Heroku Continuous Deployment

May 9, 2012 jaymoorthi

A few weeks ago, we rolled out preliminary support for automatic code coverage collection and custom post-build tasks.

Over the coming weeks, we’re rolling out better UIs in front of these features, but if you’re impatient, and you’re up for using our sample rake task, read on for end-to-end continuous deployment.

I’ll describe how we use post-build tasks and environment variables to implement continuous deployment of one of our own apps into Heroku, including running migrations.

Note: If you currently use Tddium’s push-on-pass functionality, this approach replaces it.

Step 1: Setup Environment Variables

The first step is to set ephemeral environment variables in Tddium containing sensitive parameters, like your Heroku app name and credentials.

$ tddium config:add account HEROKU_EMAIL    my_heroku_login_email@example.com
$ tddium config:add account HEROKU_API_KEY  my_heroku_api_key
$ tddium config:add account HEROKU_APP_NAME my_heroku_app_name

$ tddium config:add account HEROKU_EMAIL my_heroku_login_email@example.com

$ tddium config:add account HEROKU_API_KEY my_heroku_api_key

$ tddium config:add account HEROKU_APP_NAME my_heroku_app_name

Tddium’s environment variables allow you to pass this sensitive information to your tests and the post-build hook that we’ll create – without having to check these in to your repository.

You can find your Heroku API key by logging in to your Heroku Account page.

Step 2: Install the Post Build Task

We’ve written up a sample post-build task that will push to Heroku automatically (gist). You can customize this task as you need. Over the next few weeks, we’ll be rolling out a more streamlined UI to make post-build configuration much simpler.

def cmd(c)
  system c
end
namespace :tddium do
  desc "post_build_hook"
  task :post_build_hook do
    # This build hook should only run after CI builds.
    #
    # There are other cases where we’d want to run something after every build,
    # or only after manual builds.
    return unless ENV["TDDIUM_MODE"] == "ci"
    return unless ENV["TDDIUM_BUILD_STATUS"] == "passed"
    
    dir = File.expand_path("~/.heroku/")
    heroku_email = ENV["HEROKU_EMAIL"]
    heroku_api_key = ENV["HEROKU_API_KEY"]
    current_branch = `git symbolic-ref HEAD 2>/dev/null | cut -d"/" -f 3-`.strip
    app_name = ENV["HEROKU_APP_NAME"]
    push_target = "git@heroku.com:#{app_name}.git"
    
    abort "invalid current branch" unless current_branch

    FileUtils.mkdir_p(dir) or abort "Could not create #{dir}"

    puts "Writing Heroku Credentials"
    File.open(File.join(dir, "credentials"), "w") do |f|
      f.write([heroku_email, heroku_api_key].join("n"))
      f.write("n")
    end

    File.open(File.expand_path("~/.netrc"), "a+") do |f|
      [‘api’, ‘code’].each do |host
        f.puts "machine #{host}.heroku.com"
        f.puts "  login #{heroku_email}"
        f.puts "  password #{heroku_api_key}"
      end
    end

    puts "Pushing to Heroku: #{push_target}…"
    cmd "git push #{push_target} HEAD:master –force" or abort "could not push to #{push_target}"
    
    Bundler.with_clean_env do
      puts "Running Heroku Migrations…"
      cmd "heroku run rake db:migrate –app #{app_name}" or abort "aborted migrations"
      puts "Restarting Heroku…"
      cmd "heroku restart –app #{app_name}" or abort "aborted heroku restart"
    end
  end
end

def cmd(c)

system c

end

namespace :tddium do

desc "post_build_hook"

task :post_build_hook do

# This build hook should only run after CI builds.

# There are other cases where we’d want to run something after every build,

# or only after manual builds.

return unless ENV["TDDIUM_MODE"] == "ci"

return unless ENV["TDDIUM_BUILD_STATUS"] == "passed"

dir = File.expand_path("~/.heroku/")

heroku_email = ENV["HEROKU_EMAIL"]

heroku_api_key = ENV["HEROKU_API_KEY"]

current_branch = `git symbolic-ref HEAD 2>/dev/null | cut -d"/" -f 3-`.strip

app_name = ENV["HEROKU_APP_NAME"]

push_target = "git@heroku.com:#{app_name}.git"

abort "invalid current branch" unless current_branch

FileUtils.mkdir_p(dir) or abort "Could not create #{dir}"

puts "Writing Heroku Credentials"

File.open(File.join(dir, "credentials"), "w") do |f|

f.write([heroku_email, heroku_api_key].join("n"))

f.write("n")

end

File.open(File.expand_path("~/.netrc"), "a+") do |f|

[‘api’, ‘code’].each do |host

f.puts "machine #{host}.heroku.com"

f.puts " login #{heroku_email}"

f.puts " password #{heroku_api_key}"

end

puts "Pushing to Heroku: #{push_target}…"

cmd "git push #{push_target} HEAD:master –force" or abort "could not push to #{push_target}"

