1645427 - Capture output of child processes for Sentry breadcrumbs

Status: NEW

(Firefox Build System :: Mach Core, enhancement, P3)

Description

[Mitchell Hentges [:mhentges] 🦀]

For Sentry tickets like this one, it's not clear what the error was. We know that mach artifact toolchain --from-build win32-minidump-stackwalk failed, but it's not clear why.

If we could attach output from child processes to the Sentry event (maybe just the output of the last command called?) then that could provide insight to the failure.

Comment 1

[Mitchell Hentges [:mhentges] 🦀]

I'm worried about potential downsides to this approach:

• Performance: is listening and piping output data going to be a perf hit?
• Personal information: what if a subprocess prints information that shouldn't be sent to Sentry?
  • This is probably less likely if we just capture stderr - will this be enough information?

NI Ricky because you'll probably have some insight here

Comment 2

[Mitchell Hentges [:mhentges] 🦀]

Talked to Ricky a bit directly:

• This is tricky for "pass-though" stdout/stdin, which might behave funky if we try to intercept the data. Intercepting the data requires the allocation of new io handles, which might cause the subprocesses to behave differently. This gets more questionable on Windows
• Doing some kind of global hook would be spicy and problematic. We'd probably want to refactor to use an abstraction that captures the data, but this requires a larger amount of work adjusting each callsite.