Can't get AWS Lambda function to log (text output) to CloudWatch

Question

I'm trying to set up a Lambda function that will process a file when it's uploaded to an S3 bucket. I need a way to see the output of console.log when I upload a file, but I can't figure out how to link my Lambda function to CloudWatch.

I figured about by looking at the context object that my log group is /aws/lambda/wavToMp3 and the log stream is 2016/05/23/[$LATEST]hex_code_redacted. So I created that group and stream in CloudWatch, yet nothing is being logged to it.

Answer 1

After you update your policy, it seems that you have to update your function's settings to refresh all job instances to read new policies.

So if you just click 'test' button from Lambda console after you update your role policy in IAM, the cached Lambda instances will still have old role permissions, so you will still see no logs being written to Cloudwatch logs.

Just change your timeout by a second and click on 'save and test' button, and you will start to see logs in Cloudwatch.