Add support for Heroku-22

[edmorley]

In order to support Heroku-22 we need to generate new binaries, so it makes sense to build the latest versions for it and the other stacks rather than something outdated.

The binary build process for this buildpack uses the default nginx version specified by ngx_mruby. As such, updating ngx_mruby from 2.2.3 to 2.2.4 means the bundled nginx version is also updated from 1.19.0 to 1.21.3:
https://github.com/matsumotory/ngx_mruby/blob/v2.2.3/nginx_version
https://github.com/matsumotory/ngx_mruby/blob/v2.2.4/nginx_version

Changes:
https://github.com/matsumotory/ngx_mruby/releases/tag/v2.2.4
https://nginx.org/en/CHANGES

GUS-W-10346704.

[edmorley]

So I spotted there was a typo in the Makefile which meant the wrong Docker image was used to perform the Heroku-22 build. After fixing that and rebuilding, I'm running into:

...
(cd /tmp/ngx_mruby.42Hc/mruby && rake -j 4 MRUBY_CONFIG=/tmp/ngx_mruby.42Hc/build_config.rb NGX_MRUBY_CFLAGS="" NGX_MRUBY_LDFLAGS="")
/bin/sh: 1: rake: not found

Which is due to the removal of system Ruby from Heroku-22. The whole buildpack relies upon Ruby (not just at build time), so this is going to require a bit of a different approach.

That said, part of me wonders whether it's just time to deprecate this buildpack in favour of https://github.com/heroku/heroku-buildpack-nginx ?

[edmorley]

I've split the version bump parts of this out to #240, and will close this out for now in favour of opening a new PR for Heroku-22 once the Ruby aspect figured out.

[edmorley]

/bin/sh: 1: rake: not found
Which is due to the removal of system Ruby from Heroku-22. The whole buildpack relies upon Ruby (not just at build time), so this is going to require a bit of a different approach.

It seems our options are either:

1. Have this buildpack vendor Ruby (eg from the archives used by the Ruby buildpack) on Heroku-22+
2. If Ruby not found during the build, error out and say users need to manually add the Ruby buildpack prior to this one
3. Not support Heroku-22, and instead deprecate this buildpack in favour of the nginx buildpack
4. Add Ruby back to the stack image for Heroku-22

@hone, thoughts? :-)

[edmorley]

cc @heroku/languages (decision needed here ref how to handle system Ruby no longer being in the Heroku-22 stack image - see above for possible options)

[joshwlewis]

I'd be in favor of option 2. But I'd suggest the error messaging giving users two options: a) add the ruby buildpack, or b) switch to the nginx buildpack. For some folks, switching to the nginx buildpack might be a better choice.

[edmorley]

@dzuelke @schneems Any thoughts? :-)

[edmorley]

@hone (as original buildpack creator) + anyone else: As a heads up, our current thinking is to go with option (3):

Not support Heroku-22, and instead deprecate this buildpack in favour of the nginx buildpack

The plan is to have a migration guide in the README of this buildpack, that can be linked to from a Heroku-22 specific failure message during bin/compile, plus also from the Heroku-22 migration help on Dev Center. On older stacks we should also emit a warning that this buildpack is deprecated.

The migration guide in the README will suggest running a one-off dyno to trigger the script that generates the nginx config, then cat it, so that the resultant generated nginx config can be placed into the app's source ready for use by the nginx buildpack. That doesn't cover the dynamic request-rewriting parts of this buildpack, but it will should cover many of the more simple use-cases. We may also want to add some more examples of nginx configs to the nginx buildpack repo itself:
https://github.com/heroku/heroku-buildpack-nginx/tree/main/config

Lastly, we'll need to notify https://github.com/mars/create-react-app-buildpack that they'll need to migrate to the nginx buildpack too. (Edit: Filed mars/create-react-app-buildpack#200)

[edmorley]

#243 is now open for deprecating this buildpack