Code best practice

A construct is a logical unit of the app.

• Not recommended to have multiple cdk apps in the same repository.
• Combine the code for the infra and runtime app into a single construct.
• Represent each logical unit as a construct, while each deployment unit as a stack.
• Do env variable lookup at the top level of an cdk app and pass them as props down.
• Avoid network lookups during synthesis
• Model production stages in code
• Write unit tests

Application best practice

• Make decisions at synthesis time (don’t use CloudFormation IF-constructs and Parameters)
• Use generated resource names and don’t set custom names, see resources that support custom names https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-name.html
• Configure removal policies and log retention (use https://docs.aws.amazon.com/cdk/latest/guide/aspects.html)
• Synthesizing an app shouldn’t have side effects (like network calls to modify aws account or resources), to execute arbitrary code during deployment use custom resources

Working with stacks and constructs

• better to keep as many resources in the same stack as possible
• stateful resources should be in a separate stack than stateless (termination protection on the stateful stack)
• be careful with renaming constructs with stateful resources since they will be replaced

AWS Well-Architected Tool

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