Add an endpoint to force a server shutdown

this is only needed during development, so that if we end up with some user
running a server on a machine we can stop it remotely. Obviously this
function should be removed before we deploy for production.

src/murfey/server/__init__.py

@@ -28,6 +28,8 @@
 template_files = files("murfey") / "templates"
 templates = Jinja2Templates(directory=template_files)
 
+_running_server: uvicorn.Server | None = None
+
 
 def respond_with_template(filename: str, parameters: dict[str, Any] | None = None):
     template_parameters = {
@@ -179,16 +181,26 @@ def run():
     logger.info(
         f"Starting Murfey server version {murfey.__version__}, listening on {args.host}:{args.port}"
     )
-    uvicorn.run(
+    global _running_server
+    config = uvicorn.Config(
         "murfey.server.main:app",
         host=args.host,
         port=args.port,
         env_file=args.env_file,
         log_config=None,
     )
+    _running_server = uvicorn.Server(config=config)
+    _running_server.run()
     logger.info("Server shutting down")
 
 
+def shutdown():
+    global _running_server
+    if _running_server:
+        _running_server.should_exit = True
+        _running_server.force_exit = True
+
+
 @functools.lru_cache()
 def get_microscope():
     try:

src/murfey/server/main.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import datetime
+import logging
 
 import ispyb
 import packaging.version
@@ -11,11 +12,13 @@
 from ispyb.sqlalchemy import BLSession, Proposal
 from pydantic import BaseModel
 
-import murfey
+import murfey.server
 import murfey.server.bootstrap
 import murfey.server.websocket as ws
 from murfey.server import get_hostname, get_microscope, template_files, templates
 
+log = logging.getLogger("murfey.server.main")
+
 tags_metadata = [murfey.server.bootstrap.tag]
 
 app = FastAPI(title="Murfey server", debug=True, openapi_tags=tags_metadata)
@@ -185,3 +188,13 @@ def get_version(client_version: str = ""):
         result["client-needs-downgrade"] = client > server
 
     return result
+
+
+@app.get("/shutdown", include_in_schema=False)
+def shutdown():
+    """A method to stop the server. This should be removed before Murfey is
+    deployed in production. To remove it we need to figure out how to control
+    to process (eg. systemd) and who to run it as."""
+    log.info("Server shutdown request received")
+    murfey.server.shutdown()
+    return {"success": True}