From 99c130f7f78824226c6b2a24554ab1ee9c42ac34 Mon Sep 17 00:00:00 2001
From: Simon Ruderich <simon@ruderich.org>
Date: Mon, 4 Nov 2024 08:48:08 +0100
Subject: [PATCH] Use separate "up" and "dot" commands

---
 main.go | 41 +++++++++++++++++++++++++++++++----------
 1 file changed, 31 insertions(+), 10 deletions(-)

diff --git a/main.go b/main.go
index eb3f150..9ca00ad 100644
--- a/main.go
+++ b/main.go
@@ -13,25 +13,46 @@ import (
 )
 
 func main() {
-	if len(os.Args) != 2 && len(os.Args) != 3 {
+	if len(os.Args) < 2 {
 		log.SetFlags(0)
-		log.Fatalf("usage: %s <config> [<dot-output>]", os.Args[0])
+		log.Fatalf("usage: %[1]s <command> <args...>\n\n"+
+			"Available commands:\n"+
+			"  Start lab:        %[1]s up <config>\n"+
+			"  Stop lab:         %[1]s down <config>\n"+
+			"  Create dot graph: %[1]s dot <config> <output>\n",
+			os.Args[0])
 	}
 
-	cfg, err := LoadConfig(os.Args[1])
-	if err != nil {
-		log.Fatalf("config %q: %v", os.Args[1], err)
+	loadConfig := func() *Config {
+		cfg, err := LoadConfig(os.Args[2])
+		if err != nil {
+			log.Fatalf("config %q: %v", os.Args[2], err)
+		}
+		return cfg
 	}
 
-	// Write dot file showing the network architecture
-	if len(os.Args) == 3 {
-		err := writeDot(cfg, os.Args[2])
+	switch os.Args[1] {
+	case "up":
+		if len(os.Args) != 3 {
+			log.Fatalf("invalid arguments; expected: \"up\" <config>")
+		}
+		cfg := loadConfig()
+		mustUp(cfg)
+
+	case "dot":
+		// Write dot file showing the network architecture
+		if len(os.Args) != 4 {
+			log.Fatalf("invalid arguments; expected: \"dot\" <config> <output>")
+		}
+		cfg := loadConfig()
+		err := writeDot(cfg, os.Args[3])
 		if err != nil {
 			log.Fatal(err)
 		}
-	}
 
-	mustUp(cfg)
+	default:
+		log.Fatalf("invalid command %q", os.Args[1])
+	}
 }
 
 // vi: set noet ts=4 sw=4 sts=4:
-- 
2.45.2