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Difficulty: MediumMonitoring and Analyzing Logs with Amazon CloudWatch

A developer is troubleshooting a serverless application deployed on AWS Lambda. The application logs events in a structured JSON format to Amazon CloudWatch Logs. The developer needs to configure CloudWatch metric filters to monitor two separate issues:

1. Lambda function execution timeouts, which generate service-level log lines containing the string: `Task timed out after`
2. Application API failures, where the log events are JSON objects containing a key `statusCode` with a value of 500 or greater.

Which two configurations should the developer implement to achieve this? (Select TWO.)

  1. Create a metric filter for the execution timeouts using the filter pattern "Task timed out after".Answer
  2. B
    Create a metric filter for the execution timeouts using the JSON filter pattern { $.errorMessage = "Task timed out after*" }.
  3. Create a metric filter for the API failures using the JSON filter pattern { $.statusCode >= 500 }.Answer
  4. D
    Create a metric filter for the API failures using the space-delimited filter pattern [..., status_code >= 500, ...].
  5. E
    Catch the timeout exception in the application code and publish a custom metric using the PutMetricData API call before the function terminates.

Answer

The correct configurations are to create a metric filter for the execution timeouts using the filter pattern "Task timed out after" and to create a metric filter for the API failures using the JSON filter pattern { $.statusCode >= 500 }.
The correct options involve setting up a literal string filter pattern to match plain-text Lambda runtime log entries and a JSON path filter pattern to match structured JSON application log entries. Since Lambda service timeouts are logged as raw text lines, a literal string match is required. Since the application writes logs in JSON, the JSON path filter syntax allows matching numeric conditions on specific properties.

Step-by-Step Solution

1
Analyze the log format of the Lambda service execution timeouts.
The Lambda service logs execution timeouts as raw, unstructured text strings containing the pattern 'Task timed out after'.
Understanding the format of the log lines dictates the type of metric filter pattern needed.
2
Analyze the log format of the application API failures.
The application writes log events in a structured JSON format containing a statusCode field.
JSON logs require structured JSON query syntax to isolate specific property values.
3
Define the appropriate filter pattern syntax for each log type.
Use a literal string pattern '"Task timed out after"' for the text logs, and the JSON pattern '{ $.statusCode >= 500 }' for the JSON logs.
Applying the correct pattern ensures that the metric filter accurately parses the log stream and increments the metric.

Key Concept

Distinguishing between plain-text and structured JSON log streams when configuring Amazon CloudWatch metric filters.
Estimated Time:2m 0s
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Topics

Monitoring and Analyzing Logs with Amazon CloudWatch

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