chore(cli.py): dynamo-run-in-python handle sglang, vllm and trtllm (#1832)

examples/cli/cli.py

@@ -7,6 +7,7 @@
 
 import argparse
 import asyncio
+import signal
 import sys
 from pathlib import Path
 
@@ -15,6 +16,9 @@ import uvloop
 from dynamo.llm import EngineType, EntrypointArgs, make_engine, run_input
 from dynamo.runtime import DistributedRuntime
 
+subprocess_ref = None  # Global process reference for cleanup
+subprocess_task = None  # Global async task reference for cleanup
+
 
 def parse_args():
     in_mode = "text"
@@ -111,8 +115,39 @@ def parse_args():
     return parsed_args
 
 
+async def cleanup_subprocess_async():
+    """Clean up the sglang/vllm/trtllm subprocess if it exists."""
+    global subprocess_ref
+    if subprocess_ref and subprocess_ref.returncode is None:
+        subprocess_ref.terminate()
+        try:
+            await asyncio.wait_for(subprocess_ref.wait(), timeout=2)
+        except asyncio.TimeoutError:
+            subprocess_ref.kill()
+            await subprocess_ref.wait()
+
+        # Only cleanup once
+        subprocess_ref = None
+
+
+def signal_handler():
+    """Handle signals in async context by cleaning up subprocess and exiting."""
+    asyncio.create_task(cleanup_subprocess_async())
+    sys.exit(0)
+
+
 async def run():
+    global subprocess_ref
+    global subprocess_task
+
+    # Register signal handlers
     loop = asyncio.get_running_loop()
+    loop.add_signal_handler(signal.SIGINT, signal_handler)  # Ctrl-C
+    loop.add_signal_handler(signal.SIGTERM, signal_handler)  # kill
+
+    # If we find cases where subprocess does not stop we may need this. Seem OK so far.
+    # atexit.register(cleanup_subprocess)
+
     runtime = DistributedRuntime(loop, False)
 
     args = parse_args()
@@ -124,13 +159,63 @@ async def run():
         "dyn": EngineType.Dynamic,
     }
     out_mode = args["out_mode"]
+
+    # Handle subprocess execution for sglang and vllm
+    if out_mode in ["sglang", "vllm", "trtllm"]:
+        # Determine which script to run
+        script_name = f"{out_mode}_inc.py"
+        script_path = Path(__file__).parent / script_name
+        if not script_path.exists():
+            print(f"Error: Script '{script_path}' not found")
+            sys.exit(1)
+
+        # Build command with all relevant arguments
+        cmd = [sys.executable, str(script_path)]
+
+        # Add arguments if they exist
+        if args["model_path"]:
+            cmd.extend(["--model-path", args["model_path"]])
+
+        flags = args["flags"]
+        if flags.model_name:
+            cmd.extend(["--model-name", flags.model_name])
+        if flags.context_length:
+            cmd.extend(["--context-length", str(flags.context_length)])
+        if flags.kv_cache_block_size:
+            cmd.extend(["--kv-cache-block-size", str(flags.kv_cache_block_size)])
+
+        # Start subprocess in background and stream output
+        print(f"Starting {out_mode} subprocess: {' '.join(cmd)}")
+
+        async def stream_subprocess_output():
+            global subprocess_ref
+            subprocess_ref = await asyncio.create_subprocess_exec(
+                *cmd, stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.STDOUT
+            )
+
+            try:
+                if subprocess_ref.stdout is not None:
+                    async for line in subprocess_ref.stdout:
+                        print(f"Engine: {line.decode().rstrip()}")
+                    await subprocess_ref.wait()
+            except asyncio.CancelledError:
+                # Task was cancelled, terminate the subprocess
+                await cleanup_subprocess_async()
+                raise
+
+        task = asyncio.create_task(stream_subprocess_output())
+
+        # Store the task reference for potential cleanup
+        subprocess_task = task
+
+        # Set out_mode to "dyn" because we talk to the subprocess over NATS
+        out_mode = "dyn"
+
     engine_type = engine_type_map.get(out_mode)
     if engine_type is None:
         print(f"Unsupported output type: {out_mode}")
         sys.exit(1)
 
-    # TODO: The "vllm", "sglang" and "trtllm" cases should call Python directly
-
     entrypoint_kwargs = {"model_path": args["model_path"]}
 
     flags = args["flags"]
@@ -149,7 +234,20 @@ async def run():
 
     e = EntrypointArgs(engine_type, **entrypoint_kwargs)
     engine = await make_engine(runtime, e)
+
+    try:
         await run_input(runtime, args["in_mode"], engine)
+    finally:
+        # Clean up subprocess when main execution finishes
+        await cleanup_subprocess_async()
+
+        # Cancel the subprocess task if it exists
+        if subprocess_task:
+            subprocess_task.cancel()
+            try:
+                await subprocess_task
+            except asyncio.CancelledError:
+                pass
 
 
 if __name__ == "__main__":

