---
layout: default
navsection: installguide
title: Install Composer
...

Arvados Composer is a single-page javascript application for building Common Workflow Languge (CWL) Workflows.

h2. Prerequisites

In addition to Arvados core services, Composer requires "Arvados hosted git repositories":install-arv-git-httpd.html which are used for storing workflow files.

h2. Install

Composer may be installed on the same host as Workbench, or on a different host.  Composer communicates directly with the Arvados API server.  It does not require its own backend and should be served as a static file.

On a Debian-based system, install the following package:

<notextile>
<pre><code>~$ <span class="userinput">sudo apt-get install arvados-composer</span>
</code></pre>
</notextile>

On a Red Hat-based system, install the following package:

<notextile>
<pre><code>~$ <span class="userinput">sudo yum install arvados-composer</span>
</code></pre>
</notextile>

h2. Configure

h3. composer.yml

Edit @/etc/arvados/composer/composer.yml@ and set @apiEndPoint@ to your API server:

<pre>
apiEndPoint: https://zzzzz.arvadosapi.com
</pre>

h3. Nginx

Add Composer to your Nginx configuration.  This example will host Composer at @/composer@.

<pre>
location /composer {
  root   /var/www/arvados-composer
  index  index.html
}
</pre>

h3. Workbench link to composer

Edit the workbench @application.yml@ and set @composer_url@ to the location from which it is served.

<pre>
production:
  composer_url: 'https://workbench.zzzzz.arvadosapi.com/composer'
</pre>