Heroku error when launch rails3.1 app missing postgres gem

Question

I am trying to deploy to heroku.

Rails 3.1.0.rc4,

I get the following error from Heroku logs:

Starting process with command: `thin -p 48902 -e production -R /home/heroku_rack/heroku.ru start`
2011-06-20T11:25:44+00:00 app[web.1]: /app/.bundle/gems/ruby/1.9.1/gems/activerecord-3.1.0.rc4/lib/active_record/connection_adapters/abstract/connection_specification.rb:71:in `rescue in establish_connection': Please install the postgresql adapter: `gem install activerecord-postgresql-adapter` (pg is not part of the bundle. Add it to Gemfile.) (RuntimeError)

I tried to install the activerecord-postgresql-adapter but then I get this error:

Could not find gem 'activerecord-postgresql-adapter (>= 0)' in any of the gem sources listed in your Gemfile.

So I tried to add this to my gem file

gem 'pg'

which produced this error:

Installing pg (0.11.0) with native extensions /Users/imac/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:533:in `rescue in block in build_extensions': ERROR: Failed to build gem native extension. (Gem::Installer::ExtensionBuildError)

any ideas?

Answer 1

You don't have to install Postgres locally. In your Gemfile, put 'pg' in group :production, as johnny-grass suggests, and then when you run bundle, just specify --without production, like this:

bundle --without production

Unfortunately, you have to remember this argument when you run bundler, but at least you don't have to install and maintain postgres locally.

Please note that Heroku "strongly recommends against" using sqlite, saying that "Your production and development environment should be as close to identical as possible" http://devcenter.heroku.com/articles/rails3

Answer 2

Do you have PostgreSQL installed on your computer? If you don't then install it first, then install the pg gem.

# gemfile
group :production do
  gem 'therubyracer-heroku', '0.8.1.pre3' # you will need this too
  gem 'pg'
end

Answer 3

I found a solution in this Heroku article.

As Jared said, they suggest to create a different group for postgresql.