examples/cli/sglang_inc.py

+# SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+# `dynamo-run out=sglang` runs this script
+# Can also be used standalone: `python3 sglang_inc.py` - lots of optional cmd line params
+
+import argparse
+import asyncio
+import json
+import logging
+import sys
+from typing import Optional
+
+import sglang
+import uvloop
+from sglang.srt.entrypoints.engine import EmbeddingReqInput
+from sglang.srt.server_args import ServerArgs
+
+from dynamo.llm import ModelType, register_llm
+from dynamo.runtime import DistributedRuntime, dynamo_worker
+from dynamo.runtime.logging import configure_dynamo_logging
+
+# Only used if you run it manually from the command line
+DEFAULT_ENDPOINT = "dyn://dynamo.backend.generate"
+DEFAULT_MODEL = "Qwen/Qwen3-0.6B"
+
+configure_dynamo_logging()
+
+
+class Config:
+    """Command line parameters or defaults"""
+
+    namespace: str
+    component: str
+    endpoint: str
+    model_path: str
+    model_name: Optional[str]
+    base_gpu_id: int
+    tensor_parallel_size: int
+    kv_block_size: int
+    context_length: int
+    nnodes: int
+    node_rank: int
+    dist_init_addr: str
+    extra_engine_args: str
+
+
+class RequestHandler:
+    """
+    Request handler for the generate endpoint
+    """
+
+    def __init__(self, engine):
+        self.engine_client = engine
+
+    async def generate(self, request):
+        sampling_params = {}
+        if request["sampling_options"]["temperature"] is not None:
+            sampling_params["temperature"] = request["sampling_options"]["temperature"]
+        # sglang defaults this to 128
+        sampling_params["max_new_tokens"] = request["stop_conditions"]["max_tokens"]
+
+        # Check if this is a batch request
+        is_batch = "batch_token_ids" in request and request["batch_token_ids"]
+
+        if is_batch:
+            # Track tokens separately for each batch item
+            num_output_tokens_so_far = {}
+            gen = await self.engine_client.async_generate(
+                input_ids=request["batch_token_ids"],
+                sampling_params=sampling_params,
+                stream=True,
+            )
+        else:
+            num_output_tokens_so_far = 0
+            gen = await self.engine_client.async_generate(
+                input_ids=request["token_ids"],
+                sampling_params=sampling_params,
+                stream=True,
+            )
+
+        async for res in gen:
+            # res is a dict
+            finish_reason = res["meta_info"]["finish_reason"]
+
+            if is_batch:
+                # Handle batch response - get index from SGLang response
+                index = res.get("index", 0)
+                if index not in num_output_tokens_so_far:
+                    num_output_tokens_so_far[index] = 0
+
+                if finish_reason:
+                    logging.warning(f"finish_reason: {finish_reason}")
+                    # Final response for this batch item
+                    out = {
+                        "token_ids": [],
+                        "finish_reason": finish_reason["type"],
+                        "index": index,
+                    }
+                else:
+                    # Streaming response for this batch item
+                    next_total_toks = len(res["output_ids"])
+                    new_tokens = res["output_ids"][num_output_tokens_so_far[index] :]
+                    out = {
+                        "token_ids": new_tokens,
+                        "index": index,
+                    }
+                    num_output_tokens_so_far[index] = next_total_toks
+            else:
+                if finish_reason:
+                    out = {
+                        "token_ids": [],
+                        "finish_reason": finish_reason["type"],
+                    }
+                else:
+                    next_total_toks = len(res["output_ids"])
+                    new_tokens = res["output_ids"][num_output_tokens_so_far:]
+                    out = {
+                        "token_ids": new_tokens,
+                    }
+                    num_output_tokens_so_far = next_total_toks
+
+            yield out
+
+    async def encode(self, request):
+        obj = EmbeddingReqInput(input_ids=request["token_ids"])
+        generator = self.engine_client.tokenizer_manager.generate_request(obj, None)
+        engine_results = await anext(generator)
+
+        tokens = 0
+        embeddings = []
+        for result in engine_results:
+            embeddings.append(result["embedding"])
+            tokens += result["meta_info"]["prompt_tokens"]
+
+        out = {
+            "embeddings": embeddings,
+            "prompt_tokens": tokens,
+            "total_tokens": tokens,
+        }
+
+        yield out
+
+
+@dynamo_worker(static=False)
+async def worker(runtime: DistributedRuntime):
+    await init(runtime, cmd_line_args())
+
+
+async def init(runtime: DistributedRuntime, config: Config):
+    """
+    Instantiate and serve
+    """
+
+    arg_map = {
+        "model_path": config.model_path,
+        "skip_tokenizer_init": True,
+        "tp_size": config.tensor_parallel_size,
+        "base_gpu_id": config.base_gpu_id,
+    }
+
+    if config.kv_block_size:
+        arg_map["page_size"] = config.kv_block_size
+
