apollographql / apollographql/federation

Federation Feature Request: define custom scalars and scalar logic in gateway

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Dominant language
TypeScript
Stars
727
Forks
276
Avg merge
1h 47m
Merged PRs (30d)
1

Description

It would be nice if there was a way to define a custom scalar in the gateway as well as provide the logic to resolve that scalar. It does not make sense to have to define the scalar logic in each microservice. Take DateTime for example, it is likely the most microservices in a project will use this, but each microservice now needs to implement the logic.

For a user standpoint, scalars should always behave the same. Having a developer implement the logic in each service could lead to inconsistent results and it leads to duplicated code.

To take this a step further, the gateway should be able to define "global" objects like a scalar definition and description.

I was unable to find a way to do this. If it exists, please point me in the right direction.

I hope you will see a use case for this.

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Research direction

No files, tests, or entry points are named. Start by locating the gateway's federation schema and scalar configuration, then compare how DateTime is defined and resolved across the microservices; done means the gateway can define a shared scalar, its description, and resolution logic consistently for consumers.

Written by the indexing model from the issue text.

Assessment

Tech stack
graphql, typescript
Domain
api, backend-api-design, distributed-systems
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
30/100

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