add health command (#2659)

* add health command
* update health check implementation to allow for more checks to added over time
* add change changelog entry

cmd/headscale/cli/health.go

@@ -0,0 +1,29 @@
+package cli
+
+import (
+	v1 "github.com/juanfont/headscale/gen/go/headscale/v1"
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	rootCmd.AddCommand(healthCmd)
+}
+
+var healthCmd = &cobra.Command{
+	Use:   "health",
+	Short: "Check the health of the Headscale server",
+	Long:  "Check the health of the Headscale server. This command will return an exit code of 0 if the server is healthy, or 1 if it is not.",
+	Run: func(cmd *cobra.Command, args []string) {
+		output, _ := cmd.Flags().GetString("output")
+		ctx, client, conn, cancel := newHeadscaleCLIWithConfig()
+		defer cancel()
+		defer conn.Close()
+
+		response, err := client.Health(ctx, &v1.HealthRequest{})
+		if err != nil {
+			ErrorOutput(err, "Error checking health", output)
+		}
+
+		SuccessOutput(response, "", output)
+	},
+}