Add zeroconf host resolver

aioesphomeapi/client.py

@@ -87,8 +87,8 @@ def _bytes_to_varuint(value: bytes) -> Optional[int]:
     return None
 
 
-async def resolve_ip_address(eventloop: asyncio.events.AbstractEventLoop,
+async def resolve_ip_address_getaddrinfo(eventloop: asyncio.events.AbstractEventLoop,
-                             host: str, port: int) -> Tuple[Any, ...]:
+                                         host: str, port: int) -> Tuple[Any, ...]:
     try:
         res = await eventloop.getaddrinfo(host, port, family=socket.AF_INET,
                                           proto=socket.IPPROTO_TCP)
@@ -103,6 +103,18 @@ async def resolve_ip_address(eventloop: asyncio.events.AbstractEventLoop,
     return sockaddr
 
 
+async def resolve_ip_address(eventloop: asyncio.events.AbstractEventLoop,
+                             host: str, port: int) -> Tuple[Any, ...]:
+    try:
+        return await resolve_ip_address_getaddrinfo(eventloop, host, port)
+    except APIConnectionError as err:
+        if host.endswith('.local'):
+            from aioesphomeapi.host_resolver import resolve_host
+
+            return await eventloop.run_in_executor(None, resolve_host, host), port
+        raise err
+
+
 # Wrap some types in attr classes to make them serializable
 @attr.s
 class DeviceInfo:

aioesphomeapi/host_resolver.py

@@ -0,0 +1,74 @@
+import socket
+import time
+
+import zeroconf
+
+
+class HostResolver(zeroconf.RecordUpdateListener):
+    def __init__(self, name):
+        self.name = name
+        self.address = None
+
+    def update_record(self, zc, now, record):
+        if record is None:
+            return
+        if record.type == zeroconf._TYPE_A:
+            assert isinstance(record, zeroconf.DNSAddress)
+            if record.name == self.name:
+                self.address = record.address
+
+    def request(self, zc, timeout):
+        now = time.time()
+        delay = 0.2
+        next_ = now + delay
+        last = now + timeout
+
+        try:
+            zc.add_listener(self, zeroconf.DNSQuestion(self.name, zeroconf._TYPE_ANY,
+                                                       zeroconf._CLASS_IN))
+            while self.address is None:
+                if last <= now:
+                    # Timeout
+                    return False
+                if next_ <= now:
+                    out = zeroconf.DNSOutgoing(zeroconf._FLAGS_QR_QUERY)
+                    out.add_question(
+                        zeroconf.DNSQuestion(self.name, zeroconf._TYPE_A, zeroconf._CLASS_IN))
+                    out.add_answer_at_time(
+                        zc.cache.get_by_details(self.name, zeroconf._TYPE_A,
+                                                zeroconf._CLASS_IN), now)
+                    zc.send(out)
+                    next_ = now + delay
+                    delay *= 2
+
+                zc.wait(min(next_, last) - now)
+                now = time.time()
+        finally:
+            zc.remove_listener(self)
+
+        return True
+
+
+def resolve_host(host, timeout=3.0):
+    from aioesphomeapi import APIConnectionError
+
+    try:
+        zc = zeroconf.Zeroconf()
+    except Exception:
+        raise APIConnectionError("Cannot start mDNS sockets, is this a docker container without "
+                                 "host network mode?")
+
+    try:
+        info = HostResolver(host + '.')
+        address = None
+        if info.request(zc, timeout):
+            address = socket.inet_ntoa(info.address)
+    except Exception as err:
+        raise APIConnectionError("Error resolving mDNS hostname: {}".format(err))
+    finally:
+        zc.close()
+
+    if address is None:
+        raise APIConnectionError("Error resolving address with mDNS: Did not respond. "
+                                 "Maybe the device is offline.")
+    return address

requirements.txt

@@ -1,2 +1,3 @@
 protobuf
 attrs
+zeroconf>=0.21.3

setup.py

@@ -23,6 +23,7 @@ DOWNLOAD_URL = '{}/archive/{}.zip'.format(GITHUB_URL, VERSION)
 REQUIRES = [
     'attrs',
     'protobuf>=3.6',
+    'zeroconf>=0.21.3',
 ]
 
 setup(