June 18, 2021 I struggled recently getting AWS Gateway to implement query string caching. Here is the order of the steps you need to take: In the API Gateway console, under Resources, navigate to your API method and method. In Method Request, add a new URL Query String parameter checking Required and Caching. Deploy the API (because you always forget!) Under Stages, on the Settings tab, click the Enable API cache API.

April 2, 2021 Every time I look at the Lambda monitoring tab in the AWS Console, one of the charts drives my crazy. AWS has good intentions behind the charts. These charts show the performance of a Lambda, a tiny split-second function. AWS does a decent job of providing monitoring charts to show you the golden signals of your service performance: Traffic is displayed in the Invocations chart showing how many times the lambda was called Latency is displayed in the Duration chart showing how long the lambda took to execute Errors are displayed the Error count and success rate chart.

May 25, 2020 I was recently struggling with getting a CloudWatch alarm on a log filter metric to work. I was refactoring the creation from a CloudFormation template into just Lambda Python code. I was able to get both the filter metric (looking for errors and exceptions in logs) and alarm created. But, when I tested the alarm, it never went into an alarm state, even when then metric filter showed active data. It was driving me crazy.

November 16, 2019 Here is a Cloudformation template snippet to create a CloudTrail that is used to also record data events for Lambda invocations and S3 operations in addition to the typical management events from CloudTrail. CloudTrail: Type: AWS::CloudTrail::Trail DependsOn: - SNSTopicPolicy - S3BucketPolicy Properties: S3BucketName: Ref: S3Bucket SnsTopicName: Fn::GetAtt: - SNSTopic - TopicName IsLogging: true EnableLogFileValidation: true IncludeGlobalServiceEvents: true IsMultiRegionTrail: true EventSelectors: - DataResources: - Type: AWS::Lambda::Function Values: - arn:aws:lambda - DataResources: - Type: AWS::S3::Object Values: - "arn:aws:s3:::"

November 1, 2019 I recently tried to schedule an AWS Lambda defined through a SAM template to run every 10 minutes. I used some online cron expression builders but the syntax would not work with Cloudwatch. Somehow, I missed this reference in the Schedule Expressions for Rules. The online expression builder puts * for both day of the month and day of the week. You cannot use * in both the Day-of-month and Day-of-week fields.