How can AWS STS get-caller-identity help troubleshoot failing Lambda functions?

In the context of AWS, here are the steps given:-

Set up the AWS SDK

You should try to ensure that the AWS SDK for Python is installed. In the lambda environment, the Boto3 should be pre-installed. Here is the example given:-

Write the lambda function for calling get caller identity

Now you can write the lambda function for the purpose of calling the get caller identity by using the boto 3 and then log the identity details. Here is the example given below:-

Package com.example;

Import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;

Import software.amazon.awssdk.services.sts.StsClient;

Import software.amazon.awssdk.services.sts.model.GetCallerIdentityRequest;

Import software.amazon.awssdk.services.sts.model.GetCallerIdentityResponse;

Import org.slf4j.Logger;Import org.slf4j.LoggerFactory;

Public class LambdaHandler {

    Private static final Logger logger = LoggerFactory.getLogger(LambdaHandler.class);

    Public static void main(String[] args) {

        lambdaHandler();

    }

    Public static void lambdaHandler() {

        // Create an STS client

        StsClient stsClient = StsClient.builder()

                .credentialsProvider(ProfileCredentialsProvider.create())

                .build();

        Try {

            // Create a GetCallerIdentity request

            GetCallerIdentityRequest getCallerIdentityRequest = GetCallerIdentityRequest.builder().build();

            // Call GetCallerIdentity

            GetCallerIdentityResponse response = stsClient.getCallerIdentity(getCallerIdentityRequest);

            // Extract relevant information

            String userId = response.userId();

            String account = response.account();

            String arn = response.arn();

            // Log the caller identity information

            Logger.info(“UserId: {}, Account: {}, Arn: {}”, userId, account, arn);

        } catch (Exception e) {

            Logger.error(“Error calling GetCallerIdentity”, e);

        } finally {

            // Close the STS client

            stsClient.close();

        }

    }

}

Handling the response

The response object from “getcalleridentity” contains the user id, account and arn. These fields can be used for the purpose of logging and troubleshooting.

Package com.example;

Import com.amazonaws.services.lambda.runtime.Context;

Import com.amazonaws.services.lambda.runtime.RequestHandler;

Import com.amazonaws.services.lambda.runtime.events.SQSEvent;

Import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;

Import software.amazon.awssdk.services.sts.StsClient;

Import software.amazon.awssdk.services.sts.model.GetCallerIdentityRequest;

Import software.amazon.awssdk.services.sts.model.GetCallerIdentityResponse;

Import software.amazon.awssdk.services.sts.model.StsException;

Import org.slf4j.Logger;

Import org.slf4j.LoggerFactory;

Public class LambdaHandler implements RequestHandler {

    Private static final Logger logger = LoggerFactory.getLogger(LambdaHandler.class);

    @Override

    Public String handleRequest(SQSEvent event, Context context) {

        // Initialize the STS client

        StsClient stsClient = StsClient.builder()

                .credentialsProvider(DefaultCredentialsProvider.create())

                .build();

        Try {

            // Create a GetCallerIdentity request

            GetCallerIdentityRequest getCallerIdentityRequest = GetCallerIdentityRequest.builder().build();

            // Call GetCallerIdentity

            GetCallerIdentityResponse response = stsClient.getCallerIdentity(getCallerIdentityRequest);

            // Extract relevant information

            String userId = response.userId();

            String account = response.account();

            String arn = response.arn();

            // Log the caller identity information

            Logger.info(“UserId: {}, Account: {}, Arn: {}”, userId, account, arn);

            // Return the response details as a string

            Return String.format(“Caller Identity – UserId: %s, Account: %s, Arn: %s”, userId, account, arn);

        } catch (StsException e) {

            Logger.error(“Error calling GetCallerIdentity”, e);

            Return “Error fetching caller identity: “ + e.getMessage();

        } finally {

            // Close the STS client

            stsClient.close();

        }

    }

}