feature flags should be defined in code not context

[rittneje]

Describe the feature

Currently, AWS CDK uses feature flags defined in cdk.json to opt into or out of certain behavior. However, because these flags are applied globally to the entire app, they inevitably lead to a poor developer experience.

First, they are not easily discoverable. For example, the documentation for UsagePlan does not mention the usagePlanKeyOrderInsensitiveId feature flag, which tends to be necessary when upgrading from v1 to v2.

Second, because they get applied to the entire app instead of individual constructs, once an app is "tainted" there is no way to change the behavior even for new constructs. By extension, I cannot move a stack from one app to another if the relevant feature flags between the two apps are different.

I request that the concept of feature flags within cdk.json be deprecated. Instead, these should be handled in a first-class way inside the CDK code. At minimum, I should be able to define them at the app, stage, and stack level.

Use Case

See above.

Proposed Solution

No response

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

2.20.0

Environment details (OS name and version, etc.)

Alpine 3.15

[peterwoodworth]

Regardless of if/when this request gets implemented, the documentation surrounding feature flags needs to be improved.

[Naumel]

Flagging this as (somewhat) related to #20573, at least the initial pain-points around documentation.

[rix0rrr]

Agreed on the documentation. As for code: since feature flags are just context values, you can actually configure them in code today.

https://docs.aws.amazon.com/cdk/v2/guide/context.html#context_construct

[github-actions]

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