inspector: support non-main contexts #14465

eugeneo · 2017-07-25T01:05:36Z

Checklist

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

Affected core subsystem(s)

inspector: non-main contexts are now reported to an inspector.

This is a suggested implementation of non-main contexts support for the inspector. It is based on a recently landed V8 patch that is included into this pull request.

This solution has a number of shortcomings that need to be fixed in V8:

Inspector console is accessible from the new contexts. This is not the V8 console, e.g. using it will not print anything to stdout.
Contexts are retained by the inspector for the duration of the session. This only happens if some event is reported that concerns inspector - e.g. console output or breakpoint hit.

This pull request is a suggested alternative to #14231 - note that 14231 also adds the inspector console.

CC: @ak239

_{refack added: link to V8 patch's Gerrit}

refack · 2017-07-25T09:15:51Z

@eugeneo do you know if the patch will be available in mainline V8 5.9 or 6.0?
/cc @nodejs/v8 @nodejs/v8-inspector @TimothyGu @nodejs/diagnostics

TimothyGu · 2017-07-25T02:02:00Z

src/inspector_agent.cc

+    return;
+  std::ostringstream name;
+  name << "VM Context " << next_context_number_++;
+  client_->contextCreated(context, name.str());


Can you decouple VM from Inspector Agent? Also, can you add support for customizing VM context name and origin from JS?

eugeneo · 2017-07-25T16:04:46Z

@refack looks like V8 commit got rolled back tonight. This PR is on hold until the issue is resolved...

@TimothyGu should I make context registration happen in JS land in lib/vm.js? Re: name - what is your suggestion? I can add a symbol that is can be added to a sandbox object - e.g:

const sandbox = {};
sandbox[require('inspector').CONTEXT_NAME] = 'my context';
const ctx = require('vm').createContext(sandbox);

Surely, it will be optional.

TimothyGu · 2017-07-26T00:37:07Z

I'd prefer them to be options to createContext much like what I implemented for inspector.attachContext.

I'm fine with registering it in C++. I just want things in the Agent to be usable by everything rather than by only one thing, and want Agent to include support for every param Inspector has to offer, namely groupId, name, origin, and auxData (which is a JSON string used by Dev Tools for formatting purposes). Of course, some of these things may be unfit to be exposed to the JS side, like groupId and auxData, but Agent should be agnostic to all that IMO.

eugeneo · 2017-08-02T18:01:30Z

A new version of the V8 patch landed, should not get rolled back now... I backported it and rebased this pull request.

@TimothyGu I am still not sure what you are proposing. Should those options come through the vm.js module or you want the users to explicitly opt-in the contexts into inspector tracking?

eugeneo · 2017-08-02T21:22:23Z

CI link: https://ci.nodejs.org/job/node-test-pull-request/9459/

I believe this PR is ready for the review. It does not expose any new API and is not visible to the users, except that breakpoints will start working in new contexts. If there is a need to add an API to name the contexts, etc - that can be done separately at the later time.

jkrems

LGTM

jkrems · 2017-08-02T21:55:05Z

src/node_contextify.cc

@@ -357,6 +357,7 @@ class ContextifyContext {

  static void WeakCallback(const WeakCallbackInfo<ContextifyContext>& data) {
    ContextifyContext* context = data.GetParameter();
+


I assume this is left over from a previous iteration?

That was a line for a printf to check if the context is GCed :)

Thanks, I removed it.

eugeneo · 2017-08-02T22:38:57Z

CI failures do not seem to be related to this change.

V8 patch will be in V8 6.1 release.

ofrobots · 2017-08-04T00:15:37Z

V8 CI: https://ci.nodejs.org/job/node-test-commit-v8-linux/838/

@eugeneo what are the chances of upstream approving a backport to 6.0?

Normally we bump the V8 version when floating a patch backwards. But given that V8 6.0 is still supported upstream, it is not safe to do given that upstream will be bumping versions too. (/cc @targos in case we bring in another update of 6.0 – we will need to re-float this at that time.) If upstream backports to 6.0, this problem goes away.

targos · 2017-08-04T06:28:37Z

Could we have the patch merged to 6.1?

TimothyGu · 2017-08-04T09:12:16Z

@eugeneo Is the console property still unconditionally added? If it's not possible to remove it then at least some documentation is warranted.

eugeneo · 2017-08-04T15:32:01Z

CC: @ak239

Alexei, can you help with the information about V8 version and the backport?

eugeneo · 2017-08-04T21:36:20Z

@eugeneo Is the console property still unconditionally added? If it's not possible to remove it then at least some documentation is warranted.

I see console unconditionally added in master, even without this patch.E.g. ./node -e "console.log(require('vm').runInNewContext('console', {}))" on master prints console object, while same line on an 8.x version throws an exception ReferenceError: console is not defined

alexkozy · 2017-08-04T21:40:32Z

Ok, let me split problems: console and non-main context inspection are two different problems.
About CL required for non-main context inspection:
V8 CL is landed in 6.2. It's some kind of revert, since it just restored behavior which exists around 5.8 or 5.9. Unfortunately it's almost impossible to backport it to earlier version of V8 since AFAIK if we backport it to 6.1 or 6.0 then we need to merge it to corresponded Chrome version but this CL is not needed by Chrome (blink calls contextDestroyed method manually and manage context lifetime in different way). So is it possible to backport it only inside of Node.js?

About console:
Console was added in https://codereview.chromium.org/2785293002 and available in V8 since 6.0 so it sounds to me like if node 8 use v8 6.0 then it should always have builtin console object on any context.

eugeneo · 2017-08-09T23:13:49Z

Per the process, this PR can be landed now (48 hours had passed, there's LGTM). Any last minute objections?

