You have created a Lambda Function generating the error “ServiceException”. Which of the following is the best practice to handle this exception under AWS Step Functions?

Answer options:

A.Use Lambda Catch code with only “ErrorEquals” string.
B.Use Lambda Retry code with only “BackoffRate” string
C.Use Lambda Retry code with only “ErrorEquals” string.
D.Use Lambda Catch code with only “ResultPath” string.

Correct Answer – C
Any state under step functions can encounter runtime errors. Errors can happen for various reasons:
Task failures (for example, an exception in a Lambda function)
AWS Lambda can occasionally experience transient service errors. In this case, invoking Lambda results in a 500 error, such as 
ServiceException
, 
AWSLambdaException
, or 
SdkClientException
.
By default, when a state reports an error, AWS Step Functions causes the execution to fail entirely.
For errors such as “ServiceException”, the best practice is to Retry invoking the Lambda function. Within a Retry Code, the “ErrorEquals” field is the required string that matches error names & all other fields are optional.
Option A is incorrect as the Lambda Catch code is only used after the function performs several retries and ErrorEquals & Next are required strings.
Option B is incorrect as the BackoffRate field is optional in Lambda Retry code & if not specified, the default value of 2.0 is considered.
Option D is incorrect as the Lambda Catch code is only used after the function performs several retries. ResultPath is an optional field in a Catch Code, ErrorEquals & Next are required strings.
For more information on troubleshooting Lambda Function errors, refer to the following URL-
https://docs.aws.amazon.com/step-functions/latest/dg/concepts-error-handling.html
https://docs.aws.amazon.com/step-functions/latest/dg/bp-lambda-serviceexception.html