Provide client service through interfaces to improve decoupling and testability of client application

[bubianchi-criteo]

Checklist

• I agree to the terms within the OpenFGA Code of Conduct.

Describe the problem you'd like to have solved

I'm prototyping an application that leverages this very useful SDK. To develop our unit tests of my application code, I could not easily simulate and mock specific behaviors in particular for error cases because the OpenFgaClient is provided as a class without overridable methods.

Describe the ideal solution

We could improve the SDK extensibility and client application testability by providing features through interfaces, in particular a IOpenFgaClient interface with the public methods implemented by OpenFgaClient.
Moreover the actual construction of the OpenFga client could be managed through a factory pattern, and with its own interface would enable using natively Dependency Injection from AspNet

Alternatives and current workarounds

No response

References

No response

Additional context

No response

[rhamzeh]

Thanks for the suggestion @bubianchi-criteo - added to our backlog. Feel free to contribute the change if you are willing!

[CharlieDigital]

If I understand correctly, the work would be here: https://github.com/openfga/sdk-generator/tree/main/config/clients/dotnet/template?

[aaguiarz]

@CharlieDigital yes, that would be it

[CharlieDigital]

Might give it a shot this weekend. My thought process:

1. Add a new config/clients/dotnet/template/IOpenFgaClient.mustache
2. IOpenFgaClient.mustache will largely have the same public properties and methods as config/clients/dotnet/template/Client/Client.mustache[0] minus the IDisposable implementation
3. Update config/clients/dotnet/template/Client/Client.mustache to include IOpenFgaClient in the class declaration

Does that sound about right?

Assumptions (from going through the docs):

• Once I get the build process set up, it should pick up the new .mustache automatically and transform it
• The PR should be opened on the generator project
• I do not need to open another PR on the SDK client project
• This probably does not need additional tests as it adds no net new functionality and the client will either build or not if the interface definition does not match

Sidequest: Update the comments to be idiomatic C# XML comments

[0] https://github.com/openfga/sdk-generator/blob/main/config/clients/dotnet/template/Client/Client.mustache

[lefan-tan]

Hey folks, what's the status on this? This would be nice to allow unit testing, or is there a different strategy to allow unit testing classes that injects OpenFgaClient?

[CharlieDigital]

@aaguiarz @rhamzeh I'm trying to take this on and running into a lot of issues with the generator project. I'm following the instructions here:

https://github.com/openfga/sdk-generator?tab=readme-ov-file#getting-started

When I run make, I get the following error:

[main] INFO  o.o.codegen.TemplateManager - writing file /clients/fga-js-sdk/.openapi-generator/VERSION
Exception in thread "main" java.lang.RuntimeException: Could not generate supporting file '/clients/fga-js-sdk/.openapi-generator/VERSION'
        at org.openapitools.codegen.DefaultGenerator.generateVersionMetadata(DefaultGenerator.java:1468)
        at org.openapitools.codegen.DefaultGenerator.generateSupportingFiles(DefaultGenerator.java:784)
        at org.openapitools.codegen.DefaultGenerator.generate(DefaultGenerator.java:928)
        at org.openapitools.codegen.cmd.Generate.execute(Generate.java:487)
        at org.openapitools.codegen.cmd.OpenApiGeneratorCommand.run(OpenApiGeneratorCommand.java:32)
        at org.openapitools.codegen.OpenAPIGenerator.main(OpenAPIGenerator.java:66)
Caused by: java.nio.file.NoSuchFileException: /clients/fga-js-sdk/.openapi-generator/VERSION
        at java.base/sun.nio.fs.UnixException.translateToIOException(Unknown Source)
        at java.base/sun.nio.fs.UnixException.rethrowAsIOException(Unknown Source)
        at java.base/sun.nio.fs.UnixException.rethrowAsIOException(Unknown Source)
        at java.base/sun.nio.fs.UnixFileSystemProvider.newByteChannel(Unknown Source)
        at java.base/java.nio.file.spi.FileSystemProvider.newOutputStream(Unknown Source)
        at java.base/java.nio.file.Files.newOutputStream(Unknown Source)
        at java.base/java.nio.file.Files.write(Unknown Source)
        at org.openapitools.codegen.TemplateManager.writeToFileRaw(TemplateManager.java:255)
        at org.openapitools.codegen.TemplateManager.writeToFile(TemplateManager.java:237)
        at org.openapitools.codegen.DefaultGenerator.generateVersionMetadata(DefaultGenerator.java:1460)
        ... 5 more
make[1]: *** [build-client] Error 1
make: *** [build-client-js] Error 2

If I try to build just the .NET client. via make -d build-client-dotnet:

/Users/cchen/code/oss/openfga-sdk-generator
Exception in thread "main" java.lang.RuntimeException: Unknown library: httpclient
Available libraries:
  NONE
        at org.openapitools.codegen.DefaultCodegen.setLibrary(DefaultCodegen.java:5943)
        at org.openapitools.codegen.config.CodegenConfigurator.toClientOptInput(CodegenConfigurator.java:656)
        at org.openapitools.codegen.cmd.Generate.execute(Generate.java:479)
        at org.openapitools.codegen.cmd.OpenApiGeneratorCommand.run(OpenApiGeneratorCommand.java:32)
        at org.openapitools.codegen.OpenAPIGenerator.main(OpenAPIGenerator.java:66)
Reaping losing child 0x124e095c0 PID 57528 
make[1]: *** [build-client] Error 1
Removing child 0x124e095c0 PID 57528 from chain.
Reaping losing child 0x11e904ee0 PID 57452 
make: *** [build-client-dotnet] Error 2
Removing child 0x11e904ee0 PID 57452 from chain.

Are additional setup instructions I'm missing for the SDK generator?

[CharlieDigital]

PR here: openfga/sdk-generator#652

Not clear about the test failures.

• Java failure: missing package (but my PR does not change any Java config): package org.apache.commons.lang3.builder does not exist import org.apache.commons.lang3.builder.EqualsBuilder;
• Go: telemetry test seems to have failed, but I also did not change any Go dependencies
• Python: seems like an error in the Makefile?
• JS: may be related to updated OpenAPI generator and OPEN_API_REF

Any inputs would be appreciated.