---
layout: default
navsection: userguide
-title: "Writing a CWL workflow"
+title: "Developing workflows with CWL"
...
{% comment %}
Copyright (C) The Arvados Authors. All rights reserved.
h2. Developing workflows
-For an introduction and and detailed documentation about writing CWL, see the "CWL User Guide":https://www.commonwl.org/user_guide and the "CWL Specification":http://commonwl.org/v1.1 .
+For an introduction and and detailed documentation about writing CWL, see the "CWL User Guide":https://www.commonwl.org/user_guide and the "CWL Specification":http://commonwl.org/v1.2 .
See "Writing Portable High-Performance Workflows":{{site.baseurl}}/user/cwl/cwl-style.html and "Arvados CWL Extensions":{{site.baseurl}}/user/cwl/cwl-extensions.html for additional information about using CWL on Arvados.
See "Software for working with CWL":https://www.commonwl.org/#Software_for_working_with_CWL for links to software tools to help create CWL documents.
-h2. Using Composer
-
-You can create new workflows in the browser using "Arvados Composer":{{site.baseurl}}/user/composer/composer.html
-
-h2. Registering a workflow to use in Workbench
-
-Use @--create-workflow@ to register a CWL workflow with Arvados. This enables you to share workflows with other Arvados users, and run them by clicking the <span class="btn btn-sm btn-primary"><i class="fa fa-fw fa-gear"></i> Run a process...</span> button on the Workbench Dashboard and on the command line by UUID.
-
-<notextile>
-<pre><code>~/arvados/doc/user/cwl/bwa-mem$ <span class="userinput">arvados-cwl-runner --create-workflow bwa-mem.cwl</span>
-arvados-cwl-runner 1.0.20160628195002, arvados-python-client 0.1.20160616015107, cwltool 1.0.20160629140624
-2016-07-01 12:21:01 arvados.arv-run[15796] INFO: Upload local files: "bwa-mem.cwl"
-2016-07-01 12:21:01 arvados.arv-run[15796] INFO: Uploaded to qr1hi-4zz18-7e0hedrmkuyoei3
-2016-07-01 12:21:01 arvados.cwl-runner[15796] INFO: Created template qr1hi-p5p6p-rjleou1dwr167v5
-qr1hi-p5p6p-rjleou1dwr167v5
-</code></pre>
-</notextile>
-
-You can provide a partial input file to set default values for the workflow input parameters. You can also use the @--name@ option to set the name of the workflow:
-
-<notextile>
-<pre><code>~/arvados/doc/user/cwl/bwa-mem$ <span class="userinput">arvados-cwl-runner --name "My workflow with defaults" --create-workflow bwa-mem.cwl bwa-mem-template.yml</span>
-arvados-cwl-runner 1.0.20160628195002, arvados-python-client 0.1.20160616015107, cwltool 1.0.20160629140624
-2016-07-01 14:09:50 arvados.arv-run[3730] INFO: Upload local files: "bwa-mem.cwl"
-2016-07-01 14:09:50 arvados.arv-run[3730] INFO: Uploaded to qr1hi-4zz18-0f91qkovk4ml18o
-2016-07-01 14:09:50 arvados.cwl-runner[3730] INFO: Created template qr1hi-p5p6p-0deqe6nuuyqns2i
-qr1hi-p5p6p-zuniv58hn8d0qd8
-</code></pre>
-</notextile>
-
-h3. Running registered workflows at the command line
-
-You can run a registered workflow at the command line by its UUID:
-
-<notextile>
-<pre><code>~/arvados/doc/user/cwl/bwa-mem$ <span class="userinput">arvados-cwl-runner qr1hi-p5p6p-zuniv58hn8d0qd8 --help</span>
-/home/peter/work/scripts/venv/bin/arvados-cwl-runner 0d62edcb9d25bf4dcdb20d8872ea7b438e12fc59 1.0.20161209192028, arvados-python-client 0.1.20161212125425, cwltool 1.0.20161207161158
-Resolved 'qr1hi-p5p6p-zuniv58hn8d0qd8' to 'keep:655c6cd07550151b210961ed1d3852cf+57/bwa-mem.cwl'
-usage: qr1hi-p5p6p-zuniv58hn8d0qd8 [-h] [--PL PL] --group_id GROUP_ID
- --read_p1 READ_P1 [--read_p2 READ_P2]
- [--reference REFERENCE] --sample_id
- SAMPLE_ID
- [job_order]
-
-positional arguments:
- job_order Job input json file
-
-optional arguments:
- -h, --help show this help message and exit
- --PL PL
- --group_id GROUP_ID
- --read_p1 READ_P1 The reads, in fastq format.
- --read_p2 READ_P2 For mate paired reads, the second file (optional).
- --reference REFERENCE
- The index files produced by `bwa index`
- --sample_id SAMPLE_ID
-</code></pre>
-</notextile>
-
h2. Using cwltool
When developing a workflow, it is often helpful to run it on the local host to avoid the overhead of submitting to the cluster. To execute a workflow only on the local host (without submitting jobs to an Arvados cluster) you can use the @cwltool@ command. Note that when using @cwltool@ you must have the input data accessible on the local file system using either @arv-mount@ or @arv-get@ to fetch the data from Keep.
</notextile>
If you get the error @JavascriptException: Long-running script killed after 20 seconds.@ this may be due to the Dockerized Node.js engine taking too long to start. You may address this by installing Node.js locally (run @apt-get install nodejs@ on Debian or Ubuntu) or by specifying a longer timeout with the @--eval-timeout@ option. For example, run the workflow with @cwltool --eval-timeout=40@ for a 40-second timeout.
-
-h2. Making workflows directly executable
-
-You can make a workflow file directly executable (@cwl-runner@ should be an alias to @arvados-cwl-runner@) by adding the following line to the top of the file:
-
-<notextile>
-<pre><code>#!/usr/bin/env cwl-runner
-</code></pre>
-</notextile>
-
-<notextile>
-<pre><code>~/arvados/doc/user/cwl/bwa-mem$ <span class="userinput">./bwa-mem.cwl bwa-mem-input.yml</span>
-arvados-cwl-runner 1.0.20160628195002, arvados-python-client 0.1.20160616015107, cwltool 1.0.20160629140624
-2016-06-30 14:56:36 arvados.arv-run[27002] INFO: Upload local files: "bwa-mem.cwl"
-2016-06-30 14:56:36 arvados.arv-run[27002] INFO: Uploaded to qr1hi-4zz18-h7ljh5u76760ww2
-2016-06-30 14:56:40 arvados.cwl-runner[27002] INFO: Submitted job qr1hi-8i9sb-fm2n3b1w0l6bskg
-2016-06-30 14:56:41 arvados.cwl-runner[27002] INFO: Job bwa-mem.cwl (qr1hi-8i9sb-fm2n3b1w0l6bskg) is Running
-2016-06-30 14:57:12 arvados.cwl-runner[27002] INFO: Job bwa-mem.cwl (qr1hi-8i9sb-fm2n3b1w0l6bskg) is Complete
-2016-06-30 14:57:12 arvados.cwl-runner[27002] INFO: Overall process status is success
-{
- "aligned_sam": {
- "path": "keep:54325254b226664960de07b3b9482349+154/HWI-ST1027_129_D0THKACXX.1_1.sam",
- "checksum": "sha1$0dc46a3126d0b5d4ce213b5f0e86e2d05a54755a",
- "class": "File",
- "size": 30738986
- }
-}
-</code></pre>
-</notextile>
-
-You can even make an input file directly executable the same way with the following two lines at the top:
-
-<notextile>
-<pre><code>#!/usr/bin/env cwl-runner
-cwl:tool: <span class="userinput">bwa-mem.cwl</span>
-</code></pre>
-</notextile>
-
-<notextile>
-<pre><code>~/arvados/doc/user/cwl/bwa-mem$ <span class="userinput">./bwa-mem-input.yml</span>
-arvados-cwl-runner 1.0.20160628195002, arvados-python-client 0.1.20160616015107, cwltool 1.0.20160629140624
-2016-06-30 14:56:36 arvados.arv-run[27002] INFO: Upload local files: "bwa-mem.cwl"
-2016-06-30 14:56:36 arvados.arv-run[27002] INFO: Uploaded to qr1hi-4zz18-h7ljh5u76760ww2
-2016-06-30 14:56:40 arvados.cwl-runner[27002] INFO: Submitted job qr1hi-8i9sb-fm2n3b1w0l6bskg
-2016-06-30 14:56:41 arvados.cwl-runner[27002] INFO: Job bwa-mem.cwl (qr1hi-8i9sb-fm2n3b1w0l6bskg) is Running
-2016-06-30 14:57:12 arvados.cwl-runner[27002] INFO: Job bwa-mem.cwl (qr1hi-8i9sb-fm2n3b1w0l6bskg) is Complete
-2016-06-30 14:57:12 arvados.cwl-runner[27002] INFO: Overall process status is success
-{
- "aligned_sam": {
- "path": "keep:54325254b226664960de07b3b9482349+154/HWI-ST1027_129_D0THKACXX.1_1.sam",
- "checksum": "sha1$0dc46a3126d0b5d4ce213b5f0e86e2d05a54755a",
- "class": "File",
- "size": 30738986
- }
-}
-</code></pre>
-</notextile>
-
-h2(#migrate). Differences in running CWL on the legacy jobs API vs containers API
-
-Most users can ignore this section.
-
-When migrating your Arvados cluster from using the jobs API (--api=jobs) (sometimes referred to as "crunch v1") to the containers API (--api=containers) ("crunch v2") there are a few differences in behavior:
-
-A tool may fail to find an input file that could be found when run under the jobs API. This is because tools are limited to accessing collections explicitly listed in the input, and further limited to those individual files or subdirectories that are listed. For example, given an explicit file input @/dir/subdir/file1.txt@, a tool will not be allowed to implicitly access a file in the parent directory @/dir/file2.txt@. Use @secondaryFiles@ or a @Directory@ for files that need to be grouped together.
-
-A tool may fail when attempting to rename or delete a file in the output directory. This may happen because files listed in @InitialWorkDirRequirement@ appear in the output directory as normal files (not symlinks) but cannot be moved, renamed or deleted unless marked as "writable" in CWL. These files will be added to the output collection but without any additional copies of the underlying data.
-
-A tool may fail when attempting to access the network. This may happen because, unlike the jobs API, under the containers API network access is disabled by default. Tools which require network access should add @arv:APIRequirement: {}@ to the @requirements@ section.
projects / arvados.git / blobdiff