dashboard: refactor ping implementation to be more efficient (#6002)

esphome/dashboard/const.py

@@ -4,5 +4,7 @@ EVENT_ENTRY_ADDED = "entry_added"
 EVENT_ENTRY_REMOVED = "entry_removed"
 EVENT_ENTRY_UPDATED = "entry_updated"
 EVENT_ENTRY_STATE_CHANGED = "entry_state_changed"
+MAX_EXECUTOR_WORKERS = 48
+
 
 SENTINEL = object()

esphome/dashboard/core.py

@@ -8,6 +8,7 @@ from functools import partial
 from typing import TYPE_CHECKING, Any, Callable
 
 from ..zeroconf import DiscoveredImport
+from .dns import DNSCache
 from .entries import DashboardEntries
 from .settings import DashboardSettings
 
@@ -69,6 +70,7 @@ class ESPHomeDashboard:
         "mqtt_ping_request",
         "mdns_status",
         "settings",
+        "dns_cache",
     )
 
     def __init__(self) -> None:
@@ -81,7 +83,8 @@ class ESPHomeDashboard:
         self.ping_request: asyncio.Event | None = None
         self.mqtt_ping_request = threading.Event()
         self.mdns_status: MDNSStatus | None = None
-        self.settings: DashboardSettings = DashboardSettings()
+        self.settings = DashboardSettings()
+        self.dns_cache = DNSCache()
 
     async def async_setup(self) -> None:
         """Setup the dashboard."""

esphome/dashboard/dashboard.py

@@ -1,11 +1,19 @@
 from __future__ import annotations
 
 import asyncio
+import logging
 import os
 import socket
+import threading
+import traceback
+from asyncio import events
+from concurrent.futures import ThreadPoolExecutor
+from time import monotonic
+from typing import Any
 
 from esphome.storage_json import EsphomeStorageJSON, esphome_storage_path
 
+from .const import MAX_EXECUTOR_WORKERS
 from .core import DASHBOARD
 from .web_server import make_app, start_web_server
 
@@ -14,6 +22,95 @@ ENV_DEV = "ESPHOME_DASHBOARD_DEV"
 settings = DASHBOARD.settings
 
 
+def can_use_pidfd() -> bool:
+    """Check if pidfd_open is available.
+
+    Back ported from cpython 3.12
+    """
+    if not hasattr(os, "pidfd_open"):
+        return False
+    try:
+        pid = os.getpid()
+        os.close(os.pidfd_open(pid, 0))
+    except OSError:
+        # blocked by security policy like SECCOMP
+        return False
+    return True
+
+
+class DashboardEventLoopPolicy(asyncio.DefaultEventLoopPolicy):
+    """Event loop policy for Home Assistant."""
+
+    def __init__(self, debug: bool) -> None:
+        """Init the event loop policy."""
+        super().__init__()
+        self.debug = debug
+        self._watcher: asyncio.AbstractChildWatcher | None = None
+
+    def _init_watcher(self) -> None:
+        """Initialize the watcher for child processes.
+
+        Back ported from cpython 3.12
+        """
+        with events._lock:  # type: ignore[attr-defined] # pylint: disable=protected-access
+            if self._watcher is None:  # pragma: no branch
+                if can_use_pidfd():
+                    self._watcher = asyncio.PidfdChildWatcher()
+                else:
+                    self._watcher = asyncio.ThreadedChildWatcher()
+                if threading.current_thread() is threading.main_thread():
+                    self._watcher.attach_loop(
+                        self._local._loop  # type: ignore[attr-defined] # pylint: disable=protected-access
+                    )
+
+    @property
+    def loop_name(self) -> str:
+        """Return name of the loop."""
+        return self._loop_factory.__name__  # type: ignore[no-any-return,attr-defined]
+
+    def new_event_loop(self) -> asyncio.AbstractEventLoop:
+        """Get the event loop."""
+        loop: asyncio.AbstractEventLoop = super().new_event_loop()
+        loop.set_exception_handler(_async_loop_exception_handler)
+
+        if self.debug:
+            loop.set_debug(True)
+
+        executor = ThreadPoolExecutor(
+            thread_name_prefix="SyncWorker", max_workers=MAX_EXECUTOR_WORKERS
+        )
+        loop.set_default_executor(executor)
+        # bind the built-in time.monotonic directly as loop.time to avoid the
+        # overhead of the additional method call since its the most called loop
+        # method and its roughly 10%+ of all the call time in base_events.py
+        loop.time = monotonic  # type: ignore[method-assign]
+        return loop
+
+
+def _async_loop_exception_handler(_: Any, context: dict[str, Any]) -> None:
+    """Handle all exception inside the core loop."""
+    kwargs = {}
+    if exception := context.get("exception"):
+        kwargs["exc_info"] = (type(exception), exception, exception.__traceback__)
+
+    logger = logging.getLogger(__package__)
+    if source_traceback := context.get("source_traceback"):
+        stack_summary = "".join(traceback.format_list(source_traceback))
+        logger.error(
+            "Error doing job: %s: %s",
+            context["message"],
+            stack_summary,
+            **kwargs,  # type: ignore[arg-type]
+        )
+        return
+
+    logger.error(
+        "Error doing job: %s",
+        context["message"],
+        **kwargs,  # type: ignore[arg-type]
+    )
+
+
 def start_dashboard(args) -> None:
     """Start the dashboard."""
     settings.parse_args(args)
@@ -26,6 +123,8 @@ def start_dashboard(args) -> None:
             storage.save(path)
         settings.cookie_secret = storage.cookie_secret
 
