Rollback error handler
The Rollback error handler stops the Action Flow run and reverts changes made by modules that support transactions. They always use a database app, like MySQL or Data store. Celonis platform cannot undo actions made by modules that don't support transactions, like Gmail > Send an email or Dropbox > Delete a file.
The bundle that caused the error doesn't continue in the Action Flow flow. In addition, Celonis platform doesn't process any remaining bundles.
Celonis platform marks the Action Flow run as an error in the Action Flow history. Celonis platform won't disable the Action Flow because of consecutive errors.
For example: This demo Action Flow contains five modules. The Action Flow is useful for tests and showing the effect of an error handler:
JSON - Parse JSON provides test data in the form of an array of three record IDs.
Iterator splits the array into individual bundles.
Data store - Update a record: Updates the data in the data store.
Data store - Update a record: This module updates the data again. This time the module works differently. In the module mapping, there is a mapping that intentionally creates an error:
The mapping inserts a
nullvalue into the required Key field, which always creates theBundleValidationError.Having two data store modules doing the same thing, but one of them failing, will make a good example for the Commit and Rollback error handlers.
Slack - Send a message: Sends a message to a private testing channel.
This is how the example Action Flow looks:
When we would run the example Action Flow, we would get the BundleValidationError:
If we added the Rollback error handler to the Update a record module, the Rollback error handler would stop processing the bundle in the Action Flow. Celonis platform wouldn't process the remaining bundles.
Let's check the data in the data store as well.
Before running the Action Flow, the data store contained the following data:
The mappings for the Update a record modules. The first module updates the ID column to the number 4 and the Name column to the text Test 4.
The second module updates the ID column to the number 5 and the Name column to the text Test 5.
If you disable the Auto-commit option in the Action Flow settings, Celonis platform reverts the changes that happened when Celonis platform was processing the bundle in modules that support transactions.
The first bundle of data gets through the Action Flow flow successfully and updates the first row of data in the data store both times. The first row contains the update from the second Update a record module:
ID = 5, Name = Test 5.The second bundle gets to the first Update a record module successfully, but causes an error in the second module. The Rollback error handler reverts the update from the second bundle and stops the Action Flow.
The first row now contains the update from the first module only:
ID = 4, Name = Test 4.The second row contains the original data:
ID = 2, Name = Test 2.Celonis platform doesn't update the third row because the Rollback error handler stopped the Action Flow run already. The data in the third row remain the same:
ID = 3, Name = Test 3.
If you keep the Auto-commit option enabled, Celonis platform reverts the changes made by the module that output the error if the module supports transactions.
The first bundle of data gets through the Action Flow flow successfully and updates the first row of data in the data store both times. Celonis platform commits all changes and they cannot be rolled back later.
The first row contains the update from the second Update a record module:
ID = 5, Name = Test 5.The second bundle gets to the first Update a record module successfully. Celonis platform commits all changes and they cannot be rolled back later. The second bundle causes an error in the second module.
The Rollback error handler prevents the update in the second module and stops the Action Flow. The second row contains the update from the first module only:
ID = 4, Name = Test 4.Celonis platform doesn't update the third row because the Rollback error handler stopped the Action Flow run already. The data in the third row remain the same:
ID = 3, Name = Test 3.
You can use the Rollback error handler to stop the Action Flow run and undo changes when the module outputs an error.
For more information about error handling strategies check the overview of error handling.
Undo changes to your data when an error happens
With the Rollback error handler, you can stop the Action Flow and undo changes when the module outputs an error. You can only undo changes in modules that support transactions.
For example, the following Action Flow outputs an error in the Data Store app module:
To stop the Action Flow and undo changes where possible when an error happens, follow the steps:
Right-click the module that is causing the error. In the menu, select Add error handler.
Select the Rollback error handler.
Optional: Go to Action Flow settings and disable the Auto-commit option.
When an error happens, the module that outputs the error reverts changes if the module supports transactions. If you disable the Auto-commit option, all modules in the Action Flow that support transactions undo changes.
Save your Action Flow.
You added the Rollback error handler to your Action Flow. When an error occurs in the Data store module, the Action Flow stops and Celonis platform reverts changes made by the erroring bundle in modules that support transactions.