Introduction§

Note

If you do not set the script for a task then nothing will be run.

Note

In this tutorial we are writing our suites in the cylc-run directory.

It is possible to write them elsewhere on the system. If we do so we must register the suite with Cylc before use.

We do this using the cylc reg command which we supply with a name which will be used to refer to the suite in place of the path i.e:

cylc reg <name> <path/to/suite>
cylc validate <name>
cylc run <name>

The cylc reg command will create a directory for the suite in the cylc-run directory meaning that we will have separate suite directories and run directories.

Practical

In this practical we will add some scripts to, and run, the weather forecasting suite from the scheduling tutorial.

1. Create A New Suite.

   The following command will copy some files for us to work with into a new suite called runtime-introduction:

   rose tutorial runtime-introduction
   cd ~/cylc-run/runtime-introduction
   

   In this directory we have the suite.rc file from the weather forecasting suite with some runtime configuration added to it.

   There is also a script called get-observations located in the bin directory.

   Take a look at the [runtime] section in the suite.rc file.

2. Run The Suite.

   First validate the suite by running:

   cylc validate .
   

   Open the Cylc GUI (in the background) by running the following command:

   cylc gui runtime-introduction &
   

   Finally run the suite by executing:

   cylc run runtime-introduction
   

   The tasks will start to run - you should see them going through the “Waiting”, “Running” and “Succeeded” states.

   When the suite reaches the final cycle point and all tasks have succeeded it will shutdown automatically and the GUI will go blank.

   Tip

   You can also run a suite from the Cylc GUI by pressing the “play” button.

   

   A box will appear. Ensure that “Cold Start” is selected then press “Start”.

   

3. Inspect A Job Log.

   Try opening the file job.out for one of the get_observations jobs in a text editor. The file will be located within the job log directory:

   log/job/<cycle-point>/get_observations_heathrow/01/job.out
   

   You should see something like this:

   Suite    : runtime-introduction
   Task Job : 20000101T0000Z/get_observations_heathrow/01 (try 1)
   User@Host: username@hostname
   
   Guessing Weather Conditions
   Writing Out Wind Data
   1970-01-01T00:00:00Z NORMAL - started
   2038-01-19T03:14:08Z NORMAL - succeeded
   

   • The first three lines are information which Cylc has written to the file to provide information about the job.
   • The last two lines were also written by cylc. They provide timestamps marking the stages in the job’s life.
   • The lines in the middle are the stdout of the job itself.

4. Inspect A Work Directory.

   The get_rainfall task should create a file called rainfall in its work directory. Try opening this file, recalling that the format of the relevant path from within the work directory will be:

   work/<cycle-point>/get_rainfall/rainfall
   

   Hint

   The get_rainfall task only runs every third cycle.

5. Extension: Explore The Cylc GUI

   • Try re-running the suite.

   • Try changing the current view(s).

     Tip

     You can do this from the “View” menu or from the toolbar:

     

   • Try pressing the “Pause” button which is found in the top left-hand corner of the GUI.

   • Try right-clicking on a task. From the right-click menu you could try:

     • “Trigger (run now)”
     • “Reset State”