+    if config.context_length:
+        arg_map["context_length"] = config.context_length
+
+    if config.dist_init_addr != "":
+        arg_map["trust_remote_code"] = True
+        arg_map["nnodes"] = config.nnodes
+        arg_map["dist_init_addr"] = config.dist_init_addr
+        # In practice this is always 0 because Dynamo only manages the leader
+        arg_map["node_rank"] = config.node_rank
+
+    if config.extra_engine_args != "":
+        json_map = {}
+        # extra_engine_args is a filename
+        try:
+            with open(config.extra_engine_args) as f:
+                json_map = json.load(f)
+        except FileNotFoundError:
+            logging.error(f"File {config.extra_engine_args} not found.")
+        except json.JSONDecodeError as e:
+            logging.error(f"Invalid JSON in {config.extra_engine_args}: {e}")
+        logging.debug(f"Adding extra engine arguments: {json_map}")
+        arg_map = {**arg_map, **json_map}  # json_map gets precedence
+
+    # TODO fetch default SamplingParams from generation_config.json
+
+    engine_args = ServerArgs(**arg_map)
+    engine_client = sglang.Engine(server_args=engine_args)
+
+    component = runtime.namespace(config.namespace).component(config.component)
+    await component.create_service()
+
+    endpoint = component.endpoint(config.endpoint)
+    model_type = (
+        ModelType.Backend if not engine_args.is_embedding else ModelType.Embedding
+    )
+    await register_llm(model_type, endpoint, config.model_path, config.model_name)
+
+    # the server will gracefully shutdown (i.e., keep opened TCP streams finishes)
+    # after the lease is revoked
+    handler = RequestHandler(engine_client)
+    if engine_args.is_embedding:
+        await endpoint.serve_endpoint(handler.encode)
+    else:
+        await endpoint.serve_endpoint(handler.generate)
+
+
+def cmd_line_args():
+    parser = argparse.ArgumentParser(
+        description="SGLang server integrated with Dynamo LLM."
+    )
+    parser.add_argument(
+        "--endpoint",
+        type=str,
+        default=DEFAULT_ENDPOINT,
+        help=f"Dynamo endpoint string in 'dyn://namespace.component.endpoint' format. Default: {DEFAULT_ENDPOINT}",
+    )
+    parser.add_argument(
+        "--model-path",
+        type=str,
+        default=DEFAULT_MODEL,
+        help=f"Path to disk model or HuggingFace model identifier to load. Default: {DEFAULT_MODEL}",
+    )
+    parser.add_argument(
+        "--model-name",
+        type=str,
+        default="",
+        help="Name to serve the model under. Defaults to deriving it from model path.",
+    )
+    parser.add_argument(
+        "--base-gpu-id",
+        type=int,
+        default=0,
+        help="The base GPU ID to start allocating GPUs from. Useful when running multiple instances on the same machine.",
+    )
+    parser.add_argument(
+        "--tensor-parallel-size", type=int, default=1, help="Number of GPUs to use."
+    )
+    parser.add_argument(
+        "--kv-block-size", type=int, default=16, help="Size of a KV cache block."
+    )
+    parser.add_argument(
+        "--context-length",
+        type=int,
+        default=None,
+        help="Max model context length. Defaults to models max, usually model_max_length from tokenizer_config.json. Reducing this reduces VRAM requirements.",
+    )
+    parser.add_argument(
+        "--nnodes", type=int, default=1, help="The number of machines SGLang will use"
+    )
+    parser.add_argument(
+        "--node-rank",
+        type=int,
+        default=0,
+        help="Unique number for each node. 0 for the leader.",
+    )
+    parser.add_argument(
+        "--dist-init-addr",
+        type=str,
+        default="",
+        help="Host address (e.g., `192.168.0.2:25000`) of the node with rank 0",
+    )
+    parser.add_argument(
+        "--extra-engine-args",
+        type=str,
+        default="",
+        help="Path to a JSON file containing additional keyword arguments to pass to the SGLang Engine.",
+    )
+    args = parser.parse_args()
+
+    config = Config()
+    config.model_path = args.model_path
+    if args.model_name:
+        config.model_name = args.model_name
+    else:
+        # This becomes an `Option` on the Rust side
+        config.model_name = None
+
+    endpoint_str = args.endpoint.replace("dyn://", "", 1)
+    endpoint_parts = endpoint_str.split(".")
+    if len(endpoint_parts) != 3:
+        logging.error(
+            f"Invalid endpoint format: '{args.endpoint}'. Expected 'dyn://namespace.component.endpoint' or 'namespace.component.endpoint'."
+        )
+        sys.exit(1)
+
+    parsed_namespace, parsed_component_name, parsed_endpoint_name = endpoint_parts
+
+    config.namespace = parsed_namespace
+    config.component = parsed_component_name
+    config.endpoint = parsed_endpoint_name
+    config.base_gpu_id = args.base_gpu_id
+    config.tensor_parallel_size = args.tensor_parallel_size
+    config.kv_block_size = args.kv_block_size
+    config.context_length = args.context_length
+    config.nnodes = args.nnodes
+    config.node_rank = args.node_rank
+    config.dist_init_addr = args.dist_init_addr
+    config.extra_engine_args = args.extra_engine_args
+    return config
+
+
+if __name__ == "__main__":
+    uvloop.install()
+    asyncio.run(worker())

