inspector: new API - Session.connectToMainThread #28870

eugeneo · 2019-07-26T21:53:58Z

This API is designed to enable worker threads use Inspector protocol
on main thread (and other workers through NodeWorker domain).

Note that worker can cause dead lock by suspending itself. I will
work on a new API that will allow workers to be hidden from the
inspector.

Fixes: #28828

Checklist

make -j4 test (UNIX), or vcbuild test (Windows) passes
tests and/or benchmarks are included
documentation is changed or added
commit message follows commit guidelines

alexkozy · 2019-07-26T21:58:23Z

test/parallel/test-inspector-connect-main-thread.js

+  const callFrameId = (await pausedPromise).params.callFrames[0].callFrameId;
+
+  // Delay to ensure main thread is truly suspended
+  await new Promise((resolve) => setTimeout(resolve, 200));


Why waiting for Debugger.paused is not enough in this case?

This makes sure main thread will wait while this worker is busy (e.g. if the API client decided to do IO)

test/parallel/test-inspector-connect-main-thread.js

alexkozy · 2019-07-26T22:00:51Z

test/parallel/test-inspector-connect-main-thread.js

+
+// This ensures that worker does not terminate while waiting for
+// inspector response
+function wrapCallbackToKeepThreadAlive(callback) {


Do all clients of the new API will need something like this?

This will be fixed separately.

src/inspector_agent.h

doc/api/errors.md

doc/api/inspector.md

addaleax · 2019-07-26T22:13:00Z

doc/api/inspector.md

-a front-end connected to the Inspector WebSocket port.
+Connects a session to the inspector back-end.
+
+### session.connect()


Suggested change

### session.connect()

### session.connectToMainThread()

Also, to clarify: This connects to the parent thread and not necessarily the main thread, right?

Sorry, replied to a different thread.

Current implementation does not support "worker trees" - e.g. only workers with the main thread as a parent are reported by the NodeWorker domain. Is workers spawning workers intenteded use-case? Then it will need to be fixed and I expect that the fix will make this API work in a consistent way.

Is workers spawning workers intenteded use-case?

Yes, that’s possible, mostly because there’s no real reason to prevent it.

Then, I'll try fixing NodeWorker domain. This API will be consistent with what that domain reports.

This is the proposed fix: #28872

doc/api/errors.md

eugeneo · 2019-07-28T23:26:28Z

I added a new commit so the callback is now executed in a micro task so there are less surprises.

nodejs-github-bot · 2019-07-29T05:26:08Z

CI: https://ci.nodejs.org/job/node-test-pull-request/24739/

Trott · 2019-07-29T14:40:58Z

The test added here failed in CI in the job that runs all tests in worker threads (using tools/test.py --worker).

eugeneo · 2019-07-29T16:37:49Z

This test should only be started on a main thread, I marked it as such.

There are some other relevant test timeouts, I will be looking into them.

nodejs-github-bot · 2019-07-29T16:38:36Z

CI: https://ci.nodejs.org/job/node-test-pull-request/24746/ ✔️

Trott · 2019-07-29T22:42:49Z

CI passed. Is this ready for reviews? Or did you want to first look more closely at the timeouts you mentioned?

Trott · 2019-07-31T04:20:37Z

@eugeneo CI passed. Did you still want to look more closely at the timeouts you mentioned?

@nodejs/inspector This could use some reviews.

benjamingr

This LGTM and I'm +1 on the change and also don't have a good intuition about what we should do in the cases discussed (worker spawned worker connecting).

eugeneo · 2019-07-31T19:11:21Z

I rebased the change (there were some changes to how the Inspector works with the workers) and squashed individual changes

nodejs-github-bot · 2019-08-01T06:05:53Z

CI: https://ci.nodejs.org/job/node-test-pull-request/24806/

Trott · 2019-08-01T06:22:52Z

/ping @nodejs/workers

addaleax · 2019-08-04T10:22:52Z

doc/api/inspector.md

-a front-end connected to the Inspector WebSocket port.
+Connects a session to the inspector back-end.
+
+### session.connectToMainThread()


