This document provides tips and hacks for using the Heroku platform. It covers setting up a Heroku account, installing the Heroku toolbelt locally, deploying a Rails app to Heroku including adding gems and configuring the asset pipeline, using the Heroku command line interface to run commands and view logs, managing Git deployment to Heroku, and additional tips like configuring domains, upgrading databases, and improving performance with Unicorn.

1. HEROKU TIPS AND HACKS
1. Create an account on Heroku.
- Go to website: ​http://heroku.com/
2. Install Heroku toolbelt:​(​https://toolbelt.heroku.com/​)
- It is everything you need to get started using Heroku.
- Install: ​wget -qO- ​https://toolbelt.heroku.com/install-ubuntu.sh​| sh
3. Login to Heroku
- Run: $ heroku login (enter username and password)
- If have errors about ssh key:
http://www.ajibanda.com/2013/02/reset-git-ssh-key-to-log-in-using-a-new-heroku-
account.html
4. Add gem and config asset pipeline :
- In Gemfile:
gem ‘rails_12factor’, group:production
gem ‘thin’
- In config/application.rb:
config.assets.initialize_on_precompile = false
* Remember: Must commit ​Gemfile.lock ​to server to deploy.
* More details: ​https://devcenter.heroku.com/articles/getting-started-with-rails3
5. CLI Heroku: ​$ heroku run <...>
$ heroku run rake db:migrate
$ heroku restart <name_app_heroku>
$heroku open (open website in browser)
$ heroku run rails c
$ heroku run ruby script/imap_processor start

2. - Dùng cmd: $ heroku run bash
- View list current account: $ heroku accounts
6. Push local project to Heroku
- Git init in local project:
$ git init
- Add host to current git:
$ git remote add <​origin​> <git@heroku/app>
(​git@heroku.com​:bookmanageapp.git)
- Check remote exist or not? :
$ git remote -v
- Add and commit code
- Push code - ​Deploy code
$ git push [hostname] [branch] / $ git push ​origin/heroku​master
7. Cloning Existing Heroku Applications
$ heroku login
$ heroku git:clone -a <my_app>
$ cd my_app
* More details: ​https://devcenter.heroku.com/articles/git-clone-heroku-app
8. Delayed Job
* More details: ​https://devcenter.heroku.com/articles/delayed-job
9. View processes - logs
- View processes:
$ heroku ps
=== delayed (1X): `bundle exec rake jobs:work`
delayed.1: up 2013/11/04 19:38:01 (~ 15h ago)
=== web (1X): `bundle exec thin start -R config.ru -e $RAILS_ENV -p $PORT`
web.1: up 2013/11/05 08:12:55 (~ 2h ago)

3. - View logs:
$ heroku logs / $ heroku logs --tail
$ heroku logs -p imap.1
$ heroku logs -p web.
- View db info:
$ heroku config
* More details: ​https://devcenter.heroku.com/articles/logging
10. Multi accounts:
- Add account:
$ heroku accounts:add <name> -- auto
- Remove account:
$ heroku accounts:remove <name>
- Using account:
$ heroku accounts:set <name>
* Remember: Config (host) in: ~/.ssh/config
* More details: ​https://github.com/ddollar/heroku-accounts
- Add key: $ heroku keys:add
- Ex: Found the following SSH public keys:
1) id_rsa.pub
2) identity.heroku.app_rails.pub
3) identity.heroku.personal.pub
4) identity.heroku.work.pub
5) ssh-add id_rsa.pub
Which would you like to use with your Heroku account? => ​3
*More details: ​https://devcenter.heroku.com/articles/keys
11. Config timeout:
https://github.com/heroku/rack-timeout
http://www.rubydoc.info/gems/rack-timeout/0.0.4/frames

4. 12. Access to db postgres on Heroku
- Click to Heroku Postgres Dev on website Heroku application.
- In this page, content some info:
Host : host_path (ec2-123-321-333.compute-00.compute-1.amazonaws.com)
Database: db_name_pg
User: user_name
Password: password
- Connect to database:
$ psql -U <username> -h <host> -d <database>
$ psql -U user_name -h host_path -d db_name_pg
13. View Memory (RAM), CPU, Core based on dyno sizes:
Dyno
Size
Memory
(RAM)
CPU
Share
Multitenan
t
Compute
(​2​)
Price/dyno­hou
r
1X 512MB 1x yes 1x­4x $0.05
2X 1024MB 2x yes 4x­8x $0.10
PX 6GB 100% (1) no 40x
$0.80
*More details:​https://devcenter.heroku.com/articles/dyno-size#available-dyno-sizes
14. Config Domain:
- Add domain:
$ heroku domain add: <example.com>
or add in ​Setting ​section on heroku website.

5. - Get domain default on heroku: http://<my_app>.heroku.com
Ex: ​http://my_app.herokuapp.com
- Get IP of above domain:
$ host ​my_app.herokuapp.com
=> my_app.herokuapp.com has address ​23.23.80.206
- Go to Godaddy or others service, config your domain point to this IP.
More details: ​https://devcenter.heroku.com/articles/custom-domains
15. Upgrade Mongolab ​(From sandbox-free to Single Node SM)
Changing to or from a single-node plan on Heroku:
1. Stop your app and any other processes writing to your database
2. Backup your database using mongodump
3. Remove your existing add-on
4. Add a new add-on (see available plans ​here​)
5. Restore your database using mongorestore
6. Change your connection string info in your app
7. Restart your app
Example:
$ ​mongodump ​-h ds0123456.mongolab.com:3000 -d heroku_app -u user -p password -o .
$ heroku addons:remove mongolab
$ heroku addons:add mongolab:shared-single-small
$ ​mongorestore​-h <new_host>:<new_port> -d heroku_app -u user -p <​new_password​> .
* Get ​<​new_password​>:
Run :
$ ​heroku config | grep MONGOLAB_URI
Output:
mongodb://heroku_app:​new_password​@​ds0123456​.mongolab.com:3000/heroku_app
Compare with:
​mongodb://<dbuser>:<​dbpassword​>@​ds0123456​.mongolab.com:3000/<dbname>
Informations account :
dbuser: ​dbpassword
dbpassword: ​new_password
dbname: ​heroku_app
* More details: ​https://devcenter.heroku.com/articles/mongolab

6. 16. Improve performance with Unicorn (Concurrency)
-​​Add Gem:
gem ‘unicorn’
- Config:
Create a file configuration for Unicorn at config/unicorn.rb
- When using mongoid:
worker_processes Integer(ENV["WEB_CONCURRENCY"] || 3)
timeout 30
preload_app true
before_fork do |server, worker|
puts worker
end
after_fork do |server, worker|
puts worker
end
If using Mongoid, you don't need to manually reconnect as in the gist. Mongoid claims:
"When using Unicorn or Passenger, each time a child process is forked when using
app preloading or smart spawning, Mongoid will automatically reconnect to the
master database. If you are doing this in your application manually you may remove
your code." (​http://mongoid.org/en/mongoid/docs/rails.html​)
* More details:​​https://devcenter.heroku.com/articles/rails-unicorn
Other references:
http://railsapps.github.io/rails-heroku-tutorial.html
https://devcenter.heroku.com/articles/getting-started-with-rails3
* Developer: ​Nguyễn Thành Luân