Functions breakpoint debugging

CHANGELOG.md

@@ -0,0 +1 @@
+* Adds breakpoint debugging for the Cloud Functions emulator using the `--inspect-functions` flag (#1360).

src/commands/emulators-exec.ts

@@ -11,7 +11,7 @@ import * as controller from "../emulator/controller";
 import { DatabaseEmulator } from "../emulator/databaseEmulator";
 import { EmulatorRegistry } from "../emulator/registry";
 import { FirestoreEmulator } from "../emulator/firestoreEmulator";
-import { beforeEmulatorCommand } from "../emulator/commandUtils";
+import * as commandUtils from "../emulator/commandUtils";
 
 async function runScript(script: string): Promise<number> {
   utils.logBullet(`Running script: ${clc.bold(script)}`);
@@ -77,17 +77,12 @@ async function runScript(script: string): Promise<number> {
 }
 
 module.exports = new Command("emulators:exec <script>")
-  .before(beforeEmulatorCommand)
+  .before(commandUtils.beforeEmulatorCommand)
   .description(
     "start the local Firebase emulators, " + "run a test script, then shut down the emulators"
   )
-  .option(
-    "--only <list>",
-    "only run specific emulators. " +
-      "This is a comma separated list of emulators to start. " +
-      "Valid options are: " +
-      JSON.stringify(controller.VALID_EMULATOR_STRINGS)
-  )
+  .option(commandUtils.FLAG_ONLY, commandUtils.DESC_ONLY)
+  .option(commandUtils.FLAG_INSPECT_FUNCTIONS, commandUtils.DESC_INSPECT_FUNCTIONS)
   .action(async (script: string, options: any) => {
     let exitCode = 0;
     try {

src/commands/emulators-start.ts

@@ -1,18 +1,13 @@
 import { Command } from "../command";
 import * as controller from "../emulator/controller";
-import { beforeEmulatorCommand } from "../emulator/commandUtils";
+import * as commandUtils from "../emulator/commandUtils";
 import * as utils from "../utils";
 
 module.exports = new Command("emulators:start")
-  .before(beforeEmulatorCommand)
+  .before(commandUtils.beforeEmulatorCommand)
   .description("start the local Firebase emulators")
-  .option(
-    "--only <list>",
-    "only run specific emulators. " +
-      "This is a comma separated list of emulators to start. " +
-      "Valid options are: " +
-      JSON.stringify(controller.VALID_EMULATOR_STRINGS)
-  )
+  .option(commandUtils.FLAG_ONLY, commandUtils.DESC_ONLY)
+  .option(commandUtils.FLAG_INSPECT_FUNCTIONS, commandUtils.DESC_INSPECT_FUNCTIONS)
   .action(async (options: any) => {
     try {
       await controller.startAll(options);

src/emulator/commandUtils.ts

@@ -5,6 +5,17 @@ import requireAuth = require("../requireAuth");
 import requireConfig = require("../requireConfig");
 import { Emulators } from "../emulator/types";
 
+export const FLAG_ONLY: string = "--only <emulators>";
+export const DESC_ONLY: string =
+  "only run specific emulators. " +
+  "This is a comma separated list of emulators to start. " +
+  "Valid options are: " +
+  JSON.stringify(controller.VALID_EMULATOR_STRINGS);
+
+export const FLAG_INSPECT_FUNCTIONS = "--inspect-functions [port]";
+export const DESC_INSPECT_FUNCTIONS =
+  "emulate Cloud Functions in debug mode with the node inspector on the given port (9299 if not specified)";
+
 /**
  * We want to be able to run the Firestore and Database emulators even in the absence
  * of firebase.json. For Functions and Hosting we require the JSON file since the

src/emulator/controller.ts

@@ -132,11 +132,36 @@ export async function startAll(options: any): Promise<void> {
       options.config.get("functions.source")
     );
 
+    let inspectFunctions: number | undefined;
+
+    // If the flag is provided without a value, use the Node.js default
+    if (options.inspectFunctions === true) {
+      options.inspectFunctions = "9299";
+    }
+
+    if (options.inspectFunctions) {
+      inspectFunctions = Number(options.inspectFunctions);
+      if (isNaN(inspectFunctions) || inspectFunctions < 1024 || inspectFunctions > 65535) {
+        throw new FirebaseError(
+          `"${
+            options.inspectFunctions
+          }" is not a valid value for the --inspect-functions flag, please pass an integer between 1024 and 65535.`
+        );
+      }
+
+      // TODO(samstern): Add a link to documentation
+      utils.logLabeledWarning(
+        "functions",
+        `You are running the functions emulator in debug mode (port=${inspectFunctions}). This means that functions will execute in sequence rather than in parallel.`
+      );
+    }
+
     const functionsEmulator = new FunctionsEmulator({
       projectId,
       functionsDir,
       host: functionsAddr.host,
       port: functionsAddr.port,
+      debugPort: inspectFunctions,
     });
     await startEmulator(functionsEmulator);
   }

src/emulator/functionsEmulator.ts

@@ -8,7 +8,13 @@ import * as http from "http";
 import * as logger from "../logger";
 import * as track from "../track";
 import { Constants } from "./constants";
-import { EmulatorInfo, EmulatorInstance, EmulatorLog, Emulators } from "./types";
+import {
+  EmulatorInfo,
+  EmulatorInstance,
+  EmulatorLog,
+  Emulators,
+  FunctionsExecutionMode,
+} from "./types";
 import * as chokidar from "chokidar";
 
 import * as spawn from "cross-spawn";
@@ -29,6 +35,7 @@ import { EmulatorLogger, Verbosity } from "./emulatorLogger";
 import { RuntimeWorkerPool, RuntimeWorker } from "./functionsRuntimeWorker";
 import { PubsubEmulator } from "./pubsubEmulator";
 import { FirebaseError } from "../error";
+import { WorkQueue } from "./workQueue";
 
 const EVENT_INVOKE = "functions:invoke";
 
