From 0d92abfbf6b0e9f12e3522902379071018237a6f Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@gmail.com>
Date: Fri, 5 Jun 2020 10:42:56 +0300
Subject: [PATCH] app/vmalert: print brief usage info for `vmalert -help`

---
 app/vmalert/main.go | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/app/vmalert/main.go b/app/vmalert/main.go
index c21737f776..526e783129 100644
--- a/app/vmalert/main.go
+++ b/app/vmalert/main.go
@@ -62,6 +62,7 @@ absolute path to all .yaml files in root.`)
 func main() {
 	// Write flags and help message to stdout, since it is easier to grep or pipe.
 	flag.CommandLine.SetOutput(os.Stdout)
+	flag.Usage = usage
 	envflag.Parse()
 	buildinfo.Init()
 	logger.Init()
@@ -172,3 +173,15 @@ func checkFlags() {
 		logger.Fatalf("datasource.url is empty")
 	}
 }
+
+func usage() {
+	const s = `
+vmalert processes alerts and recording rules.
+
+See the docs at https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/app/vmalert/README.md .
+`
+
+	f := flag.CommandLine.Output()
+	fmt.Fprintf(f, "%s\n", s)
+	flag.PrintDefaults()
+}