From 87a6165430062104fe1dcf42040830af629b62c5 Mon Sep 17 00:00:00 2001
From: Tyler Goodlet <tgoodlet@gmail.com>
Date: Sat, 12 Jan 2019 14:31:17 -0500
Subject: [PATCH] Add a `Context` type for task/protocol RPC state

This is loosely based off the nanomsg concept found here:
https://nanomsg.github.io/nng/man/v1.1.0/nng_ctx.5
---
 tractor/__init__.py |  2 +-
 tractor/_ipc.py     | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/tractor/__init__.py b/tractor/__init__.py
index d8d6489..5ffcfd5 100644
--- a/tractor/__init__.py
+++ b/tractor/__init__.py
@@ -11,7 +11,7 @@ import trio  # type: ignore
 from trio import MultiError
 
 from .log import get_console_log, get_logger, get_loglevel
-from ._ipc import _connect_chan, Channel
+from ._ipc import _connect_chan, Channel, Context
 from ._actor import (
     Actor, _start_actor, Arbiter, get_arbiter, find_actor, wait_for_actor
 )
diff --git a/tractor/_ipc.py b/tractor/_ipc.py
index f7bebbe..41b8061 100644
--- a/tractor/_ipc.py
+++ b/tractor/_ipc.py
@@ -205,6 +205,28 @@ class Channel:
         return self.squeue.connected() if self.squeue else False
 
 
+class Context:
+    """An IAC (inter-actor communication) context.
+
+    Allows maintaining task or protocol specific state between communicating
+    actors. A unique context is created on the receiving end for every request
+    to a remote actor.
+    """
+    def __init__(
+        self,
+        channel: Channel,
+        command_id: str,
+    ):
+        self.chan: Channel = channel
+        self.cid: str = command_id
+
+    async def send_yield(self, data):
+        await self.chan.send({'yield': data, 'cid': self.cid})
+
+    async def send_stop(self):
+        await self.chan.send({'stop': True, 'cid': self.cid})
+
+
 @asynccontextmanager
 async def _connect_chan(
     host: str, port: int