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layout: default
navsection: installguide
title: Install Composer
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{% comment %}
Copyright (C) The Arvados Authors. All rights reserved.

SPDX-License-Identifier: CC-BY-SA-3.0
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Arvados Composer is a web-based 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. 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. composer.yml

Create @/var/www/arvados-composer/composer.yml@ and set @API_HOST@ to your API server:

<pre>
API_HOST: zzzzz.arvadosapi.com
</pre>

h3. Workbench link to composer

Edit @config.yml@ and set @Services.Composer.ExternalURL@ to the location from which it is served:

<notextile>
<pre><code>Clusters:
  zzzzz:
    Services:
      Composer:
        ExternalURL: <span class="userinput">https://workbench.zzzzz.arvadosapi.com/composer</span></code></pre>
</notextile>