onError
add custom data to exception
Provide custom error information if the step raises an exception. This lets you add extra information to the error itself.
If this step errors, write the contents of onError to
runErrors[n].customError in context. Steps inside a
failure handler
then can use this information. Alternatively, subsequent steps can also use this
information, assuming you’ve got a swallow somewhere
in the call chain.
onError can be a simple string, or your your own dict, or any given object.
You can use substitutions to assign values dynamically at run-time.
simple string extra error data
You can add a simple string for extra error information:
# ./onerror-decorator.yaml
steps:
- name: pypyr.steps.assert
comment: deliberately raise error
with custom error info
in:
assert: False
onError: this is a custom error
on_failure:
- name: pypyr.steps.echo
comment: the custom error is in runErrors
it's the 1st and only error in
this pipeline, hence index 0.
in:
echoMe: "the error was: {runErrors[0][customError]}"When you run this pipeline, this is the result:
$ pypyr onerror-decorator
Error while running step pypyr.steps.assert at pipeline yaml line: 3, col: 5
Something went wrong. Will now try to run on_failure.
the error was: this is a custom error
AssertionError: assert False evaluated to False.create custom exception object
onError will take any given type. You can add your own custom object here.
In this pipeline, add an error code and a description to the custom exception object:
# ./onerror-complex-obj.yaml
steps:
- name: pypyr.steps.set
comment: arbitrarily set a context value.
will be using this value in error
object.
in:
set:
arbKey: FROM SUBSTITUTION EXPRESSION
- name: pypyr.steps.assert
comment: deliberately raise error
with custom error object
in:
assert: False
onError:
myerr_code: 123
myerr_description: "my err {arbKey} description"
on_failure:
- name: pypyr.steps.echo
comment: the custom error is in runErrors
notice your custom error object
is here with substitutions applied.
in:
echoMe: |
the error code: {runErrors[0][customError][myerr_code]}
the error description: {runErrors[0][customError][myerr_description]} When you run this pipeline, this is the result:
$ pypyr onerror-complex-obj
Error while running step pypyr.steps.assert at pipeline yaml line: 10, col: 5
Something went wrong. Will now try to run on_failure.
the error code: 123
the error description: my err FROM SUBSTITUTION EXPRESSION description
AssertionError: assert False evaluated to False.