This guide will walk you through deploying a Perl application on Deis.

• A User Account on a Deis Controller.
• A Deis Formation that is ready to host applications

If you do not yet have a controller or a Deis formation, please review the Deis installation instructions.

• Install RubyGems to get the gem command on your workstation
• Install Foreman with gem install foreman
• Install Perl (we still recommend perl5 for library compatibility)

If you want to use an existing application, no problem. You can also use the Deis sample application located at https://github.com/opdemand/example-perl. Clone the example application to your local workstation:

$ git clone https://github.com/opdemand/example-perl.git
$ cd example-perl

To use a Perl application with Deis, you will need to conform to 3 basic requirements:

1. Use Cpanfile to manage dependencies
2. Use Foreman to manage processes
3. Use Environment Variables to manage configuration inside your application

If you're deploying the example application, it already conforms to these requirements.

Cpanfile requires that you explicitly declare your dependencies using a cpanfile file. Here is a very basic example:

requires 'Plack' => '1.0028';
requires 'CGI::Emulate::PSGI' => '0.15';
requires 'CGI::Compile' => '0.16';

Dependencies are then automatically installed when you run plackup.

Deis relies on a Foreman Procfile that lives in the root of your repository. This is where you define the command(s) used to run your application. Here is an example Procfile:

web: plackup --port $PORT ./app.psgi

This tells Deis to run web workers using the command plackup --port $PORT ./app.psgi. You can test this locally by running foreman start.

$ foreman start
15:55:03 web.1  | started with pid 63629
15:55:03 web.1  | HTTP::Server::PSGI: Accepting connections at http://0:5000/

You should now be able to access your application locally at http://localhost:5000.

Deis uses environment variables to manage your application's configuration. For example, your application listener must use the value of the PORT environment variable. The following code snippet demonstrates how this can work inside your application:

[ sprintf('Port is %s', $ENV{'PORT'} || '5000') ],

Per the prerequisites, we assume you have access to an existing Deis formation. If not, please review the Deis installation instuctions.

Use the following command to create an application on an existing Deis formation.

$ deis create --formation=<formationName> --id=<appName>
Creating application... done, created <appName>
Git remote deis added

If an ID is not provided, one will be auto-generated for you.

Use git push deis master to deploy your application.

$ git push deis master
Counting objects: 8, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (6/6), done.
Writing objects: 100% (6/6), 3.12 KiB, done.
Total 6 (delta 3), reused 0 (delta 0)
       Perl/PSGI app detected
-----> Installing dependencies
-----> Installing Starman
       Starman is up to date. (0.4008)

Once your application has been deployed, use deis open to view it in a browser. To find out more info about your application, use deis info.

To scale your application's Docker containers, use deis scale and specify the number of containers for each process type defined in your application's Procfile. For example, deis scale web=8.

$ deis scale web=8
Scaling containers... but first, coffee!
done in 16s

=== <appName> Containers

--- web: `plackup --port $PORT ./app.psgi`
web.1 up 2013-11-04T22:06:53.492Z (dev-runtime-1)
web.2 up 2013-11-04T22:58:34.244Z (dev-runtime-1)
web.3 up 2013-11-04T22:58:34.258Z (dev-runtime-1)
web.4 up 2013-11-04T22:58:34.272Z (dev-runtime-1)
web.5 up 2013-11-04T22:58:34.288Z (dev-runtime-1)
web.6 up 2013-11-04T22:58:34.304Z (dev-runtime-1)
web.7 up 2013-11-04T22:58:34.322Z (dev-runtime-1)
web.8 up 2013-11-04T22:58:34.342Z (dev-runtime-1)

Deis applications are configured using environment variables. The example application includes a special POWERED_BY variable to help demonstrate how you would provide application-level configuration.

$ curl -s http://yourapp.yourformation.com
Powered by Deis
$ deis config:set POWERED_BY=Perl
=== <appName>
POWERED_BY: Perl
$ curl -s http://yourapp.yourformation.com
Powered by Perl

deis config:set is also how you connect your application to backing services like databases, queues and caches. You can use deis run to execute one-off commands against your application for things like database administration, initial application setup and inspecting your container environment.

$ deis run ls -la
total 52
drwxr-xr-x  6 root root 4096 Nov  4 22:57 .
drwxr-xr-x 57 root root 4096 Nov  4 22:59 ..
drwxr-xr-x  2 root root 4096 Nov  4 22:57 .profile.d
-rw-r--r--  1 root root  181 Nov  4 22:57 .release
-rw-r--r--  1 root root 1083 Nov  4 22:57 LICENSE.txt
-rw-r--r--  1 root root   37 Nov  4 22:57 Procfile
-rw-r--r--  1 root root 6913 Nov  4 22:57 README.md
-rwxr-xr-x  1 root root  197 Nov  4 22:57 app.psgi
drwxr-xr-x  2 root root 4096 Nov  4 22:57 cgi-bin
-rw-r--r--  1 root root  106 Nov  4 22:57 cpanfile
drwxr-xr-x  2 root root 4096 Nov  4 22:57 htdocs
drwxrwxr-x  5 root root 4096 Nov  4 22:05 local

To view your application's log output, including any errors or stack traces, use deis logs.

$ deis logs
Nov  4 22:58:48 ip-172-31-3-111 jagged-inventor[web.8]: find: `/app/.profile.d/*.sh': No such file or directory
Nov  4 22:58:48 ip-172-31-3-111 jagged-inventor[web.7]: HTTP::Server::PSGI: Accepting connections at http://0:10007/
Nov  4 22:58:48 ip-172-31-3-111 jagged-inventor[web.8]: HTTP::Server::PSGI: Accepting connections at http://0:10008/

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