examples/cli/trtllm_inc.py

+# SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+# TODO:
+# - Support disaggregated serving
+# - Update examples to use this engine.
+#
+# `dynamo-run out=trtllm` runs this script
+# Can be used standalone: `python3 trtllm_inc.py` - lots of optional cmd line params
+#
+# Disaggregated serving:
+# - Ingress: dynamo run in=http out=dyn
+# - Decode Worker: python3 trtllm_inc.py --task=decode --extra-engine-args=trtllm_config/sample.yaml
+# - Prefill Worker: python3 trtllm_inc.py --task=prefill --extra-engine-args=trtllm_config/sample.yaml
+
+
+import argparse
+import asyncio
+import base64
+import copy
+import logging
+import sys
+import warnings
+from dataclasses import asdict, dataclass
+from typing import Optional
+
+import uvloop
+
+# Import TRTLLM and related modules
+from tensorrt_llm import SamplingParams
+from tensorrt_llm.llmapi import DisaggregatedParams
+from tensorrt_llm.llmapi.llm_utils import update_llm_args_with_extra_options
+from tensorrt_llm.llmapi.tokenizer import tokenizer_factory
+
+from dynamo.llm import (
+    ModelType,
+    get_tensorrtllm_engine,
+    get_tensorrtllm_publisher,
+    register_llm,
+)
+from dynamo.runtime import DistributedRuntime, dynamo_worker
+from dynamo.runtime.logging import configure_dynamo_logging
+
+# Only used if you run it manually from the command line
+DEFAULT_ENDPOINT = "dyn://dynamo.backend.generate"
+# Qwen/Qwen3-0.6B is not supported by TRTLLM yet.
+DEFAULT_MODEL = "TinyLlama/TinyLlama-1.1B-Chat-v1.0"
+# Default endpoint for the remote prefill service.
+DEFAULT_PREFILL_ENDPOINT = "dyn://dynamo.prefill.generate"
+
+# Default buffer size for kv cache events.
+DEFAULT_KV_EVENT_BUFFER_MAX_SIZE = 1024
+
+configure_dynamo_logging()
+
+
+def parse_endpoint(endpoint: str) -> tuple[str, str, str]:
+    endpoint_str = endpoint.replace("dyn://", "", 1)
+    endpoint_parts = endpoint_str.split(".")
+    if len(endpoint_parts) != 3:
+        raise ValueError(
+            f"Invalid endpoint format: '{endpoint}'. "
+            "Expected 'dyn://namespace.component.endpoint' or 'namespace.component.endpoint'."
+        )
+
+    return tuple(endpoint_parts)
+
+
+class DisaggregatedParamsCodec:
+    """
+    Codec for encoding and decoding disaggregated params for network transfer.
+    """
+
+    @staticmethod
+    def decode(
+        disaggregated_params: DisaggregatedParams,
+    ) -> DisaggregatedParams:
+        if disaggregated_params is None:
+            return None
+
+        opaque_state = (
+            base64.b64decode(disaggregated_params.opaque_state)
+            if disaggregated_params.opaque_state is not None
+            else None
+        )
+        return DisaggregatedParams(
+            request_type=disaggregated_params.request_type,
+            first_gen_tokens=disaggregated_params.first_gen_tokens,
+            ctx_request_id=disaggregated_params.ctx_request_id,
+            opaque_state=opaque_state,
+            draft_tokens=disaggregated_params.draft_tokens,
+        )
+
+    @staticmethod
+    def encode(
+        disaggregated_params: DisaggregatedParams,
+    ) -> DisaggregatedParams:
+        if disaggregated_params is None:
+            return None
+
+        encoded_opaque_state = (
+            base64.b64encode(disaggregated_params.opaque_state).decode("utf-8")
+            if disaggregated_params.opaque_state is not None
+            else None
+        )
+        return DisaggregatedParams(
+            request_type=disaggregated_params.request_type,
+            first_gen_tokens=disaggregated_params.first_gen_tokens,
+            ctx_request_id=disaggregated_params.ctx_request_id,
+            opaque_state=encoded_opaque_state,
+            draft_tokens=disaggregated_params.draft_tokens,
+        )
+
+
+class Config:
+    """Command line parameters or defaults"""
+
+    namespace: str
+    component: str
+    endpoint: str
+    model_path: str
+    model_name: Optional[str] = None
+    tensor_parallel_size: int
+    kv_block_size: int
+    extra_engine_args: str
+    publish_events_and_metrics: bool
+    disaggregation_mode: str
+    remote_prefill_endpoint: str
+
+    def __str__(self) -> str:
+        return (
+            f"Config(namespace={self.namespace}, "
+            f"component={self.component}, "
+            f"endpoint={self.endpoint}, "
+            f"model_path={self.model_path}, "
+            f"model_name={self.model_name}, "
+            f"tensor_parallel_size={self.tensor_parallel_size}, "
+            f"kv_block_size={self.kv_block_size}, "
+            f"extra_engine_args={self.extra_engine_args}, "
+            f"publish_events_and_metrics={self.publish_events_and_metrics}, "
+            f"disaggregation_mode={self.disaggregation_mode}, "
+            f"remote_prefill_endpoint={self.remote_prefill_endpoint})"
+        )
+
+
+@dataclass
+class RequestHandlerConfig:
+    """
+    Configuration for the request handler
+    """
+
+    component: object
+    engine: object
+    default_sampling_params: object
+    publisher: object
+    disaggregation_mode: str
+    remote_prefill_client: object
+
+
+class RequestHandler:
+    """
+    Request handler for the generate endpoint
+    """
+
+    def __init__(self, config: RequestHandlerConfig):
+        self.engine = config.engine
+        self.component = config.component
+        self.default_sampling_params = config.default_sampling_params
+        self.publisher = config.publisher
+        self.disaggregation_mode = config.disaggregation_mode
+        self.remote_prefill_client = config.remote_prefill_client
+        self.first_generation = True
+
+    async def remote_prefill(self, request):
+        """
+        Send a prefill request to the remote prefill worker.
+
+        Args:
+            request: The original request to be sent for prefill
+
+        Returns:
+            The response from the remote prefill worker
+
+        Raises:
+            ValueError: If prefill client is not initialized or multiple responses received
+        """
+
+        prefill_request = copy.deepcopy(request)
+        # TRTLLM requires max_tokens to be set for prefill requests.
+        prefill_request["stop_conditions"]["max_tokens"] = 1
+
+        # Set the disaggregated params to context_only for remote prefill
+        prefill_request["disaggregated_params"] = asdict(
+            DisaggregatedParamsCodec.encode(
+                DisaggregatedParams(request_type="context_only")
+            )
+        )
+
+        if self.remote_prefill_client is None:
+            raise ValueError("Prefill client not initialized")
+        try:
+            # TODO: Use smart KV router to determine which prefill worker to use. This would also require supporting publishing events for prefill workers.
+            remote_prefill_responses = [
+                remote_prefill_response
+                async for remote_prefill_response in await self.remote_prefill_client.round_robin(
+                    prefill_request
+                )
+            ]
+        except Exception as e:
+            raise ValueError(f"Error in remote prefill: {e}")
+
+        if len(remote_prefill_responses) > 1:
+            raise ValueError(
