ai-agent-book 精选快照（<2MB 代码与文档，来自 github.com/bojieli/ai-agent-book）

chapter9/browser-use-rpa/browser-use/browser_use/browser/watchdogs/crash_watchdog.py

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+"""Browser watchdog for monitoring crashes and network timeouts using CDP."""
+
+import asyncio
+import time
+from typing import TYPE_CHECKING, ClassVar
+
+import psutil
+from bubus import BaseEvent
+from cdp_use.cdp.target import SessionID, TargetID
+from cdp_use.cdp.target.events import TargetCrashedEvent
+from pydantic import Field, PrivateAttr
+
+from browser_use.browser.events import (
+	BrowserConnectedEvent,
+	BrowserErrorEvent,
+	BrowserStoppedEvent,
+	TabCreatedEvent,
+)
+from browser_use.browser.watchdog_base import BaseWatchdog
+
+if TYPE_CHECKING:
+	pass
+
+
+class NetworkRequestTracker:
+	"""Tracks ongoing network requests."""
+
+	def __init__(self, request_id: str, start_time: float, url: str, method: str, resource_type: str | None = None):
+		self.request_id = request_id
+		self.start_time = start_time
+		self.url = url
+		self.method = method
+		self.resource_type = resource_type
+
+
+class CrashWatchdog(BaseWatchdog):
+	"""Monitors browser health for crashes and network timeouts using CDP."""
+
+	# Event contracts
+	LISTENS_TO: ClassVar[list[type[BaseEvent]]] = [
+		BrowserConnectedEvent,
+		BrowserStoppedEvent,
+		TabCreatedEvent,
+	]
+	EMITS: ClassVar[list[type[BaseEvent]]] = [BrowserErrorEvent]
+
+	# Configuration
+	network_timeout_seconds: float = Field(default=10.0)
+	check_interval_seconds: float = Field(default=5.0)  # Reduced frequency to reduce noise
+
+	# Private state
+	_active_requests: dict[str, NetworkRequestTracker] = PrivateAttr(default_factory=dict)
+	_monitoring_task: asyncio.Task | None = PrivateAttr(default=None)
+	_last_responsive_checks: dict[str, float] = PrivateAttr(default_factory=dict)  # target_url -> timestamp
+	_cdp_event_tasks: set[asyncio.Task] = PrivateAttr(default_factory=set)  # Track CDP event handler tasks
+	_sessions_with_listeners: set[str] = PrivateAttr(default_factory=set)  # Track sessions that already have event listeners
+
+	async def on_BrowserConnectedEvent(self, event: BrowserConnectedEvent) -> None:
+		"""Start monitoring when browser is connected."""
+		# logger.debug('[CrashWatchdog] Browser connected event received, beginning monitoring')
+
+		asyncio.create_task(self._start_monitoring())
+		# logger.debug(f'[CrashWatchdog] Monitoring task started: {self._monitoring_task and not self._monitoring_task.done()}')
+
+	async def on_BrowserStoppedEvent(self, event: BrowserStoppedEvent) -> None:
+		"""Stop monitoring when browser stops."""
+		# logger.debug('[CrashWatchdog] Browser stopped, ending monitoring')
+		await self._stop_monitoring()
+
+	async def on_TabCreatedEvent(self, event: TabCreatedEvent) -> None:
+		"""Attach to new tab."""
+		assert self.browser_session.agent_focus is not None, 'No current target ID'
+		await self.attach_to_target(self.browser_session.agent_focus.target_id)
+
+	async def attach_to_target(self, target_id: TargetID) -> None:
+		"""Set up crash monitoring for a specific target using CDP."""
