Command Keys¶

This tutorial walks you through using command keys.

Command keys allow you to specify and run different commands for a Rose app.

They work just like the default command for an app but have to be specified explicitly as an option of rose task-run.

Example¶

Create a new Rose suite configuration called command-keys:

mkdir -p ~/rose-tutorial/command-keys
cd ~/rose-tutorial/command-keys

Create a blank rose-suite.conf and a suite.rc file that looks like this:

[cylc]
    UTC mode = True # Ignore DST
[scheduling]
    [[dependencies]]
        graph = gather_ingredients => breadmaker

[runtime]
    [[gather_ingredients]]
        script = sleep 10; echo 'Done'
    [[breadmaker]]
        script = rose task-run

In your suite directory create an app directory.

In the app directory create a new directory called breadmaker.

In the breadmaker directory create a rose-app.conf file that looks like this:

[command]
default=sleep 10; echo 'fresh bread'

This sets up a simple suite that contains the following:

A breadmaker app
A gather_ingredients task
A breadmaker task that runs the breadmaker app

Save your changes then run the suite using rose suite-run.

Once it has finished use rose suite-log to view the suite log. In the page that appears, click the “out” link for the breadmaker task. In the page you are taken to you should see a line saying “fresh bread”.

Adding Alternative Commands¶

Open the rose-app.conf file and edit to look like this:

[command]
default=sleep 10; echo 'fresh bread'
make_dough=sleep 8; echo 'dough for later'
timed_bread=sleep 15; echo 'fresh bread when you want it'

Save your changes and open up your suite.rc file. Alter the [[breadmaker]] task to look like this:

[[breadmaker]]
    script=rose task-run --command-key=make_dough

Save your changes and run the suite. If you inspect the output from the breadmaker task you should see the line “dough for later”.

Edit the script for the [[breadmaker]] task to change the command key to timed_bread. Run the suite and confirm the timed_bread command has been run.

Summary¶

You have successfully made use of command keys to run alternate commands in an app.

Possible uses of command keys might be:

Running an app in different modes of verbosity
Running an app in different configurations
Specifying different options to an app
During suite development to aid in debugging an app