+    asyncio.set_event_loop_policy(DashboardEventLoopPolicy(settings.verbose))
+
     try:
         asyncio.run(async_start(args))
     except KeyboardInterrupt:

esphome/dashboard/dns.py

@@ -0,0 +1,43 @@
+from __future__ import annotations
+
+import asyncio
+import sys
+
+from icmplib import NameLookupError, async_resolve
+
+if sys.version_info >= (3, 11):
+    from asyncio import timeout as async_timeout
+else:
+    from async_timeout import timeout as async_timeout
+
+
+async def _async_resolve_wrapper(hostname: str) -> list[str] | Exception:
+    """Wrap the icmplib async_resolve function."""
+    try:
+        async with async_timeout(2):
+            return await async_resolve(hostname)
+    except (asyncio.TimeoutError, NameLookupError, UnicodeError) as ex:
+        return ex
+
+
+class DNSCache:
+    """DNS cache for the dashboard."""
+
+    def __init__(self, ttl: int | None = 120) -> None:
+        """Initialize the DNSCache."""
+        self._cache: dict[str, tuple[float, list[str] | Exception]] = {}
+        self._ttl = ttl
+
+    async def async_resolve(
+        self, hostname: str, now_monotonic: float
+    ) -> list[str] | Exception:
+        """Resolve a hostname to a list of IP address."""
+        if expire_time_addresses := self._cache.get(hostname):
+            expire_time, addresses = expire_time_addresses
+            if expire_time > now_monotonic:
+                return addresses
+
+        expires = now_monotonic + self._ttl
+        addresses = await _async_resolve_wrapper(hostname)
+        self._cache[hostname] = (expires, addresses)
+        return addresses

esphome/dashboard/settings.py

@@ -14,7 +14,19 @@ from .util.password import password_hash
 class DashboardSettings:
     """Settings for the dashboard."""
 
+    __slots__ = (
+        "config_dir",
+        "password_hash",
+        "username",
+        "using_password",
+        "on_ha_addon",
+        "cookie_secret",
+        "absolute_config_dir",
+        "verbose",
+    )
+
     def __init__(self) -> None:
+        """Initialize the dashboard settings."""
         self.config_dir: str = ""
         self.password_hash: str = ""
         self.username: str = ""
@@ -22,8 +34,10 @@ class DashboardSettings:
         self.on_ha_addon: bool = False
         self.cookie_secret: str | None = None
         self.absolute_config_dir: Path | None = None
+        self.verbose: bool = False
 
     def parse_args(self, args: Any) -> None:
+        """Parse the arguments."""
         self.on_ha_addon: bool = args.ha_addon
         password = args.password or os.getenv("PASSWORD") or ""
         if not self.on_ha_addon:
@@ -33,6 +47,7 @@ class DashboardSettings:
             self.password_hash = password_hash(password)
         self.config_dir = args.configuration
         self.absolute_config_dir = Path(self.config_dir).resolve()
+        self.verbose = args.verbose
         CORE.config_path = os.path.join(self.config_dir, ".")
 
     @property

esphome/dashboard/status/ping.py

@@ -1,20 +1,20 @@
 from __future__ import annotations
 
 import asyncio
-import os
+import logging
+import time
 from typing import cast
 
+from icmplib import Host, SocketPermissionError, async_ping
+
+from ..const import MAX_EXECUTOR_WORKERS
 from ..core import DASHBOARD
-from ..entries import DashboardEntry, bool_to_entry_state
+from ..entries import DashboardEntry, EntryState, bool_to_entry_state
 from ..util.itertools import chunked
-from ..util.subprocess import async_system_command_status
 
+_LOGGER = logging.getLogger(__name__)
 
