feat(node): Application mode sessions

[ahmedetefy]

This PR adds API to capture application mode sessions associated with a specific release, and send them to Sentry as part of the Release Health functionality.

• When you call Sentry.init we start a session
• autoSessionTracking is now a global option in both @sentry/browser & @sentry/node and is true by default
• If we are not able to detect (or the users sets) a release we do not send any sessions
• A session is crashed if an error/promise was captured with the global handlers and handled: false
• A session is errored if an error/promise was captured with handled: true fix(node): Sets mechanism handled to false when it is a crash #3493
• beforeExit we capture it -> sending it to Sentry
  • if the session state was in a terminal, we do not send it before the process exists because our error handlers captured it before

See getsentry/develop#323 for more info

[github-actions]

size-limit report

Path	Size
@sentry/browser - CDN Bundle (gzipped)	20.63 KB (-0.02% 🔽)
@sentry/browser - Webpack	21.5 KB (0%)
@sentry/react - Webpack	21.53 KB (0%)
@sentry/browser + @sentry/tracing - CDN Bundle (gzipped)	27.92 KB (0%)

[rhcarvalho]

Looks really good now. Thanks for the hard work! We're missing here a test exercising and showing how a user creates an application mode session (using the @sentry/node SDK).

[rhcarvalho]

• JS over TS was probably a bad idea; missing linters and type checks.
• need to be sure process.on('exit', ...) is the right approach
• we're limited to one test with the current approach

[rhcarvalho]

Wrong type here, this is the signature of close:

public close(timeout?: number): PromiseLike<boolean>

[ahmedetefy]

Findings so far:

1. process.on('exit') will not function correctly because endSession is asynchronous and according to https://nodejs.org/api/process.html#process_event_exit

Listener functions must only perform synchronous operations. The Node.js process will exit immediately after calling the 'exit' event listeners causing any additional work still queued in the event loop to be abandoned. In the following example, for instance, the timeout will never occur:

Possible Solutions

• https://stackoverflow.com/questions/40574218/how-to-perform-an-async-operation-on-exit
• Or using beforeExit event, however beforeExit has certain limitations

The 'beforeExit' event is not emitted for conditions causing explicit termination, such as calling process.exit() or uncaught exceptions.

The 'beforeExit' should not be used as an alternative to the 'exit' event unless the intention is to schedule additional work.

https://nodejs.org/api/process.html#process_event_beforeexit

[HazAT]

nit: Let's explain why we do this here.
If I understood correctly it's because if a session is in that state we've already sent the session to sentry and we don't want to do it twice.