TimothyGu

My original concern about console has resolved itself in 6.0 it seems.

Pajn · 2017-08-10T06:45:15Z

What is the status of this, how long may it take before this and the V8 patch is propagated to a release?
The V8 patch seems to have been reverted as well, which feels less fun. Would be great to get debugging support working with Jest in Node 8

eugeneo · 2017-08-10T16:01:59Z

@Pajn V8 patch is still there :) - v8/v8@f19b889

eugeneo · 2017-08-11T18:37:25Z

Landed in two commits - cherry pick as
73c59bb and Node side as 63fc89a

Original commit message: [inspector] support for cases when embedder doesn't call contextDestroyed Node.js doesn't have good place to call contextDestroyed. We need to cleanup everything on our side to allow clients to not call contextDestroyed method. [email protected],[email protected] Bug: none Change-Id: Ibe3f01fd18afbfa579e5db66ab6f174d5fad7c82 Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_chromium_rel_ng Reviewed-on: https://chromium-review.googlesource.com/575519 Reviewed-by: Dmitry Gozman <[email protected]> Commit-Queue: Aleksey Kozyatinskiy <[email protected]> Cr-Original-Commit-Position: refs/heads/master@{#46849} Reviewed-on: https://chromium-review.googlesource.com/596549 Cr-Commit-Position: refs/heads/master@{#47060} Ref: https://chromium.googlesource.com/v8/v8.git/+/f19b889be801bdebc04c49090e37c787f7ba8805 PR-URL: #14465 Reviewed-By: Jan Krems <[email protected]> Reviewed-By: Timothy Gu <[email protected]> Reviewed-By: Aleksey Kozyatinskiy <[email protected]>

This enables inspector support for contexts created using the vm module. PR-URL: #14465 Reviewed-By: Jan Krems <[email protected]> Reviewed-By: Timothy Gu <[email protected]> Reviewed-By: Aleksey Kozyatinskiy <[email protected]>

Notable changes * **HTTP2** * Experimental support for the built-in `http2` has been added via the `--expose-http2` flag. [#14239](#14239) * **Inspector** * `require()` is available in the inspector console now. [#8837](#8837) * Multiple contexts, as created by the `vm` module, are supported now. [#14465](#14465) * **N-API** * New APIs for creating number values have been introduced. [#14573](#14573) * **Stream** * For `Duplex` streams, the high water mark option can now be set independently for the readable and the writable side. [#14636](#14636) * **Util** * `util.format` now supports the `%o` and `%O` specifiers for printing objects. [#14558](#14558) PR-URL: #14811

Notable changes * **HTTP2** * Experimental support for the built-in `http2` has been added via the `--expose-http2` flag. [#14239](nodejs/node#14239) * **Inspector** * `require()` is available in the inspector console now. [#8837](nodejs/node#8837) * Multiple contexts, as created by the `vm` module, are supported now. [#14465](nodejs/node#14465) * **N-API** * New APIs for creating number values have been introduced. [#14573](nodejs/node#14573) * **Stream** * For `Duplex` streams, the high water mark option can now be set independently for the readable and the writable side. [#14636](nodejs/node#14636) * **Util** * `util.format` now supports the `%o` and `%O` specifiers for printing objects. [#14558](nodejs/node#14558) PR-URL: nodejs/node#14811

nodejs-github-bot added the lib / src Issues and PRs related to general changes in the lib or src directory. label Jul 25, 2017

refack added inspector Issues and PRs related to the V8 inspector protocol v8 engine Issues and PRs related to the V8 dependency. labels Jul 25, 2017

TimothyGu reviewed Jul 25, 2017

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jkrems approved these changes Aug 2, 2017

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TimothyGu approved these changes Aug 9, 2017

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TimothyGu mentioned this pull request Aug 10, 2017

[wip] src, inspector: support opted-in VM contexts #14231

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alexkozy approved these changes Aug 10, 2017

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eugeneo closed this Aug 11, 2017

eugeneo deleted the contexts-v8 branch August 11, 2017 18:35

eugeneo merged commit 63fc89a into nodejs:master Aug 11, 2017

This was referenced Aug 11, 2017

v8_inspector: Support the V8 debugger from within VM contexts #7593

Closed

inspector: add contexts when using vm module #9272

Closed

addaleax mentioned this pull request Aug 13, 2017

v8.4.0 proposal #14811

Merged

addaleax added the notable-change PRs with changes that should be highlighted in changelogs. label Aug 13, 2017

This was referenced Aug 15, 2017

debugger; and breakpoints don't work with node --inspect jestjs/jest#1652

Closed

🎨 add first class debugging support facebook/create-react-app#2041

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Trott mentioned this pull request Aug 16, 2017

node --inspect ignores debugger statements and breakpoints inside vm.runInContext #12096

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MylesBorins added the baking-for-lts PRs that need to wait before landing in a LTS release. label Sep 19, 2017

honzajavorek mentioned this pull request Jan 11, 2018

When using Node 8, the console is available for the sandboxed code apiaryio/pitboss#13

Closed

MylesBorins removed the baking-for-lts PRs that need to wait before landing in a LTS release. label Aug 17, 2018

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inspector: support non-main contexts #14465

inspector: support non-main contexts #14465

eugeneo commented Jul 25, 2017 •

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eugeneo commented Aug 11, 2017

		@@ -357,6 +357,7 @@ class ContextifyContext {

		static void WeakCallback(const WeakCallbackInfo<ContextifyContext>& data) {
		ContextifyContext* context = data.GetParameter();

inspector: support non-main contexts #14465

inspector: support non-main contexts #14465

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eugeneo commented Jul 25, 2017 • edited by refack Loading

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