+                "Prefill worker returned more than one response. This is currently not supported in remote prefill mode."
+            )
+
+        if len(remote_prefill_responses) == 0:
+            raise ValueError("No response received from remote prefill worker")
+
+        remote_prefill_response = remote_prefill_responses[0]
+        return remote_prefill_response
+
+    async def generate(self, request):
+        # Check if there is an error in the publisher error queue
+        publishers_error = (
+            self.publisher.check_error_queue() if self.publisher else None
+        )
+        if publishers_error:
+            raise publishers_error
+
+        inputs = request["token_ids"]
+
+        # Decode the disaggregated params from the request
+        if "disaggregated_params" in request:
+            disaggregated_params = DisaggregatedParamsCodec.decode(
+                DisaggregatedParams(**request["disaggregated_params"])
+            )
+        else:
+            disaggregated_params = None
+
+        num_output_tokens_so_far = 0
+
+        if self.disaggregation_mode == "decode":
+            # Run prefill/context phase remotely if disaggregation mode is decode.
+            try:
+                prefill_result = await self.remote_prefill(request)
+            except Exception as e:
+                raise ValueError(f"Error in remote prefill: {e}")
+
+            remote_prefill_response = prefill_result.data()
+            if (
+                remote_prefill_response["finish_reason"] == "stop"
+                or remote_prefill_response["finish_reason"] == "error"
+            ):
+                yield remote_prefill_response
+                return
+            num_output_tokens_so_far = len(remote_prefill_response["token_ids"])
+
+            # Decode the disaggregated params from the remote prefill response
+            disaggregated_params = DisaggregatedParamsCodec.decode(
+                DisaggregatedParams(**remote_prefill_response["disaggregated_params"])
+            )
+
+            # Send the first token response to the client
+            first_token_response = remote_prefill_response
+            first_token_response.pop("disaggregated_params")
+            yield first_token_response
+
+            # Set the disaggregated params to generation_only for the rest of the generation
+            disaggregated_params.request_type = "generation_only"
+
+        sampling_params = self.default_sampling_params
+        for key, value in request["sampling_options"].items():
+            if not value:
+                continue
+            if hasattr(sampling_params, key):
+                setattr(sampling_params, key, value)
+
+        max_tokens = request["stop_conditions"]["max_tokens"]
+        if max_tokens:
+            sampling_params.max_tokens = max_tokens
+
+        # TODO: Disable streaming for context only requests when adding disagg support
+        async for res in self.engine.llm.generate_async(
+            inputs=inputs,
+            sampling_params=sampling_params,
+            disaggregated_params=disaggregated_params,
+            streaming=(self.disaggregation_mode != "prefill"),
+        ):
+            # TRTLLM engine needs to start generating tokens first before stats
+            # can be retrieved.
+            if self.first_generation and self.publisher:
+                self.publisher.start()
+                self.first_generation = False
+
+            if res.finished and self.disaggregation_mode != "prefill":
+                yield {"finish_reason": "stop", "token_ids": []}
+                break
+
+            if not res.outputs:
+                yield {"finish_reason": "error", "token_ids": []}
+                break
+
+            output = res.outputs[0]
+            next_total_toks = len(output.token_ids)
+            out = {"token_ids": output.token_ids[num_output_tokens_so_far:]}
+            if output.finish_reason:
+                out["finish_reason"] = output.finish_reason
+            if output.stop_reason:
+                out["stop_reason"] = output.stop_reason
+            if self.disaggregation_mode == "prefill":
+                # Return the disaggregated params only when operating in prefill mode.
+                out["disaggregated_params"] = asdict(
+                    DisaggregatedParamsCodec.encode(output.disaggregated_params)
+                )
+            yield out
+            num_output_tokens_so_far = next_total_toks
+
+
+@dynamo_worker(static=False)
+async def worker(runtime: DistributedRuntime):
+    await init(runtime, cmd_line_args())
+
+
+async def init(runtime: DistributedRuntime, config: Config):
+    """
+    Instantiate and serve
+    """
+
+    logging.info(f"Initializing the worker with config: {config}")
+
+    remote_prefill_client = None
+    if config.disaggregation_mode == "decode":
+        logging.info(
+            f"Initializing remote prefill client for endpoint: {config.remote_prefill_endpoint}"
+        )
+        parsed_namespace, parsed_component_name, parsed_endpoint_name = parse_endpoint(
+            config.remote_prefill_endpoint
+        )
+        remote_prefill_client = (
+            await runtime.namespace(parsed_namespace)
+            .component(parsed_component_name)
+            .endpoint(parsed_endpoint_name)
+            .client()
+        )
+
+    component = runtime.namespace(config.namespace).component(config.component)
+    await component.create_service()
+
+    # Convert model path to Path object if it's a local path, otherwise keep as string
+    model_path = str(config.model_path)
+
+    arg_map = {
+        "model": model_path,
+        "tensor_parallel_size": config.tensor_parallel_size,
+        "backend": "pytorch",
+        "skip_tokenizer_init": True,
+    }
+    if config.extra_engine_args != "":
+        # TODO: Support extra engine args from json file as well.
+        arg_map = update_llm_args_with_extra_options(arg_map, config.extra_engine_args)
+    if config.publish_events_and_metrics:
+        # 'event_buffer_max_size' is required to enable TRTLLM to publish kv cache events.
+        kv_cache_config = None
+        if "kv_cache_config" not in arg_map:
+            kv_cache_config = {}
+            kv_cache_config["event_buffer_max_size"] = DEFAULT_KV_EVENT_BUFFER_MAX_SIZE
+        else:
+            kv_cache_config = arg_map["kv_cache_config"]
+            if "event_buffer_max_size" not in kv_cache_config:
+                kv_cache_config[
+                    "event_buffer_max_size"
+                ] = DEFAULT_KV_EVENT_BUFFER_MAX_SIZE
+        arg_map["kv_cache_config"] = kv_cache_config
+
+        # Only pytorch backend is supported for now to publish events and metrics.
+        if "backend" not in arg_map:
+            arg_map["backend"] = "pytorch"
+        elif arg_map["backend"] != "pytorch":
+            logging.error(
+                "Only pytorch backend is supported for now to publish events and metrics."
+            )
+            sys.exit(1)
+
+    logging.info(f"TRTLLM engine args: {arg_map}")
+    engine_args = arg_map
+
+    # Populate default sampling params from the model
+    tokenizer = tokenizer_factory(arg_map["model"])
+    default_sampling_params = SamplingParams()
+    default_sampling_params._setup(tokenizer)
