These jenkins.osmocom.org job definitions, managed by
https://docs.openstack.org/infra/jenkins-job-builder/index.html[Jenkins Job Builder]

*Prepare:*

Install jenkins-job-builder:

  apt-get install jenkins-job-builder

Have a jenkins-job-builder.ini file. One of

    ~/.config/jenkins_jobs/jenkins_jobs.ini
    /etc/jenkins_jobs/jenkins_jobs.ini

or place one in here and pass it to jenkins-jobs using the --conf file.

Make sure the file not world readable to minimally safeguard your jenkins password.
Instead of using your jenkins password, use an *API Token*. To retrieve your token go
to Jenkins via a Webbrowser, click on your Username in the right corner, click on configure,
click on *Show API Toke...*.

jenkins_jobs.ini:

    [jenkins]
    user=my_user_name
    password=my_api_token
    url=https://jenkins.osmocom.org/jenkins

and

    chmod go-rwx jenkins_jobs.ini

*Update a single job on jenkins.osmocom.org:*

    jenkins-jobs --conf jenkins_jobs.ini update gerrit-verifications.yml gerrit-osmo-msc

NOTE: when you supply a name not defined in that yml file, you will not get an
error message, just nothing will happen.

*Update all jobs of one file:*

    jenkins-jobs --conf jenkins_jobs.ini update gerrit-verifications.yml

*Update all jobs in all files:*

    jenkins-jobs --conf jenkins_jobs.ini update ./

*Troubleshooting:*

- 'jenkins.JenkinsException: create[gerrit-osmo-msc] failed'

jenkins.osmocom.org is not reachable, or URL in the config file is erratic.
Make sure it is exactly

    url=https://jenkins.osmocom.org/jenkins

- newlines:

Use 'key: |' to keep new lines in multiline values, e.g.:
  - shell: |
      echo hello
      echo world

See also:
* https://yaml-multiline.info/
* https://stackoverflow.com/a/21699210

- jobs named on cmdline are not updated:

Make sure the job name is correct, or just issue an entire yml file without
individual job names.

Also be aware that jobs are only actually updated when anything changed.

*Jenkins labels*

Most jenkins jobs should run a docker container and install all required
dependencies inside that, so we don't need to install them on the jenkins node.
These jobs don't need to set a label, they can just run on any generic jenkins
node that has docker available. So if you add a new job, you probably don't
need a label at all.

Existing jobs typically have a label set by the topic they belong to, e.g.:
- osmocom-master
- osmocom-gerrit
- ttcn3

Other labels indicate specific software/hardware works here, e.g.:
- coverity
- hdlc
- osmo-gsm-tester
- podman

*ccache*

The jobs from master-builds and gerrit-verifications use ccache. View the
statistics with SSH on the build nodes with:

 $ CCACHE_DIR=~/ccache/gerrit-verifications ccache -s
 $ CCACHE_DIR=~/ccache/master-builds ccache -s

Note that running multiple jobs in parallel influence the ccache statistics,
and it's impossible to tell which job caused which change in the stats (that's
why they are not printed at the end of each job, it would be confusing).
