agent/proxy: manager configures the daemon pid path to write pids

agent/proxy/manager.go

@@ -354,11 +354,14 @@ func (m *Manager) newProxy(mp *local.ManagedProxy) (Proxy, error) {
 			return nil, fmt.Errorf("daemon mode managed proxy requires command")
 		}
 
+		// We reuse the service ID a few times
+		id := p.ProxyService.ID
+
 		// Build the command to execute.
 		var cmd exec.Cmd
 		cmd.Path = command[0]
 		cmd.Args = command // idx 0 is path but preserved since it should be
-		if err := m.configureLogDir(p.ProxyService.ID, &cmd); err != nil {
+		if err := m.configureLogDir(id, &cmd); err != nil {
 			return nil, fmt.Errorf("error configuring proxy logs: %s", err)
 		}
 
@@ -367,6 +370,7 @@ func (m *Manager) newProxy(mp *local.ManagedProxy) (Proxy, error) {
 			Command:    &cmd,
 			ProxyToken: mp.ProxyToken,
 			Logger:     m.Logger,
+			PidPath:    pidPath(filepath.Join(m.DataDir, "pids"), id),
 		}, nil
 
 	default:
@@ -414,3 +418,14 @@ func (m *Manager) configureLogDir(id string, cmd *exec.Cmd) error {
 func logPath(dir, id, stream string) string {
 	return filepath.Join(dir, fmt.Sprintf("%s-%s.log", id, stream))
 }
+
+// pidPath is a helper to return the path to the pid file for the given
+// directory and service ID.
+func pidPath(dir, id string) string {
+	// If no directory is given we do not write a pid
+	if dir == "" {
+		return ""
+	}
+
+	return filepath.Join(dir, fmt.Sprintf("%s.pid", id))
+}

agent/proxy/manager_test.go

@@ -227,6 +227,40 @@ func TestManagerRun_daemonLogs(t *testing.T) {
 	require.Equal([]byte(expectedErr), actual)
 }
 
+func TestManagerRun_daemonPid(t *testing.T) {
+	t.Parallel()
+
+	require := require.New(t)
+	state := local.TestState(t)
+	m, closer := testManager(t)
+	defer closer()
+	m.State = state
+	defer m.Kill()
+
+	// Configure a log dir so that we can read the logs
+	pidDir := filepath.Join(m.DataDir, "pids")
+
+	// Create the service and calculate the log paths
+	path := filepath.Join(m.DataDir, "notify")
+	id := testStateProxy(t, state, "web", helperProcess("output", path))
+	pidPath := pidPath(pidDir, id)
+
+	// Start the manager
+	go m.Run()
+
+	// We should see the path appear shortly
+	retry.Run(t, func(r *retry.R) {
+		if _, err := os.Stat(path); err != nil {
+			r.Fatalf("error waiting for stdout path: %s", err)
+		}
+	})
+
+	// Verify the pid file is not empty
+	pidRaw, err := ioutil.ReadFile(pidPath)
+	require.NoError(err)
+	require.NotEmpty(pidRaw)
+}
+
 func testManager(t *testing.T) (*Manager, func()) {
 	m := NewManager()