unable to configure federation directive namespace

[thumbnail]

In federation version 2 the directives have namespaces (federation__ by default). Currently this prefix is non-configurable which may cause issues when other subgraphs use a different namespace or import them without a namespace.

In Apollo studio I got the following error:

The federation "@inaccessible" directive is imported with mismatched name between subgraphs: it is imported as "@inaccessible" in subgraphs "X" and "Y" but "@federation__inaccessible" in subgraphs "A" and "B"

In this case, A and B are ruby applications, and X and Y are not.

It can be partially fixed by configuring the graph as v1 and overriding Schema#federation_dsl to prepend an import for all directives. But it's not very elegant 😬

[geshwho]

Hey @thumbnail, thanks for reporting this! @daemonsy and I will take a look this week.

[geshwho]

Hey @thumbnail, we took a look at this today and it seems like there are a couple of enhancements that would help us get closer to spec compliant with federation version 2.

• We need to provide an option that allows the user to override the default namespace (similar to the example in the docs which uses fed2 as the namespace)
• We need to provide an option for users to specify the import argument on the link directive such that they will not be prefixed. From the docs:

The import argument enables you to import external definitions into your namespace, so they are not prefixed.

I believe the latter one would help resolve the issue that you are seeing. Do you have any interest in working on a solution for either of these enhancements?

[geshwho]

Hey @lennyburdette, I was just rereading your comment here and realized that it directly conflicts with what I just suggested above. Namely, per your comment, code-first libraries will not be providing an API to rename imports (second bullet point). However, I wanted to ask: should we consider an API to allow overriding the default namespace (first bullet point)?

[lennyburdette]

Hmm this is odd. It appears to me that this error occurs with @inaccessible but not @key or @shareable so I think this is a bug related to backward-compatibility with @tag and @inaccessible. I'll reach out to the team tomorrow and get back to you.

https://github.com/apollographql/federation/blob/main/composition-js/src/merging/merge.ts#L198-L201
https://github.com/apollographql/federation/blob/main/composition-js/src/merging/merge.ts#L285-L287
https://github.com/apollographql/federation/blob/main/composition-js/src/merging/merge.ts#L292-L322

[geshwho]

Ah, good point! This should be backwards compatible. We'll wait until we hear more from the team before we do anything.

[lennyburdette]

I had a good conversation with my team about this and learned a bunch. I still consider this a bug, but it may not be a high priority to fix. And we'll eventually need an API for configuring future @linked directives, so it's probably worth addressing now.

Here's my summary of the conversation: apollographql/federation#1976 (comment)

[grxy]

I'm going to close this since this was solved in 03fdfea