refactor: Make base client concrete and usable

The openAIModelServerClient could not be instantiated directly as it
declared no supported APIs. While this may have been intended to
enforce it as a base class, making it concrete provides more
flexibility.

This change allows the client to be used with any generic
OpenAI-compatible endpoint. It also centralizes the API list so
redundant overrides can be removed from the vLLM, TGI, and SGLang
subclasses, improving maintainability.

Author: LukeAVanDrie

inference_perf/client/modelserver/openai_client.py

@@ -130,7 +130,7 @@ async def process_request(self, data: InferenceAPIData, stage_id: int, scheduled
                 )
 
     def get_supported_apis(self) -> List[APIType]:
-        return []
+        return [APIType.Completion, APIType.Chat]
 
     @abstractmethod
     def get_prometheus_metric_metadata(self) -> PrometheusMetricMetadata:

inference_perf/client/modelserver/sglang_client.py

@@ -48,8 +48,6 @@ def __init__(
         )
         self.metric_filters = [f"model_name='{model_name}'", *additional_filters]
 
-    def get_supported_apis(self) -> List[APIType]:
-        return [APIType.Completion, APIType.Chat]
 
     def get_prometheus_metric_metadata(self) -> PrometheusMetricMetadata:
         return PrometheusMetricMetadata(

inference_perf/client/modelserver/tgi_client.py

@@ -48,9 +48,6 @@ def __init__(
         )
         self.metric_filters = additional_filters
 
-    def get_supported_apis(self) -> List[APIType]:
-        return [APIType.Completion, APIType.Chat]
-
     def get_prometheus_metric_metadata(self) -> PrometheusMetricMetadata:
         return PrometheusMetricMetadata(
             avg_queue_length=ModelServerPrometheusMetric(

inference_perf/client/modelserver/vllm_client.py

@@ -48,9 +48,6 @@ def __init__(
         )
         self.metric_filters = [f"model_name='{model_name}'", *additional_filters]
 
-    def get_supported_apis(self) -> List[APIType]:
-        return [APIType.Completion, APIType.Chat]
-
     def get_prometheus_metric_metadata(self) -> PrometheusMetricMetadata:
         return PrometheusMetricMetadata(
             avg_queue_length=ModelServerPrometheusMetric(