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Defining variables
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Defining Variables

You can define variables:

  • Using _export parameter in YAML

  • Starting a session with variables

_export:

In a YAML file, the _export: directive defines variables. This is useful to load static configurations such as the host name of a database.

If a task has _export directive, the task and its children can use the variables because it defines variables in a scope. With following example, all tasks can use foo=1 but only +step1 (and +analyze) can use bar=.

_export:
  foo: 1

+prepare:
  py>: tasks.MyWorkflow.prepare

+analyze:
  _export:
    bar: 2

  +step1:
    py>: tasks.MyWorkflow.analyze_step1

+dump:
  py>: tasks.MyWorkflow.dump

Starting a Session with Variables

You can set variables when you start a new workflow session.

To set variables

  1. Use the -p KEY=VALUE multiple times. For example:
$ td wf run -p my_var1=foo -p my_var2=abc
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