fix(coderd): subscribe to workspace when streaming agent logs to detect outdated build (#9729)

Fixes #9721

coderd/workspaceagents.go

@@ -570,11 +570,27 @@ func (api *API) workspaceAgentLogs(rw http.ResponseWriter, r *http.Request) {
 		lastSentLogID = logs[len(logs)-1].ID
 	}
 
+	workspaceNotifyCh := make(chan struct{}, 1)
 	notifyCh := make(chan struct{}, 1)
 	// Allow us to immediately check if we missed any logs
 	// between initial fetch and subscribe.
 	notifyCh <- struct{}{}
 
+	// Subscribe to workspace to detect new builds.
+	closeSubscribeWorkspace, err := api.Pubsub.Subscribe(codersdk.WorkspaceNotifyChannel(workspace.ID), func(_ context.Context, _ []byte) {
+		select {
+		case workspaceNotifyCh <- struct{}{}:
+		default:
+		}
+	})
+	if err != nil {
+		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
+			Message: "Failed to subscribe to workspace for log streaming.",
+			Detail:  err.Error(),
+		})
+		return
+	}
+	defer closeSubscribeWorkspace()
 	// Subscribe early to prevent missing log events.
 	closeSubscribe, err := api.Pubsub.Subscribe(agentsdk.LogsNotifyChannel(workspaceAgent.ID), func(_ context.Context, _ []byte) {
 		// The message is not important, we're tracking lastSentLogID manually.
@@ -585,7 +601,7 @@ func (api *API) workspaceAgentLogs(rw http.ResponseWriter, r *http.Request) {
 	})
 	if err != nil {
 		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
-			Message: "Failed to subscribe to logs.",
+			Message: "Failed to subscribe to agent for log streaming.",
 			Detail:  err.Error(),
 		})
 		return
@@ -600,20 +616,33 @@ func (api *API) workspaceAgentLogs(rw http.ResponseWriter, r *http.Request) {
 	defer t.Stop()
 
 	go func() {
-		defer close(bufferedLogs)
+		defer func() {
+			logger.Debug(ctx, "end log streaming loop")
+			close(bufferedLogs)
+		}()
+		logger.Debug(ctx, "start log streaming loop", slog.F("last_sent_log_id", lastSentLogID))
 
 		keepGoing := true
 		for keepGoing {
+			var (
+				debugTriggeredBy     string
+				onlyCheckLatestBuild bool
+			)
 			select {
 			case <-ctx.Done():
 				return
 			case <-t.C:
+				debugTriggeredBy = "timer"
+			case <-workspaceNotifyCh:
+				debugTriggeredBy = "workspace"
+				onlyCheckLatestBuild = true
 			case <-notifyCh:
+				debugTriggeredBy = "log"
 				t.Reset(recheckInterval)
 			}
 
 			agents, err := api.Database.GetWorkspaceAgentsInLatestBuildByWorkspaceID(ctx, workspace.ID)
-			if err != nil {
+			if err != nil && !xerrors.Is(err, sql.ErrNoRows) {
 				if xerrors.Is(err, context.Canceled) {
 					return
 				}
@@ -624,6 +653,20 @@ func (api *API) workspaceAgentLogs(rw http.ResponseWriter, r *http.Request) {
 			// checking once.
 			keepGoing = slices.ContainsFunc(agents, func(agent database.WorkspaceAgent) bool { return agent.ID == workspaceAgent.ID })
 
+			logger.Debug(
+				ctx,
+				"checking for new logs",
+				slog.F("triggered_by", debugTriggeredBy),
+				slog.F("only_check_latest_build", onlyCheckLatestBuild),
+				slog.F("keep_going", keepGoing),
+				slog.F("last_sent_log_id", lastSentLogID),
+				slog.F("workspace_has_agents", len(agents) > 0),
+			)
+
+			if onlyCheckLatestBuild && keepGoing {
+				continue
+			}
+
 			logs, err := api.Database.GetWorkspaceAgentLogsAfter(ctx, database.GetWorkspaceAgentLogsAfterParams{
 				AgentID:      workspaceAgent.ID,
 				CreatedAfter: lastSentLogID,

coderd/workspaceagents_test.go

@@ -385,34 +385,14 @@ func TestWorkspaceAgentStartupLogs(t *testing.T) {
 			_ = closer.Close()
 		}()
 
-		first := make(chan struct{})
-		go func() {
-			select {
-			case <-ctx.Done():
-				assert.Fail(t, "context done while waiting in goroutine")
-			case <-logs:
-				close(first)
-			}
-		}()
 		select {
 		case <-ctx.Done():
 			require.FailNow(t, "context done while waiting for first log")
-		case <-first:
+		case <-logs:
 		}
 
 		_ = coderdtest.CreateWorkspaceBuild(t, client, workspace, database.WorkspaceTransitionStart)
 
-		// Send a new log message to trigger a re-check.
-		err = agentClient.PatchLogs(ctx, agentsdk.PatchLogs{
-			Logs: []agentsdk.Log{
-				{
-					CreatedAt: dbtime.Now(),
-					Output:    "testing2",
-				},
-			},
-		})
-		require.NoError(t, err)
-
 		select {
 		case <-ctx.Done():
 			require.FailNow(t, "context done while waiting for logs close")

codersdk/workspaceagents.go

@@ -703,7 +703,7 @@ func (c *Client) WorkspaceAgentLogsAfter(ctx context.Context, agentID uuid.UUID,
 		}
 		return nil, nil, ReadBodyAsError(res)
 	}
-	logChunks := make(chan []WorkspaceAgentLog)
+	logChunks := make(chan []WorkspaceAgentLog, 1)
 	closed := make(chan struct{})
 	ctx, wsNetConn := websocketNetConn(ctx, conn, websocket.MessageText)
 	decoder := json.NewDecoder(wsNetConn)