def test_add_message(self): """Test MessageCache.add_message and has_message_reference""" cache = ForwardMsgCache() session = _create_mock_session() msg = _create_dataframe_msg([1, 2, 3]) cache.add_message(msg, session, 0) self.assertTrue(cache.has_message_reference(msg, session, 0)) self.assertFalse(cache.has_message_reference(msg, _create_mock_session(), 0))
def test_message_expiration(self): """Test MessageCache's expiration logic""" config._set_option("global.maxCachedMessageAge", 1, "test") cache = ForwardMsgCache() session1 = _create_mock_session() runcount1 = 0 msg = _create_dataframe_msg([1, 2, 3]) msg_hash = populate_hash_if_needed(msg) cache.add_message(msg, session1, runcount1) # Increment session1's run_count. This should not resolve in expiry. runcount1 += 1 self.assertTrue(cache.has_message_reference(msg, session1, runcount1)) # Increment again. The message will now be expired for session1, # though it won't have actually been removed yet. runcount1 += 1 self.assertFalse(cache.has_message_reference(msg, session1, runcount1)) self.assertIsNotNone(cache.get_message(msg_hash)) # Add another reference to the message session2 = _create_mock_session() runcount2 = 0 cache.add_message(msg, session2, runcount2) # Remove session1's expired entries. This should not remove the # entry from the cache, because session2 still has a reference to it. cache.remove_expired_session_entries(session1, runcount1) self.assertFalse(cache.has_message_reference(msg, session1, runcount1)) self.assertTrue(cache.has_message_reference(msg, session2, runcount2)) # Expire session2's reference. The message should no longer be # in the cache at all. runcount2 += 2 cache.remove_expired_session_entries(session2, runcount2) self.assertIsNone(cache.get_message(msg_hash))
class Server: _singleton: Optional["Server"] = None @classmethod def get_current(cls) -> "Server": """ Returns ------- Server The singleton Server object. """ if Server._singleton is None: raise RuntimeError("Server has not been initialized yet") return Server._singleton def __init__(self, ioloop: IOLoop, script_path: str, command_line: Optional[str]): """Create the server. It won't be started yet.""" if Server._singleton is not None: raise RuntimeError("Server already initialized. Use .get_current() instead") Server._singleton = self _set_tornado_log_levels() self._ioloop = ioloop self._script_path = script_path self._command_line = command_line # Mapping of ReportSession.id -> SessionInfo. self._session_info_by_id: Dict[str, SessionInfo] = {} self._must_stop = threading.Event() self._state = State.INITIAL self._message_cache = ForwardMsgCache() self._uploaded_file_mgr = UploadedFileManager() self._uploaded_file_mgr.on_files_updated.connect(self.on_files_updated) self._report: Optional[Report] = None self._preheated_session_id: Optional[str] = None def __repr__(self) -> str: return util.repr_(self) @property def script_path(self) -> str: return self._script_path def get_session_by_id(self, session_id: str) -> Optional[ReportSession]: """Return the ReportSession corresponding to the given id, or None if no such session exists.""" session_info = self._get_session_info(session_id) if session_info is None: return None return session_info.session def on_files_updated(self, session_id: str) -> None: """Event handler for UploadedFileManager.on_file_added. Ensures that uploaded files from stale sessions get deleted. """ session_info = self._get_session_info(session_id) if session_info is None: # If an uploaded file doesn't belong to an existing session, # remove it so it doesn't stick around forever. self._uploaded_file_mgr.remove_session_files(session_id) def _get_session_info(self, session_id: str) -> Optional[SessionInfo]: """Return the SessionInfo with the given id, or None if no such session exists. """ return self._session_info_by_id.get(session_id, None) def start(self, on_started: Callable[["Server"], Any]) -> None: """Start the server. Parameters ---------- on_started : callable A callback that will be called when the server's run-loop has started, and the server is ready to begin receiving clients. """ if self._state != State.INITIAL: raise RuntimeError("Server has already been started") LOGGER.debug("Starting server...") app = self._create_app() start_listening(app) port = config.get_option("server.port") LOGGER.debug("Server started on port %s", port) self._ioloop.spawn_callback(self._loop_coroutine, on_started) def get_debug(self) -> Dict[str, Dict[str, Any]]: if self._report: return {"report": self._report.get_debug()} return {} def _create_app(self) -> tornado.web.Application: """Create our tornado web app.""" base = config.get_option("server.baseUrlPath") routes = [ ( make_url_path_regex(base, "stream"), _BrowserWebSocketHandler, dict(server=self), ), ( make_url_path_regex(base, "healthz"), HealthHandler, dict(callback=lambda: self.is_ready_for_browser_connection), ), (make_url_path_regex(base, "debugz"), DebugHandler, dict(server=self)), (make_url_path_regex(base, "metrics"), MetricsHandler), ( make_url_path_regex(base, "message"), MessageCacheHandler, dict(cache=self._message_cache), ), ( make_url_path_regex( base, UPLOAD_FILE_ROUTE, ), UploadFileRequestHandler, dict( file_mgr=self._uploaded_file_mgr, get_session_info=self._get_session_info, ), ), ( make_url_path_regex(base, "assets/(.*)"), AssetsFileHandler, {"path": "%s/" % file_util.get_assets_dir()}, ), (make_url_path_regex(base, "media/(.*)"), MediaFileHandler, {"path": ""}), ( make_url_path_regex(base, "component/(.*)"), ComponentRequestHandler, dict(registry=ComponentRegistry.instance()), ), ] if config.get_option("server.scriptHealthCheckEnabled"): routes.extend( [ ( make_url_path_regex(base, "script-health-check"), HealthHandler, dict(callback=lambda: self.does_script_run_without_error()), ) ] ) if config.get_option("global.developmentMode"): LOGGER.debug("Serving static content from the Node dev server") else: static_path = file_util.get_static_dir() LOGGER.debug("Serving static content from %s", static_path) routes.extend( [ ( make_url_path_regex(base, "(.*)"), StaticFileHandler, {"path": "%s/" % static_path, "default_filename": "index.html"}, ), (make_url_path_regex(base, trailing_slash=False), AddSlashHandler), ] ) return tornado.web.Application( routes, # type: ignore[arg-type] cookie_secret=config.get_option("server.cookieSecret"), xsrf_cookies=config.get_option("server.enableXsrfProtection"), **TORNADO_SETTINGS, # type: ignore[arg-type] ) def _set_state(self, new_state: State) -> None: LOGGER.debug("Server state: %s -> %s" % (self._state, new_state)) self._state = new_state @property async def is_ready_for_browser_connection(self) -> Tuple[bool, str]: if self._state not in (State.INITIAL, State.STOPPING, State.STOPPED): return True, "ok" return False, "unavailable" async def does_script_run_without_error(self) -> Tuple[bool, str]: """Load and execute the app's script to verify it runs without an error. Returns ------- (True, "ok") if the script completes without error, or (False, err_msg) if the script raises an exception. """ session = ReportSession( ioloop=self._ioloop, script_path=self._script_path, command_line=self._command_line, uploaded_file_manager=self._uploaded_file_mgr, ) try: session.request_rerun(None) now = time.perf_counter() while ( SCRIPT_RUN_WITHOUT_ERRORS_KEY not in session.session_state and (time.perf_counter() - now) < SCRIPT_RUN_CHECK_TIMEOUT ): await tornado.gen.sleep(0.1) if SCRIPT_RUN_WITHOUT_ERRORS_KEY not in session.session_state: return False, "timeout" ok = session.session_state[SCRIPT_RUN_WITHOUT_ERRORS_KEY] msg = "ok" if ok else "error" return ok, msg finally: session.shutdown() @property def browser_is_connected(self) -> bool: return self._state == State.ONE_OR_MORE_BROWSERS_CONNECTED @property def is_running_hello(self) -> bool: from streamlit.hello import hello return self._script_path == hello.__file__ @tornado.gen.coroutine def _loop_coroutine( self, on_started: Optional[Callable[["Server"], Any]] = None ) -> Generator[Any, None, None]: try: if self._state == State.INITIAL: self._set_state(State.WAITING_FOR_FIRST_BROWSER) elif self._state == State.ONE_OR_MORE_BROWSERS_CONNECTED: pass else: raise RuntimeError("Bad server state at start: %s" % self._state) if on_started is not None: on_started(self) while not self._must_stop.is_set(): if self._state == State.WAITING_FOR_FIRST_BROWSER: pass elif self._state == State.ONE_OR_MORE_BROWSERS_CONNECTED: # Shallow-clone our sessions into a list, so we can iterate # over it and not worry about whether it's being changed # outside this coroutine. session_infos = list(self._session_info_by_id.values()) for session_info in session_infos: if session_info.ws is None: # Preheated. continue msg_list = session_info.session.flush_browser_queue() for msg in msg_list: try: self._send_message(session_info, msg) except tornado.websocket.WebSocketClosedError: self._close_report_session(session_info.session.id) yield yield elif self._state == State.NO_BROWSERS_CONNECTED: pass else: # Break out of the thread loop if we encounter any other state. break yield tornado.gen.sleep(0.01) # Shut down all ReportSessions for session_info in