CodePipeline lambda Function: Complete Example

Hello! It takes a few pieces to assemble a working lambda action for CodePipeline. I like to start from a simple example and build up to what I need. Here's the code I use as a starting point. First, a few notes: My pipeline lambda functions are usually small, often only a few dozen lines … Continue reading CodePipeline lambda Function: Complete Example

CloudFormation Custom Resource: Complete Example

Hello! It takes a few pieces to assemble a working CloudFormation Custom Resource. I like to start from a simple example and build up to what I need. Here's the code I use as a starting point. First, a few notes: My custom resources are usually small, often only a few dozen lines (more than … Continue reading CloudFormation Custom Resource: Complete Example

Don’t Import requests From botocore.vendored

Hello! I've seen this anti-pattern scattered around plenty DevOps code, especially in AWS lambda functions: Vendoring libraries like requests into other libraries like botocore is arguably an anti-pattern in general, but reaching in to botocore and importing it in your own code is definitely one. Here are some of the reasons: The maintainers may un-vendor … Continue reading Don’t Import requests From botocore.vendored

CloudWatch Logs Structured as JSON with Python Lambda Functions

Hello! If you're setting up JSON logging in a script and instead of a lambda function, check out this instead. The pattern is a little simpler. Update 2020-08-30: Replaced the explanation of the missing aws_request_id with a link to a new article explaining how to pass that value. Recently, I've been switching to logs structured … Continue reading CloudWatch Logs Structured as JSON with Python Lambda Functions

CodePipeline: Python AWS Lambda Functions Without Timeouts

Hello! If you're new to CodePipeline lambda actions check out this complete example first. There’s a gotcha when writing CodePipeline lambda functions that’s easy to miss and if you miss it your pipeline can get stuck in timeout loops that you can't cancel. Here’s how to avoid that. This article assumes you're familiar with CodePipeline … Continue reading CodePipeline: Python AWS Lambda Functions Without Timeouts

Boto3 Best Practices: Assert to Stop Silent Failures

Good morning! Today's post covers a pattern I use to increase my confidence that my infrastructure code is working. It turns silent errors into loud ones. I've handled plenty of code that runs without errors but still ends up doing the wrong thing, so I'm never really sure if it's safe to go to sleep … Continue reading Boto3 Best Practices: Assert to Stop Silent Failures

Lambda: boto3 CloudWatch Logs

Good morning! If you're writing a regular script (i.e. not a lambda function), check out this article. This pattern outputs traditional delimited strings. If you want to upgrade that into output structured as JSON objects, check out this article. For those custom cases that don't fit into Terraform or CloudFormation, a little bit of Python and some … Continue reading Lambda: boto3 CloudWatch Logs