llama-stack-mirror/llama_stack/distribution/server/server.py

# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the terms described in the LICENSE file in
# the root directory of this source tree.

import argparse
import asyncio
import inspect
import json
import os
import sys
import traceback
import warnings
from contextlib import asynccontextmanager
from importlib.metadata import version as parse_version
from pathlib import Path
from typing import Annotated, Any

import yaml
from fastapi import Body, FastAPI, HTTPException, Request
from fastapi import Path as FastapiPath
from fastapi.exceptions import RequestValidationError
from fastapi.responses import JSONResponse, StreamingResponse
from openai import BadRequestError
from pydantic import BaseModel, ValidationError

from llama_stack.distribution.datatypes import LoggingConfig, StackRunConfig
from llama_stack.distribution.distribution import builtin_automatically_routed_apis
from llama_stack.distribution.request_headers import (
    PROVIDER_DATA_VAR,
    request_provider_data_context,
)
from llama_stack.distribution.resolver import InvalidProviderError
from llama_stack.distribution.server.endpoints import (
    find_matching_endpoint,
    initialize_endpoint_impls,
)
from llama_stack.distribution.stack import (
    construct_stack,
    replace_env_vars,
    validate_env_pair,
)
from llama_stack.distribution.utils.config import redact_sensitive_fields
from llama_stack.distribution.utils.context import preserve_contexts_async_generator
from llama_stack.log import get_logger
from llama_stack.providers.datatypes import Api
from llama_stack.providers.inline.telemetry.meta_reference.config import TelemetryConfig
from llama_stack.providers.inline.telemetry.meta_reference.telemetry import (
    TelemetryAdapter,
)
from llama_stack.providers.utils.telemetry.tracing import (
    CURRENT_TRACE_CONTEXT,
    end_trace,
    setup_logger,
    start_trace,
)

from .auth import AuthenticationMiddleware
from .endpoints import get_all_api_endpoints

REPO_ROOT = Path(__file__).parent.parent.parent.parent

logger = get_logger(name=__name__, category="server")


def warn_with_traceback(message, category, filename, lineno, file=None, line=None):
    log = file if hasattr(file, "write") else sys.stderr
    traceback.print_stack(file=log)
    log.write(warnings.formatwarning(message, category, filename, lineno, line))


if os.environ.get("LLAMA_STACK_TRACE_WARNINGS"):
    warnings.showwarning = warn_with_traceback


def create_sse_event(data: Any) -> str:
    if isinstance(data, BaseModel):
        data = data.model_dump_json()
    else:
        data = json.dumps(data)

    return f"data: {data}\n\n"


async def global_exception_handler(request: Request, exc: Exception):
    traceback.print_exception(exc)
    http_exc = translate_exception(exc)

    return JSONResponse(status_code=http_exc.status_code, content={"error": {"detail": http_exc.detail}})


def translate_exception(exc: Exception) -> HTTPException | RequestValidationError:
    if isinstance(exc, ValidationError):
        exc = RequestValidationError(exc.errors())

    if isinstance(exc, RequestValidationError):
        return HTTPException(
            status_code=400,
            detail={
                "errors": [
                    {
                        "loc": list(error["loc"]),
                        "msg": error["msg"],
                        "type": error["type"],
                    }
                    for error in exc.errors()
                ]
            },
        )
    elif isinstance(exc, ValueError):
        return HTTPException(status_code=400, detail=f"Invalid value: {str(exc)}")
    elif isinstance(exc, BadRequestError):
        return HTTPException(status_code=400, detail=str(exc))
    elif isinstance(exc, PermissionError):
        return HTTPException(status_code=403, detail=f"Permission denied: {str(exc)}")
    elif isinstance(exc, TimeoutError):
        return HTTPException(status_code=504, detail=f"Operation timed out: {str(exc)}")
    elif isinstance(exc, NotImplementedError):
        return HTTPException(status_code=501, detail=f"Not implemented: {str(exc)}")
    else:
        return HTTPException(
            status_code=500,
            detail="Internal server error: An unexpected error occurred.",
        )


async def shutdown(app):
    """Initiate a graceful shutdown of the application.

