Inject commit SHA or bundle ID into FAB, for things like Rollbar

In https://github.com/bitgenics/linc/issues/14 @qnm mentioned he needs a way to set a unique value for Rollup that changes whenever the Javascript source changes.

Right now the work-around is to use the repository tree_id, but that isn’t ideal, because now the bundle changes on every repository change, even if that change never got into the bundle.

With a pre-package hook in fab-compile we could do something like calculate a checksum of the client JavaScript assets and set that as a id in the settings.

[evanderkoogh]

Oh yeah, loading sourcemaps at runtime is absolutely a terrible idea 😃

The problem is that a bundle_id is a hash of the entire FAB, so can only be made after the entire FAB has been built, which is well after webpack finished.

So I think the ideal solution would be to generate the sourcemaps during built, figure out the bundle_id after FAB is built and upload them to Rollbar with the bundle_id. And then use the ServerContext.bundle_id to pass that on to HTML.

That will also bundle your errors for commits where the code was actually the same.

But it will probably be easier to just get the commit_sha during build and use that as normal.

I’ll try to find some time to sit with @geelen to see if it is possible to capture this logic in a FAB plugin. Would be great to be able to solve this for any FAB once and for all 😃

[qnm]

This is for sourcemaps, so for context the process is roughly this:

1. build occurs, assets are created, including sourcemaps
2. we pick a unique id, could be a built identifier, or a git SHA
3. sourcemaps are loaded into Rollbar using e.g. curl or https://github.com/thredup/rollbar-sourcemap-webpack-plugin, containing the the ID in (2) as part of the payload
4. rollbar runtime is configured using the same id in (2). this allows the running code to be associated with the correct source map

How can I have an ID available at both compile-time and run-time?

I’m assuming that loading source maps into Rollbar at run-time is a bad idea.