Buildpack Development

The buildpack is based on heroku-buildpack-nginx, but with substantial modifications:

nginx is built with the auth_request module and a minimal number of other modules and dependencies.
The buildpack uses a .profile.d script to configure enviroment, start, and monitor nginx as a background job. The $PORT environment variable passed to the application is changed to a local, not externally accessible port. The script waits for this local port to be bound by the application before nginx is started. This way, the Heroku Dyno Manager/Vegur router does not pass requests to nginx when the application is not yet ready to process them. These changes allow to enable the buildpack with a single command (no need to modify Procfile and to modify an app to listen on a Unix domain socket, as is the case with the original nginx buildpack).
In accordance with Heroku guidance, nginx is terminated gracefully on SIGTERM.
nginx configs are modified to perform authentication/authorization before requests are forwarded to the application. The buildpack doesn't currently support supplying a custom nginx.conf.
Configuration templates are changed to use envsubst instead of more powerful erb templates. erb required the buildpack to install Ruby on Heroku stack 22.

Upgrading Nginx or changing compilation options

Use only stable, even-numbered Nginx releases.

Revise the version variables or compilation options in scripts/build_nginx, and then run the builds in a container (requires Docker) via:

$ make build

The binaries will be packed into tar files and placed in the repository's root directory. Commit & pull-request the resulting changes.

Get WWWHISPER_URL by running heroku config for a Heroku app with the wwwhisper add-on enabled.

WWWHISPER_URL="PUT_YOUR_WWWHISPER_URL_HERE" ./scripts/devel_start