 +1,47 @@
+apiVersion: extensions/v1beta1
+kind: Deployment
+metadata:
+  name: ws-example
+spec:
+  replicas: 3
+  template:
+    metadata:
+      labels:
+        app: wseg
+    spec:
+      containers:
+      - name: websocketexample
+        image: nicksardo/websocketexample
+        imagePullPolicy: Always
+        ports:
+        - name: http
+          containerPort: 8080
+        env:
+        - name: podname
+          valueFrom:
+            fieldRef:
+              fieldPath: metadata.name
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: ws-example-svc
+  labels:
+    app: wseg
+spec:
+  type: NodePort
+  ports:
+  - port: 80
+    targetPort: 8080
+    protocol: TCP
+  selector:
+    app: wseg
+---
+apiVersion: extensions/v1beta1
+kind: Ingress
+metadata:
+  name: ws-example-ing
+spec:
+  backend:
+    serviceName: ws-example-svc
+    servicePort: 80

controllers/gce/examples/websocket/server.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/gorilla/websocket"
+)
+
+var podName string
+var upgrader = websocket.Upgrader{
+	CheckOrigin: func(r *http.Request) bool {
+		return true // Ignore http origin
+	},
+}
+
+func init() {
+	podName = os.Getenv("podname")
+}
+
+func ws(w http.ResponseWriter, r *http.Request) {
+	log.Println("Received request", r.RemoteAddr)
+	c, err := upgrader.Upgrade(w, r, nil)
+	if err != nil {
+		log.Println("failed to upgrade:", err)
+		return
+	}
+	defer c.Close()
+
+	s := fmt.Sprintf("Connected to %v", podName)
+	c.WriteMessage(websocket.TextMessage, []byte(s))
+	handleWSConn(c)
+}
+
+func handleWSConn(c *websocket.Conn) {
+	stop := make(chan struct{})
+	go func() {
+		for {
+			time.Sleep(5 * time.Second)
+
+			select {
+			case <-stop:
+				return
+			default:
+			}
+
+			s := fmt.Sprintf("%s reports time: %v", podName, time.Now().String())
+			c.WriteMessage(websocket.TextMessage, []byte(s))
+		}
+	}()
+	for {
+		mt, message, err := c.ReadMessage()
+		if err != nil {
+			log.Println("Error while reading:", err)
+			break
+		}
+		if err = c.WriteMessage(mt, message); err != nil {
+			log.Println("Error while writing:", err)
+			break
+		}
+	}
+	close(stop)
+}
+
+func root(w http.ResponseWriter, r *http.Request) {
+	if r.URL.Path != "/" {
+		http.NotFound(w, r)
+		return
+	}
+	w.Write([]byte(`Websocket example. Connect to /ws`))
+}
+
+func main() {
+	log.Println("Starting")
+	http.HandleFunc("/ws", ws)
+	http.HandleFunc("/", root)
+	log.Fatal(http.ListenAndServe(":8080", nil))
+}

docs/faq/gce.md

@@ -26,6 +26,7 @@ Table of Contents
 * [What GCE resources are shared between Ingresses?](#what-gce-resources-are-shared-between-ingresses)
 * [How do I debug a controller spin loop?](#host-do-i-debug-a-controller-spinloop)
 * [Creating an Internal Load Balancer without existing ingress](#creating-an-internal-load-balancer-without-existing-ingress)
+* [Can I use websockets?](#can-i-use-websockets)
 
 
 ## How do I deploy an Ingress controller?
@@ -380,3 +381,9 @@ kubectl get nodes
 gcloud compute instance-groups unmanaged add-instances $GROUPNAME --zone {ZONE} --instances=A,B,C...
 ```
 You can now follow the GCP Console wizard for creating an internal load balancer and point to the `k8s-ig--{UID}` instance group.
+
+## Can I use websockets?
+Yes!  
+The GCP HTTP(S) Load Balancer supports websockets. You do not need to change your http server or Kubernetes deployment. You will need to manually configure the created Backend Service's `timeout` setting. This value is the interpreted as the max connection duration. The default value of 30 seconds is probably too small for you. You can increase it to the supported maximum: 86400 (a day) through the GCP Console or the gcloud CLI.
+
+View the [example](/controllers/gce/examples/websocket/).