@@ -47,6 +54,7 @@ export interface FunctionsEmulatorArgs {
   host?: string;
   quiet?: boolean;
   disabledRuntimeFeatures?: FunctionsRuntimeFeatures;
+  debugPort?: number;
 }
 
 // FunctionsRuntimeInstance is the handler for a running function invocation
@@ -99,14 +107,26 @@ export class FunctionsEmulator implements EmulatorInstance {
   private server?: http.Server;
   private triggers: EmulatedTriggerDefinition[] = [];
   private knownTriggerIDs: { [triggerId: string]: boolean } = {};
-  private workerPool: RuntimeWorkerPool = new RuntimeWorkerPool();
+
+  private workerPool: RuntimeWorkerPool;
+  private workQueue: WorkQueue;
 
   constructor(private args: FunctionsEmulatorArgs) {
     // TODO: Would prefer not to have static state but here we are!
     EmulatorLogger.verbosity = this.args.quiet ? Verbosity.QUIET : Verbosity.DEBUG;
+
+    const mode = this.args.debugPort
+      ? FunctionsExecutionMode.SEQUENTIAL
+      : FunctionsExecutionMode.AUTO;
+    this.workerPool = new RuntimeWorkerPool(mode);
+    this.workQueue = new WorkQueue(mode);
   }
 
   createHubServer(): express.Application {
+    // TODO(samstern): Should not need this here but some tests are directly calling this method
+    // because FunctionsEmulator.start() is not test-safe due to askInstallNodeVersion.
+    this.workQueue.start();
+
     const hub = express();
 
     hub.use((req, res, next) => {
@@ -140,14 +160,18 @@ export class FunctionsEmulator implements EmulatorInstance {
       req: express.Request,
       res: express.Response
     ) => {
-      this.handleBackgroundTrigger(req, res);
+      this.workQueue.submit(() => {
+        return this.handleBackgroundTrigger(req, res);
+      });
     };
 
     const httpsHandler: express.RequestHandler = async (
       req: express.Request,
       res: express.Response
     ) => {
-      this.handleHttpsTrigger(req, res);
+      this.workQueue.submit(() => {
+        return this.handleHttpsTrigger(req, res);
+      });
     };
 
     // The ordering here is important. The longer routes (background)
@@ -185,6 +209,7 @@ export class FunctionsEmulator implements EmulatorInstance {
   async start(): Promise<void> {
     this.nodeBinary = await this.askInstallNodeVersion(this.args.functionsDir);
     const { host, port } = this.getInfo();
+    this.workQueue.start();
     this.server = this.createHubServer().listen(port, host);
   }
 
@@ -216,6 +241,7 @@ export class FunctionsEmulator implements EmulatorInstance {
       A "diagnostic" FunctionsRuntimeBundle looks just like a normal bundle except functionId == "".
        */
 
+      // TODO(samstern): This is probably not the right behavior when debugging.
       // Before loading any triggers we need to make sure there are no 'stale' workers
       // in the pool that would cause us to run old code.
       this.workerPool.refresh();
@@ -315,6 +341,7 @@ export class FunctionsEmulator implements EmulatorInstance {
   }
 
   async stop(): Promise<void> {
+    this.workQueue.stop();
     this.workerPool.exit();
     Promise.resolve(this.server && this.server.close());
   }
@@ -566,6 +593,10 @@ export class FunctionsEmulator implements EmulatorInstance {
       args.unshift("--no-warnings");
     }
 
+    if (this.args.debugPort) {
+      args.unshift(`--inspect=${this.args.debugPort}`);
+    }
+
     const childProcess = spawn(opts.nodeBinary, args, {
       env: { node: opts.nodeBinary, ...opts.env, ...process.env },
       cwd: frb.cwd,

src/emulator/functionsEmulatorRuntime.ts

@@ -1095,6 +1095,11 @@ async function flushAndExit(code: number) {
   process.exit(code);
 }
 
+async function goIdle() {
+  new EmulatorLog("SYSTEM", "runtime-status", "Runtime is now idle", { state: "idle" }).log();
+  await EmulatorLog.waitForFlush();
+}
+
 async function handleMessage(message: string) {
   let runtimeArgs: FunctionsRuntimeArgs;
   try {
@@ -1116,9 +1121,9 @@ async function handleMessage(message: string) {
     return;
   }
 
-  // If there's no trigger id it's just a diagnostic call. We throw away the runtime.
+  // If there's no trigger id it's just a diagnostic call. We can go idle right away.
   if (!runtimeArgs.frb.triggerId) {
-    await flushAndExit(0);
+    await goIdle();
     return;
   }
 
@@ -1140,8 +1145,7 @@ async function handleMessage(message: string) {
     if (runtimeArgs.opts && runtimeArgs.opts.serializedTriggers) {
       await flushAndExit(0);
     } else {
-      new EmulatorLog("SYSTEM", "runtime-status", "Runtime is now idle", { state: "idle" }).log();
-      await EmulatorLog.waitForFlush();
+      await goIdle();
     }
   } catch (err) {
     new EmulatorLog("FATAL", "runtime-error", err.stack ? err.stack : err).log();