+		try:
+			# Create temporary session for monitoring without switching focus
+			cdp_session = await self.browser_session.get_or_create_cdp_session(target_id, focus=False)
+
+			# Check if we already have listeners for this session
+			if cdp_session.session_id in self._sessions_with_listeners:
+				self.logger.debug(f'[CrashWatchdog] Event listeners already exist for session: {cdp_session.session_id}')
+				return
+
+			# Set up network event handlers
+			# def on_request_will_be_sent(event):
+			# 	# Create and track the task
+			# 	task = asyncio.create_task(self._on_request_cdp(event))
+			# 	self._cdp_event_tasks.add(task)
+			# 	# Remove from set when done
+			# 	task.add_done_callback(lambda t: self._cdp_event_tasks.discard(t))
+
+			# def on_response_received(event):
+			# 	self._on_response_cdp(event)
+
+			# def on_loading_failed(event):
+			# 	self._on_request_failed_cdp(event)
+
+			# def on_loading_finished(event):
+			# 	self._on_request_finished_cdp(event)
+
+			# Register event handlers
+			# TEMPORARILY DISABLED: Network events causing too much logging
+			# cdp_client.on('Network.requestWillBeSent', on_request_will_be_sent, session_id=session_id)
+			# cdp_client.on('Network.responseReceived', on_response_received, session_id=session_id)
+			# cdp_client.on('Network.loadingFailed', on_loading_failed, session_id=session_id)
+			# cdp_client.on('Network.loadingFinished', on_loading_finished, session_id=session_id)
+
+			def on_target_crashed(event: TargetCrashedEvent, session_id: SessionID | None = None):
+				# Create and track the task
+				task = asyncio.create_task(self._on_target_crash_cdp(target_id))
+				self._cdp_event_tasks.add(task)
+				# Remove from set when done
+				task.add_done_callback(lambda t: self._cdp_event_tasks.discard(t))
+
+			cdp_session.cdp_client.register.Target.targetCrashed(on_target_crashed)
+
+			# Track that we've added listeners to this session
+			self._sessions_with_listeners.add(cdp_session.session_id)
+
+			# Get target info for logging
+			targets = await cdp_session.cdp_client.send.Target.getTargets()
+			target_info = next((t for t in targets['targetInfos'] if t['targetId'] == target_id), None)
+			if target_info:
+				self.logger.debug(f'[CrashWatchdog] Added target to monitoring: {target_info.get("url", "unknown")}')
+
+		except Exception as e:
+			self.logger.warning(f'[CrashWatchdog] Failed to attach to target {target_id}: {e}')
+
+	async def _on_request_cdp(self, event: dict) -> None:
+		"""Track new network request from CDP event."""
+		request_id = event.get('requestId', '')
+		request = event.get('request', {})
+
+		self._active_requests[request_id] = NetworkRequestTracker(
+			request_id=request_id,
+			start_time=time.time(),
+			url=request.get('url', ''),
+			method=request.get('method', ''),
+			resource_type=event.get('type'),
+		)
+		# logger.debug(f'[CrashWatchdog] Tracking request: {request.get("method", "")} {request.get("url", "")[:50]}...')
+
+	def _on_response_cdp(self, event: dict) -> None:
+		"""Remove request from tracking on response."""
+		request_id = event.get('requestId', '')
+		if request_id in self._active_requests:
+			elapsed = time.time() - self._active_requests[request_id].start_time
+			response = event.get('response', {})
+			self.logger.debug(f'[CrashWatchdog] Request completed in {elapsed:.2f}s: {response.get("url", "")[:50]}...')
+			# Don't remove yet - wait for loadingFinished
+
+	def _on_request_failed_cdp(self, event: dict) -> None:
+		"""Remove request from tracking on failure."""
+		request_id = event.get('requestId', '')
+		if request_id in self._active_requests:
+			elapsed = time.time() - self._active_requests[request_id].start_time
+			self.logger.debug(
+				f'[CrashWatchdog] Request failed after {elapsed:.2f}s: {self._active_requests[request_id].url[:50]}...'
+			)
+			del self._active_requests[request_id]
+
+	def _on_request_finished_cdp(self, event: dict) -> None:
+		"""Remove request from tracking when loading is finished."""
+		request_id = event.get('requestId', '')
+		self._active_requests.pop(request_id, None)
+
+	async def _on_target_crash_cdp(self, target_id: TargetID) -> None:
+		"""Handle target crash detected via CDP."""