list(self._session_info_by_id.values()): session_info.session.shutdown() self._set_state(State.STOPPED) except Exception: # Can't just re-raise here because co-routines use Tornado # exceptions for control flow, which appears to swallow the reraised # exception. traceback.print_exc() LOGGER.info( """ Please report this bug at https://github.com/streamlit/streamlit/issues. """ ) finally: self._on_stopped() def _send_message(self, session_info: SessionInfo, msg: ForwardMsg) -> None: """Send a message to a client. If the client is likely to have already cached the message, we may instead send a "reference" message that contains only the hash of the message. Parameters ---------- session_info : SessionInfo The SessionInfo associated with websocket msg : ForwardMsg The message to send to the client """ msg.metadata.cacheable = is_cacheable_msg(msg) msg_to_send = msg if msg.metadata.cacheable: populate_hash_if_needed(msg) if self._message_cache.has_message_reference( msg, session_info.session, session_info.report_run_count ): # This session has probably cached this message. Send # a reference instead. LOGGER.debug("Sending cached message ref (hash=%s)" % msg.hash) msg_to_send = create_reference_msg(msg) # Cache the message so it can be referenced in the future. # If the message is already cached, this will reset its # age. LOGGER.debug("Caching message (hash=%s)" % msg.hash) self._message_cache.add_message( msg, session_info.session, session_info.report_run_count ) # If this was a `report_finished` message, we increment the # report_run_count for this session, and update the cache if ( msg.WhichOneof("type") == "report_finished" and msg.report_finished == ForwardMsg.FINISHED_SUCCESSFULLY ): LOGGER.debug( "Report finished successfully; " "removing expired entries from MessageCache " "(max_age=%s)", config.get_option("global.maxCachedMessageAge"), ) session_info.report_run_count += 1 self._message_cache.remove_expired_session_entries( session_info.session, session_info.report_run_count ) # Ship it off! if session_info.ws is not None: session_info.ws.write_message( serialize_forward_msg(msg_to_send), binary=True ) def stop(self) -> None: click.secho(" Stopping...", fg="blue") self._set_state(State.STOPPING) self._must_stop.set() def _on_stopped(self) -> None: """Called when our runloop is exiting, to shut down the ioloop. This will end our process. (Tests can patch this method out, to prevent the test's ioloop from being shutdown.) """ self._ioloop.stop() def add_preheated_report_session(self) -> None: """Register a fake browser with the server and run the script. This is used to start running the user's script even before the first browser connects. """ session = self._create_or_reuse_report_session(ws=None) session.handle_rerun_script_request(is_preheat=True) def _create_or_reuse_report_session( self, ws: Optional[WebSocketHandler] ) -> ReportSession: """Register a connected browser with the server. Parameters ---------- ws : _BrowserWebSocketHandler or None The newly-connected websocket handler or None if preheated connection. Returns ------- ReportSession The newly-created ReportSession for this browser connection. """ if self._preheated_session_id is not None: assert len(self._session_info_by_id) == 1 assert ws is not None session_id = self._preheated_session_id self._preheated_session_id = None session_info = self._session_info_by_id[session_id] session_info.ws = ws session = session_info.session LOGGER.debug( "Reused preheated session for ws %s. Session ID: %s", id(ws), session_id ) else: session = ReportSession( ioloop=self._ioloop, script_path=self._script_path, command_line=self._command_line, uploaded_file_manager=self._uploaded_file_mgr, ) LOGGER.debug( "Created new session for ws %s. Session ID: %s", id(ws), session.id ) assert session.id not in self._session_info_by_id, ( "session.id '%s' registered multiple times!" % session.id ) self._session_info_by_id[session.id] = SessionInfo(ws, session) if ws is None: self._preheated_session_id = session.id else: self._set_state(State.ONE_OR_MORE_BROWSERS_CONNECTED) return session def _close_report_session(self, session_id: str) -> None: """Shutdown and remove a ReportSession. This function may be called multiple times for the same session, which is not an error. (Subsequent calls just no-op.) Parameters ---------- session_id : str The ReportSession's id string. """ if session_id in self._session_info_by_id: session_info = self._session_info_by_id[session_id] del self._session_info_by_id[session_id] session_info.session.shutdown() if len(self._session_info_by_id) == 0: self._set_state(State.NO_BROWSERS_CONNECTED)