To clarify again: This does connect to the parent thread and not the main thread, right? In that case the naming should reflect that, imo

All workers will connect to a main thread, I added a test case. This is based on #28872 that makes all workers be reported by the main thread.

addaleax · 2019-08-04T10:25:30Z

test/parallel/test-inspector-connect-main-thread.js

+const common = require('../common');
+
+common.skipIfInspectorDisabled();
+common.skipIfWorker();


Why do we skip this if the process is a Worker thread? We should definitely also test what happens if this code is run inside a Worker, if we can. For now, this check breaks the test, because it doesn’t allow running this file in a Worker, not even from the test itself.

If there’s concern about the isMainThread check below, you can use a solution based on environment variables, e.g. the process.env.HAS_STARTED_WORKER bit in test/parallel/test-worker-exit-code.js. That’s a standard way of dealing with it in our test suite.

This test will not work in a worker as it expects the code to be ran on the main thread. I updated the check.

addaleax · 2019-08-04T10:25:54Z

test/parallel/test-inspector-connect-main-thread.js

+  return new Promise((resolve) => session.once(notification, resolve));
+}
+
+function WaitForWorker() {


We generally use lowerCamelCase for JS functions (ditto for the functions below)

addaleax · 2019-08-04T10:26:39Z

test/parallel/test-inspector-connect-main-thread.js

+function doConsoleLogIn5ms() {
+  setTimeout(() => {
+    console.log('Message for a test');
+  }, 5);


Is this used somewhere?

Yes, it is for ensureListenerDoesNotInterrupt

addaleax · 2019-08-04T10:28:05Z

test/parallel/test-inspector-connect-main-thread.js

+if (isMainThread) {
+  RunTestWorker();
+} else {
+  RunDebugging();


Suggested change

RunDebugging();

runDebugging().then(common.mustCall());

addaleax · 2019-08-04T10:28:32Z

test/parallel/test-inspector-connect-main-thread.js

+}
+
+if (isMainThread) {
+  RunTestWorker();


Suggested change

RunTestWorker();

runTestWorker().then(common.mustCall());

(Adding “Changes requested” because the test really does not work in its current form)

eugeneo · 2019-08-06T23:41:14Z

@addaleax thank you for the review. I did my best to update the test to better reflect semantics. Please, take another look.

Note that merge commit will go away after the rebase/squash, I did the merge so code review comments are easier to trace.

eugeneo · 2019-08-16T18:19:36Z

@addaleax please let me know if there are still any changes that need to be implemented.

Trott · 2019-08-25T23:43:57Z

@addaleax Does this look good to you now? Or are there still changes you'd like to see?

addaleax

Thanks for the ping; yeah, I think everything here has been addressed, I just didn’t have time to fully review this yet.

addaleax · 2019-08-25T23:49:52Z

test/parallel/test-inspector-connect-main-thread.js

+               () => { consoleLogHappened = true; });
+  parentPort.postMessage({ consoleLogIn10ms: true });
+  while ((Date.now() - currentTime) < 50) {
+    // Spin wait for 200ms


The comment and the code seem to mismatch here 🙂

done

nodejs-github-bot · 2019-08-26T20:54:12Z

CI: https://ci.nodejs.org/job/node-test-pull-request/25254/

eugeneo · 2019-08-26T20:54:29Z

I fixed the comment and did the rebase - hence the force-push.

Trott · 2019-09-16T18:45:42Z

Given that it's a timeout and it's on FreeBSD (which is a bit of a canary in terms of being the first thing to have problems when tests are in parallel that perhaps should not be), perhaps the test should be in sequential? I say that without looking at it though....

