Error Handling in Common Fallback state with JSONata Query Language #400

ginjups · 2025-08-13T07:44:51Z

Issue #, if available:

Description of changes:

Adding a new workflow of JSONata type that demonstrates practical solutions for fetching failed state name in JSONata StateMachine with common fallback state for multiple task states. AWS Step Functions users commonly seek to implement centralized error reporting within their workflows to avoid duplicating error handling logic across multiple states. While implementing a shared error reporting task is straightforward, a significant challenge arises: the error reporting task can access the error message from the failed state, but cannot inherently determine which specific state triggered the error.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

bfreiberg · 2025-08-22T07:54:02Z

common-fallback-state-jsonata/statemachine/statemachine.asl.json

@@ -0,0 +1,116 @@
+{
+  "Comment": "StateMachine using JSONata QueryLanguage with common fallback state for multiple task states",


Suggested change

"Comment": "StateMachine using JSONata QueryLanguage with common fallback state for multiple task states",

"Comment": "State machine using JSONata query language with common fallback state for multiple task states",

bfreiberg · 2025-08-22T07:54:57Z

common-fallback-state-jsonata/statemachine/statemachine.asl.json

+      "End": true
+    }
+  },
+  "QueryLanguage": "JSONata"


move to top, just to be more visible

Moved to top

bfreiberg · 2025-08-22T07:55:31Z

common-fallback-state-jsonata/README.md

@@ -0,0 +1,66 @@
+# Common Fallback State - JSONata


Would maybe "Shared Fallback State" be a better description?

Updated Title

bfreiberg · 2025-08-22T07:55:44Z

common-fallback-state-jsonata/example-workflow.json

@@ -0,0 +1,69 @@
+{
+    "title": "Common Fallback State JSONata",


Use same title as in the README

bfreiberg · 2025-08-22T07:59:13Z

common-fallback-state-jsonata/example-workflow.json

+    "introBox": {
+      "headline": "How it works",
+      "text": [
+        "This example workflow illustrate practical solutions for fetching failed state name in JSONata StateMachine with common fallback state for multiple task states. AWS Step Functions users commonly seek to implement centralized error reporting within their workflows to avoid duplicating error handling logic across multiple states. While implementing a shared error reporting task is straightforward, a significant challenge arises: the error reporting task can access the error message from the failed state, but cannot inherently determine which specific state triggered the error. This limitation becomes particularly problematic in workflows containing numerous Lambda functions, as it complicates identifying the exact point of failure. Using JSONata as our query language, we demonstrate approach to overcome this limitation, enabling comprehensive error tracking while maintaining workflow efficiency."


This is a bit too verbose, condense and leave out filler words like "practical", "particular", "comprehensive" etc.
Make the same changes to the README

Re-written the explanation

bfreiberg · 2025-08-22T07:59:29Z

common-fallback-state-jsonata/example-workflow.json

+    "cleanup": {
+      "headline": "Cleanup",
+      "text": [
+        "1. Delete the stack: <code>sam delete</code>."


Suggested change

"1. Delete the stack: <code>sam delete</code>."

"Delete the stack: <code>sam delete</code>."

bfreiberg · 2025-08-22T08:00:45Z

common-fallback-state-jsonata/README.md

+
+The workflow doesn't require any input. By default, the third lambda function in "ThirdLambdaState" task state is programmed to fail. Thus, the workflow execution fails at this task state and transitions into "FallbackState" with input as "FailedStateName": "ThirdLambdaState". 
+
+The "ThirdLambdaFunction" is intentionally programmed to simulate the failure.


Add to paragraph above and then remove

bfreiberg · 2025-08-22T08:01:17Z

common-fallback-state-jsonata/README.md

+
+## Testing
+
+To test the workflow, simply start an execution of the state machine. This workflow doesn't require any input payload. Observe the execution once it has completed.


Please include a description of what the user should expect

bfreiberg · 2025-08-22T11:15:54Z

common-fallback-state-jsonata/README.md

+
+1. Delete the stack
+    ```bash
+    aws cloudformation delete-stack --stack-name STACK_NAME


You deployed using SAM, why not use sam delete?

Done, used sam delete

bfreiberg · 2025-08-22T11:16:03Z

common-fallback-state-jsonata/README.md

+    aws cloudformation list-stacks --query "StackSummaries[?contains(StackName,'STACK_NAME')].StackStatus"
+    ```
+----
+Copyright 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.


ginjups · 2025-08-25T06:13:56Z

Published the commit 6d22f67 including all the above changes suggested. Thank you!

bfreiberg

Looks good, one minor change and we are ready

shared-fallback-state-jsonata/README.md

Co-authored-by: Ben <[email protected]>

bfreiberg · 2025-08-25T13:32:50Z

Looks good, thanks for your contribution. Your submission will be merged to Serverlessland soon

adding common fallback state jsonata

f3bed6e

bfreiberg suggested changes Aug 22, 2025

View reviewed changes

Included suggested changes

6d22f67

bfreiberg suggested changes Aug 25, 2025

View reviewed changes

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Update shared-fallback-state-jsonata/README.md

8b7d85e

Co-authored-by: Ben <[email protected]>

julianwood merged commit 1feff72 into aws-samples:main Aug 27, 2025

		@@ -0,0 +1,116 @@
		{
		"Comment": "StateMachine using JSONata QueryLanguage with common fallback state for multiple task states",

	"Comment": "StateMachine using JSONata QueryLanguage with common fallback state for multiple task states",
	"Comment": "State machine using JSONata query language with common fallback state for multiple task states",

	"1. Delete the stack: <code>sam delete</code>."
	"Delete the stack: <code>sam delete</code>."


		The workflow doesn't require any input. By default, the third lambda function in "ThirdLambdaState" task state is programmed to fail. Thus, the workflow execution fails at this task state and transitions into "FallbackState" with input as "FailedStateName": "ThirdLambdaState".

		The "ThirdLambdaFunction" is intentionally programmed to simulate the failure.


		## Testing

		To test the workflow, simply start an execution of the state machine. This workflow doesn't require any input payload. Observe the execution once it has completed.

	Copyright 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
	Copyright 2025 Amazon.com, Inc. or its affiliates. All Rights Reserved.

Error Handling in Common Fallback state with JSONata Query Language #400

Error Handling in Common Fallback state with JSONata Query Language #400

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ginjups commented Aug 25, 2025

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bfreiberg commented Aug 25, 2025

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