process: delay and simplify the setup of async hooks trace events

[joyeecheung]

src: move async hooks trace events setup to pre_execution.js

Reasons:

• Moves more environment-dependent setup out of bootstrap/node.js
• No async operations should be done before the call to
  the setup functions in pre_execution.js so no async hooks should be
  triggered before that. Therefore it is safe to delay the setup
  until then.

process: simplify the setup of async hooks trace events

• Remove trace_category_state from Environment - since this is
  only accessed in the bootstrap process and later in the
  trace category update handler, we could just pass the initial
  values into JS land via the trace_events binding, and pass
  the dynamic values directly to the handler later, instead of
  accessing them out-of-band via the AliasedBuffer.
• Instead of creating the hooks directly in
  trace_events_async_hooks.js, export the hook factory and
  create the hooks in trace category state toggle.

test: add test for node.async_hooks tracing in workers

test: add test for dynamically enabling node.async_hooks tracing

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

[nodejs-github-bot]

@joyeecheung build started: https://ci.nodejs.org/blue/organizations/jenkins/node-test-pull-request-lite-pipeline/detail/node-test-pull-request-lite-pipeline/2583/pipeline

[joyeecheung]

CI: https://ci.nodejs.org/job/node-test-pull-request/20747/

[jasnell]

Trace events are not available in worker threads.

I think I missed something. Why is this? They should be available.

[addaleax]

@jasnell Right – it’s just the JS module that’s not accessible… Is there a test for this code? I think that should have failed in CI if this PR breaks trace_events + Workers, but it looks like everything passed here

[joyeecheung]

@addaleax I don't think there is a test, it could be added but I don't think the dynamic switch can be tested in workers since dynamically enabling the category requires the trace_events module. I could add the preparation code to the worker bootstrap script though, at least that allows us to test the initial enabling of the events.

[joyeecheung]

I added the setup to the worker bootstrap, fixed a bug in the C++ part (when the category is enabled the value is 0x7, not 1, so we should test for != 0 instead), and added two tests. @jasnell @addaleax PTAL.

CI: https://ci.nodejs.org/job/node-test-pull-request/20879/

[joyeecheung]

Added hasTracing guards in tests. Not sure why the CI complained about missing dynamically linked deps and libc, let's see what happens in a new CI: https://ci.nodejs.org/job/node-test-pull-request/20907/

[joyeecheung]

@richardlau Thanks! I've updated the env passed to spawnSync. CI: https://ci.nodejs.org/job/node-test-pull-request/20913/

[joyeecheung]

Landed in dec3dad...85df2c4