[router] cache-aware load-balancing router v1 (#2114)

rust/py_src/sglang_router/router.py

@@ -9,16 +9,23 @@ class Router:
     A high-performance router for distributing requests across worker nodes.
 
     Args:
-        worker_urls: List of URLs for worker nodes that will handle requests
+        worker_urls: List of URLs for worker nodes that will handle requests. Each URL should include
+            the protocol, host, and port (e.g., ['http://worker1:8000', 'http://worker2:8000'])
         policy: Load balancing policy to use. Options:
             - PolicyType.Random: Randomly select workers
             - PolicyType.RoundRobin: Distribute requests in round-robin fashion
-            - PolicyType.ApproxTree: Tree-based routing using tokenizer similarity
-        host: Host address to bind the router server
-        port: Port number to bind the router server
-        tokenizer_path: Path to tokenizer model file (required for ApproxTree policy)
-        cache_threshold: Caching threshold value between 0-1
-
+            - PolicyType.CacheAware: Distribute requests in cache-aware fashion
+        host: Host address to bind the router server. Default: '127.0.0.1'
+        port: Port number to bind the router server. Default: 3001
+        cache_threshold: Cache threshold (0.0-1.0) for cache-aware routing. Routes to cached worker
+            if the match rate exceeds threshold, otherwise routes to the worker with the smallest
+            tree. Default: 0.5
+        cache_routing_prob: Probability of using cache-aware routing (0.0-1.0). Default 1.0 for
+            full cache-aware routing, suitable for perfectly divided prefix workloads. For uneven
+            workloads, use a lower value to better distribute requests
+        eviction_interval_secs: Interval in seconds between cache eviction operations in cache-aware
+            routing. Default: 60
+        max_tree_size: Maximum size of the approximation tree for cache-aware routing. Default: 2^24
     """
 
     def __init__(
@@ -27,17 +34,20 @@ class Router:
         policy: PolicyType = PolicyType.RoundRobin,
         host: str = "127.0.0.1",
         port: int = 3001,
-        tokenizer_path: Optional[str] = None,
         cache_threshold: float = 0.50,
+        cache_routing_prob: float = 1.0,
+        eviction_interval_secs: int = 60,
+        max_tree_size: int = 2**24,
     ):
-
         self._router = _Router(
             worker_urls=worker_urls,
             policy=policy,
             host=host,
             port=port,
-            tokenizer_path=tokenizer_path,
             cache_threshold=cache_threshold,
+            cache_routing_prob=cache_routing_prob,
+            eviction_interval_secs=eviction_interval_secs,
+            max_tree_size=max_tree_size,
         )
 
     def start(self) -> None: