Add constrained_json_whitespace_pattern to ServerArgs (#1438)

python/sglang/srt/constrained/fsm_cache.py

@@ -29,6 +29,7 @@ class FSMCache(BaseToolCache):
         tokenizer_args_dict,
         enable=True,
         skip_tokenizer_init=False,
+        constrained_json_whitespace_pattern=None,
     ):
         super().__init__(enable=enable)
 
@@ -63,11 +64,14 @@ class FSMCache(BaseToolCache):
             self.outlines_tokenizer.vocabulary = (
                 self.outlines_tokenizer.tokenizer.get_vocab()
             )
+        self.constrained_json_whitespace_pattern = constrained_json_whitespace_pattern
 
     def init_value(self, key):
         key_type, key_string = key
         if key_type == "json":
-            regex = build_regex_from_schema(key_string, whitespace_pattern=r"[\n\t ]*")
+            regex = build_regex_from_schema(
+                key_string, whitespace_pattern=self.constrained_json_whitespace_pattern
+            )
         elif key_type == "regex":
             regex = key_string
         else:

python/sglang/srt/managers/tp_worker.py

@@ -198,6 +198,7 @@ class ModelTpServer:
                     "trust_remote_code": server_args.trust_remote_code,
                 },
                 skip_tokenizer_init=server_args.skip_tokenizer_init,
+                constrained_json_whitespace_pattern=server_args.constrained_json_whitespace_pattern,
             )
         self.jump_forward_cache = JumpForwardCache()
 
@@ -807,12 +808,10 @@ class ModelTpServer:
                 unfinished_indices.append(i)
 
             if req.finished() or (
-                (
-                    req.stream
-                    and (
-                        self.decode_forward_ct % self.stream_interval == 0
-                        or len(req.output_ids) == 1
-                    )
+                req.stream
+                and (
+                    self.decode_forward_ct % self.stream_interval == 0
+                    or len(req.output_ids) == 1
                 )
             ):
                 output_rids.append(req.rid)

python/sglang/srt/server_args.py

@@ -70,6 +70,7 @@ class ServerArgs:
     tp_size: int = 1
     stream_interval: int = 1
     random_seed: Optional[int] = None
+    constrained_json_whitespace_pattern: Optional[str] = None
 
     # Logging
     log_level: str = "info"
@@ -370,6 +371,12 @@ class ServerArgs:
             default=ServerArgs.random_seed,
             help="The random seed.",
         )
+        parser.add_argument(
+            "--constrained-json-whitespace-pattern",
+            type=str,
+            default=ServerArgs.constrained_json_whitespace_pattern,
+            help=r"Regex pattern for syntactic whitespaces allowed in JSON constrained output. For example, to allow the model generate consecutive whitespaces, set the pattern to [\n\t ]*",
+        )
         parser.add_argument(
             "--log-level",
             type=str,