Error handling during workflow integration - CloudFlow - Alibaba Cloud Documentation Center

This topic describes the overview and examples of error handling during workflow integration.

Overview

Expected or unexpected errors may occur in the workflow integration of CloudFlow. You can retry the current state or move to the next state based on the scenario. The FnF.ALL keyword is a special option that hits all errors.

The following table describes the attributes of the error handling logic.

Attribute	Type	Required	Description	Example
Errors	String	Yes	The errors that can be hit.	string{"err1","err2"}
Description	String	No	The description of the error.	describe it here
Retry	String	No	The retry policy. This attribute and the Next attribute are mutually exclusive. This attribute has a lower priority than the Next attribute.	See Retry.
Next	String	No	The next state that is executed after the current state is complete. This attribute and the Retry attribute are mutually exclusive. This attribute has a higher priority than the Retry attribute.	Pass1
OutputConstructor	Map[String]Any	No	The output constructor. This attribute is used together with the Next attribute.	See OutputConstructor.

Retry

Attribute	Type	Required	Description	Example
MaxAttempts	Int	Yes	The maximum number of retries.	5
FixedBackoff	Int	No	The first backoff delay.	2
Multiplier	Float	No	The backoff exponent.	1.5

Next

The OutputConstructor attribute is used together with the Next attribute. If an error occurs in a state, no expected outputs are generated in the state. The flow cannot proceed even if the flow transits to the next state. In this case, you can use the OutputConstructor attribute to construct an output and use the output as the input of the next state.

Example

Type: StateMachine
Name: my-wkfl
SpecVersion: v1
StartAt: Pass1
States:
  - Type: Task
	  Name: Mytestfc
	  Action: FC:InvokeFunction
	  TaskMode: RequestComplete
	  OnErrors:
	    - Errors:
	        - MyCustomException
	      Description: my retry policy
	      Retry:
	        MaxAttempts: 5
	        FixedBackoff: 2
	        Multiplier: 2.5
	    - Errors:
	        - FnF.ALL
	      Description: my catch policy
	      OutputConstructor:
	        FieldQ: 123
	      Next: Pass1
    - Type: Pass
      Name: Pass1
      End: true

In the preceding example, if an error occur in the Mytestfc integration and the error hits MyCustomException, the system retries the state up to five times based on the retry policy. After the maximum number of retries is exhausted, the flow ends. If other errors occur, the errors hit FnF.ALL. The system uses the OutputConstructor attribute to construct an output and uses the output as the input of the Pass1 state. Then, the flow transits to the Pass1 state.