Debug with CloudWatch logs

  1. Open Postman to call api.

    • Click + to add a new tab.
    • Select GET method.
    • Enter URL of the listing API that recorded from the previous step.
    • Click Send. CloudWatchLog
    • After completing, the data of the Books table is returned. CloudWatchLog

  2. Open AWS Lambda console.

    • Click Functions on the left menu.
    • Choose the books_list function. CloudWatchLog

  3. At books_list page.

    • Click the Monitor tab.
    • Click the View CloudWatch logs button. CloudWatchLog

  4. At /aws/lambda/books_list page.

    • You will see all the logs saved each time the function books_list is executed. CloudWatchLog

  5. Next, we will fix the code to make the function run failed. Copy the following code.

    books_data = table.scan(
    TableName='Book',
    IndexName=secondary_index
)
    • Back to books_list page.
      • Click the Code tab.
      • Change the code as the copied one above.
      • Click the Deploy button. CloudWatchLog

  6. After books_list is deployed successfully. Recall the API as in step 1, the error returned is Internal server error. CloudWatchLog

  7. Back to /aws/lambda/books_list CloudWatch Logs page.

    • Click the Refresh icon.
    • Click the latest log at the Log streams. CloudWatchLog

  8. At the detailed log page. You could see the error. The error is because we changed TableName=‘Books’ to TableName=‘Book’ (Books is the name of the DynamoDB table that we just created before). CloudWatchLog