Trott · 2019-09-16T18:47:37Z

This makes me think it should probably be in sequential:

  // Delay to ensure main thread is truly suspended
  await new Promise((resolve) => setTimeout(resolve, 50));

@nodejs/testing

Trott · 2019-09-16T18:49:30Z

Not sure if this is an unrelated issue or not:

$ tools/test.py -j 96 --repeat 192 test/parallel/test-inspector-connect-main-thread.js 
=== release test-inspector-connect-main-thread ===                   
Path: parallel/test-inspector-connect-main-thread
Message NodeWorker.enable was sent
Skip child is done
Message Debugger.enable was sent
Message Runtime.enable was sent
Message Debugger.setBreakpointByUrl was sent
Message for a test
Message Debugger.evaluateOnCallFrame was sent
Message Debugger.resume was sent
Worker is done
out/Release/node[47372]: ../src/node_platform.cc:283:void node::PerIsolatePlatformData::Shutdown(): Assertion `(foreground_tasks_.Pop()) == nullptr' failed.
 1: 0x100078e0c node::Abort() [/Users/trott/io.js/out/Release/node]
 2: 0x100078bb9 node::AppendExceptionLine(node::Environment*, v8::Local<v8::Value>, v8::Local<v8::Message>, node::ErrorHandlingMode) [/Users/trott/io.js/out/Release/node]
 3: 0x1000cd679 node::PerIsolatePlatformData::Shutdown() [/Users/trott/io.js/out/Release/node]
 4: 0x1000cdd04 node::NodePlatform::UnregisterIsolate(v8::Isolate*) [/Users/trott/io.js/out/Release/node]
 5: 0x1000e69e5 node::worker::WorkerThreadData::~WorkerThreadData() [/Users/trott/io.js/out/Release/node]
 6: 0x1000e4e24 node::worker::Worker::Run() [/Users/trott/io.js/out/Release/node]
 7: 0x1000e6cd6 node::worker::Worker::StartThread(v8::FunctionCallbackInfo<v8::Value> const&)::$_2::__invoke(void*) [/Users/trott/io.js/out/Release/node]
 8: 0x7fff7c1002eb _pthread_body [/usr/lib/system/libsystem_pthread.dylib]
 9: 0x7fff7c103249 _pthread_start [/usr/lib/system/libsystem_pthread.dylib]
10: 0x7fff7c0ff40d thread_start [/usr/lib/system/libsystem_pthread.dylib]
Command: out/Release/node /Users/trott/io.js/test/parallel/test-inspector-connect-main-thread.js
--- CRASHED (Signal: 6) ---

Trott · 2019-09-16T18:52:20Z

#29582

Using `console.log()` likely interferes with the functionality of the test, which also checks the interaction between inspector and `console.log()` as part of the test. Using `process._rawDebug()` solves that issue. Refs: nodejs#28870 Refs: nodejs#29582

Using `console.log()` likely interferes with the functionality of the test, which also checks the interaction between inspector and `console.log()` as part of the test. Using `process._rawDebug()` solves that issue. Refs: nodejs#28870 Refs: nodejs#29582 PR-URL: nodejs#29588 Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: David Carlier <[email protected]> Reviewed-By: Michaël Zasso <[email protected]>

While V8 itself should not have any remaining tasks on the queue during platform shutdown, our inspector implementation may do so. Thus, the checks verifying that no tasks are queued at that point make some of the inspector tasks flaky. Remove the checks and replace them by explicitly destroying all tasks that are left. Refs: nodejs#25653 Refs: nodejs#28870 (comment)

This API is designed to enable worker threads use Inspector protocol on main thread (and other workers through NodeWorker domain). Note that worker can cause dead lock by suspending itself. I will work on a new API that will allow workers to be hidden from the inspector. Fixes: #28828 PR-URL: #28870 Reviewed-By: Aleksei Koziatinskii <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Benjamin Gruenbaum <[email protected]>

Using `console.log()` likely interferes with the functionality of the test, which also checks the interaction between inspector and `console.log()` as part of the test. Using `process._rawDebug()` solves that issue. Refs: #28870 Refs: #29582 PR-URL: #29588 Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: David Carlier <[email protected]> Reviewed-By: Michaël Zasso <[email protected]>

While V8 itself should not have any remaining tasks on the queue during platform shutdown, our inspector implementation may do so. Thus, the checks verifying that no tasks are queued at that point make some of the inspector tasks flaky. Remove the checks and replace them by explicitly destroying all tasks that are left. Refs: #25653 Refs: #28870 (comment) PR-URL: #29587 Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: David Carlier <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Eugene Ostroukhov <[email protected]> Reviewed-By: Minwoo Jung <[email protected]>

