add healthcheck service

cmd/utility/main.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"fmt"
+	"net"
+	"net/http"
+	"os"
+)
+
+func main() {
+	monitorAddress := os.Getenv("DEVSIM_MONITOR_ADDR")
+	if monitorAddress == "" {
+		return
+	}
+
+	host, port, err := net.SplitHostPort(monitorAddress)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "provided address is invalid: %v", err)
+		os.Exit(1)
+	}
+
+	if host == "" {
+		host = "127.0.0.1"
+	}
+
+	if len(os.Args) == 1 {
+		fmt.Fprintf(os.Stderr, "no command provided")
+		os.Exit(1)
+	}
+
+	destinationAddress := net.JoinHostPort(host, port)
+
+	cmd := os.Args[1]
+	var resp *http.Response
+	switch cmd {
+	case "health":
+		resp, err = http.Get("http://" + destinationAddress + "/health")
+	case "ready":
+		resp, err = http.Get("http://" + destinationAddress + "/ready")
+	default:
+		fmt.Fprintf(os.Stderr, "unable to check %s", cmd)
+		os.Exit(1)
+	}
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "unable to proceed request %v", err)
+		os.Exit(1)
+	}
+
+	code := resp.StatusCode
+	status := resp.Header.Get("X-Readiness-Probe")
+
+	if code != http.StatusOK {
+		println("code not ok")
+		os.Exit(1)
+	}
+
+	if status != "" && status != "ok" {
+		println("status not ok")
+		os.Exit(1)
+	}
+
+	println("ok")
+}