Add the readyfile flag and a readiness probe to the controller.

cmd/main.go

@@ -68,6 +68,8 @@ var (
 		"out-of-cluster runs")
 	kubeconfigF = flag.String("kubeconfig", "", "config path for the "+
 		"cluster master URL, for out-of-cluster runs")
+	readyfileF = flag.String("readyfile", "", "path of a file to touch "+
+		"when the controller is ready, for readiness probes")
 	logFormat = logrus.TextFormatter{
 		DisableColors: true,
 		FullTimestamp: true,
@@ -97,6 +99,14 @@ func main() {
 		os.Exit(0)
 	}
 
+	if *readyfileF != "" {
+		if err := os.Remove(*readyfileF); err != nil && !os.IsNotExist(err) {
+			fmt.Printf("Cannot remove ready file %s: %v",
+				*readyfileF, err)
+			os.Exit(-1)
+		}
+	}
+
 	lvl := strings.ToLower(*loglvlF)
 	switch lvl {
 	case "panic":
@@ -167,7 +177,7 @@ func main() {
 		vController, informerFactory, vcrInformerFactory)
 	go handleTermination(log, ingController, vController, varnishDone)
 	informerFactory.Start(informerStop)
-	ingController.Run()
+	ingController.Run(*readyfileF)
 }
 
 func handleTermination(

deploy/controller.yaml

@@ -25,7 +25,11 @@ spec:
             - -P
             - "0"
             - k8s-ingress
+        readinessProbe:
+          exec:
+            command:
+            - /usr/bin/test
+            - -e
+            - /ready
         args:
-        # log-level default is info, so this can be left out.
-        # Shown here to demonstrate setting options for the controller.
-        - -log-level=info
+        - -readyfile=/ready

docs/ref-cli-options.md

@@ -25,6 +25,8 @@ Usage of ./k8s-ingress:
     	cluster master URL, for out-of-cluster runs
   -namespace string
     	namespace in which to listen for resources (default all)
+  -readyfile string
+    	path of a file to touch when the controller is ready, for readiness probes
   -stderrthreshold value
     	logs at or above this threshold go to stderr
   -templatedir string
@@ -69,6 +71,11 @@ controller uses the value of the environment variable
 ``TEMPLATE_DIR``, or the current working director if neither of the
 command-line option nor the environment variable are set.
 
+If ``-readyfile /path/to/file`` is set, then the controller removes
+the file at that path immediately at startup, if any exists, and
+touches it when it is ready. Readiness probes can then test the file
+for existence. By default, no readiness file is created.
+
 ``-log-level`` sets the log level for the main controller code,
 ``INFO`` by default.
 

pkg/controller/controller.go

@@ -30,6 +30,7 @@ package controller
 
 import (
 	"fmt"
+	"os"
 	"time"
 
 	vcr_informers "code.uplex.de/uplex-varnish/k8s-ingress/pkg/client/informers/externalversions"
@@ -217,7 +218,10 @@ func (ingc *IngressController) updateObj(old, new interface{}) {
 // Run the Ingress controller -- start the informers in goroutines,
 // wait for the caches to sync, and call Run() for the
 // NamespaceQueues. Then block until Stop() is invoked.
-func (ingc *IngressController) Run() {
+//
+// If readyFile is non-empty, it is the path of a file to touch when
+// the controller is ready (after informers have launched).
+func (ingc *IngressController) Run(readyFile string) {
 	defer utilruntime.HandleCrash()
 	defer ingc.nsQs.Stop()
 
@@ -228,6 +232,24 @@ func (ingc *IngressController) Run() {
 	go ingc.informers.secr.Run(ingc.stopCh)
 	go ingc.informers.vcfg.Run(ingc.stopCh)
 
+	ingc.log.Info("Controller ready")
+	if readyFile != "" {
+		f, err := os.Create(readyFile)
+		if err != nil {
+			e := fmt.Errorf("Cannot create ready file %s: %v",
+				readyFile, err)
+			utilruntime.HandleError(e)
+			return
+		}
+		if err = f.Close(); err != nil {
+			e := fmt.Errorf("Cannot close ready file %s: %v",
+				readyFile, err)
+			utilruntime.HandleError(e)
+			defer f.Close()
+		}
+		ingc.log.Infof("Created ready file %s", readyFile)
+	}
+
 	ingc.log.Info("Waiting for caches to sync")
 	if ok := cache.WaitForCacheSync(ingc.stopCh,
 		ingc.informers.ing.HasSynced,