feat: add pricing table and cost calculation in telemetry emitter

src/polygateway/client.py

@@ -22,6 +22,7 @@ from polygateway.middleware.cache import CacheMW
 from polygateway.middleware.retry import RetryMW
 from polygateway.middleware.structured import StructuredMW
 from polygateway.middleware.telemetry import TelemetryEmitter, TelemetryMW
+from polygateway.pricing import PricingTable
 from polygateway.providers import get_provider
 from polygateway.sources import LeastInflightSelector, RoundRobinSelector, SourceCooldownMemo
 from polygateway.transports.openai_compat import OpenAICompatTransport
@@ -68,6 +69,7 @@ class GatewayClient:
         backpressure: BackpressurePolicy,
         quota_full: str = "wait",
         telemetry: TelemetryRecorder | None = None,
+        pricing: PricingTable | None = None,
         cache: CacheBackend | None = None,
         cache_namespace: str | None = None,
         cache_ttl_s: int | None = None,
@@ -78,7 +80,7 @@ class GatewayClient:
         sleep: Any = asyncio.sleep,
         rng: Any = random.random,
     ) -> None:
-        emitter = TelemetryEmitter(telemetry) if telemetry is not None else None
+        emitter = TelemetryEmitter(telemetry, pricing=pricing) if telemetry is not None else None
         terminal = RetryMW(
             scope=scope,
             sources=sources,
@@ -207,6 +209,9 @@ class GatewayClient:
             backpressure=settings.backpressure,
             quota_full=settings.quota_full,
             telemetry=telemetry if telemetry is not None else _build_telemetry(settings),
+            pricing=PricingTable.from_file(settings.pricing_path)
+            if settings.pricing_path is not None
+            else None,
             cache=cache if cache is not None else _build_cache(settings),
             cache_namespace=settings.cache_namespace,
             cache_ttl_s=settings.cache_ttl_s,