Federation v2 support

[lethak]

Hi,

Thanks for your work, I am currently starting to build a new federation project, and looking for v2 support in PHP libs as some of my subgraphs are built upon webonyx.

Do you have any plan to support Federation v2 any time soon ?

https://www.apollographql.com/docs/federation/other-servers/

Thanks

[Aeliot-Tm]

@lethak FYI: I work on it. I'm going to finish implementation this week.

https://github.com/Aeliot-Tm/apollo-federation-php/tree/implement_v2

[ldiego08]

@lethak - #26 has been submitted by @Aeliot-Tm and is under review. But maybe you can give it a test run and see how it works for you?

[rsouverain]

Awesome, I plan on using/testing this in a few weeks

[smyrick]

Federation v2 support can be added incrementally so while the complicated @link can take a bit more validation code things like @tag and @override only need to be defined and be able to be added on types or fields.

I am not a PHP expert, but I have commented as ideally, we wouldn't have to wait for a library to be able to add @tag in a code-first server, but that does not seem possible today. If someone wanted to add support for those directive definitions first, that could help users use new GraphOS features like Contracts, without requiring full Fed 2 support