openstack/mistral
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Add details into docs about semantics of 'on-XXX' clauses.

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Change-Id: I003b7940ed8e2eee9d7dbd61261a6585964df029
Closes-Bug: #1642908
This commit is contained in:
Renat Akhmerov 2017-02-14 17:05:54 +07:00
parent c85ebd5c5d
commit c82166329b
1 changed files with 14 additions and 1 deletions
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15
doc/source/dsl/dsl_v2.rst
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@ -205,7 +205,7 @@ attributes:
Published variables will be accessible for downstream tasks via using
expressions. *Optional*.
- **publish-on-error** - Same as **publish** but evaluated in case of
task execution failures. *Optional*
task execution failures. *Optional*
- **with-items** - If configured, it allows to run action or workflow
associated with a task multiple times on a provided list of items.
See `Processing collections using
@ -413,6 +413,19 @@ Direct workflow task attributes
- **on-complete** - List of tasks which will run after the task has
completed regardless of whether it is successful or not. *Optional*.
It is important to understand the semantics of **on-success**, **on-error**
and **on-complete** around handling action errors.
In case if task action returned an error **on-success** and **on-complete**
won't prevent from failing the entire workflow execution. Only **on-error**
will. The closest analogy is *try-catch-finally* blocks in regular
programming languages. **on-error** is similar to *catch* and it serves
as an exception handler for possible errors expected by design. Whereas
**on-complete** is like *finally* that will run in any case but it won't
stop the exception from bubbling up to an upper layer. So **on-complete**
should only be understood as a language construction that allows to
define some clean up actions.
Transitions with YAQL expressions
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