0001-buildpack-order.md

Proposed Buildpack Ordering in a Builder

Summary

pack inspect-builder gcr.io/paketo-buildpack/builder should display a valid Detection Order.

Motivation

After a change to the builder detection order it became impossible for php apps to detect, because nginx and httpd were before php in the detect order. The httpd.conf or nginx.conf included in php apps will cause the nginx or http buildpacks to detect true before php ever gets to run detect, making it impossible to access the php buildpack.

Detailed Explanation

We propose the following order based on the historical needs of app developers:

• paketo-buildpacks/staticfile
• paketo-community/ruby
• paketo-buildpacks/dotnet-core
• paketo-buildpacks/nodejs
• paketo-buildpacks/go
• paketo-community/python
• paketo-buildpacks/php
• paketo-buildpacks/nginx
• paketo-buildpacks/httpd
• paketo-buildpacks/java
• paketo-buildpacks/procfile

Any new buidpack will need careful consideration before deciding its place in the order.

Rationale and Alternatives

An alternative solution can be found here, in which we propose an algorithm to order buildpacks.

This was rejected because, based on experience in cloud foundry, we found that a certain ordering makes the most sense for the most developers.

For example, dotnet-core apps often contain package.json files, so dotnet-core must come before nodejs.

Also, staticfile must come first because it can not infer detection from the source code, but must rely on buildpack.yml property.