+    default_sampling_params.stop = None
+
+    async with get_tensorrtllm_engine(engine_args) as engine:
+        endpoint = component.endpoint(config.endpoint)
+
+        if config.disaggregation_mode != "prefill":
+            # Register the model with the endpoint if disaggregation mode is not prefill.
+            # Prefill worker will get the request directly from the Decode worker and not
+            # through the ingress.
+            # FIXME: Enable publishing events and metrics for disaggregated prefill.
+            # Currently prefill workers are chosen in round-robin fashion.
+            await register_llm(
+                ModelType.Backend,
+                endpoint,
+                config.model_path,
+                config.model_name,
+                kv_cache_block_size=config.kv_block_size,
+            )
+
+        # publisher will be set later if publishing is enabled.
+        handler_config = RequestHandlerConfig(
+            component=component,
+            engine=engine,
+            default_sampling_params=default_sampling_params,
+            publisher=None,
+            disaggregation_mode=config.disaggregation_mode,
+            remote_prefill_client=remote_prefill_client,
+        )
+
+        if (
+            config.publish_events_and_metrics
+            and config.disaggregation_mode != "prefill"
+        ):
+            # Initialize and pass in the publisher to the request handler to
+            # publish events and metrics.
+            kv_listener = runtime.namespace(config.namespace).component(
+                config.component
+            )
+            async with get_tensorrtllm_publisher(
+                component,
+                engine,
+                kv_listener,
+                int(endpoint.lease_id()),
+                config.kv_block_size,
+            ) as publisher:
+                handler_config.publisher = publisher
+                handler = RequestHandler(handler_config)
+                await endpoint.serve_endpoint(handler.generate)
+        else:
+            handler = RequestHandler(handler_config)
+            await endpoint.serve_endpoint(handler.generate)
+
+
+def cmd_line_args():
+    parser = argparse.ArgumentParser(
+        description="TensorRT-LLM server integrated with Dynamo LLM."
+    )
+    parser.add_argument(
+        "--endpoint",
+        type=str,
+        default=DEFAULT_ENDPOINT,
+        help=f"Dynamo endpoint string in 'dyn://namespace.component.endpoint' format. Default: {DEFAULT_ENDPOINT}",
+    )
+    parser.add_argument(
+        "--model-path",
+        type=str,
+        default=DEFAULT_MODEL,
+        help=f"Path to disk model or HuggingFace model identifier to load. Default: {DEFAULT_MODEL}",
+    )
+    parser.add_argument(
+        "--model-name",
+        type=str,
+        default="",
+        help="Name to serve the model under. Defaults to deriving it from model path.",
+    )
+    parser.add_argument(
+        "--tensor-parallel-size", type=int, default=1, help="Number of GPUs to use."
+    )
+    # IMPORTANT: We should ideally not expose this to users. We should be able to
+    # query the block size from the TRTLLM engine.
+    parser.add_argument(
+        "--kv-block-size", type=int, default=32, help="Size of a KV cache block."
+    )
+    parser.add_argument(
+        "--context-length",
+        type=int,
+        default=None,
+        help="This argument is not used by TRTLLM. Please provide max_input_len, max_seq_len and max_output_len in yaml file and point --extra-engine-args to the yaml file.",
+    )
+    parser.add_argument(
+        "--extra-engine-args",
+        type=str,
+        default="",
+        help="Path to a YAML file containing additional keyword arguments to pass to the TRTLLM engine.",
+    )
+    parser.add_argument(
+        "--publish-events-and-metrics",
+        action="store_true",
+        help="Publish events and metrics to the dynamo components. Note: This is not supported when running in prefill disaggregation mode.",
+    )
+    parser.add_argument(
+        "--task",
+        type=str,
+        action="append",
+        choices=["prefill", "decode", "prefill_and_decode"],
+        default=[],
+        help="Specifies the task for the engine. Can be specified multiple time for different tasks. Will raise an error if conflicting tasks are specified.",
+    )
+    parser.add_argument(
+        "--remote-prefill-endpoint",
+        type=str,
+        default=DEFAULT_PREFILL_ENDPOINT,
+        help=f"Endpoint(in 'dyn://namespace.component.endpoint' format) to send prefill requests to when running in decode disaggregation mode. Default: {DEFAULT_PREFILL_ENDPOINT}",
+    )
+    args = parser.parse_args()
+
+    # Validate arguments
+    if args.context_length is not None:
+        warnings.warn(
+            "--context-length is accepted for compatibility but will be ignored for TensorRT-LLM. Please provide max_input_len, max_seq_len and max_output_len in yaml file and point --extra-engine-args to the yaml file.",
+            UserWarning,
+        )
+
+    endpoint = args.endpoint
+
+    # disaggregation mode
+    disaggregation_mode = None
+    for choice in ["prefill", "decode", "prefill_and_decode"]:
+        if choice in args.task:
+            if disaggregation_mode is not None:
+                raise ValueError(
+                    f"Conflicting tasks specified: {args.task}. Please specify only one task."
+                )
+            disaggregation_mode = choice
+
+    if disaggregation_mode is None:
+        disaggregation_mode = "prefill_and_decode"
+
+    if disaggregation_mode == "prefill":
+        if args.remote_prefill_endpoint != DEFAULT_PREFILL_ENDPOINT:
+            logging.error(
+                "--remote-prefill-endpoint is not supported when running in prefill disaggregation mode."
+            )
+            sys.exit(1)
+        else:
+            endpoint = DEFAULT_PREFILL_ENDPOINT
+
+        if args.publish_events_and_metrics:
+            warnings.warn(
+                "--publish-events-and-metrics is not supported when running in prefill disaggregation mode.",
+                UserWarning,
+            )
+
+    config = Config()
+    config.model_path = args.model_path
+    if args.model_name:
+        config.model_name = args.model_name
+    else:
+        # This becomes an `Option` on the Rust side
+        config.model_name = None
+
+    parsed_namespace, parsed_component_name, parsed_endpoint_name = parse_endpoint(
+        endpoint
+    )
+
+    config.namespace = parsed_namespace
+    config.component = parsed_component_name
+    config.endpoint = parsed_endpoint_name
+    config.tensor_parallel_size = args.tensor_parallel_size
+    config.kv_block_size = args.kv_block_size
+    config.extra_engine_args = args.extra_engine_args
+    config.publish_events_and_metrics = args.publish_events_and_metrics
+    config.disaggregation_mode = disaggregation_mode
+    config.remote_prefill_endpoint = args.remote_prefill_endpoint
+
+    return config
+
+
+if __name__ == "__main__":
+    uvloop.install()
+    try:
+        asyncio.run(worker())
+    except KeyboardInterrupt:
+        logging.info("Received SIGINT, shutting down...")