+		# Remove crashed session from pool
+		if session := self.browser_session._cdp_session_pool.pop(target_id, None):
+			await session.disconnect()
+			self.logger.debug(f'[CrashWatchdog] Removed crashed session from pool: {target_id}')
+
+		# Get target info
+		cdp_client = self.browser_session.cdp_client
+		targets = await cdp_client.send.Target.getTargets()
+		target_info = next((t for t in targets['targetInfos'] if t['targetId'] == target_id), None)
+		if (
+			target_info
+			and self.browser_session.agent_focus
+			and target_info['targetId'] == self.browser_session.agent_focus.target_id
+		):
+			self.browser_session.agent_focus.target_id = None  # type: ignore
+			self.browser_session.agent_focus.session_id = None  # type: ignore
+			self.logger.error(
+				f'[CrashWatchdog] 💥 Target crashed, navigating Agent to a new tab: {target_info.get("url", "unknown")}'
+			)
+
+		# Also emit generic browser error
+		self.event_bus.dispatch(
+			BrowserErrorEvent(
+				error_type='TargetCrash',
+				message=f'Target crashed: {target_id}',
+				details={
+					# 'url': target_url,  # TODO: add url to details
+					'target_id': target_id,
+				},
+			)
+		)
+
+	async def _start_monitoring(self) -> None:
+		"""Start the monitoring loop."""
+		assert self.browser_session.cdp_client is not None, 'Root CDP client not initialized - browser may not be connected yet'
+
+		if self._monitoring_task and not self._monitoring_task.done():
+			# logger.info('[CrashWatchdog] Monitoring already running')
+			return
+
+		self._monitoring_task = asyncio.create_task(self._monitoring_loop())
+		# logger.debug('[CrashWatchdog] Monitoring loop created and started')
+
+	async def _stop_monitoring(self) -> None:
+		"""Stop the monitoring loop."""
+		if self._monitoring_task and not self._monitoring_task.done():
+			self._monitoring_task.cancel()
+			try:
+				await self._monitoring_task
+			except asyncio.CancelledError:
+				pass
+			self.logger.debug('[CrashWatchdog] Monitoring loop stopped')
+
+		# Cancel all CDP event handler tasks
+		for task in list(self._cdp_event_tasks):
+			if not task.done():
+				task.cancel()
+		# Wait for all tasks to complete cancellation
+		if self._cdp_event_tasks:
+			await asyncio.gather(*self._cdp_event_tasks, return_exceptions=True)
+		self._cdp_event_tasks.clear()
+
+		# Clear tracking (CDP sessions are cached and managed by BrowserSession)
+		self._active_requests.clear()
+		self._sessions_with_listeners.clear()
+
+	async def _monitoring_loop(self) -> None:
+		"""Main monitoring loop."""
+		await asyncio.sleep(10)  # give browser time to start up and load the first page after first LLM call
+		while True:
+			try:
+				await self._check_network_timeouts()
+				await self._check_browser_health()
+				await asyncio.sleep(self.check_interval_seconds)
+			except asyncio.CancelledError:
+				break
+			except Exception as e:
+				self.logger.error(f'[CrashWatchdog] Error in monitoring loop: {e}')
+
+	async def _check_network_timeouts(self) -> None:
+		"""Check for network requests exceeding timeout."""
+		current_time = time.time()
+		timed_out_requests = []
+
+		# Debug logging
+		if self._active_requests:
+			self.logger.debug(
+				f'[CrashWatchdog] Checking {len(self._active_requests)} active requests for timeouts (threshold: {self.network_timeout_seconds}s)'
+			)
+
+		for request_id, tracker in self._active_requests.items():
+			elapsed = current_time - tracker.start_time
+			self.logger.debug(
+				f'[CrashWatchdog] Request {tracker.url[:30]}... elapsed: {elapsed:.1f}s, timeout: {self.network_timeout_seconds}s'
+			)
+			if elapsed >= self.network_timeout_seconds:
+				timed_out_requests.append((request_id, tracker))
+
+		# Emit events for timed out requests
+		for request_id, tracker in timed_out_requests:
+			self.logger.warning(
+				f'[CrashWatchdog] Network request timeout after {self.network_timeout_seconds}s: '
+				f'{tracker.method} {tracker.url[:100]}...'
