This tutorial walks you through using family triggers.
Family triggers allow you to build dependencies based on sets of tasks sharing the same namespace, sometimes referred to as "families".
Family triggers are used to specify a condition to be met by a set of tasks in a particular family that will trigger the next entry in the dependencies graph.
Like regular task based triggers, family triggers can depend on the success or failure of tasks. However, because a family can contain multiple tasks, you need to specify whether you are concerned with all or any of the tasks in that family reaching the desired state.
Create a new suite (or just a new directory somewhere - e.g. in your homespace) containing a blank rose-suite.conf and a suite.rc file that looks like this:
[cylc]
UTC mode = True # Ignore DST
[scheduling]
[[dependencies]]
graph = visit_mine => MINERS
[runtime]
[[visit_mine]]
script = sleep 5; echo 'off to work we go'
[[MINERS]]
script = """
sleep 5;
if (($RANDOM % 2)); then
echo 'Diamonds!'; true;
else
echo 'Nothing...'; false;
fi
"""
[[doc, grumpy, sleepy, happy, bashful, sneezy, dopey]]
inherit = MINERS
You have now created a suite that:
Save your changes and run the suite using
rose suite-run. The cylc
gui should launch and you should see the
visit_mine task run, then trigger the
members of the MINERS family. Note that
some of the MINERS tasks may fail so you
should stop your suite using the stop button in the
cylc gui in order to allow it to
shutdown.
As you will have noticed by watching the suite run, some of the tasks in the MINERS family succeed and some fail.
We would like to add a task to sell any diamonds we find, but wait for all the miners to report back first so we only make the one trip.
We can address this by using family triggers. In particular, we are going to use the finish-all trigger to check for all members of the MINERS family finishing, and the succeed-any trigger to check for any of the tasks in the MINERS family succeeding.
Open your suite.rc file and change the [[dependencies]] to look like this:
[[dependencies]]
graph = """visit_mine => MINERS
MINERS:finish-all & MINERS:succeed-any => sell_diamonds"""
Then, add the following task to the [runtime] section:
[[sell_diamonds]]
script = sleep 5
These changes add a sell_diamonds task to the suite which is run once all the MINERS tasks have finished and if any of them have succeeded.
Save your changes and run your suite. You should
see the new sell_diamonds task being run
once all the miners have finished and at least one of
them has succeeded. As before, stop your suite using
the stop button in the cylc gui.
Cylc also allows us to trigger off failure of tasks in a particular family.
We would like to add another task to close down unproductive mineshafts once all the miners have reported back and had time to discuss their findings.
To do this we will make use of family triggers in a similar manner to before.
Open your suite.rc file and change the [[dependencies]] to look like this:
[[dependencies]]
graph = """visit_mine => MINERS
MINERS:finish-all & MINERS:succeed-any => sell_diamonds
MINERS:finish-all & MINERS:fail-any => close_shafts
close_shafts => !MINERS
"""
and alter the [[sell_diamonds]] section to look like this:
[[close_shafts, sell_diamonds]]
script = sleep 5
These changes add a close_shafts task which is run once all the MINERS tasks have finished and any of them have failed. On completion it applies a suicide trigger to the MINERS family in order to allow the suite to shutdown.
Save your changes and run your suite. You should see the new close_shafts run should any of the MINERS tasks be in the failed state once they have all finished.
Other types of triggers beyond those covered in the example are also available.
The following types of "all" type triggers are available:
The following types of "any" type triggers are available: