Add application

Dockerfile

@@ -0,0 +1,8 @@
+FROM golang:latest
+MAINTAINER Gianluca Borello <[email protected]>
+
+COPY healthchecker /go/src/github.com/gianlucaborello/healthchecker-kubernetes/healthchecker
+RUN go get -d -v github.com/gianlucaborello/healthchecker-kubernetes/healthchecker
+RUN go install -v github.com/gianlucaborello/healthchecker-kubernetes/healthchecker
+
+ENTRYPOINT ["/go/bin/healthchecker"]

healthchecker/main.go

@@ -0,0 +1,91 @@
+package main
+
+import "fmt"
+import "bufio"
+import "net"
+import "time"
+import "os"
+import "flag"
+import "gopkg.in/redis.v4"
+
+func resolveTarget(target string) (ip net.IP, err error) {
+	ips, err := net.LookupIP(target)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, i := range ips {
+		if i.To4() != nil {
+			ip = i
+			break
+		}
+	}
+
+	return ip, nil
+}
+
+func doHealthCheck(ip net.IP) (respTime int, err error) {
+	fmt.Printf("Pinging service... ")
+
+	t1 := time.Now()
+
+	conn, err := net.DialTimeout("tcp", ip.String() + ":80", 1 * time.Second)
+	if err != nil {
+		return 0, err
+	}
+
+	fmt.Fprintf(conn, "GET / HTTP/1.0\r\n\r\n")
+	status, err := bufio.NewReader(conn).ReadString('\n')
+	if err != nil {
+		return 0, err
+	}
+
+	t2 := time.Now()
+	respTime = int((t2.Sub(t1)) / time.Microsecond)
+
+	fmt.Printf("service returned %v bytes in %v us\n", len(status), respTime)
+	return respTime, nil
+}
+
+func storeInRedis(redisClient *redis.Client, target string, respTime interface{}) (err error) {
+	redisClient.Set("response_times:"+target, respTime, 0)
+	return nil
+}
+
+func main() {
+
+	target := flag.String("target", "", "Target host for health check")
+	interval := flag.Int("interval", 1, "Interval in seconds for health check")
+	redisHost := flag.String("redis", "", "Redis server for stat storing")
+
+	flag.Parse()
+
+	redisClient := redis.NewClient(&redis.Options{
+		Addr: *redisHost + ":6379",
+	})
+
+	_, err := redisClient.Ping().Result()
+	if err != nil {
+		fmt.Printf("Error: %s\n", err)
+		os.Exit(1)
+	}
+
+	ip, err := resolveTarget(*target)
+	if err != nil {
+		fmt.Printf("Error: %s\n", err)
+		os.Exit(1)
+	}
+
+	for {
+		time.Sleep(time.Duration(*interval) * time.Second)
+
+		respTime, err := doHealthCheck(ip)
+		if err != nil {
+			fmt.Printf("Error during health check\n")
+			storeInRedis(redisClient, *target, "error")
+			continue
+		}
+
+		storeInRedis(redisClient, *target, respTime)
+	}
+}

manifests/backend.yaml

@@ -7,7 +7,7 @@ metadata:
     app: critical-app
     role: backend
 spec:
-  clusterIP: None
+  # clusterIP: None
   ports:
     - port: 80
   selector:

manifests/healthchecker.yaml

@@ -0,0 +1,15 @@
+apiVersion: extensions/v1beta1
+kind: Deployment
+metadata:
+  name: healthchecker
+  namespace: critical-app
+spec:
+  template:
+    metadata:
+      labels:
+        app: critical-app
+        role: healthchecker
+    spec:
+      containers:
+        - name: healthchecker
+          image: healthchecker