[router][grpc] Fix proto3 default value mismatches and cleanup unused fields (sgl-project#11283)

Author: CatherineSue

python/sglang/srt/entrypoints/grpc_server.py

@@ -14,6 +14,7 @@
 from typing import AsyncIterator, Dict, Optional, Tuple
 
 import grpc
+from google.protobuf.json_format import MessageToDict
 from grpc_reflection.v1alpha import reflection
 
 from sglang.srt.disaggregation.utils import FAKE_BOOTSTRAP_HOST, DisaggregationMode
@@ -483,28 +484,52 @@ def _convert_sampling_params(
         elif grpc_params.HasField("structural_tag"):
             structural_tag = grpc_params.structural_tag
 
+        # Handle optional parameters conversion
+        custom_params = (
+            MessageToDict(grpc_params.custom_params)
+            if grpc_params.HasField("custom_params")
+            else None
+        )
+        max_new_tokens = (
+            grpc_params.max_new_tokens
+            if grpc_params.HasField("max_new_tokens")
+            else None
+        )
+        stream_interval = (
+            grpc_params.stream_interval
+            if grpc_params.HasField("stream_interval")
+            else None
+        )
+        logit_bias = dict(grpc_params.logit_bias) if grpc_params.logit_bias else None
+        stop = list(grpc_params.stop) if grpc_params.stop else None
+        stop_token_ids = (
+            list(grpc_params.stop_token_ids) if grpc_params.stop_token_ids else None
+        )
+
         return SGLSamplingParams(
-            temperature=grpc_params.temperature or 1.0,
-            top_p=grpc_params.top_p or 1.0,
-            top_k=grpc_params.top_k or -1,
-            min_p=grpc_params.min_p or 0.0,
-            frequency_penalty=grpc_params.frequency_penalty or 0.0,
-            presence_penalty=grpc_params.presence_penalty or 0.0,
-            repetition_penalty=grpc_params.repetition_penalty or 1.0,
-            max_new_tokens=grpc_params.max_new_tokens or 128,
-            min_new_tokens=grpc_params.min_new_tokens or 0,
-            stop=list(grpc_params.stop) if grpc_params.stop else [],
-            stop_token_ids=(
-                list(grpc_params.stop_token_ids) if grpc_params.stop_token_ids else []
-            ),
+            temperature=grpc_params.temperature,
+            top_p=grpc_params.top_p,
+            top_k=grpc_params.top_k,
+            min_p=grpc_params.min_p,
+            frequency_penalty=grpc_params.frequency_penalty,
+            presence_penalty=grpc_params.presence_penalty,
+            repetition_penalty=grpc_params.repetition_penalty,
+            max_new_tokens=max_new_tokens,
+            min_new_tokens=grpc_params.min_new_tokens,
+            stop=stop,
+            stop_token_ids=stop_token_ids,
             skip_special_tokens=grpc_params.skip_special_tokens,
             spaces_between_special_tokens=grpc_params.spaces_between_special_tokens,
+            no_stop_trim=grpc_params.no_stop_trim,
             regex=regex,
             json_schema=json_schema,
             ebnf=ebnf_grammar,
             structural_tag=structural_tag,
-            n=grpc_params.n or 1,
+            n=grpc_params.n,
             ignore_eos=grpc_params.ignore_eos,
+            stream_interval=stream_interval,
+            logit_bias=logit_bias,
+            custom_params=custom_params,
         )
 
     def _convert_output_logprobs_to_proto(

python/sglang/srt/grpc/sglang_scheduler.proto

@@ -27,6 +27,11 @@ service SglangScheduler {
 // =====================
 
 // Sampling parameters matching SGLang's SamplingParams
+//
+// IMPORTANT: Do not use SamplingParams::default() directly!
+// The proto3 defaults (0 for numeric fields) do NOT match the semantic defaults
+// (temperature=1.0, top_p=1.0, top_k=-1, etc.). Always construct with explicit values
+// or use the conversion functions in sglang_scheduler.rs / grpc_server.py.
 message SamplingParams {
   float temperature = 1;
   float top_p = 2;
@@ -50,24 +55,18 @@ message SamplingParams {
     string structural_tag = 16;
   }
 
-  // LoRA adapter
-  string lora_path = 17;
-
   // Speculative decoding
-  int32 n = 18;  // Number of samples
-
-  // Token healing
-  bool token_healing = 19;
+  int32 n = 17;  // Number of samples
 
   // Additional parameters
-  int32 min_new_tokens = 20;
-  bool ignore_eos = 21;
-  bool no_stop_trim = 22;
-  int32 stream_interval = 23;
-  map<string, float> logit_bias = 24;
+  int32 min_new_tokens = 18;
+  bool ignore_eos = 19;
+  bool no_stop_trim = 20;
+  optional int32 stream_interval = 21;
+  map<string, float> logit_bias = 22;
 
   // Custom parameters for extensibility
-  google.protobuf.Struct custom_params = 25;
+  google.protobuf.Struct custom_params = 23;
 }