Cleanup - maybe working...

cmd/vppn/main.go

@@ -5,8 +5,11 @@ import (
 	"log"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"vppn/peer"
+
+	"git.crumpington.com/lib/go/flock"
 )
 
 func main() {
@@ -14,24 +17,34 @@ func main() {
 
 	name := flag.String("name", "", "network name (required)")
 	hub := flag.String("hub", "", "hub base URL (required)")
-	apiKey := flag.String("api-key", "", "API key (required)")
 	flag.Parse()
 
-	if *name == "" || *hub == "" || *apiKey == "" {
+	if *name == "" || *hub == "" {
 		flag.Usage()
 		os.Exit(1)
 	}
 
-	// TODO: Acquire flock on lock file.
+	apiKey, err := loadAPIKey(*name)
+	if err != nil {
+		log.Fatalf("api key: %v", err)
+	}
 
-	statePath := networkStatePath(*name)
+	// Directory existence is guaranteed by the apikey file read above.
+	lockFile, err := flock.TryLock(vppnPath(*name, "lock"))
+	if err != nil {
+		log.Fatalf("lock: %v", err)
+	}
+	if lockFile == nil {
+		log.Fatalf("already running for network %q", *name)
+	}
+	defer flock.Unlock(lockFile)
 
-	state, err := peer.LoadOrInit(statePath, *hub, *apiKey)
+	state, err := peer.LoadOrInit(vppnPath(*name, "state.json"), *hub, apiKey)
 	if err != nil {
 		log.Fatalf("init: %v", err)
 	}
 
-	app, err := peer.New(state, *hub, *apiKey, *name)
+	app, err := peer.New(state, *hub, apiKey, *name)
 	if err != nil {
 		log.Fatalf("start: %v", err)
 	}
@@ -41,10 +54,18 @@ func main() {
 	}
 }
 
-func networkStatePath(name string) string {
+func loadAPIKey(name string) (string, error) {
+	data, err := os.ReadFile(vppnPath(name, "apikey"))
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(string(data)), nil
+}
+
+func vppnPath(name, file string) string {
 	home, err := os.UserHomeDir()
 	if err != nil {
-		return filepath.Join(".vppn", name, "state.json")
+		return filepath.Join(".vppn", name, file)
 	}
-	return filepath.Join(home, ".vppn", name, "state.json")
+	return filepath.Join(home, ".vppn", name, file)
 }