Merge pull request #192 from bprashanth/custom_controller_example

Add a custom controller example

docs/catalog.md

@@ -2,4 +2,6 @@
 
 This is a non-comprehensive list of existing ingress controllers.
 
+* [Dummy controller backend](/examples/custom-controller)
+
 

docs/dev/devel.md

@@ -1,3 +1,4 @@
 # Writing Ingress controllers
 
 This doc outlines the basic steps needed to write an Ingress controller.
+If you want the tl;dr version, skip straight to the [example](/examples/custom-controller).

docs/faq/README.md

@@ -85,7 +85,7 @@ as well as in [this](/examples/pipeline) example.
 
 First check the [catalog](#is-there-a-catalog-of-existing-ingress-controllers), to make sure you really need to write one.
 
-1. Write a [generic backend](https://github.com/kubernetes/ingress/blob/master/core/pkg/ingress/doc.go)
+1. Write a [generic backend](/examples/custom-controller)
 2. Keep it in your own repo, make sure it passes the [conformance suite](https://github.com/kubernetes/kubernetes/blob/master/test/e2e/ingress_utils.go#L112)
 3. Submit an example(s) in the appropriate subdirectories [here](/examples/README.md)
 4. Add it to the catalog

examples/README.md

@@ -69,4 +69,10 @@ Websockets | websockets loadbalancing | nginx | Intermediate
 HTTP/2 | HTTP/2 loadbalancing | * | Intermediate
 Proxy protocol | leverage the proxy protocol for source IP | nginx | Advanced
 
+## Custom controllers
+
+Name | Description | Platform   | Complexity Level
+-----| ----------- | ---------- | ----------------
+Dummy  | A simple dummy controller that logs updates | * | Advanced
+
 

examples/custom-controller/Dockerfile

@@ -0,0 +1,20 @@
+# Copyright 2017[<0;55;12M The Kubernetes Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# TODO(ingress#191): Change this to something more appropriate, like busybox
+From ubuntu:15.10
+MAINTAINER Prashanth B <beeps@google.com>
+RUN apt-get update && apt-get install ssl-cert -y
+COPY server /
+ENTRYPOINT ["/server"]

examples/custom-controller/Makefile

@@ -0,0 +1,39 @@
+# Copyright 2017 The Kubernetes Authors All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Build the default backend binary or image for amd64, arm, arm64 and ppc64le
+#
+# Usage:
+# 	[PREFIX=gcr.io/google_containers/dummy-ingress-controller] [ARCH=amd64] [TAG=1.1] make (server|container|push)
+
+all: push
+
+TAG=0.1
+PREFIX?=bprashanth/dummy-ingress-controller
+ARCH?=amd64
+GOLANG_VERSION=1.6
+TEMP_DIR:=$(shell mktemp -d)
+
+server: server.go
+	CGO_ENABLED=0 GOOS=linux GOARCH=$(ARCH) GOARM=6 godep go build -a -installsuffix cgo -ldflags '-w' -o server ./server.go
+
+container: server
+	docker build --pull -t $(PREFIX)-$(ARCH):$(TAG) .
+
+push: container
+	gcloud docker push $(PREFIX)-$(ARCH):$(TAG)
+
+clean:
+	rm -f server
+

examples/custom-controller/README.md

@@ -0,0 +1,29 @@
+# Dummy controller
+
+This example contains the source code of a simple dummy controller. If you want
+more details on the interface, or what the generic controller is actually doing,
+please read [this doc](/docs/dev/devel.md). You can deploy the controller as
+follows:
+
+```console
+$ kubectl create -f deployment.yaml
+service "default-backend" created
+deployment "dummy-ingress-controller" created
+
+$ kubectl get po
+NAME                                        READY     STATUS    RESTARTS   AGE
+dummy-ingress-controller-3685541482-082nl   1/1       Running   0          10m
+
+$ kubectl logs dummy-ingress-controller-3685541482-082nl
+I0131 02:29:02.462123       1 launch.go:92] &{dummy 0.0.0 git-00000000 git://foo.bar.com}
+I0131 02:29:02.462513       1 launch.go:221] Creating API server client for https://10.0.0.1:443
+I0131 02:29:02.494571       1 launch.go:111] validated default/default-backend as the default backend
+I0131 02:29:02.503180       1 controller.go:1038] starting Ingress controller
+I0131 02:29:02.513528       1 leaderelection.go:247] lock is held by dummy-ingress-controller-3685541482-50jh0 and has not yet expired
+W0131 02:29:03.510699       1 queue.go:87] requeuing kube-system/kube-scheduler, err deferring sync till endpoints controller has synced
+W0131 02:29:03.514445       1 queue.go:87] requeuing kube-system/node-controller-token-826dl, err deferring sync till endpoints controller has synced
+2017/01/31 02:29:12 Received OnUpdate notification
+2017/01/31 02:29:12 upstream-default-backend: 10.180.1.20
+```
+
+