+			)
+
+			self.event_bus.dispatch(
+				BrowserErrorEvent(
+					error_type='NetworkTimeout',
+					message=f'Network request timed out after {self.network_timeout_seconds}s',
+					details={
+						'url': tracker.url,
+						'method': tracker.method,
+						'resource_type': tracker.resource_type,
+						'elapsed_seconds': current_time - tracker.start_time,
+					},
+				)
+			)
+
+			# Remove from tracking
+			del self._active_requests[request_id]
+
+	async def _check_browser_health(self) -> None:
+		"""Check if browser and targets are still responsive."""
+
+		try:
+			try:
+				self.logger.debug(f'[CrashWatchdog] Checking browser health for target {self.browser_session.agent_focus}')
+				cdp_session = await self.browser_session.get_or_create_cdp_session()
+			except Exception as e:
+				self.logger.debug(
+					f'[CrashWatchdog] Checking browser health for target {self.browser_session.agent_focus} error: {type(e).__name__}: {e}'
+				)
+				self.agent_focus = cdp_session = await self.browser_session.get_or_create_cdp_session(
+					target_id=self.agent_focus.target_id, new_socket=True, focus=True
+				)
+
+			for target in (await self.browser_session.cdp_client.send.Target.getTargets()).get('targetInfos', []):
+				if target.get('type') == 'page':
+					cdp_session = await self.browser_session.get_or_create_cdp_session(target_id=target.get('targetId'))
+					if self._is_new_tab_page(target.get('url')) and target.get('url') != 'about:blank':
+						self.logger.debug(
+							f'[CrashWatchdog] Redirecting chrome://new-tab-page/ to about:blank {target.get("url")}'
+						)
+						await cdp_session.cdp_client.send.Page.navigate(
+							params={'url': 'about:blank'}, session_id=cdp_session.session_id
+						)
+
+			# Quick ping to check if session is alive
+			self.logger.debug(f'[CrashWatchdog] Attempting to run simple JS test expression in session {cdp_session} 1+1')
+			await asyncio.wait_for(
+				cdp_session.cdp_client.send.Runtime.evaluate(params={'expression': '1+1'}, session_id=cdp_session.session_id),
+				timeout=1.0,
+			)
+			self.logger.debug(f'[CrashWatchdog] Browser health check passed for target {self.browser_session.agent_focus}')
+		except Exception as e:
+			self.logger.error(
+				f'[CrashWatchdog] ❌ Crashed session detected for target {self.browser_session.agent_focus} error: {type(e).__name__}: {e}'
+			)
+			# Remove crashed session from pool
+			if self.browser_session.agent_focus and (target_id := self.browser_session.agent_focus.target_id):
+				if session := self.browser_session._cdp_session_pool.pop(target_id, None):
+					await session.disconnect()
+					self.logger.debug(f'[CrashWatchdog] Removed crashed session from pool: {target_id}')
+			self.browser_session.agent_focus.target_id = None  # type: ignore
+
+		# Check browser process if we have PID
+		if self.browser_session._local_browser_watchdog and (proc := self.browser_session._local_browser_watchdog._subprocess):
+			try:
+				if proc.status() in (psutil.STATUS_ZOMBIE, psutil.STATUS_DEAD):
+					self.logger.error(f'[CrashWatchdog] Browser process {proc.pid} has crashed')
+					# Clear all sessions from pool when browser crashes
+					for session in self.browser_session._cdp_session_pool.values():
+						await session.disconnect()
+					self.browser_session._cdp_session_pool.clear()
+					self.logger.debug('[CrashWatchdog] Cleared all sessions from pool due to browser crash')
+
+					self.event_bus.dispatch(
+						BrowserErrorEvent(
+							error_type='BrowserProcessCrashed',
+							message=f'Browser process {proc.pid} has crashed',
+							details={'pid': proc.pid, 'status': proc.status()},
+						)
+					)
+					await self._stop_monitoring()
+					return
+			except Exception:
+				pass  # psutil not available or process doesn't exist
+
+	@staticmethod
+	def _is_new_tab_page(url: str) -> bool:
+		"""Check if URL is a new tab page."""
+		return url in ['about:blank', 'chrome://new-tab-page/', 'chrome://newtab/']