Notable changes: * crypto: * Add `oaepLabel` option #29489 * deps: * Update V8 to 7.7.299.11 #28918 * More efficient memory handling * Stack trace serialization got faster * The `Intl.NumberFormat` API gained new functionality * For more information: https://v8.dev/blog/v8-release-77 * events: * Add support for `EventTarget` in `once` #29498 * fs: * Expose memory file mapping flag `UV_FS_O_FILEMAP` #29260 * inspector: * New API - `Session.connectToMainThread` #28870 * process: * Initial SourceMap support via `env.NODE_V8_COVERAGE` #28960 * stream: * Make `_write()` optional when `_writev()` is implemented #29639 * tls: * Add option to override signature algorithms #29598 * util: * Add `encodeInto` to `TextEncoder` #29524 * worker: * The `worker_thread` module is now stable #29512

This API is designed to enable worker threads use Inspector protocol on main thread (and other workers through NodeWorker domain). Note that worker can cause dead lock by suspending itself. I will work on a new API that will allow workers to be hidden from the inspector. Fixes: #28828 PR-URL: #28870 Reviewed-By: Aleksei Koziatinskii <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Benjamin Gruenbaum <[email protected]>

Using `console.log()` likely interferes with the functionality of the test, which also checks the interaction between inspector and `console.log()` as part of the test. Using `process._rawDebug()` solves that issue. Refs: #28870 Refs: #29582 PR-URL: #29588 Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: David Carlier <[email protected]> Reviewed-By: Michaël Zasso <[email protected]>

While V8 itself should not have any remaining tasks on the queue during platform shutdown, our inspector implementation may do so. Thus, the checks verifying that no tasks are queued at that point make some of the inspector tasks flaky. Remove the checks and replace them by explicitly destroying all tasks that are left. Refs: #25653 Refs: #28870 (comment) PR-URL: #29587 Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: David Carlier <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Eugene Ostroukhov <[email protected]> Reviewed-By: Minwoo Jung <[email protected]>

Notable changes: * crypto: * Add `oaepLabel` option #29489 * deps: * Update V8 to 7.7.299.11 #28918 * More efficient memory handling * Stack trace serialization got faster * The `Intl.NumberFormat` API gained new functionality * For more information: https://v8.dev/blog/v8-release-77 * events: * Add support for `EventTarget` in `once` #29498 * fs: * Expose memory file mapping flag `UV_FS_O_FILEMAP` #29260 * inspector: * New API - `Session.connectToMainThread` #28870 * process: * Initial SourceMap support via `env.NODE_V8_COVERAGE` #28960 * stream: * Make `_write()` optional when `_writev()` is implemented #29639 * tls: * Add option to override signature algorithms #29598 * util: * Add `encodeInto` to `TextEncoder` #29524 * worker: * The `worker_thread` module is now stable #29512 PR-URL: #29695

theanarkh · 2023-01-13T08:53:31Z

@eugeneo Can we use connectToMainThread API to send a Runtime.evaluate command to V8 inspector for running JavaScript code ? Because connectToMainThread is implemented by RequestInterrupt, and this discussion said that JavaScript code should not be called in RequestInterrupt callback.

nodejs-github-bot added c++ Issues and PRs that require attention from people who are familiar with C++. lib / src Issues and PRs related to general changes in the lib or src directory. labels Jul 26, 2019

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addaleax mentioned this pull request Sep 17, 2019

test: move test-inspector-connect-main-thread to sequential #29582

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This was referenced Sep 17, 2019

src: discard remaining foreground tasks on platform shutdown #29587

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test: fix flaky test-inspector-connect-main-thread #29588

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BridgeAR mentioned this pull request Sep 24, 2019

v12.11.0 proposal #29695

Merged

inspector: new API - Session.connectToMainThread #28870

inspector: new API - Session.connectToMainThread #28870

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eugeneo commented Jul 26, 2019

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eugeneo commented Jul 28, 2019

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