| layout | title | description | permalink | javascript | |
|---|---|---|---|---|---|
exercise |
Rails App |
Phase Eleven - Deploying Your Application |
/exercises/rails-eleven/ |
|
One of the more complicated tasks in the lifecycle of an application is getting it on a server for people to look at. This can be a rather complex task, but we will use a service that is specifically designed to make this a relatively painless task.
The Heroku service is a platform that allows you to run web applications written in most of the popular web languages.
For this, we need to follow the Heroku Quickstart Guide.
Heroku works with git, which makes deploying a snap. However, there are a few things we need to do to make this work better.
We need to tell git to ignore certain files. Specifically files that are
updated though the server (e.g. the log files and image uploads). For this we
need to edit a special file .gitignore. You can do this in an editor, or for
fun, you can do it through the console.
{% highlight console %} $ echo "public/uploads" >> .gitignore $ echo "tmp" >> .gitignore $ echo "logs" >> .gitignore $ git commit -am "Ignore files not needed for deployment" {% endhighlight %}
We have been using a database system in our default Rails application called
SQLite. However, Heroku uses a far more robust system called PostgreSQL. If we
deployed our application as is, we'll run in to problems since our application
doesn't know how to "talk" to a PostgreSQL server. We need to tell Rails about
this dependency in our production environment by updating the Gemfile.
Find the line that reads gem 'sqlite3' and update it to look like this:
{% highlight ruby %} group :development do gem 'sqlite3' end
group :production do gem 'pg' end {% endhighlight %}
Heroku requires applications to adhere to Twelve-Factor
App principals. To make this easier for you, there's a
gem that will configure your application in production to adhere to these
principals. All we need to do is add the rails_12factor gem to the production
environment in the Gemfile. Update the :production group as follows.
{% highlight ruby %} group :production do gem 'pg' gem 'rails_12factor' end {% endhighlight %}
Now you can update the dependencies, but we can run only what we need in development with the following:
{% highlight console %} $ bundle install --without production {% endhighlight %}
Now, add and commit the updated Gemfile and Gemfile.lock.
By default, you web application runs through a web server named Webrick. This is a great server in a development environment, but is really horrible as a server in production environments. Heroku enourages you to use Unicorn. We don't need to do this right now, but if you want to continue developing this application, this is something you will want to do.
To create a new application on heroku (assuming you installed the heroku
toolbelt) with the heroku create command.
{% highlight console %} $ heroku create Creating shielded-temple-5358... done, stack is cedar http://shielded-temple-5358.herokuapp.com/ | git@heroku.com:shielded-temple-5358.git Git remote heroku added {% endhighlight %}
In my case, my app is named shielded-temple-5358. Part of this setup is that we have a new git remote named heroku. Now we can push the master branch to this remote.
{% highlight console %} $ git push heroku master Initializing repository, done. Counting objects: 277, done. Delta compression using up to 8 threads. Compressing objects: 100% (257/257), done. Writing objects: 100% (277/277), 46.21 KiB | 0 bytes/s, done. Total 277 (delta 119), reused 0 (delta 0)
-----> Ruby app detected -----> Compiling Ruby/Rails -----> Using Ruby version: ruby-2.0.0 -----> Installing dependencies using 1.6.3 Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment Fetching gem metadata from https://rubygems.org/.......... Fetching additional metadata from https://rubygems.org/.. ... Bundle completed (23.42s) Cleaning up the bundler cache. -----> Preparing app for Rails asset pipeline Running: rake assets:precompile I, [2014-08-01T13:26:28.837146 #1055] INFO -- : Writing /tmp/build_773a12b8-29a6-4f50-b9bf-532c14eba8dc/public/assets/application-c23ffbdd24d84fb51367f46fe4f80265.js I, [2014-08-01T13:26:28.902130 #1055] INFO -- : Writing /tmp/build_773a12b8-29a6-4f50-b9bf-532c14eba8dc/public/assets/application-8d28fbaea5f9f776a348eec2dacde8c6.css Asset precompilation completed (7.42s) Cleaning assets Running: rake assets:clean
You have not declared a Ruby version in your Gemfile.
To set your Ruby version add this line to your Gemfile:
ruby '2.0.0'
# See https://devcenter.heroku.com/articles/ruby-versions for more information.
No Procfile detected, using the default web server (webrick)
https://devcenter.heroku.com/articles/ruby-default-web-server
-----> Discovering process types Procfile declares types -> (none) Default types for Ruby -> console, rake, web, worker
-----> Compressing... done, 21.5MB -----> Launching... done, v6 http://shielded-temple-5358.herokuapp.com/ deployed to Heroku
To git@heroku.com:shielded-temple-5358.git
- [new branch] master -> master {% endhighlight %}
You'll know you're done when you see the "Launching..." text in the console.
We also need to migrate the database. We do this by telling heroku to run the
rake db:migrate task.
{% highlight console %}
$ heroku run rake db:migrate
Running rake db:migrate attached to terminal... up, run.4973
== 20140627192049 CreateTranscriptions: migrating =============================
-- create_table(:transcriptions)
-> 0.0786s
== 20140627192049 CreateTranscriptions: migrated (0.0788s) ====================
== 20140719205623 DeviseCreateUsers: migrating ================================ -- create_table(:users) -> 0.0809s -- add_index(:users, :email, {:unique=>true}) -> 0.0398s -- add_index(:users, :reset_password_token, {:unique=>true}) -> 0.0283s == 20140719205623 DeviseCreateUsers: migrated (0.1497s) =======================
== 20140730172249 CreateComments: migrating =================================== -- create_table(:comments) -> 0.0820s == 20140730172249 CreateComments: migrated (0.0822s) ========================== {% endhighlight %}
The simplest way to get to your application is from the terminal and typing
heroku open. Is it working?
A few things to note, Heroku is a cloud platform with no persistant storage. If you read the Heroku notes, you'll see the following:
Each dyno gets its own ephemeral filesystem, with a fresh copy of the most recently deployed code. During the dyno’s lifetime its running processes can use the filesystem as a temporary scratchpad, but no files that are written are visible to processes in any other dyno and any files written will be discarded the moment the dyno is stopped or restarted.
You can do an experiment here; go to your application and upload a new
transcription image. Then, in the console, run heroku restart to restart your
application. If you go back to the web page, your image should no longer be
visible.
A common approach to this is to use a service like Amazon S3 (Simple Storage Service) or Rackspace CloudFiles. This is relatively inexpensive (generally less than $0.10/GB) and provides you a method to save your media uploads.
We wont' get in to this here either, but again, if you want to go further with this application, here are some useful links for implementing this:
You now have an application you can share with your friends and family. And, without getting into a "back in my day" talk, this is one of the simplest ways to deploy an application, but it's not the only way. Similar services to heroku (if you don't have your own IT staff) include: