bug: JsonPathParserError in TimestampPath when any path fragments begin with a number

[attila]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

Hi again,

It looks like the path parser cannot parse JSON inputs when any path fragments begin with a number.

Given the stepfunction example below, starting an execution gives the following error:

localstack  | 2024-04-19T08:41:44.527  INFO --- [   asgi_gw_0] localstack.request.aws     : AWS stepfunctions.StartExecution => 200
localstack  | 2024-04-19T08:41:44.550 ERROR --- [ad-10 (eval)] l.s.s.a.c.eval_component   : Exception=JsonPathParserError, Details=['Parse error at 1:3 near token DayBeforeTimeStamp (ID)'] at '(TimestampPath| {'path': '$.1DayBeforeTimeStamp'}'
localstack  | 2024-04-19T08:41:44.551 ERROR --- [ad-10 (eval)] l.s.s.a.c.eval_component   : Exception=JsonPathParserError, Details=['Parse error at 1:3 near token DayBeforeTimeStamp (ID)'] at '(StateWait| {'comment': None, 'input_path': (InputPath| {'input_path_src': '$'}, 'output_path': (OutputPath| {'output_path': '$'}, 'state_entered_event_type': 'WaitStateEntered', 'state_exited_event_type': 'WaitStateExited', 'name': 'WaitFor1DayBefore', 'state_type': <StateType.Wait: 21>, 'continue_with': <localstack.services.stepfunctions.asl.component.state.state_continue_with.ContinueWithNext object at 0x7fcda9295c10>, 'wait_function': (TimestampPath| {'path': '$.1DayBeforeTimeStamp'}}'
localstack  | 2024-04-19T08:41:44.551 ERROR --- [ad-10 (eval)] l.s.s.a.c.program.program  : Stepfunctions computation ended with exception 'JsonPathParserError(Parse error at 1:3 near token DayBeforeTimeStamp (ID))'.

Expected Behavior

JSON path fragments that begin with numbers are still treated as strings and path traversal works as expected, just like in the production AWS service or in AWS' own stepfunctions-local.

How are you starting LocalStack?

With a docker-compose file

Steps To Reproduce

How are you starting localstack (e.g., bin/localstack command, arguments, or docker-compose.yml)

docker compose up

Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)

awslocal stepfunctions create-state-machine --name 'example' --role-arn "arn:aws:iam::000000000000:role/stepfunctions-role" --definition '{"StartAt":"WaitFor1DayBefore","States":{"WaitFor1DayBefore":{"Type": "Wait","TimestampPath":"$.1DayBeforeTimeStamp","Next":"1DayBefore"},"1DayBefore":{"Type":"Pass","End":true}}}'

awslocal stepfunctions start-execution --state-machine-arn 'arn:aws:states:eu-west-1:000000000000:stateMachine:example' --input '{"1DayBeforeTimeStamp":"2024-04-21T12:34:56Z"}'

I inlined the definition in the example but here it is for better readability:

{
  "StartAt": "WaitFor1DayBefore",
  "States": {
    "WaitFor1DayBefore": {
      "Type": "Wait",
      "TimestampPath": "$.1DayBeforeTimeStamp",
      "Next": "1DayBefore"
    },
    "1DayBefore": {
      "Type": "Pass",
      "End": true
    }
  }
}

Input specified:

{
  "1DayBeforeTimestamp": "2024-04-21T12:34:56Z"
}

Environment

- OS: MacOS 14
- LocalStack: 3.3.0

Anything else?

No response

[TheDanGior]

I am seeing a similar bug when my JSON path starts with a symbol. The @class JSON path is included automatically by our library when serializing to JSON from Java.

Input:

{
    "@class":"com.company.name.InputData",
    "id":"123abc",
    "sourceUserId":"101",
    "inputFileS3Keys": [ "00000000-1111-2222-3333-444444444" ]
}

Error:

Exception=JsonPathParserError, Details=['Parse error at 1:1 near token $ ($)'] at '(StatePass| {'comment': None, 'input_path': (InputPath| {'input_path_src': '$$.Execution.Id'}, 'output_path': (OutputPath| {'output_path': '$'}, 'state_entered_event_type': 'PassStateEntered', 'state_exited_event_type': 'PassStateExited', 'result': None, 'result_path': (ResultPath| {'result_path_src': '$.id'}, 'parameters': None, 'name': 'EmbedId', 'state_type': <StateType.Pass: 20>, 'continue_with': <localstack.services.stepfunctions.asl.component.state.state_continue_with.ContinueWithNext object at 0x7f0820510550>}'

[MEPalma]

Thank you for compiling this bug report! The issue appears to be related to some limitations to the JsonPath library that the StepFunctions interpreter relies on https://github.com/h2non/jsonpath-ng.
These are issues related to the same issue: #10603, #9937 (comment).
Nevertheless, we are looking into this limitation and I will be happy to update you as soon as a solution is implemented.