-async def _async_ping_host(host: str) -> bool:
+GROUP_SIZE = int(MAX_EXECUTOR_WORKERS / 2)
-    """Ping a host."""
-    return await async_system_command_status(
-        ["ping", "-n" if os.name == "nt" else "-c", "1", host]
-    )
 
 
 class PingStatus:
@@ -27,6 +27,10 @@ class PingStatus:
         """Run the ping status."""
         dashboard = DASHBOARD
         entries = dashboard.entries
+        privileged = await _can_use_icmp_lib_with_privilege()
+        if privileged is None:
+            _LOGGER.warning("Cannot use icmplib because privileges are insufficient")
+            return
 
         while not dashboard.stop_event.is_set():
             # Only ping if the dashboard is open
@@ -36,15 +40,68 @@ class PingStatus:
             to_ping: list[DashboardEntry] = [
                 entry for entry in current_entries if entry.address is not None
             ]
-            for ping_group in chunked(to_ping, 16):
+
+            # Resolve DNS for all entries
+            entries_with_addresses: dict[DashboardEntry, list[str]] = {}
+            for ping_group in chunked(to_ping, GROUP_SIZE):
                 ping_group = cast(list[DashboardEntry], ping_group)
-                results = await asyncio.gather(
+                now_monotonic = time.monotonic()
-                    *(_async_ping_host(entry.address) for entry in ping_group),
+                dns_results = await asyncio.gather(
+                    *(
+                        dashboard.dns_cache.async_resolve(entry.address, now_monotonic)
+                        for entry in ping_group
+                    ),
                     return_exceptions=True,
                 )
-                for entry, result in zip(ping_group, results):
+
+                for entry, result in zip(ping_group, dns_results):
                     if isinstance(result, Exception):
-                        result = False
+                        entries.async_set_state(entry, EntryState.UNKNOWN)
+                        continue
+                    if isinstance(result, BaseException):
+                        raise result
+                    entries_with_addresses[entry] = result
+
+            # Ping all entries with valid addresses
+            for ping_group in chunked(entries_with_addresses.items(), GROUP_SIZE):
+                entry_addresses = cast(tuple[DashboardEntry, list[str]], ping_group)
+
+                results = await asyncio.gather(
+                    *(
+                        async_ping(addresses[0], privileged=privileged)
+                        for _, addresses in entry_addresses
+                    ),
+                    return_exceptions=True,
+                )
+
+                for entry_addresses, result in zip(entry_addresses, results):
+                    if isinstance(result, Exception):
+                        ping_result = False
                     elif isinstance(result, BaseException):
                         raise result
-                    entries.async_set_state(entry, bool_to_entry_state(result))
+                    else:
+                        host: Host = result
+                        ping_result = host.is_alive
+                    entry, _ = entry_addresses
+                    entries.async_set_state(entry, bool_to_entry_state(ping_result))
+
+
+async def _can_use_icmp_lib_with_privilege() -> None | bool:
+    """Verify we can create a raw socket."""
+    try:
+        await async_ping("127.0.0.1", count=0, timeout=0, privileged=True)
+    except SocketPermissionError:
+        try:
+            await async_ping("127.0.0.1", count=0, timeout=0, privileged=False)
+        except SocketPermissionError:
+            _LOGGER.debug(
+                "Cannot use icmplib because privileges are insufficient to create the"
+                " socket"
+            )
+            return None
+
+        _LOGGER.debug("Using icmplib in privileged=False mode")
+        return False
+
+    _LOGGER.debug("Using icmplib in privileged=True mode")
+    return True

esphome/dashboard/web_server.py

@@ -9,6 +9,7 @@ import hashlib
 import json
 import logging
 import os
+import time
 import secrets
 import shutil
 import subprocess
@@ -302,16 +303,28 @@ class EsphomePortCommandWebSocket(EsphomeCommandWebSocket):
         port = json_message["port"]
         if (
             port == "OTA"  # pylint: disable=too-many-boolean-expressions
-            and (mdns := dashboard.mdns_status)
             and (entry := entries.get(config_file))
             and entry.loaded_integrations
             and "api" in entry.loaded_integrations
-            and (address := await mdns.async_resolve_host(entry.name))
+        ):
+            if (mdns := dashboard.mdns_status) and (
+                address := await mdns.async_resolve_host(entry.name)
             ):
                 # Use the IP address if available but only
                 # if the API is loaded and the device is online
                 # since MQTT logging will not work otherwise
                 port = address
+            elif (
+                entry.address
+                and (
+                    address_list := await dashboard.dns_cache.async_resolve(
+                        entry.address, time.monotonic()
+                    )
+                )
+                and not isinstance(address_list, Exception)
+            ):
+                # If mdns is not available, try to use the DNS cache
+                port = address_list[0]
 
         return [
             *DASHBOARD_COMMAND,

requirements.txt

@@ -1,7 +1,9 @@
+async_timeout==4.0.3; python_version <= "3.10"
 voluptuous==0.14.1
 PyYAML==6.0.1
 paho-mqtt==1.6.1
 colorama==0.4.6
+icmplib==3.0.4
 tornado==6.4
 tzlocal==5.2    # from time
 tzdata>=2021.1  # from time