Gem::Ext::BuildError: ERROR: Failed to build gem native extension. postgresql and ROR

Question

I need to install postgresql in production environment in an application ROR for after use this with heroku, but when I try to install the gem 'pg' the following error is triggered. I'm a newbie, so I don't know that do

I'm using ruby 1.9.3p547 (2014-05-14 revision 45962) [i686-linux] rails

Rails 3.2.19 Ubuntu 12.04

GemFile

source 'https://rubygems.org'

gem 'rails', '3.2.19'

# Bundle edge Rails instead:
# gem 'rails', :git => 'git://github.com/rails/rails.git'

gem 'mysql2'
gem 'hirb'

# Gems used only for assets and not required
# in production environments by default.
group :assets do
  gem 'sass-rails',   '~> 3.2.3'
  gem 'coffee-rails', '~> 3.2.1'

  # See https://github.com/sstephenson/execjs#readme for more supported runtimes
  # gem 'therubyracer', :platforms => :ruby

  gem 'uglifier', '>= 1.0.3'
end

gem 'jquery-rails'

group :production do
  gem 'pg'

end


# To use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'

# To use Jbuilder templates for JSON
# gem 'jbuilder'

# Use unicorn as the app server
# gem 'unicorn'

# Deploy with Capistrano
# gem 'capistrano'

# To use debugger
# gem 'debugger'

The problem appears when I run bundle update or bundle install

Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    /home/fernando/.rvm/rubies/ruby-1.9.3-p547/bin/ruby -r ./siteconf20141203-14261-3uu564.rb 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
    --without-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=/home/fernando/.rvm/rubies/ruby-1.9.3-p547/bin/ruby
    --with-pg
    --without-pg
    --with-pg-config
    --without-pg-config
    --with-pg_config
    --without-pg_config
    --with-pg-dir
    --without-pg-dir
    --with-pg-include
    --without-pg-include=${pg-dir}/include
    --with-pg-lib
    --without-pg-lib=${pg-dir}/lib

extconf failed, exit code 1

Gem files will remain installed in /home/fernando/.rvm/gems/ruby-1.9.3-p547@ticket_master/gems/pg-0.17.1 for inspection.
Results logged to /home/fernando/.rvm/gems/ruby-1.9.3-p547@ticket_master/extensions/x86-linux/1.9.1/pg-0.17.1/gem_make.out
An error occurred while installing pg (0.17.1), and Bundler cannot continue.
Make sure that `gem install pg -v '0.17.1'` succeeds before bundling.

Answer 1

Your problem is described in the log No pg_config... trying anyway.

This config is related to the libpq dependency, when I was starting with rails I faced this kind of problems, so, I think that the answer is just follow the following steps

Run this command in your console.

sudo apt-get install libpq-dev 
sudo gem install pg