CloudFormation Archives | theburningmonk.com

This is why you should keep stateful and stateless resources together

AWS, CloudFormation, Serverless / January 9, 2023 January 9, 2023

Loose coupling and high cohesion are two of the most essential software engineering principles. Unrelated things should stay apart, while related elements should be kept together. These principles apply at all levels of our application — from the system-level architecture all the way down to individual modules or functions. With this simple principle in mind, …

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How to work around CloudFormation circular dependencies

AppSync, AppSync Masterclass, AWS, CloudFormation, Lambda, Programming / May 16, 2022 August 13, 2022

An interesting question came up on the AppSync Masterclass forum, and it highlights a common way you can get into CloudFormation circular dependencies. In the CloudFormation stack, there is an AppSync API, which uses a Cognito User Pool for authentication and authorization. When a user signs up, the app should fire an update on a …

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How I scaled an AppSync project to 200+ resolvers

AppSync, AWS, CloudFormation, Programming, Serverless / July 30, 2020 July 30, 2020

I have been working on a large AppSync project for a client these past few months. The initial version of the app was built in just a few weeks, but the client has commissioned additional features and the project has kept growing. At the time of writing, this project has over 200 AppSync resolvers and …

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Why you should use temporary stacks when you do serverless

AWS, CloudFormation, Programming, Serverless / September 12, 2019 July 17, 2022

One of the benefits of serverless is the pay-per-use pricing model you get from the platform. That is, if your code doesn’t run, you don’t pay for them! Combined with the simplified deployment flow (compared with applications running in containers or VMs) it has enabled many teams to make use of temporary CloudFormation stacks. In …

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How to use the power of CloudFormation custom resources for great good

AWS, CloudFormation, Lambda, Programming, Serverless / September 1, 2019 October 6, 2019

Disclaimer: if you’re new to CloudFormation custom resources, then I recommend you start by reading this excellent post by Alex Debrie first. Custom resources bring a whole new dimension to CloudFormation and enable some fascinating use cases. For example: provision DataDog dashboards as part of your CloudFormation stack run a load test every time you …

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How to include Serverless Repository apps in serverless.yml

AWS, CloudFormation, Lambda, Programming, Serverless / May 12, 2019 September 5, 2020

Over the past year, the Serverless Application Repository (SAR) service has improved a lot. I have grown to enjoy it more and more, and have contributed a few applications myself: lambda-janitor: cron job to delete old, unused versions of all Lambda functions in the region to free up storage space. auto-subscribe-log-group-to-arn: subscribes new and existing …

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CloudFormation protip: use !Sub instead of !Join

AWS, CloudFormation, Programming, Serverless / May 12, 2019 October 6, 2019

Update 12/05/2019: as Moshe pointed out in the comments, Fn::Sub is not supported by the Serverless framework because it too uses the ${} syntax to support its own variables system. However, as is often the case with the Serverless framework, you can work around this issue with a plugin. Check out the serverless-cloudformation-sub-variables plugin which …

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