trace_events: add version metadata

[jasnell]

Use TRACE_EVENT_METADATA1 to include Node.js, v8, and libuv version
details in the trace log (helpful for log analysis when trace detail
may vary from one Node.js version to another).

/cc @ofrobots

Checklist

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

[jasnell]

CI: https://ci.nodejs.org/job/node-test-pull-request/14987/

[jasnell]

Failures in CI are known flakies

[cjihrig]

Is there a reason not to more closely mimic process.versions?

[jasnell]

Mimic in which way?

[ofrobots]

LGTM w/ nit.

[ofrobots]

nit: I'm trying to understand the + 1. If you're skipping the v in the version string: 1) why? 2) it would be good to add a comment explaining what the + 1 does as it is not immediately obvious. I would prefer if the v was included too.

[devsnek]

i thought we had a lint rule against messing with pointers like that

[jasnell]

It is for consistency with the value of process.versions.node (which does not include the v)

[richardlau]

If we don't want the v why not use NODE_VERSION_STRING instead?

node/src/node_version.h

Line 65 in 32873c5

#defineNODE_VERSION "v" NODE_VERSION_STRING

[jasnell]

@ofrobots ... btw, I was going to output all of the versions with a single TRACE_EVENT_METADATA call but the underlying implementation only supports a single argument, and I did not want to have to create and allocate a serializable structure for the version information.

I don't want this to get too out of sync with the V8 version, but it would be helpful to have a TRACE_EVENT_METADATA macro that (a) was not one of the INTERNAL_ macros and (b) supported an arbitrary number of arguments.

[cjihrig]

Mimic in which way?

I meant using the same names (for example n-api vs napi), and including the other missing dependencies.

[jasnell]

I meant using the same names (for example n-api vs napi), and including the other missing dependencies.

Certainly can do that, yes.

[jasnell]

Updated .... After talking it over more with @ofrobots ... I removed everything but the node version in this to give us more flexibility later. We need to think about the best approach to handling complex data as opposed to emitting multiple trace events. Emitting the node version covers the most basic use case for this -- that is, knowing what Node.js version generated the trace file -- so it covers the immediate need.

[jasnell]

New CI: https://ci.nodejs.org/job/node-test-pull-request/15173/

[jasnell]

Landed in e60eed1