    Handled by the lifespan context manager. The shutdown process involves
    shutting down all implementations registered in the application.
    """
    for impl in app.__llama_stack_impls__.values():
        impl_name = impl.__class__.__name__
        logger.info("Shutting down %s", impl_name)
        try:
            if hasattr(impl, "shutdown"):
                await asyncio.wait_for(impl.shutdown(), timeout=5)
            else:
                logger.warning("No shutdown method for %s", impl_name)
        except asyncio.TimeoutError:
            logger.exception("Shutdown timeout for %s ", impl_name, exc_info=True)
        except (Exception, asyncio.CancelledError) as e:
            logger.exception("Failed to shutdown %s: %s", impl_name, {e})


@asynccontextmanager
async def lifespan(app: FastAPI):
    logger.info("Starting up")
    yield
    logger.info("Shutting down")
    await shutdown(app)


def is_streaming_request(func_name: str, request: Request, **kwargs):
    # TODO: pass the api method and punt it to the Protocol definition directly
    return kwargs.get("stream", False)


async def maybe_await(value):
    if inspect.iscoroutine(value):
        return await value
    return value


async def sse_generator(event_gen_coroutine):
    event_gen = None
    try:
        event_gen = await event_gen_coroutine
        async for item in event_gen:
            yield create_sse_event(item)
            await asyncio.sleep(0.01)
    except asyncio.CancelledError:
        logger.info("Generator cancelled")
        if event_gen:
            await event_gen.aclose()
    except Exception as e:
        logger.exception("Error in sse_generator")
        yield create_sse_event(
            {
                "error": {
                    "message": str(translate_exception(e)),
                },
            }
        )


def create_dynamic_typed_route(func: Any, method: str, route: str):
    async def endpoint(request: Request, **kwargs):
        # Get auth attributes from the request scope
        user_attributes = request.scope.get("user_attributes", {})

        # Use context manager with both provider data and auth attributes
        with request_provider_data_context(request.headers, user_attributes):
            is_streaming = is_streaming_request(func.__name__, request, **kwargs)

            try:
                if is_streaming:
                    gen = preserve_contexts_async_generator(
                        sse_generator(func(**kwargs)), [CURRENT_TRACE_CONTEXT, PROVIDER_DATA_VAR]
                    )
                    return StreamingResponse(gen, media_type="text/event-stream")
                else:
                    value = func(**kwargs)
                    return await maybe_await(value)
            except Exception as e:
                logger.exception(f"Error executing endpoint {route=} {method=}")
                raise translate_exception(e) from e

    sig = inspect.signature(func)

    new_params = [inspect.Parameter("request", inspect.Parameter.POSITIONAL_OR_KEYWORD, annotation=Request)]
    new_params.extend(sig.parameters.values())

    path_params = extract_path_params(route)
    if method == "post":
        # Annotate parameters that are in the path with Path(...) and others with Body(...)
        new_params = [new_params[0]] + [
            (
                param.replace(annotation=Annotated[param.annotation, FastapiPath(..., title=param.name)])
                if param.name in path_params
                else param.replace(annotation=Annotated[param.annotation, Body(..., embed=True)])
            )
            for param in new_params[1:]
        ]

    endpoint.__signature__ = sig.replace(parameters=new_params)

    return endpoint


class TracingMiddleware:
    def __init__(self, app, impls):
        self.app = app
        self.impls = impls
        # FastAPI built-in paths that should bypass custom routing
        self.fastapi_paths = ("/docs", "/redoc", "/openapi.json", "/favicon.ico", "/static")

    async def __call__(self, scope, receive, send):
        if scope.get("type") == "lifespan":
            return await self.app(scope, receive, send)

        path = scope.get("path", "")

        # Check if the path is a FastAPI built-in path
        if path.startswith(self.fastapi_paths):
            # Pass through to FastAPI's built-in handlers
            logger.debug(f"Bypassing custom routing for FastAPI built-in path: {path}")
            return await self.app(scope, receive, send)

        if not hasattr(self, "endpoint_impls"):
            self.endpoint_impls = initialize_endpoint_impls(self.impls)

        try:
            _, _, trace_path = find_matching_endpoint(scope.get("method", "GET"), path, self.endpoint_impls)
        except ValueError:
            # If no matching endpoint is found, pass through to FastAPI
            logger.debug(f"No matching endpoint found for path: {path}, falling back to FastAPI")
            return await self.app(scope, receive, send)

        trace_context = await start_trace(trace_path, {"__location__": "server", "raw_path": path})

