title: "Debugging a Crunch script"
...
-To test changes to a script by running a job, the change must be pushed into @git@, the job queued asynchronously, and the actual execution may be run on any compute server. As a result, debugging a script can be difficult and time consuming. This tutorial demonstrates using @arv-crunch-job@ to run your job in your local VM. This avoids the job queue and allows you to execute the script from your uncomitted git tree.
+To test changes to a script by running a job, the change must be pushed to your hosted repository, and the job might have to wait in the queue before it runs. This cycle can be an inefficient way to develop and debug scripts. This tutorial demonstrates an alternative: using @arv-crunch-job@ to run your job in your local VM. This avoids the job queue and allows you to execute the script directly from your git working tree without committing or pushing.
-*This tutorial assumes that you are "logged into an Arvados VM instance":{{site.baseurl}}/user/getting_started/ssh-access.html#login, and have a "working environment.":{{site.baseurl}}/user/getting_started/check-environment.html*
+{% include 'tutorial_expectations' %}
This tutorial uses *@you@* to denote your username. Replace *@you@* with your user name in all the following examples.
h2. Create a new script
-Change to your git directory and create a new script in "crunch_scripts/".
+Change to your Git working directory and create a new script in @crunch_scripts/@.
<notextile>
<pre><code>~$ <span class="userinput">cd <b>you</b>/crunch_scripts</span>
h2. Using arv-crunch-job to run the job in your VM
-Instead of a git commit hash, we provide the path to the directory in the "script_version" parameter. The script specified in "script" will actually be searched for in the "crunch_scripts/" subdirectory of the directory specified "script_version". Although we are running the script locally, the script still requires access to the Arvados API server and Keep storage service. The job will be recorded in the Arvados job history, and visible in Workbench.
+Instead of a Git commit hash, we provide the path to the directory in the "script_version" parameter. The script specified in "script" is expected to be in the @crunch_scripts/@ subdirectory of the directory specified "script_version". Although we are running the script locally, the script still requires access to the Arvados API server and Keep storage service. The job will be recorded in the Arvados job history, and visible in Workbench.
<notextile>
<pre><code>~/<b>you</b>/crunch_scripts$ <span class="userinput">cat >~/the_job <<EOF
{
+ "repository":"",
"script":"hello-world.py",
- "script_version":"/home/<b>you</b>/<b>you</b>",
+ "script_version":"$HOME/$USER",
"script_parameters":{}
}
EOF</span>
-~/<b>you</b>/crunch_scripts</span>$ <span class="userinput">arv-crunch-job --job "$(cat ~/the_job)"</span>
+</code></pre>
+</notextile>
+
+Your shell should fill in values for @$HOME@ and @$USER@ so that the saved JSON points "script_version" at the directory with your checkout. Now you can run that job:
+
+<notextile>
+<pre><code>~/<b>you</b>/crunch_scripts</span>$ <span class="userinput">arv-crunch-job --job "$(cat ~/the_job)"</span>
2013-12-12_21:36:42 qr1hi-8i9sb-okzukfzkpbrnhst 29827 check slurm allocation
2013-12-12_21:36:42 qr1hi-8i9sb-okzukfzkpbrnhst 29827 node localhost - 1 slots
2013-12-12_21:36:42 qr1hi-8i9sb-okzukfzkpbrnhst 29827 start
2013-12-12_21:36:42 qr1hi-8i9sb-okzukfzkpbrnhst 29827 0 stderr hello world
2013-12-12_21:36:43 qr1hi-8i9sb-okzukfzkpbrnhst 29827 0 child 29834 on localhost.1 exit 0 signal 0 success=
2013-12-12_21:36:43 qr1hi-8i9sb-okzukfzkpbrnhst 29827 0 failure (#1, permanent) after 0 seconds
-2013-12-12_21:36:43 qr1hi-8i9sb-okzukfzkpbrnhst 29827 0 output
+2013-12-12_21:36:43 qr1hi-8i9sb-okzukfzkpbrnhst 29827 0 output
2013-12-12_21:36:43 qr1hi-8i9sb-okzukfzkpbrnhst 29827 Every node has failed -- giving up on this round
2013-12-12_21:36:43 qr1hi-8i9sb-okzukfzkpbrnhst 29827 wait for last 0 children to finish
2013-12-12_21:36:43 qr1hi-8i9sb-okzukfzkpbrnhst 29827 status: 0 done, 0 running, 0 todo
~/<b>you</b>/crunch_scripts$ <span class="userinput">chmod +x hello-world-fixed.py</span>
~/<b>you</b>/crunch_scripts$ <span class="userinput">cat >~/the_job <<EOF
{
+ "repository":"",
"script":"hello-world-fixed.py",
- "script_version":"/home/<b>you</b>/<b>you</b>",
+ "script_version":"$HOME/$USER",
"script_parameters":{}
}
EOF</span>
projects / arvados.git / blobdiff