IPC primitives improvements

- Rename the `Client` to `Channel`
- Add better `__repr__()`
- use laddr, raddr instead of sockaddr, peer
- don't allow re-entrant `Channel.connect()` calls
- Make `Channel` an async iterable

piker/ipc.py

@@ -1,13 +1,13 @@
 """
 Inter-process comms abstractions
 """
-from typing import Coroutine
+from typing import Coroutine, Tuple
 
 import msgpack
 import trio
 
 from .log import get_logger
-log = get_logger('broker.core')
+log = get_logger('ipc')
 
 
 class StreamQueue:
@@ -15,30 +15,41 @@ class StreamQueue:
     """
     def __init__(self, stream):
         self.stream = stream
-        self.peer = stream.socket.getpeername()
         self._agen = self._iter_packets()
+        self._laddr = self.stream.socket.getsockname()[:2]
+        self._raddr = self.stream.socket.getpeername()[:2]
+        self._send_lock = trio.Lock()
 
     async def _iter_packets(self):
         """Yield packets from the underlying stream.
         """
-        unpacker = msgpack.Unpacker(raw=False)
+        unpacker = msgpack.Unpacker(raw=False, use_list=False)
         while True:
             try:
                 data = await self.stream.receive_some(2**10)
                 log.trace(f"Data is {data}")
             except trio.BrokenStreamError:
-                log.error(f"Stream connection {self.peer} broke")
+                log.error(f"Stream connection {self.raddr} broke")
                 return
 
             if data == b'':
-                log.debug("Stream connection was closed")
+                log.debug(f"Stream connection {self.raddr} was closed")
                 return
 
             unpacker.feed(data)
             for packet in unpacker:
                 yield packet
 
+    @property
+    def laddr(self):
+        return self._laddr
+
+    @property
+    def raddr(self):
+        return self._raddr
+
     async def put(self, data):
+        async with self._send_lock:
             return await self.stream.send_all(
                 msgpack.dumps(data, use_bin_type=True))
 
@@ -49,25 +60,48 @@ class StreamQueue:
         return self._agen
 
 
-class Client:
-    """The most basic client.
+class Channel:
+    """A channel to actors in other processes.
 
     Use this to talk to any micro-service daemon or other client(s) over a
-    TCP socket managed by ``trio``.
+    a transport managed by ``trio``.
     """
     def __init__(
-        self, sockaddr: tuple,
-        on_reconnect: Coroutine,
-        auto_reconnect: bool = True,
-    ):
-        self.sockaddr = sockaddr
+        self,
+        destaddr: tuple = None,
+        on_reconnect: Coroutine = None,
+        auto_reconnect: bool = False,
+        stream: trio.SocketStream = None,  # expected to be active
+    ) -> None:
         self._recon_seq = on_reconnect
         self._autorecon = auto_reconnect
-        self.squeue = None
+        self.squeue = StreamQueue(stream) if stream else None
+        if self.squeue and destaddr:
+            raise ValueError(
+                f"A stream was provided with local addr {self.laddr}"
+            )
+        self._destaddr = destaddr or self.squeue.raddr
 
-    async def connect(self, sockaddr: tuple = None, **kwargs):
-        sockaddr = sockaddr or self.sockaddr
-        stream = await trio.open_tcp_stream(*sockaddr, **kwargs)
+    def __repr__(self):
+        if self.squeue:
+            return repr(
+                self.squeue.stream.socket._sock).replace(
+                        "socket.socket", "Channel")
+        return object.__repr__(self)
+
+    @property
+    def laddr(self):
+        return self.squeue.laddr if self.squeue else (None, None)
+
+    @property
+    def raddr(self):
+        return self.squeue.raddr if self.squeue else (None, None)
+
+    async def connect(self, destaddr: Tuple[str, int] = None, **kwargs):
+        if self.squeue is not None:
+            raise RuntimeError("channel is already connected?")
+        destaddr = destaddr or self._destaddr
+        stream = await trio.open_tcp_stream(*destaddr, **kwargs)
         self.squeue = StreamQueue(stream)
         return stream
 
@@ -77,21 +111,25 @@ class Client:
     async def recv(self):
         try:
             return await self.squeue.get()
-        except trio.BrokenStreamError as err:
+        except trio.BrokenStreamError:
             if self._autorecon:
                 await self._reconnect()
                 return await self.recv()
 
     async def aclose(self, *args):
         await self.squeue.stream.aclose()
+        self.squeue = None
 
     async def __aenter__(self):
-        await self.connect(self.sockaddr)
+        await self.connect()
         return self
 
     async def __aexit__(self, *args):
         await self.aclose(*args)
 
+    async def __aiter__(self):
+        return self.aiter_recv()
+
     async def _reconnect(self):
         """Handle connection failures by polling until a reconnect can be
         established.
@@ -109,13 +147,15 @@ class Client:
                 else:
                     log.warn("Stream connection re-established!")
                     # run any reconnection sequence
-                    await self._recon_seq(self)
+                    on_recon = self._recon_seq
+                    if on_recon:
+                        await on_recon(self)
                     break
             except (OSError, ConnectionRefusedError):
                 if not down:
                     down = True
                     log.warn(
-                        f"Connection to {self.sockaddr} went down, waiting"
+                        f"Connection to {self.raddr} went down, waiting"
                         " for re-establishment")
                 await trio.sleep(1)
 
@@ -126,9 +166,15 @@ class Client:
             try:
                 async for item in self.squeue:
                     yield item
-            except trio.BrokenStreamError as err:
+                    # sent = yield item
+                    # if sent is not None:
+                    #     # optimization, passing None through all the
+                    #     # time is pointless
+                    #     await self.squeue.put(sent)
+            except trio.BrokenStreamError:
                 if not self._autorecon:
                     raise
+            self.squeue = None
             if self._autorecon:  # attempt reconnect
                 await self._reconnect()
                 continue