I have enabled subprocess output in my AWS lambda - why is this log output not being pushed to CloudWatch?

Question

I have a piece of code which is failing and I am trying to debug using AWS Cloudwatch logs. The piece of code, with logging enabled is as follows:

def run_command(args, cwd):
try:
        proc = subprocess.run(args,
            cwd=cwd,
            timeout=720,
            check=True,
            capture_output=True)
        stdout = proc.stdout
        stderr = proc.stderr
    except subprocess.TimeoutExpired as e:
        logging.debug(proc.stdout)
        print(e.output)
        print(e)

I expect the subprocess output to be displayed in my AWS Cloudwatch logs. However, here is the output:

START RequestId: 1234567 Version: $LATEST
Command '['my command']' returned non-zero exit status 1.
END RequestId: 1234567

I am running the function like: run_command('ls',cwd) . I am expecting more information on the second line, as I added the capture_output=True statement. Why is the output of the subprocess command not being logged to my Cloudwatch group, and is it possible to do this?

Thanks

Answer 1

Do quick test and ensure that your Lambda function has been assigned the AWSLambdaBasicExecutionRole.

Also, There's a very good article from this guy named Paul Singman. He explains why we shouldn't be using the print to log. Check here