Adding a new task

The task’s bash file

Create zppy/templates/<task-name>.bash. This is where the bulk of the work required for a task will be. Most of the file is task-specific, so it is difficult to describe precise steps. Some key parts, however, are displayed below:

{% include '' %}

{{ environment_commands }}

# Turn on debug output if needed
debug={{ debug }}
if [[ "${debug,,}" == "true" ]]; then
  set -x

# Script dir
cd {{ scriptDir }}

# Get jobid

# Update status file
STARTTIME=$(date +%s)
echo "RUNNING ${id}" > {{ prefix }}.status
# Update status file and exit
{% raw %}
ENDTIME=$(date +%s)
{% endraw %}
echo ==============================================
echo "Elapsed time: $ELAPSEDTIME seconds"
echo ==============================================
echo 'OK' > {{ prefix }}.status
exit 0

Variables of the form {{ <variable-name> }} can come from a number of sources:

  1. zppy/templates/default.ini (in the form of <variable-name> = <variable-type>(default=<default-value>))

  2. zppy/templates/<campaign>.cfg (in the form of <variable-name> = <value>); overrides values from #1

  3. The user’s configuration file (in the form of <variable-name> = <value>); overrides values from #1, #2

Another possible source is zppy/<task-name>.py (in the form of c["<variable-name>"] where c is defined in for c in tasks).

The task’s Python file

Create zppy/<task-name>.py. The basic outline of the file should be similar to the below example, adapted from zppy/

import os
import pprint

import jinja2

from zppy.utils import checkStatus, getTasks, getYears, submitScript

# -----------------------------------------------------------------------------
def <task-name>(config, scriptDir):

    # Initialize jinja2 template engine
    templateLoader = jinja2.FileSystemLoader(
    templateEnv = jinja2.Environment(loader=templateLoader)
    template = templateEnv.get_template("<task-name>.bash")

    # --- List of <task-name> tasks ---
    tasks = getTasks(config, "<task-name>")
    if len(tasks) == 0:

    # --- Generate and submit <task-name> scripts ---
    for c in tasks:

        # Loop over year sets
        year_sets = getYears(c["years"])
        for s in year_sets:
            c["year1"] = s[0]
            c["year2"] = s[1]
            c["scriptDir"] = scriptDir
            if c["subsection"]:
                sub = c["subsection"]
                sub = c["grid"]
            prefix = "<task-name>_%s_%s_%04d-%04d" % (
            c["prefix"] = prefix
            scriptFile = os.path.join(scriptDir, "%s.bash" % (prefix))
            statusFile = os.path.join(scriptDir, "%s.status" % (prefix))
            settingsFile = os.path.join(scriptDir, "%s.settings" % (prefix))
            skip = checkStatus(statusFile)
            if skip:

            # Create script
            with open(scriptFile, "w") as f:

            # List of dependencies
            dependencies = []

           # Add dependencies
           # Example:
           dependencies.append(os.path.join(scriptDir, "%s_%04d-%04d.status" % (<name-of-dependency>, c["year1"], c["year2"]),))

            with open(settingsFile, "w") as sf:
                p = pprint.PrettyPrinter(indent=2, stream=sf)

            if not c["dry_run"]:
                # Submit job
                jobid = submitScript(
                    scriptFile, dependFiles=dependencies, export="NONE"

                if jobid != -1:
                    # Update status file
                    with open(statusFile, "w") as f:
                        f.write("WAITING %d\n" % (jobid))

The main file

Add the task to zppy/

from <task_name> import <task_name>
# <task-name> tasks
<task-name>(config, scriptDir)

Update defaults

Add default values for parameters in zppy/templates/default.ini.


    [[__many__]] # Only if the task supports sub-tasks
    ... # List the same parameters but with `default=None`

Update the tutorial

Add example values for parameters in docs/source/post.mysimulation.cfg.

[ <task-name> ]
... # Specify parameters that would likely apply to all sub-tasks

    [[ <subtask-name> ]] # Only if the task supports sub-tasks
    ... # Specify parameters that make more sense defined in the sub-tasks

Explain new parameters

In docs/source/parameters.rst

Copy defaults from zppy/templates/default.ini and add a comment line above each explaining the parameter.

Update the tests

In tests/integration/test_*.cfg

Copy example values from docs/source/post.mysimulation.cfg. The expected files will have to be updated as well.