Debugging with CloudWatch logs

  1. Copy the value of Distribution at the Outputs tab of the stack and paste it into your browser. Then click Sign up

CreateRepository

  • Enter your information to register an account and click Sign up

CreateRepository

  1. Open the email you registered with to get the verification code.
    • Enter the verification code into the app.
    • Click Submit

CreateRepository

  1. Enter the account information you have registered and click Sign in

CreateRepository

  1. Click Upload

CreateRepository

  1. Click Add files
    • Select the files you want to upload
    • Enter tags for files or ignore
    • Click Upload

CreateRepository

  • You have successfully uploaded the files:

CreateRepository

  1. Open the AWS Lambda console

  2. Select Funtions on the left menu and select upload_docs function. CreateRepository

  3. Select Monitor tab and click View CloudWatch logs

CreateRepository

  1. Select the latest log

CreateRepository

  • You should see the function running normally and without any errors. Next, we will fix the code that causes the function to fail.

CreateRepository

  1. Edit the code as follows:
    try:
        table.put_item(Item = item)
    except Exception as e:
        print(e)

We add try-except to catch the error when we cannot connect to DynamoDB. Next, click Deploy.

CreateRepository

  • Select Configuration tab and select Environment variables on the left menu.
  • Click Edit

CreateRepository

  • Change the table name to another name
  • Click Save

CreateRepository

  1. Open the Amazon API Gateway console
  2. Select Serverless - FCJ Document Management System
  3. Select POST and click Test

CreateRepository

  1. Add the following code to Request Body section and click Test.
{
    "user_id": "abcd1234",
    "file": "dynamoDB.json",
    "folder": "",
    "identityId": "123456cvbn",
    "modified": "13-03-2023",
    "size": 1024,
    "type": "json",
    "tag": "aws, serverless"
}

CreateRepository

  1. Result returned error

CreateRepository

  1. Return to CloudWatch log console to check log
  2. The error displayed as AccessDeniedException is different from the error returned for API Gateway

CreateRepository

  1. If you want the error returned to be the same as the error recorded in the log, add the following code to the upload_docs function
        return {
            "statusCode": 400,
            "headers": {
                "Content-Type": "application/json",
                "Access-Control-Allow-Origin": "*",
                "Access-Control-Allow-Methods": "GET,PUT,POST,DELETE, OPTIONS",
                "Access-Control-Allow-Headers": "Access-Control-Allow-Headers, Origin,Accept, X-Requested-With, Content-Type, Access-Control-Request-Method,X-Access-Token,XKey,Authorization"
            },
            "body": str(e)
            }
  • Then click Deploy

CreateRepository

  1. Back to API Gateway, press Test. You will see the error returned.

CreateRepository