examples/custom-controller/deployment.yaml

@@ -0,0 +1,51 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: default-backend
+  namespace: default
+  labels:
+    name: default-backend
+    app: dummy-ingress-controller
+spec:
+  ports:
+  - port: 80
+    targetPort: 10254
+  selector:
+    # Point back the the dummy controller's
+    # healthz port
+    app: dummy-ingress-controller
+---
+apiVersion: extensions/v1beta1
+kind: Deployment
+metadata:
+  name: dummy-ingress-controller
+  namespace: default
+  labels:
+    app: dummy-ingress-controller
+spec:
+  selector:
+    matchLabels:
+      app: dummy-ingress-controller
+  template:
+    metadata:
+      labels:
+        app: dummy-ingress-controller
+    spec:
+      containers:
+      - name: server
+        image: bprashanth/dummy-ingress-controller-amd64:0.1
+        imagePullPolicy: Always
+        ports:
+        - containerPort: 10254
+        env:
+          - name: POD_NAME
+            valueFrom:
+              fieldRef:
+                fieldPath: metadata.name
+          - name: POD_NAMESPACE
+            valueFrom:
+              fieldRef:
+                fieldPath: metadata.namespace
+        args:
+        - /server
+        - --default-backend-service=$(POD_NAMESPACE)/default-backend

examples/custom-controller/server.go

@@ -0,0 +1,82 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"os/exec"
+	"strings"
+
+	nginxconfig "k8s.io/ingress/controllers/nginx/pkg/config"
+	"k8s.io/ingress/core/pkg/ingress"
+	"k8s.io/ingress/core/pkg/ingress/controller"
+	"k8s.io/ingress/core/pkg/ingress/defaults"
+	"k8s.io/kubernetes/pkg/api"
+)
+
+func main() {
+	dc := newDummyController()
+	ic := controller.NewIngressController(dc)
+	defer func() {
+		log.Printf("Shutting down ingress controller...")
+		ic.Stop()
+	}()
+	ic.Start()
+}
+
+func newDummyController() ingress.Controller {
+	return &DummyController{}
+}
+
+type DummyController struct{}
+
+func (dc DummyController) SetConfig(cfgMap *api.ConfigMap) {
+	log.Printf("Config map %+v", cfgMap)
+}
+
+func (dc DummyController) Reload(data []byte) ([]byte, bool, error) {
+	out, err := exec.Command("echo", string(data)).CombinedOutput()
+	if err != nil {
+		log.Printf("Reloaded new config %s", out)
+	} else {
+		return out, false, err
+	}
+	return out, true, err
+}
+
+func (dc DummyController) Test(file string) *exec.Cmd {
+	return exec.Command("echo", file)
+}
+
+func (dc DummyController) OnUpdate(updatePayload ingress.Configuration) ([]byte, error) {
+	log.Printf("Received OnUpdate notification")
+	for _, b := range updatePayload.Backends {
+		eps := []string{}
+		for _, e := range b.Endpoints {
+			eps = append(eps, e.Address)
+		}
+		log.Printf("%v: %v", b.Name, strings.Join(eps, ", "))
+	}
+	return []byte(`<string containing a configuration file>`), nil
+}
+
+func (dc DummyController) BackendDefaults() defaults.Backend {
+	// Just adopt nginx's default backend config
+	return nginxconfig.NewDefault().Backend
+}
+
+func (n DummyController) Name() string {
+	return "dummy Controller"
+}
+
+func (n DummyController) Check(_ *http.Request) error {
+	return nil
+}
+
+func (dc DummyController) Info() *ingress.BackendInfo {
+	return &ingress.BackendInfo{
+		Name:       "dummy",
+		Release:    "0.0.0",
+		Build:      "git-00000000",
+		Repository: "git://foo.bar.com",
+	}
+}