Bundler.with_clean_env do

puts "Running Heroku Migrations…"

cmd "heroku run rake db:migrate –app #{app_name}" or abort "aborted migrations"

puts "Restarting Heroku…"

cmd "heroku restart –app #{app_name}" or abort "aborted heroku restart"

end

Step 3: Authorize Tddium’s Worker Key

Run tddium account to get the Tddium worker key you need to authorize with Heroku.
Save the key in a file: tddium-worker-key.pub.
Then run heroku keys:add tddium-worker-key.pub

Step 4: Trigger A Build

That’s it! Push to your git repo to trigger Tddium CI, or trigger a build manually on your Tddium Dashboard.

When the push and migration completes, you’ll see a post_build_hook.log.

If you haven’t configured Tddium CI, read our getting started guide for more information.

If you don’t yet have a Tddium account, sign up now for a free trial!

Don’t hesitate to contact us at support@tddium.com for more information.

Update (10/25/2012):

Our awesome customers have pointed out a few gotchas and solutions:

Make sure you have the ‘heroku’ gem in your Gemfile, or the above Heroku commands won’t work. We’ll soon be automatically including the heroku toolbelt in our workers, but until then…
If you’re using Rails 3.1+ and the asset pipeline, make sure you enable the heroku user-env-compile labs feature.

Update (6/21/2013):

The Heroku toolbelt package has been installed in test VMs for some time now so it is safe to use instead of the gem.

Update (7/15/2013):

If you are using Ruby 2.0, you will need to use Bundler.with_clean_env to run the Heroku toolbelt command.

14 Comments

Miguel Madero June 20, 2013 at 6:24 am

This was working, but seems like it broke with some of the latest changes.

Reply
- William Josephson June 20, 2013 at 11:03 am
  
  Miguel, in your case it looks as though there is an authentication problem — i.e. you need to authorize the proper key in Heroku. Some users also have had excessively long running post-build hooks and the default timeout is now enforced.
  
  Reply
  - Geoff Tidey (@GeoffTidey) June 21, 2013 at 12:20 pm
    
    Wiiliam, How do you increase the timeout duration?
    
    Reply
    - William Josephson June 21, 2013 at 3:00 pm
      
      Geoff, there is a hard cap at the moment, but you can increase the timeout up to that cap by setting the {:tddium => {:timeout_hook => seconds } } (as YAML) in tddium.yml.
      
      Reply
  - Dharampal H S June 26, 2013 at 9:22 am
    
    William, what’s the hard cap as of now?
    
    Reply
    - William Josephson June 26, 2013 at 2:24 pm
      
      Dharampal,
      
      The hard cap is long enough that it should not pose a problem unless you are doing significant computation in the hook, which you really shouldn’t be doing. If you have trouble and are hitting the cap, please contact support for now. We’ll be improving the hook infrastructure and the associated documentation in the short term.
      
      Reply
  - codemangler June 26, 2013 at 9:35 am
    
    What’s the hard cap on build hook timeouts as of now?
    
    Reply
Geoff Tidey (@GeoffTidey) June 21, 2013 at 12:18 pm

Couple of observations –

1.) The post-build task link in the first paragraph is dead – http://docs.tddium.com/getting-started/post-build-tasks

2.) It would be cool if you had one gist that contained the rake task in Step 2.) embedded in this page. Currently there are several on github, which is the official & most current? https://gist.github.com/search?q=tddium_post_build.rake
Why not use revision history?

Reply
- William Josephson June 21, 2013 at 2:58 pm
  
  Geoff — thanks for pointing out the broken link! We’ve fixed it. There is a link in the post to the current gist; we’ll be updating it.
  
  Reply
James Stewart July 25, 2013 at 6:08 pm

In a rails app where should the tddium_post_build.rake file go?

Reply
- Jay Moorthi July 25, 2013 at 6:13 pm
  
  @James: If you commit it as $RAILS_ROOT/lib/tddium_post_build.rake, it should get picked up automatically.
  
  Reply
  - James Stewart July 25, 2013 at 10:06 pm
    
    Thanks, also I get an error of no directory ‘credentials’ for the line:
    File.open(File.join(dir, “credentials”)
    
    Reply
  - Justin Finkelstein September 23, 2013 at 12:44 pm
    
    If I’m not using a Rails app, where do I put this file and how do I reference it from tddium.yml, if this is necessary?
    
    Reply
Nate R July 16, 2014 at 10:58 pm

https://gist.github.com/nvreynolds/5ad0c78582d9b0eeee08

Reply

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