examples/cli/vllm_inc.py

+# SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+# `dynamo-run out=vllm` runs this script
+# Can also be used standalone: `python3 vllm_inc.py` - lots of optional cmd line params
+
+# Setup checklist:
+# - We are in a virtualenv with vllm installed - and patched if using kv routing.
+# - `libdynamo_llm_capi.so` is in system lib path or it's containing folder is in LD_LIBRARY_PATH
+#   It builds in target/debug/ by default.
+
+import argparse
+import asyncio
+import json
+import logging
+import os
+import sys
+import uuid
+from typing import Optional
+
+import uvloop
+from vllm import SamplingParams
+from vllm.engine.arg_utils import AsyncEngineArgs
+from vllm.entrypoints.openai.api_server import (
+    build_async_engine_client_from_engine_args,
+)
+from vllm.inputs import TokensPrompt
+
+from dynamo.llm import (
+    ForwardPassMetrics,
+    KvStats,
+    ModelType,
+    WorkerMetricsPublisher,
+    WorkerStats,
+    register_llm,
+)
+from dynamo.runtime import DistributedRuntime, dynamo_worker
+from dynamo.runtime.logging import configure_dynamo_logging
+
+# Only used if you run it manually from the command line
+DEFAULT_ENDPOINT = "dyn://dynamo.backend.generate"
+DEFAULT_MODEL = "Qwen/Qwen3-0.6B"
+
+configure_dynamo_logging()
+
+
+class Config:
+    """Command line parameters or defaults"""
+
+    namespace: str
+    component: str
+    endpoint: str
+    model_path: str
+    model_name: Optional[str]
+    tensor_parallel_size: int
+    kv_block_size: int
+    context_length: int
+    extra_engine_args: str
+
+
+class RequestHandler:
+    """
+    Request handler for the generate endpoint
+    """
+
+    def __init__(self, component, engine, default_sampling_params):
+        self.component = component
+        self.engine_client = engine
+        self.default_sampling_params = default_sampling_params
+        self.metrics_publisher = WorkerMetricsPublisher()
+
+    def setup_kv_metrics(self):
+        if not hasattr(self.engine_client, "set_metrics_publisher"):
+            logging.debug("VLLM version does not support KV metrics")
+            return
+
+        self.engine_client.set_metrics_publisher(self.metrics_publisher)
+        # Initially send dummy metrics to kick start,
+        # vLLM will not update stat until forward pass is triggered
+
+        # Create the structured metrics objects
+        worker_stats = WorkerStats(
+            request_active_slots=0,
+            request_total_slots=1024,
+            num_requests_waiting=0,
+            data_parallel_rank=None,
+        )
+
+        kv_stats = KvStats(
+            kv_active_blocks=0,
+            kv_total_blocks=1024,
+            gpu_cache_usage_perc=0.0,
+            gpu_prefix_cache_hit_rate=0.0,
+        )
+
+        metrics = ForwardPassMetrics(
+            worker_stats=worker_stats, kv_stats=kv_stats, spec_decode_stats=None
+        )
+
+        # Publish the metrics as a single object
+        self.metrics_publisher.publish(metrics)
+
+        task = asyncio.create_task(self.create_metrics_publisher_endpoint())
+        task.add_done_callback(
+            lambda _: logging.debug("metrics publisher endpoint created")
+        )
+
+    async def create_metrics_publisher_endpoint(self):
+        logging.debug("Creating metrics publisher endpoint")
+        await self.metrics_publisher.create_endpoint(self.component)
+
+    async def generate(self, request):
+        # logging.debug(f"Received request: {request}")
+        request_id = str(uuid.uuid4().hex)
+
+        prompt = TokensPrompt(prompt_token_ids=request["token_ids"])
+
+        sampling_params = SamplingParams(**self.default_sampling_params)
+        for key, value in request["sampling_options"].items():
+            if not value:
+                continue
+            if hasattr(sampling_params, key):
+                setattr(sampling_params, key, value)
+
+        max_tokens = request["stop_conditions"]["max_tokens"]
+        if max_tokens:
+            sampling_params.max_tokens = max_tokens
+
+        num_output_tokens_so_far = 0
+        gen = self.engine_client.generate(prompt, sampling_params, request_id)
+        async for res in gen:
+            # res is vllm's RequestOutput
+
+            # This is the expected way for a request to end.
+            # The new token ID will be eos, don't forward it.
+            if res.finished:
+                yield {"finish_reason": "stop", "token_ids": []}
+                break
+
+            if not res.outputs:
+                yield {"finish_reason": "error", "token_ids": []}
+                break
+
+            output = res.outputs[0]
+            next_total_toks = len(output.token_ids)
+            out = {"token_ids": output.token_ids[num_output_tokens_so_far:]}
+            if output.finish_reason:
+                out["finish_reason"] = output.finish_reason
+            if output.stop_reason:
+                out["stop_reason"] = output.stop_reason
+            yield out
+            num_output_tokens_so_far = next_total_toks
+
+
+@dynamo_worker(static=False)
+async def worker(runtime: DistributedRuntime):
+    await init(runtime, cmd_line_args())
+
+
+def _check_and_set_env_value(key, expected, allow_override=False):
+    if not allow_override and key in os.environ and os.environ[key] != expected:
+        raise ValueError(
+            f"{key} is set and doesn't equal expected {expected}. Please unset variable before launch."
+        )
+    os.environ.setdefault(key, expected)
+
+
+async def init(runtime: DistributedRuntime, config: Config):
