Implement Monlet MVP stack and UI updates

agent/internal/ids/ids.go

@@ -2,38 +2,24 @@ package ids
 
 import (
 	"fmt"
-	"os"
-	"path/filepath"
 	"strings"
 
-	"github.com/google/uuid"
-
 	"github.com/monlet/agent/internal/config"
 )
 
-// LoadOrCreateAgentID returns configured ID if non-empty, otherwise loads
-// state_dir/agent_id, generating and persisting it on first run.
-func LoadOrCreateAgentID(stateDir, configured string) (string, error) {
+func ResolveAgentID(configured, hostname string) (string, error) {
 	if configured != "" {
-		return configured, nil
-	}
-	if err := os.MkdirAll(stateDir, 0o755); err != nil {
-		return "", fmt.Errorf("create state dir: %w", err)
-	}
-	path := filepath.Join(stateDir, "agent_id")
-	b, err := os.ReadFile(path)
-	if err == nil {
-		id := strings.TrimSpace(string(b))
+		id := strings.TrimSpace(configured)
 		if err := config.ValidateID("agent_id", id); err != nil {
-			return "", fmt.Errorf("persisted agent_id invalid: %w", err)
+			return "", err
 		}
 		return id, nil
 	}
-	if !os.IsNotExist(err) {
-		return "", err
+	id := strings.TrimSpace(hostname)
+	if id == "" {
+		return "", fmt.Errorf("hostname is empty")
 	}
-	id := uuid.NewString()
-	if err := os.WriteFile(path, []byte(id+"\n"), 0o600); err != nil {
+	if err := config.ValidateID("hostname as agent_id", id); err != nil {
 		return "", err
 	}
 	return id, nil

agent/internal/ids/ids_test.go

@@ -1,33 +1,17 @@
 package ids
 
-import (
-	"os"
-	"path/filepath"
-	"testing"
-)
+import "testing"
 
 func TestConfiguredWins(t *testing.T) {
-	id, err := LoadOrCreateAgentID(t.TempDir(), "fixed")
+	id, err := ResolveAgentID("fixed", "host")
 	if err != nil || id != "fixed" {
 		t.Fatalf("got %q %v", id, err)
 	}
 }
 
-func TestGenerateAndReuse(t *testing.T) {
-	dir := t.TempDir()
-	id1, err := LoadOrCreateAgentID(dir, "")
-	if err != nil {
-		t.Fatal(err)
-	}
-	id2, err := LoadOrCreateAgentID(dir, "")
-	if err != nil {
-		t.Fatal(err)
-	}
-	if id1 != id2 {
-		t.Fatalf("not stable: %q vs %q", id1, id2)
-	}
-	b, _ := os.ReadFile(filepath.Join(dir, "agent_id"))
-	if len(b) == 0 {
-		t.Fatal("agent_id not persisted")
+func TestHostnameFallback(t *testing.T) {
+	id, err := ResolveAgentID("", "host-1")
+	if err != nil || id != "host-1" {
+		t.Fatalf("got %q %v", id, err)
 	}
 }