        async def send_with_trace_id(message):
            if message["type"] == "http.response.start":
                headers = message.get("headers", [])
                headers.append([b"x-trace-id", str(trace_context.trace_id).encode()])
                message["headers"] = headers
            await send(message)

        try:
            return await self.app(scope, receive, send_with_trace_id)
        finally:
            await end_trace()


class ClientVersionMiddleware:
    def __init__(self, app):
        self.app = app
        self.server_version = parse_version("llama-stack")

    async def __call__(self, scope, receive, send):
        if scope["type"] == "http":
            headers = dict(scope.get("headers", []))
            client_version = headers.get(b"x-llamastack-client-version", b"").decode()
            if client_version:
                try:
                    client_version_parts = tuple(map(int, client_version.split(".")[:2]))
                    server_version_parts = tuple(map(int, self.server_version.split(".")[:2]))
                    if client_version_parts != server_version_parts:

                        async def send_version_error(send):
                            await send(
                                {
                                    "type": "http.response.start",
                                    "status": 426,
                                    "headers": [[b"content-type", b"application/json"]],
                                }
                            )
                            error_msg = json.dumps(
                                {
                                    "error": {
                                        "message": f"Client version {client_version} is not compatible with server version {self.server_version}. Please update your client."
                                    }
                                }
                            ).encode()
                            await send({"type": "http.response.body", "body": error_msg})

                        return await send_version_error(send)
                except (ValueError, IndexError):
                    # If version parsing fails, let the request through
                    pass

        return await self.app(scope, receive, send)


def main(args: argparse.Namespace | None = None):
    """Start the LlamaStack server."""
    parser = argparse.ArgumentParser(description="Start the LlamaStack server.")
    parser.add_argument(
        "--yaml-config",
        dest="config",
        help="(Deprecated) Path to YAML configuration file - use --config instead",
    )
    parser.add_argument(
        "--config",
        dest="config",
        help="Path to YAML configuration file",
    )
    parser.add_argument(
        "--template",
        help="One of the template names in llama_stack/templates (e.g., tgi, fireworks, remote-vllm, etc.)",
    )
    parser.add_argument(
        "--port",
        type=int,
        default=int(os.getenv("LLAMA_STACK_PORT", 8321)),
        help="Port to listen on",
    )
    parser.add_argument("--disable-ipv6", action="store_true", help="Whether to disable IPv6 support")
    parser.add_argument(
        "--env",
        action="append",
        help="Environment variables in KEY=value format. Can be specified multiple times.",
    )
    parser.add_argument(
        "--tls-keyfile",
        help="Path to TLS key file for HTTPS",
        required="--tls-certfile" in sys.argv,
    )
    parser.add_argument(
        "--tls-certfile",
        help="Path to TLS certificate file for HTTPS",
        required="--tls-keyfile" in sys.argv,
    )

    # Determine whether the server args are being passed by the "run" command, if this is the case
    # the args will be passed as a Namespace object to the main function, otherwise they will be
    # parsed from the command line
    if args is None:
        args = parser.parse_args()

    # Check for deprecated argument usage
    if "--yaml-config" in sys.argv:
        warnings.warn(
            "The '--yaml-config' argument is deprecated and will be removed in a future version. Use '--config' instead.",
            DeprecationWarning,
            stacklevel=2,
        )

    log_line = ""
    if args.config:
        # if the user provided a config file, use it, even if template was specified
        config_file = Path(args.config)
        if not config_file.exists():
            raise ValueError(f"Config file {config_file} does not exist")
        log_line = f"Using config file: {config_file}"
    elif args.template:
        config_file = Path(REPO_ROOT) / "llama_stack" / "templates" / args.template / "run.yaml"
        if not config_file.exists():
            raise ValueError(f"Template {args.template} does not exist")
        log_line = f"Using template {args.template} config file: {config_file}"
    else:
        raise ValueError("Either --yaml-config or --template must be provided")

    logger_config = None
    with open(config_file) as fp:
        config_contents = yaml.safe_load(fp)
        if isinstance(config_contents, dict) and (cfg := config_contents.get("logging_config")):
            logger_config = LoggingConfig(**cfg)
        logger = get_logger(name=__name__, category="server", config=logger_config)
        if args.env:
            for env_pair in args.env:
                try:
                    key, value = validate_env_pair(env_pair)
                    logger.info(f"Setting CLI environment variable {key} => {value}")
                    os.environ[key] = value
                except ValueError as e:
                    logger.error(f"Error: {str(e)}")
                    sys.exit(1)
        config = replace_env_vars(config_contents)
        config = StackRunConfig(**config)

