Integrated Fantastic coffie (decaffeinated) base version

cmd/healthcheck/healthcheck.go

@@ -0,0 +1,48 @@
+/*
+Healthcheck is a simple program that sends an HTTP request to the local host (self) to a configured port number.
+It's used in environment where you need a simple probe for health checks (e.g., an empty container in docker).
+The probe URL is http://localhost:3000/liveness . Only the port can be changed.
+
+Usage:
+
+	healthcheck [flags]
+
+The flags are:
+
+	-port <1-65535>
+		Change the port where the request is sent.
+
+Return values (exit codes):
+
+	0
+		The request was successful (HTTP 200 or HTTP 204)
+
+	> 0
+		The request was not successful (connection error or unexpected HTTP status code)
+*/
+package main
+
+import (
+	"flag"
+	"fmt"
+	"net/http"
+	"os"
+)
+
+func main() {
+	var port = flag.Int("port", 3000, "HTTP port for healthcheck")
+
+	flag.Parse()
+
+	res, err := http.Get(fmt.Sprintf("http://localhost:%d/liveness", *port))
+	if err != nil {
+		_, _ = fmt.Fprintln(os.Stderr, err.Error())
+		os.Exit(1)
+	} else if res.StatusCode != http.StatusOK && res.StatusCode != http.StatusNoContent {
+		_ = res.Body.Close()
+		_, _ = fmt.Fprintln(os.Stderr, "Healthcheck request not OK: ", res.Status)
+		os.Exit(1)
+	}
+	_ = res.Body.Close()
+	os.Exit(0)
+}