feat(cli): add auto-reload for server command

pyproject.toml

@@ -14,6 +14,7 @@ dependencies = [
     "click>=8.1.8",
     "rich>=14.0.0",
     "python-dotenv>=1.1.0",
+    "watchfiles>=1.1.0",
 ]
 license = "Apache-2.0"
 urls = { Homepage = "https://cocoindex.io/" }

python/cocoindex/cli.py

@@ -1,18 +1,24 @@
+import asyncio
 import atexit
 import datetime
 import importlib.util
 import os
+import signal
 import sys
+import threading
 import types
+from types import FrameType
 from typing import Any
 
 import click
+import watchfiles
 from dotenv import find_dotenv, load_dotenv
 from rich.console import Console
 from rich.panel import Panel
 from rich.table import Table
 
 from . import flow, lib, setting
+from .runtime import execution_context
 from .setup import apply_setup_changes, drop_setup, flow_names_with_setup, sync_setup
 
 # Create ServerSettings lazily upon first call, as environment variables may be loaded from files, etc.
@@ -116,6 +122,12 @@ def _load_user_app(app_target: str) -> types.ModuleType:
         )
 
 
+def _initialize_cocoindex_in_process() -> None:
+    settings = setting.Settings.from_env()
+    lib.init(settings)
+    atexit.register(lib.stop)
+
+
 @click.group()
 @click.version_option(package_name="cocoindex", message="%(prog)s version %(version)s")
 @click.option(
@@ -139,9 +151,7 @@ def cli(env_file: str | None = None) -> None:
         click.echo(f"Loaded environment variables from: {loaded_env_path}", err=True)
 
     try:
-        settings = setting.Settings.from_env()
-        lib.init(settings)
-        atexit.register(lib.stop)
+        _initialize_cocoindex_in_process()
     except Exception as e:
         raise click.ClickException(f"Failed to initialize CocoIndex library: {e}")
 
@@ -485,6 +495,14 @@ def evaluate(
     default=False,
     help="Avoid printing anything to the standard output, e.g. statistics.",
 )
+@click.option(
+    "-r",
+    "--reload",
+    is_flag=True,
+    show_default=True,
+    default=False,
+    help="Enable auto-reload on code changes.",
+)
 def server(
     app_target: str,
     address: str | None,
@@ -493,6 +511,7 @@ def server(
     cors_origin: str | None,
     cors_cocoindex: bool,
     cors_local: int | None,
+    reload: bool,
 ) -> None:
     """
     Start a HTTP server providing REST APIs.
@@ -502,6 +521,65 @@ def server(
     APP_TARGET: path/to/app.py or installed_module.
     """
     app_ref = _get_app_ref_from_specifier(app_target)
+
+    if reload:
+        watch_paths = {os.getcwd()}
+        if os.path.isfile(app_ref):
+            watch_paths.add(os.path.dirname(os.path.abspath(app_ref)))
+        else:
+            try:
+                spec = importlib.util.find_spec(app_ref)
+                if spec and spec.origin:
+                    watch_paths.add(os.path.dirname(os.path.abspath(spec.origin)))
+            except ImportError:
+                pass
+
+        watchfiles.run_process(
+            *watch_paths,
+            target=_reloadable_server_target,
+            args=(
+                app_ref,
+                address,
+                cors_origin,
+                cors_cocoindex,
+                cors_local,
+                live_update,
+                quiet,
+            ),
+            watch_filter=watchfiles.PythonFilter(),
+            callback=lambda changes: click.secho(
+                f"\nDetected changes in {len(changes)} file(s), reloading server...\n",
+                fg="cyan",
+            ),
+        )
+    else:
+        _run_server(
+            app_ref,
+            address=address,
+            cors_origin=cors_origin,
+            cors_cocoindex=cors_cocoindex,
+            cors_local=cors_local,
+            live_update=live_update,
+            quiet=quiet,
+        )
+
+
+def _reloadable_server_target(*args: Any, **kwargs: Any) -> None:
+    """Reloadable target for the watchfiles process."""
+    _initialize_cocoindex_in_process()
+    _run_server(*args, **kwargs)
+
+
+def _run_server(
+    app_ref: str,
+    address: str | None = None,
+    cors_origin: str | None = None,
+    cors_cocoindex: bool = False,
+    cors_local: int | None = None,
+    live_update: bool = False,
+    quiet: bool = False,
+) -> None:
+    """Helper function to run the server with specified settings."""
     _load_user_app(app_ref)
 
     server_settings = setting.ServerSettings.from_env()
@@ -525,7 +603,20 @@ def server(
     if live_update:
         options = flow.FlowLiveUpdaterOptions(live_mode=True, print_stats=not quiet)
         flow.update_all_flows(options)
-    input("Press Enter to stop...")
+
+    click.secho("Press Ctrl+C to stop the server.", fg="yellow")
+
+    shutdown_event = threading.Event()
+
+    def handle_signal(signum: int, frame: FrameType | None) -> None:
+        shutdown_event.set()
+
+    async def _wait_for_shutdown_signal() -> None:
+        await asyncio.to_thread(shutdown_event.wait)
+
+    signal.signal(signal.SIGINT, handle_signal)
+    signal.signal(signal.SIGTERM, handle_signal)
+    execution_context.run(_wait_for_shutdown_signal())
 
 
 def _flow_name(name: str | None) -> str: