Pass command line environment variable to suite's rose-app.conf file

Cylc Cylc Support
4

What I’d really like to do is to be able to pass variables from the command line; i.e. where I run rose suite-run from. Is that possible?

Sure, Rose/Cylc support passing through Jinja2 variables from the command line.

suite.rc

#!Jinja2
[runtime]
    [[mytask]]
        script = rose task-run
        [[[environment]]]
            # translate jinja2 variable into environment variable
            MY_VARIABLE={{ MY_VARIABLE }}

# the rose way
$ rose suite-run -S 'MY_VARIABLE=42'  # note capital 'S'
# the cylc way
$ cylc run -s 'MY_VARIABLE=42'  # note lower 's'

Note you can define default values in your suite configuration file which you can (optionally) override on the command line using -S:

rose-suite.conf

[jinja2:suite.rc]
MY_VARIABLE=42

Note: If you are overriding variables often you many want to group commonly used options into files which you can turn on or off. Rose provides a mechanism for doing this called optional configurations, these work for suite and application configurations. See also the related ROSE_APP_OPT_CONF_KEYS and ROSE_SUITE_OPT_CONF_KEYS environment variables.

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