feat(GODT-2585): Only Start IMAP/SMTP once one user is loaded

Update ServerManager to follow the new expected behavior. The servers
will only be started when one user is active.

If all users are logged out or removed from the system, the servers will
stop.

If the network goes down, the servers will stop and resume once network
has been restored.

internal/bridge/bridge_test.go

@@ -173,7 +173,19 @@ func TestBridge_UserAgent(t *testing.T) {
 
 func TestBridge_UserAgent_Persistence(t *testing.T) {
 	withEnv(t, func(ctx context.Context, s *server.Server, netCtl *proton.NetCtl, locator bridge.Locator, vaultKey []byte) {
+		otherPassword := []byte("bar")
+		otherUser := "foo"
+		_, _, err := s.CreateUser(otherUser, otherPassword)
+		require.NoError(t, err)
+
 		withBridge(ctx, t, s.GetHostURL(), netCtl, locator, vaultKey, func(b *bridge.Bridge, mocks *bridge.Mocks) {
+			imapWaiter := waitForIMAPServerReady(b)
+			defer imapWaiter.Done()
+
+			require.NoError(t, getErr(b.LoginFull(ctx, otherUser, otherPassword, nil, nil)))
+
+			imapWaiter.Wait()
+
 			currentUserAgent := b.GetCurrentUserAgent()
 			require.Contains(t, currentUserAgent, vault.DefaultUserAgent)
 
@@ -220,7 +232,19 @@ func TestBridge_UserAgentFromIMAPID(t *testing.T) {
 			calls = append(calls, call)
 		})
 
+		otherPassword := []byte("bar")
+		otherUser := "foo"
+		_, _, err := s.CreateUser(otherUser, otherPassword)
+		require.NoError(t, err)
+
 		withBridge(ctx, t, s.GetHostURL(), netCtl, locator, vaultKey, func(b *bridge.Bridge, mocks *bridge.Mocks) {
+			imapWaiter := waitForIMAPServerReady(b)
+			defer imapWaiter.Done()
+
+			require.NoError(t, getErr(b.LoginFull(ctx, otherUser, otherPassword, nil, nil)))
+
+			imapWaiter.Wait()
+
 			imapClient, err := client.Dial(fmt.Sprintf("%v:%v", constants.Host, b.GetIMAPPort()))
 			require.NoError(t, err)
 			defer func() { _ = imapClient.Logout() }()
@@ -592,9 +616,17 @@ func TestBridge_InitGluonDirectory(t *testing.T) {
 func TestBridge_LoginFailed(t *testing.T) {
 	withEnv(t, func(ctx context.Context, s *server.Server, netCtl *proton.NetCtl, locator bridge.Locator, vaultKey []byte) {
 		withBridge(ctx, t, s.GetHostURL(), netCtl, locator, vaultKey, func(bridge *bridge.Bridge, mocks *bridge.Mocks) {
+			imapWaiter := waitForIMAPServerReady(bridge)
+			defer imapWaiter.Done()
+
 			failCh, done := chToType[events.Event, events.IMAPLoginFailed](bridge.GetEvents(events.IMAPLoginFailed{}))
 			defer done()
 
+			_, err := bridge.LoginFull(ctx, username, password, nil, nil)
+			require.NoError(t, err)
+
+			imapWaiter.Wait()
+
 			imapClient, err := client.Dial(net.JoinHostPort(constants.Host, fmt.Sprint(bridge.GetIMAPPort())))
 			require.NoError(t, err)
 
@@ -622,6 +654,9 @@ func TestBridge_ChangeCacheDirectory(t *testing.T) {
 			configDir, err := b.GetGluonDataDir()
 			require.NoError(t, err)
 
+			imapWaiter := waitForIMAPServerReady(b)
+			defer imapWaiter.Done()
+
 			// Login the user.
 			syncCh, done := chToType[events.Event, events.SyncFinished](b.GetEvents(events.SyncFinished{}))
 			defer done()
@@ -655,6 +690,8 @@ func TestBridge_ChangeCacheDirectory(t *testing.T) {
 			require.NoError(t, err)
 			require.True(t, info.State == bridge.Connected)
 
+			imapWaiter.Wait()
+
 			client, err := client.Dial(fmt.Sprintf("%v:%v", constants.Host, b.GetIMAPPort()))
 			require.NoError(t, err)
 			require.NoError(t, client.Login(info.Addresses[0], string(info.BridgePass)))
@@ -778,6 +815,7 @@ func withBridgeNoMocks(
 	locator bridge.Locator,
 	vaultKey []byte,
 	tests func(*bridge.Bridge),
+	waitOnServers bool,
 ) {
 	// Bridge will disable the proxy by default at startup.
 	mocks.ProxyCtl.EXPECT().DisallowProxy()
@@ -828,15 +866,18 @@ func withBridgeNoMocks(
 
 	// Wait for bridge to finish loading users.
 	waitForEvent(t, eventCh, events.AllUsersLoaded{})
-	// Wait for bridge to start the IMAP server.
-	waitForEvent(t, eventCh, events.IMAPServerReady{})
-	// Wait for bridge to start the SMTP server.
-	waitForEvent(t, eventCh, events.SMTPServerReady{})
 
 	// Set random IMAP and SMTP ports for the tests.
 	require.NoError(t, bridge.SetIMAPPort(ctx, 0))
 	require.NoError(t, bridge.SetSMTPPort(ctx, 0))
 
+	if waitOnServers {
+		// Wait for bridge to start the IMAP server.
+		waitForEvent(t, eventCh, events.IMAPServerReady{})
+		// Wait for bridge to start the SMTP server.
+		waitForEvent(t, eventCh, events.SMTPServerReady{})
+	}
+
 	// Close the bridge when done.
 	defer bridge.Close(ctx)
 
@@ -857,7 +898,24 @@ func withBridge(
 	withMocks(t, func(mocks *bridge.Mocks) {
 		withBridgeNoMocks(ctx, t, mocks, apiURL, netCtl, locator, vaultKey, func(bridge *bridge.Bridge) {
 			tests(bridge, mocks)
-		})
+		}, false)
+	})
+}
+
+// withBridgeWaitForServers is the same as withBridge, but it will wait until IMAP & SMTP servers are ready.
+func withBridgeWaitForServers(
+	ctx context.Context,
+	t *testing.T,
+	apiURL string,
+	netCtl *proton.NetCtl,
+	locator bridge.Locator,
+	vaultKey []byte,
+	tests func(*bridge.Bridge, *bridge.Mocks),
+) {
+	withMocks(t, func(mocks *bridge.Mocks) {
+		withBridgeNoMocks(ctx, t, mocks, apiURL, netCtl, locator, vaultKey, func(bridge *bridge.Bridge) {
+			tests(bridge, mocks)
+		}, true)
 	})
 }
 
@@ -910,3 +968,40 @@ func chToType[In, Out any](inCh <-chan In, done func()) (<-chan Out, func()) {
 
 	return outCh, done
 }
+
+type eventWaiter struct {
+	evtCh  <-chan events.Event
+	cancel func()
+}
+
+func (e *eventWaiter) Done() {
+	e.cancel()
+}
+
+func (e *eventWaiter) Wait() {
+	<-e.evtCh
+}
+
+func waitForSMTPServerReady(b *bridge.Bridge) *eventWaiter {
+	evtCh, cancel := b.GetEvents(events.SMTPServerReady{})
+	return &eventWaiter{
+		evtCh:  evtCh,
+		cancel: cancel,
+	}
+}
+
+func waitForIMAPServerReady(b *bridge.Bridge) *eventWaiter {
+	evtCh, cancel := b.GetEvents(events.IMAPServerReady{})
+	return &eventWaiter{
+		evtCh:  evtCh,
+		cancel: cancel,
+	}
+}
+
+func waitForIMAPServerStopped(b *bridge.Bridge) *eventWaiter {
+	evtCh, cancel := b.GetEvents(events.IMAPServerStopped{})
+	return &eventWaiter{
+		evtCh:  evtCh,
+		cancel: cancel,
+	}
+}