    # now that the logger is initialized, print the line about which type of config we are using.
    logger.info(log_line)

    logger.info("Run configuration:")
    safe_config = redact_sensitive_fields(config.model_dump())
    logger.info(yaml.dump(safe_config, indent=2))

    app = FastAPI(
        lifespan=lifespan,
        docs_url="/docs",
        redoc_url="/redoc",
        openapi_url="/openapi.json",
    )
    if not os.environ.get("LLAMA_STACK_DISABLE_VERSION_CHECK"):
        app.add_middleware(ClientVersionMiddleware)

    # Add authentication middleware if configured
    if config.server.auth:
        logger.info(f"Enabling authentication with provider: {config.server.auth.provider_type.value}")
        app.add_middleware(AuthenticationMiddleware, auth_config=config.server.auth)

    try:
        impls = asyncio.run(construct_stack(config))
    except InvalidProviderError as e:
        logger.error(f"Error: {str(e)}")
        sys.exit(1)

    if Api.telemetry in impls:
        setup_logger(impls[Api.telemetry])
    else:
        setup_logger(TelemetryAdapter(TelemetryConfig(), {}))

    all_endpoints = get_all_api_endpoints()

    if config.apis:
        apis_to_serve = set(config.apis)
    else:
        apis_to_serve = set(impls.keys())

    for inf in builtin_automatically_routed_apis():
        # if we do not serve the corresponding router API, we should not serve the routing table API
        if inf.router_api.value not in apis_to_serve:
            continue
        apis_to_serve.add(inf.routing_table_api.value)

    apis_to_serve.add("inspect")
    apis_to_serve.add("providers")
    for api_str in apis_to_serve:
        api = Api(api_str)

        endpoints = all_endpoints[api]
        impl = impls[api]

        for endpoint in endpoints:
            if not hasattr(impl, endpoint.name):
                # ideally this should be a typing violation already
                raise ValueError(f"Could not find method {endpoint.name} on {impl}!!")

            impl_method = getattr(impl, endpoint.name)
            logger.debug(f"{endpoint.method.upper()} {endpoint.route}")

            with warnings.catch_warnings():
                warnings.filterwarnings("ignore", category=UserWarning, module="pydantic._internal._fields")
                getattr(app, endpoint.method)(endpoint.route, response_model=None)(
                    create_dynamic_typed_route(
                        impl_method,
                        endpoint.method,
                        endpoint.route,
                    )
                )

    logger.debug(f"serving APIs: {apis_to_serve}")

    app.exception_handler(RequestValidationError)(global_exception_handler)
    app.exception_handler(Exception)(global_exception_handler)

    app.__llama_stack_impls__ = impls
    app.add_middleware(TracingMiddleware, impls=impls)

    import uvicorn

    # Configure SSL if certificates are provided
    port = args.port or config.server.port

    ssl_config = None
    if args.tls_keyfile:
        keyfile = args.tls_keyfile
        certfile = args.tls_certfile
    else:
        keyfile = config.server.tls_keyfile
        certfile = config.server.tls_certfile

    if keyfile and certfile:
        ssl_config = {
            "ssl_keyfile": keyfile,
            "ssl_certfile": certfile,
        }
        logger.info(f"HTTPS enabled with certificates:\n  Key: {keyfile}\n  Cert: {certfile}")

    listen_host = ["::", "0.0.0.0"] if not args.disable_ipv6 else "0.0.0.0"
    logger.info(f"Listening on {listen_host}:{port}")

    uvicorn_config = {
        "app": app,
        "host": listen_host,
        "port": port,
        "lifespan": "on",
        "log_level": logger.getEffectiveLevel(),
    }
    if ssl_config:
        uvicorn_config.update(ssl_config)

    uvicorn.run(**uvicorn_config)


def extract_path_params(route: str) -> list[str]:
    segments = route.split("/")
    params = [seg[1:-1] for seg in segments if seg.startswith("{") and seg.endswith("}")]
    # to handle path params like {param:path}
    params = [param.split(":")[0] for param in params]
    return params


if __name__ == "__main__":
    main()