feat: support to build more gems

Author: Steven Chen

Dockerfile

@@ -1,7 +1,8 @@
 FROM centos:centos6
 
 
-ADD ./Gemfile /opt/build/
+ADD ./Gemfile  /opt/build/
+ADD ./build.sh /opt/build/
 
 RUN \
   yum update -y && \
@@ -17,8 +18,9 @@ RUN \
 RUN \
   gem update --system && \
   cd /opt/build && \
-  bundle install --path vendor/bundle && \
-  cd vendor/bundle/ruby && \
-  tar zcvf nokogiri-1.8.2.tar.gz 2.2.0/extensions/x86_64-linux/2.2.0-static/nokogiri-1.8.2 && \
-  mv nokogiri-1.8.2.tar.gz /opt/build && \
-  cd -
+  /bin/bash build.sh
+#  bundle install --path vendor/bundle && \
+#  cd vendor/bundle/ruby && \
+#  tar zcvf nokogiri-1.8.2.tar.gz 2.2.0/extensions/x86_64-linux/2.2.0-static/nokogiri-1.8.2 && \
+#  mv nokogiri-1.8.2.tar.gz /opt/build && \
+#  cd -

Gemfile

@@ -1,4 +1,7 @@
 ruby '2.2.2'
 source 'https://rubygems.org'
 
+# Add you gems here
 gem 'nokogiri', '1.8.2'
+gem 'json', '1.8.2'
+

README.md

@@ -1,16 +1,15 @@
-# Ruby Gem native extensions
+# Building Ruby gem native extensions
 
-Some Ruby Gems depend on C/C++ native extensions which makes it platform dependent. `nokogiri` will
-be one of these. [Traveling Ruby](https://github.com/phusion/traveling-ruby) provides a solution to
-include native extensions for several specific platforms, however, the extensions provided by
-Traveling Ruby is quite outdated and it is quite non-trivial to build its packages. I encountered
-failures with `yum update` in the `chroot` environment every now and then. Thus, I would rather
-build it on my own.
+Some Ruby gems depend on C/C++ native extensions which are platform dependent. `nokogiri` is one of
+these. Fortunately, [Traveling Ruby](https://github.com/phusion/traveling-ruby) provides a solution
+to include native extensions for several specific platforms. However, those extensions provided by
+Traveling Ruby are quite obsolete and it is quite non-trivial to build those packages using
+Traveling Ruby. I encountered failures with `yum update` in the `chroot` environment every now and
+then. Thus, I would rather build it on my own.
 
-As a workaround, we can build specific library in `centos:centos6` container and copy over the
-extensions. Note that the final artifact of the extension should contain the following (use
-`nokogiri` as an example), which can be found at
-`ruby/2.2.0/extensions/x86_64-linux/2.2.0-static/xxxx` in your bundle `--path`:
+As a workaround, we can build specific library in `centos:centos6` container and copy those
+extensions after the build. Note that the final artifact of an extension should contain the
+following (use `nokogiri` as an example), which can be found at your bundle `--path`:
 
 ```
 2.2.0
@@ -33,7 +32,13 @@ tar zcvf nokogiri-1.8.2.tar.gz 2.2.0
 ```
 
 Alternatively, the Dockerfile provided in the directory will generate `nokogiri-1.8.2.tar.gz` and
-store it into `/opt/build`. And we can use this tarball as an upgrade for what `Traveling Ruby`
-provides.
+store it into `/opt/build/target`. And we can use this tarball as an upgrade for what `Traveling Ruby`
+provides. To build native extensions for more gems, add those gem into `Gemfile`, and run the
+following:
+
+```
+$ docker build -t rubygem-native-builder .
+$ docker cp rubygem-native-builder:/opt/build/target /path/to/host/directory
+```
 
 Have fun!

build.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+
+set -ex
+
+EXT_DIR=2.2.0/extensions/x86_64-linux/2.2.0-static
+TARGET_DIR=/opt/build/target
+BUNDLE_INSTALL_DIR=/opt/build/vendor/bundle
+
+mkdir -p ${TARGET_DIR}
+bundle install --path ${BUNDLE_INSTALL_DIR}
+cd ${BUNDLE_INSTALL_DIR}/ruby
+
+GEMS=$(ls "${EXT_DIR}")
+
+for gem in $GEMS; do
+  tar zcvf ${gem}.tar.gz ${EXT_DIR}/${gem}
+  mv ${gem}.tar.gz ${TARGET_DIR}
+done