Use of provider vs. RESTDataSource

[nathanchapman]

I would love to see some examples in the documentation of when to use a provider vs. RESTDataSource

Do they work together? It seems like a provider would be re-implementing a lot of methods that already exist in a RESTDataSource. Also I'm guessing any RESTDataSources would go into the contextBuilder?

[ardatan]

DataSources feature looks quite similar to providers while providers feature is part of Dependency Injection and can be connected to each other in modular approach. And providers are constructed in application scope, not in request scope while DataSources are created inside a factory function on each request. But you can call providers inside datasources by using injector inside context, or get datasources inside providers by using onRequest hook inside of providers.
We can think about request scope providers. What do you think @dotansimha @darkbasic @kamilkisiela?

[dotansimha]

That's a great questions, @nathanchapman !
@ardatan is right, DataSources of apollo-server is similar to Providers in graphql-modules.
Actually, before we started to develop graphql-modules, we used DataSources in some of our projects.
DataSources is great as a simple bridge for your data, it's an abstraction that prevents from your resolvers to access directly the data source.
The problem is that each DataSource stands by itself, and they cannot interact with each other easily, and Providers can interact and communicate with other Providers with dependency-injection.

[ardatan]

Then I am planning to create a PR about request scope providers.