Error with 'pg gem' installation when running 'bundle install'

Question

I'm suddenly running into this issue when running 'bundle install'. Everything seems to be installing correctly, but then I run into an issue with 'pg', as so many others seem to do. As the message says, I try running 'gem install pg - '0.12.2'' but it still fails.

I'm on Snow Leopard 10.6 and this is the error I'm getting:

Installing pg (0.12.2) with native extensions 
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

        /Users/thomaskim/.rvm/rubies/ruby-1.9.3-p327/bin/ruby extconf.rb 
checking for pg_config... no
No pg_config... trying anyway. If building fails, please try again with
 --with-pg-config=/path/to/pg_config
checking for libpq-fe.h... no
Can't find the 'libpq-fe.h header
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
    --with-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/Users/thomaskim/.rvm/rubies/ruby-1.9.3-p327/bin/ruby
    --with-pg
    --without-pg
    --with-pg-dir
    --without-pg-dir
    --with-pg-include
    --without-pg-include=${pg-dir}/include
    --with-pg-lib
    --without-pg-lib=${pg-dir}/lib
    --with-pg-config
    --without-pg-config
    --with-pg_config
    --without-pg_config


Gem files will remain installed in /Users/thomaskim/.bundler/tmp/1336/gems/pg-0.12.2 for inspection.
Results logged to /Users/thomaskim/.bundler/tmp/1336/gems/pg-0.12.2/ext/gem_make.out
An error occurred while installing pg (0.12.2), and Bundler cannot continue.
Make sure that `gem install pg -v '0.12.2'` succeeds before bundling.

Answer 1

First you need to make sure you have command line tools (package for Xcode) installed. Since you're on old version of OSX - you will have to research how to do that.

Than, using homebrew install postgress

brew install postgres 

After that, everything should bundle with no issues.

Answer 2

It appears that you do not have postgres installed properly. I got a similar error when I was trying to install a pg module with npm. It disappeared after installing postgres properly. Here's a link to download: http://www.postgresql.org/download/macosx/

Answer 3

If you run rails on your machine only in dev mode and use sql lite for that, you need don't need to install the production bundles.

So if your gemfile looke like that:

group :production do
  gem 'pg'
end

Try installing the bundles with the following command:

gem install --without production