Error testing step function locally: The security token included in the request is invalid

Question

I am trying to test a step function locally. I have defined my stateMachine.json and added my credentials (aws_access_key_id and aws_secret_access_key) with aws configure .

I am following this steps to run the state machine: https://docs.aws.amazon.com/step-functions/latest/dg/sfn-local-lambda.html. But when I start the execution I get this error:

2021-08-08 05:37:56.464: arn:aws:states:us-east-1:123456789012:execution:StateMachine:firstTest : {"Type":"LambdaFunctionFailed","PreviousEventId":4,"LambdaFunctionFailedEventDetails":{"Error":"Lambda.AWSLambdaException","Cause":"The security token included in the request is invalid. (Service: AWSLambda; Status Code: 403; Error Code: UnrecognizedClientException; Request ID: 66622740-bcbc-4397-8c97-75454dca550d; Proxy: null)"}}

Which can be the error?

Answer 1

You need to set environmental variable LAMBDA_ENDPOINT as host.docker.internal.

---

At Step 3, you run this command:

sam local start-lambda

The output is like:

...
* Running on http://127.0.0.1:3001/ (Press CTRL+C to quit)

Remember 3001, this will be used below.

Then, refer to Step Functions Local configuration options. It says, aws-stepfunctions-local-credentials.txt contains credentials.

Include LAMBDA_ENDPOINT=http://host.docker.internal:3001.

Example of credential file:

AWS_ACCOUNT_ID= ...
AWS_DEFAULT_REGION= ...
AWS_ACCESS_KEY_ID= ...
AWS_SECRET_ACCESS_KEY= ...
LAMBDA_ENDPOINT=http://host.docker.internal:3001