A developer has configured an AWS Lambda function written in Python to process events from an Amazon SQS queue and write the results to an Amazon DynamoDB table. Active tracing is enabled on both the SQS queue and the Lambda function. When reviewing the AWS X-Ray console, the developer observes that the service map shows the SQS queue and the Lambda function, but the downstream calls to DynamoDB are missing from the trace. Which action should the developer take to trace the downstream DynamoDB calls in AWS X-Ray?
- AManually extract the _X_AMZN_TRACE_ID tracing header from the SQS event object and pass it as a custom parameter in the DynamoDB API request payload.
- BInitialize the Boto3 DynamoDB client with hardcoded AWS access keys and secret keys that have X-Ray write permissions.
- Import the AWS X-Ray SDK in the Lambda function code and invoke the patch_all() function before initializing the Boto3 client.Answer
- DIncrease the SQS visibility timeout of the source queue to allow the Boto3 SDK sufficient time to complete and flush the DynamoDB trace segments.
Answer
Import the AWS X-Ray SDK in the Lambda function code and invoke the patch_all() function before initializing the Boto3 client.
The correct answer is to import the AWS X-Ray SDK and run the patch_all() function. When running a Python Lambda function with active tracing enabled, downstream SDK calls are not traced by default unless the Boto3 library is instrumented. Patching the library automatically wraps Boto3 clients so that downstream calls (like DynamoDB operations) are recorded as subsegments in the X-Ray trace.
Step-by-Step Solution
Key Concept
AWS SDK client instrumentation using the X-Ray SDK to trace downstream AWS service calls.