You've developed a Lambda function and now want to debug it, after the execution completes.
You add the necessary print statements in the code to assist in the debugging process.
You go to Cloudwatch logs but there are no logs for the Lambda function.
Which of the following could be the underlying issue for this?
Click on the arrows to vote for the correct answer
A. B. C. D.Answer - B.
The AWS Documentation mentions the following.
Note.
"If your Lambda function code is executing, but you don't see any log data being generated after several minutes, this could mean your execution role for the Lambda function did not grant permissions to write log data to CloudWatch Logs.
For information about how to make sure that you have set up the execution role correctly to grant these permissions, see Manage Permissions: Using an IAM Role (Execution Role)".
Option A is incorrect since versioning will not help in this case.
Options C and D are incorrect since these were the cases if the function would not complete execution, but the question says debugging starts after the execution is completed.
For more information on monitoring Lambda functions, please refer to the below URL-
https://docs.aws.amazon.com/lambda/latest/dg/monitoring-functions.htmlWhen you create a Lambda function, you can choose to have it write its logs to CloudWatch Logs. CloudWatch Logs is a managed service that makes it easy to centralize and monitor logs from all your AWS resources, including Lambda functions. You can use CloudWatch Logs to troubleshoot and debug your Lambda function code by reviewing the logs generated during the execution of the function.
If you have added print statements in your Lambda function code to assist in the debugging process, but you don't see any logs in CloudWatch Logs after the execution completes, it could be due to one of the following reasons:
A. You've not enabled versioning for the Lambda function: When you enable versioning for a Lambda function, AWS creates a new immutable version of the function each time you update it. This ensures that the function code and configuration remains unchanged and can be invoked repeatedly. If versioning is not enabled, the function code and configuration may change unexpectedly, leading to issues with logging. However, the lack of versioning is unlikely to be the primary cause of the absence of logs in CloudWatch Logs.
B. The IAM role needed for the lambda function to write the logs to Cloudwatch logs does not have the necessary permissions: When a Lambda function writes logs to CloudWatch Logs, it needs an AWS Identity and Access Management (IAM) role with the necessary permissions. If the role associated with the Lambda function does not have the necessary permissions to write logs to CloudWatch Logs, no logs will be generated. Therefore, this is a possible cause of the issue.
C. There is not enough memory assigned to the function: When a Lambda function is executed, it is assigned a certain amount of memory, which determines the amount of CPU and network resources that are allocated to it. If the function runs out of memory during execution, it may terminate prematurely and fail to generate logs. However, the lack of memory is unlikely to be the primary cause of the absence of logs in CloudWatch Logs.
D. There is not enough time assigned to the function: When a Lambda function is executed, it is also assigned a maximum execution time, which determines how long the function can run before it is terminated. If the function exceeds its maximum execution time, it may terminate prematurely and fail to generate logs. However, the lack of time is unlikely to be the primary cause of the absence of logs in CloudWatch Logs.
Therefore, the most likely cause of the issue is that the IAM role associated with the Lambda function does not have the necessary permissions to write logs to CloudWatch Logs. You can resolve this by adding the necessary permissions to the role or by creating a new role with the necessary permissions and associating it with the Lambda function.