Handle truncation errors (#436)

python/sglang/global_config.py

@@ -16,7 +16,7 @@ class GlobalConfig:
 
         # Optimization configs
         self.eager_fill_image = False
-        self.enable_prefix_sharing = True
+        self.enable_precache_with_tracing = True
         self.enable_parallel_encoding = True
         self.enable_parallel_decoding = True
 

python/sglang/lang/interpreter.py

@@ -86,9 +86,9 @@ def run_program_batch(
     if hasattr(backend, "endpoint"):
         backend = backend.endpoint
 
-    # Extract prefix by tracing and cache it
-    if len(batch_arguments) > 1:
-        pin_program(program, backend)
+    # Pre-cache the common prefix for a batch. The prefix is extracted by tracing the program.
+    if global_config.enable_precache_with_tracing and len(batch_arguments) > 1:
+        cache_program(program, backend)
 
     # Run all programs
     if num_threads == "auto":
@@ -154,21 +154,12 @@ def run_program_batch(
     return rets
 
 
-def pin_program(program, backend):
-    if global_config.enable_prefix_sharing and program.pin_prefix_rid is None:
-        # TODO: handle multiple backends
-        from sglang.lang.tracer import extract_prefix_by_tracing
+def cache_program(program, backend):
+    from sglang.lang.tracer import extract_prefix_by_tracing
 
-        prefix = extract_prefix_by_tracing(program, backend)
-        if prefix and len(prefix) > 64:
-            prefix_rid = backend.cache_prefix(prefix)
-            program.pin_prefix_rid = prefix_rid
-            return prefix_rid
-    return None
-
-
-def unpin_program(program, backend):
-    pass
+    prefix = extract_prefix_by_tracing(program, backend)
+    if prefix and len(prefix) > 64:
+        backend.cache_prefix(prefix)
 
 
 class StreamExecutor:
@@ -322,7 +313,7 @@ class StreamExecutor:
             try:
                 self._execute(expr)
             except Exception as e:
-                print(f"Error in stream_executor: {get_exception_traceback()}")
+                # print(f"Error in stream_executor: {get_exception_traceback()}")
                 error = e
                 break
             self.queue.task_done()
@@ -702,9 +693,10 @@ class ProgramState:
         return self.stream_executor.messages()
 
     def sync(self):
-        ret = self.stream_executor.sync()
-        self.error = self.stream_executor.error
-        return ret
+        return self.stream_executor.sync()
+
+    def error(self):
+        return self.stream_executor.error
 
     def text_iter(self, var_name: Optional[str] = None):
         if self.stream_executor.stream:

python/sglang/lang/ir.py

@@ -193,17 +193,11 @@ class SglFunction:
         backend = backend or global_config.default_backend
         return trace_program(self, kwargs, backend)
 
-    def pin(self, backend=None):
-        from sglang.lang.interpreter import pin_program
+    def cache(self, backend=None):
+        from sglang.lang.interpreter import cache_program
 
         backend = backend or global_config.default_backend
-        return pin_program(self, backend)
-
-    def unpin(self, backend=None):
-        from sglang.lang.interpreter import unpin_program
-
-        backend = backend or global_config.default_backend
-        return unpin_program(self, backend)
+        return cache_program(self, backend)
 
     def compile(self, *, backend=None):
         from sglang.lang.compiler import compile_func

python/sglang/srt/managers/router/infer_batch.py

@@ -20,6 +20,16 @@ class FinishReason(IntEnum):
     LENGTH = auto()
     STOP_STR = auto()
 
+    def to_str(self):
+        if self == FinishReason.EOS_TOKEN:
+            return None
+        elif self == FinishReason.LENGTH:
+            return "length"
+        elif self == FinishReason.STOP_STR:
+            return "stop"
+        else:
+            raise ValueError(f"Invalid finish reason: {self}")
+
 
 class Req:
     def __init__(self, rid, input_text, input_ids):

python/sglang/srt/managers/router/model_rpc.py

@@ -612,7 +612,7 @@ class ModelRpcServer:
                     + len(req.output_ids)
                     - req.prompt_tokens,
                     "completion_tokens_wo_jump_forward": req.completion_tokens_wo_jump_forward,
-                    "finish_reason": str(req.finish_reason),  # FIXME: convert to the correct string
+                    "finish_reason": req.finish_reason.to_str(),
                     "hit_stop_str": req.hit_stop_str,
                 }
                 if req.return_logprob:

python/sglang/srt/managers/tokenizer_manager.py

@@ -98,7 +98,6 @@ class TokenizerManager:
         self.hf_config = get_config(
             self.model_path, trust_remote_code=server_args.trust_remote_code
         )
-
         self.context_len = get_context_length(self.hf_config)
 
         if is_multimodal_model(self.model_path):
@@ -156,6 +155,12 @@ class TokenizerManager:
             else:
                 input_ids = obj.input_ids
 
+            if len(input_ids) >= self.context_len:
+                raise ValueError(
+                    f"The input ({len(input_ids)} tokens) is longer than the "
+                    f"model's context length ({self.context_len} tokens)"
+                )
+
             sampling_params = SamplingParams(**obj.sampling_params)
             if sampling_params.max_new_tokens != 0:
                 sampling_params.normalize(self.tokenizer)

python/sglang/srt/server.py

@@ -20,7 +20,7 @@ import requests
 import uvicorn
 import uvloop
 from fastapi import FastAPI, Request
-from fastapi.responses import Response, StreamingResponse
+from fastapi.responses import JSONResponse, Response, StreamingResponse
 
 from sglang.backend.runtime_endpoint import RuntimeEndpoint
 from sglang.srt.constrained import disable_cache
@@ -90,8 +90,11 @@ async def generate_request(obj: GenerateReqInput):
 
         return StreamingResponse(stream_results(), media_type="text/event-stream")
 
-    ret = await tokenizer_manager.generate_request(obj).__anext__()
-    return ret
+    try:
+        ret = await tokenizer_manager.generate_request(obj).__anext__()
+        return ret
+    except ValueError as e:
+        return JSONResponse({"error": str(e)}, status_code=400)
 
 
 @app.post("/v1/completions")