[Frontend]-config-cli-args

docs/source/serving/openai_compatible_server.md

@@ -111,6 +111,29 @@ directory [here](https://github.com/vllm-project/vllm/tree/main/examples/)
 :prog: vllm serve
 ```
 
+### Config file
+
+You may also supply these CLI args using a config file. For example:
+
+```yaml
+# config.yaml
+
+host: "127.0.0.1"
+port: 6379
+uvicorn-log-level: "info"
+```
+
+```bash
+$ vllm serve SOME_MODEL --config config.yaml
+```
+
+---
+**NOTE** 
+
+In case an argument is supplied using CLI and the config file, the value from the CLI will take precedence.
+
+---
+
 ## Tool calling in the chat completion API
 vLLM supports only named function calling in the chat completion API. The `tool_choice` options `auto` and `required` are **not yet supported** but on the roadmap.
 

vllm/scripts.py

@@ -4,16 +4,20 @@
 import os
 import signal
 import sys
-from typing import List, Optional
+from typing import Dict, List, Optional, Union
 
+import yaml
 from openai import OpenAI
 from openai.types.chat import ChatCompletionMessageParam
 
 from vllm.engine.arg_utils import EngineArgs
 from vllm.entrypoints.openai.api_server import run_server
 from vllm.entrypoints.openai.cli_args import make_arg_parser
+from vllm.logger import init_logger
 from vllm.utils import FlexibleArgumentParser
 
+logger = init_logger(__name__)
+
 
 def register_signal_handlers():
 
@@ -24,7 +28,49 @@ def signal_handler(sig, frame):
     signal.signal(signal.SIGTSTP, signal_handler)
 
 
+def _merge_args_and_config(args: argparse.Namespace):
+    """
+        merge args from cli and config file supplied in the cli. 
+        If an argument is present in cli and args then choose args value
+        over config file.
+
+        example:
+        # config.yaml
+        port: 1231
+
+        # invoke server
+        $ vllm serve --config ../config.yaml --port 3122
+
+        # selected port = 3122
+    """
+    assert args.config, 'No config file specified.'
+
+    # only expecting a flat dictionary of atomic types
+    config: Dict[str, Union[int, str]] = {}
+
+    try:
+        with open(args.config, 'r') as config_file:
+            config = yaml.safe_load(config_file)
+    except Exception as ex:
+        logger.error("Unable to read the config file at %s", args.config)
+        logger.error(ex)
+
+    for key, value in config.items():
+        if hasattr(args, key):
+            logger.info("Argument %s is specified via config and commandline.",
+                        key)
+            logger.info("Selecting the %s=%s from commandline.", key,
+                        getattr(args, key))
+            continue
+
+        setattr(args, key, value)
+
+
 def serve(args: argparse.Namespace) -> None:
+
+    if args.config:
+        _merge_args_and_config(args)
+
     # The default value of `--model`
     if args.model != EngineArgs.model:
         raise ValueError(
@@ -125,6 +171,15 @@ def main():
     serve_parser.add_argument("model_tag",
                               type=str,
                               help="The model tag to serve")
+    serve_parser.add_argument(
+        "--config",
+        type=str,
+        required=False,
+        default='',
+        help="Read CLI options from a config file."
+        "Must be a YAML with the following options:"
+        "https://docs.vllm.ai/en/latest/serving/openai_compatible_server.html#command-line-arguments-for-the-server"
+    )
     serve_parser = make_arg_parser(serve_parser)
     serve_parser.set_defaults(dispatch_function=serve)