by mcolyer

GitHub Readme.md

Heroku buildpack: libxml2

This is a Heroku buildpack of libxml2.

Unfortunately libxml2-2.7.6 has a nasty bug when using Nokogiri, this buildpack includes version 2.7.7 which fixes the bug.

Unfortunately after much effort, attempting to set an environment variable to force nokogiri to build against the injected library rather than the system library doesn't work. However jamming in the injected version at runtime seems to fix my bug (via LD_PRELOAD).

  • LD_LIBRARY_PATH - doesn't seem to have an effect.
  • Which requires that we use LD_PRELOAD to fix the issue.
  • LIBRARY_PATH would seeming do what we want but it comes after paths specified by -L to gcc so it won't override the system library. Unfortunately mkmf in nokogiri insists on including /usr/lib/ in the Makefile which I believe is due to the fact those flags are used when building ruby.
  • Writing to /opt/* /usr/* is restricted, so we can't slip in our versions that way.
  • Writing libraries to vendor/ruby*/lib don't seem to be picked up.
  • bundle config build.nokogiri --with-xml2-lib=dir doesn't inject it's -L soon enough.


Example usage:

$ heroku create --stack cedar --buildpack https://github.com/mcolyer/heroku-buildpack-libxml2.git

# or if your app is already created:
$ heroku config:add BUILDPACK_URL=https://github.com/mcolyer/heroku-buildpack-libxml2.git

$ git push heroku master

Instructions for building the binary

heroku run bash

cd ~/
mkdir -p vendor/
cd vendor
curl -O "http://xmlsoft.org/sources/libxml2-2.7.7.tar.gz"
tar -zxvf libxml2-2.7.7.tar.gz
cd libxml2-2.7.7
./configure --prefix /app/vendor/libxml2
make install
cd ..
tar -cvjf libxml2-2.7.7-x86_64.tar.bz2 libxml2

curl  -o s3 https://raw.github.com/nzoschke/s3/master/s3.py
chmod +x s3

S3_SECRET_ACCESS_KEY= S3_ACCESS_KEY_ID= ./s3 put s3://some-bucket/libxml2-2.7.7-x86_64.tar.bz2
curl --request PUT --upload-file libxml2-2.7.7-x86_64.tar.bz2 "URL"


Use my fork of heroku-buildpack-multi to allow for proper export of variables to subsequent buildpacks, which currently doesn't do anything useful.