+    """
+    Instantiate and serve
+    """
+
+    arg_map = {
+        "model": config.model_path,
+        "task": "generate",
+        "tensor_parallel_size": config.tensor_parallel_size,
+        "skip_tokenizer_init": True,
+        "disable_log_requests": True,
+        "enable_prefix_caching": True,
+        # KV routing relies on logging KV metrics
+        "disable_log_stats": False,
+    }
+    assert config.kv_block_size > 0, "Must use non-negative integer for KV Block Size"
+    arg_map["block_size"] = config.kv_block_size
+
+    if config.context_length:
+        # Usually we want it to default to the max (from tokenizer_config.json)
+        arg_map["max_model_len"] = config.context_length
+
+    if config.extra_engine_args != "":
+        json_map = {}
+        # extra_engine_args is a filename
+        try:
+            with open(config.extra_engine_args) as f:
+                json_map = json.load(f)
+        except FileNotFoundError:
+            logging.error(f"File {config.extra_engine_args} not found.")
+        except json.JSONDecodeError as e:
+            logging.error(f"Invalid JSON in {config.extra_engine_args}: {e}")
+        logging.debug(f"Adding extra engine arguments: {json_map}")
+        arg_map = {**arg_map, **json_map}  # json_map gets precedence
+
+    # Patch won't start KVCacheEventManager unless these four are set
+
+    component = runtime.namespace(config.namespace).component(config.component)
+    await component.create_service()
+    endpoint = component.endpoint(config.endpoint)
+
+    _check_and_set_env_value("VLLM_WORKER_ID", str(endpoint.lease_id()))
+    _check_and_set_env_value(
+        "VLLM_KV_CAPI_PATH", "libdynamo_llm_capi.so", allow_override=True
+    )
+    _check_and_set_env_value("VLLM_KV_NAMESPACE", config.namespace)
+    _check_and_set_env_value("VLLM_KV_COMPONENT", config.component)
+    _check_and_set_env_value(
+        "VLLM_NO_USAGE_STATS", "1", allow_override=True
+    )  # Avoid internal HTTP requests
+    engine_args = AsyncEngineArgs(**arg_map)
+    model_config = engine_args.create_model_config()
+    # Load default sampling params from `generation_config.json`
+    default_sampling_params = model_config.get_diff_sampling_param()
+
+    engine_context = build_async_engine_client_from_engine_args(engine_args)
+    engine_client = await engine_context.__aenter__()
+
+    await register_llm(
+        ModelType.Backend,
+        endpoint,
+        config.model_path,
+        config.model_name,
+        context_length=arg_map.get(
+            "max_model_len", None
+        ),  # if None, takes length from tokenizer
+        kv_cache_block_size=arg_map["block_size"],
+    )
+    handler = RequestHandler(component, engine_client, default_sampling_params)
+    handler.setup_kv_metrics()
+
+    # the server will gracefully shutdown (i.e., keep opened TCP streams finishes)
+    # after the lease is revoked
+    await endpoint.serve_endpoint(handler.generate)
+
+
+def cmd_line_args():
+    parser = argparse.ArgumentParser(
+        description="vLLM server integrated with Dynamo LLM."
+    )
+    parser.add_argument(
+        "--endpoint",
+        type=str,
+        default=DEFAULT_ENDPOINT,
+        help=f"Dynamo endpoint string in 'dyn://namespace.component.endpoint' format. Default: {DEFAULT_ENDPOINT}",
+    )
+    parser.add_argument(
+        "--model-path",
+        type=str,
+        default=DEFAULT_MODEL,
+        help=f"Path to disk model or HuggingFace model identifier to load. Default: {DEFAULT_MODEL}",
+    )
+    parser.add_argument(
+        "--model-name",
+        type=str,
+        default="",
+        help="Name to serve the model under. Defaults to deriving it from model path.",
+    )
+    parser.add_argument(
+        "--tensor-parallel-size", type=int, default=1, help="Number of GPUs to use."
+    )
+    parser.add_argument(
+        "--kv-block-size", type=int, default=16, help="Size of a KV cache block."
+    )
+    parser.add_argument(
+        "--context-length",
+        type=int,
+        default=None,
+        help="Max model context length. Defaults to models max, usually model_max_length from tokenizer_config.json. Reducing this reduces VRAM requirements.",
+    )
+    parser.add_argument(
+        "--extra-engine-args",
+        type=str,
+        default="",
+        help="Path to a JSON file containing additional keyword arguments to pass to the vLLM AsyncLLMEngine.",
+    )
+    args = parser.parse_args()
+
+    config = Config()
+    config.model_path = args.model_path
+    if args.model_name:
+        config.model_name = args.model_name
+    else:
+        # This becomes an `Option` on the Rust side
+        config.model_name = None
+
+    endpoint_str = args.endpoint.replace("dyn://", "", 1)
+    endpoint_parts = endpoint_str.split(".")
+    if len(endpoint_parts) != 3:
+        logging.error(
+            f"Invalid endpoint format: '{args.endpoint}'. Expected 'dyn://namespace.component.endpoint' or 'namespace.component.endpoint'."
+        )
+        sys.exit(1)
+
+    parsed_namespace, parsed_component_name, parsed_endpoint_name = endpoint_parts
+
+    config.namespace = parsed_namespace
+    config.component = parsed_component_name
+    config.endpoint = parsed_endpoint_name
+    config.tensor_parallel_size = args.tensor_parallel_size
+    config.kv_block_size = args.kv_block_size
+    config.context_length = args.context_length
+    config.extra_engine_args = args.extra_engine_args
+
+    return config
+
+
+if __name__ == "__main__":
+    uvloop.install()
+    asyncio.run(worker())