Allow setting Store Id per request for multi tenant implementations

[joarobles]

Describe the problem you'd like to have solved

In multitenant solutions it would be nice to have a single client instance and the possibility to set the store id for each request, this way the connection pool can be reused without the need to have multiple client instances.

Describe the ideal solution

The store id should available as a client option:

var request = new ClientCheckRequest()
    .user("user:81684243-9356-4421-8fbf-a4f8d36aa31b")
    .relation("writer")
    ._object("document:0192ab2a-d83f-756d-9397-c5ed9f3cb69a");
var options = new ClientCheckOptions()
    .additionalHeaders(Map.of("Some-Http-Header", "Some value"))
    // You can rely on the model id set in the configuration or override it for this specific request
    .authorizationModelId("01GXSA8YR785C4FYS3C0RTG7B1")
    // SET THE STORE ID PER REQUEST
    .storeId("01ARZ3NDEKTSV4RRFFQ69G5FAV");

var response = fgaClient.check(request, options).get();
// response.getAllowed() = true

Alternatives and current workarounds

There are two alternatives:

1. Having one client for each store id
2. Explicitly calling fgaClient.setStoreId(store.getId()); on each request, but my guess is there could be race condition issues

Additional context

N/A

[jimmyjames]

Thanks @joarobles for raising! Yes, the Java SDK should support per-request storeId override, as the Go, .NET, and JS SDKs do.

For any method that includes a storeId in the path, we should allow for an per-request override, and if set use that. We should be able to do this just as we handle for authorizationModelId from the options: https://github.com/openfga/java-sdk/blob/main/src/main/java/dev/openfga/sdk/api/client/OpenFgaClient.java#L561

[joarobles]

Excellent @jimmyjames! If you give me a couple of hints I can try to submit a PR

[jimmyjames]

❤ that would be great @joarobles!

I pushed a temporary branch with an example of how it could look for check. Note the TODOs, there's improvments needed, but in general the pattern will be:

• for requests that use the storeId in the path, update the request options object to include a storeId
• In OpenFgaClient, if the options are not null and storeId is non-null and non-empty, use that to build the path. Otherwise, use the storeId configured on the client
• Update the tests to verify that the storeId can be overridden per request, and that the value on the client is used if not overridden.

In general, it should be pretty similar to how the authorizationModelId is allowed to be overridden per request.

Hope that helps!

[joarobles]

Excellent, I'm on it!