Add url option to healthcheck command

cmd/healthcheck/healthcheck.go

@@ -2,6 +2,7 @@ package healthcheck
 
 import (
 	"errors"
+	"flag"
 	"fmt"
 	"net/http"
 	"os"
@@ -22,11 +23,26 @@ func NewCmd(traefikConfiguration *static.Configuration, loaders []cli.ResourceLo
 	}
 }
 
-func runCmd(traefikConfiguration *static.Configuration) func(_ []string) error {
+func runCmd(traefikConfiguration *static.Configuration) func(args []string) error {
-	return func(_ []string) error {
+	return func(args []string) error {
+		fs := flag.NewFlagSet("healthcheck", flag.ContinueOnError)
+		urlFlag := fs.String("url", "", "")
+		fs.SetOutput(os.Stderr)
+		if err := fs.Parse(args); err != nil {
+			return err
+		}
+
 		traefikConfiguration.SetEffectiveConfiguration()
 
-		resp, errPing := Do(*traefikConfiguration)
+		var resp *http.Response
+		var errPing error
+		if *urlFlag != "" {
+			client := &http.Client{Timeout: 5 * time.Second}
+			resp, errPing = client.Head(*urlFlag)
+		} else {
+			resp, errPing = Do(*traefikConfiguration)
+		}
+
 		if resp != nil {
 			resp.Body.Close()
 		}

docs/content/reference/install-configuration/observability/healthcheck.md

@@ -27,6 +27,16 @@ $ traefik healthcheck
 OK: http://:8082/ping
 ```
 
+### URL Option
+
+The URL to check can be specified with the `--url` flag, which defaults to `http://localhost:8080/ping`.
+
+Example:
+
+```sh
+traefik healthcheck --url=http://localhost:8080/ping
+```
+
 ## Ping
 
 The `/ping` health-check URL is enabled with the command-line `--ping` or config file option `[ping]`.