From b463841019255ab801616b9c4744e6fd8c0b3247 Mon Sep 17 00:00:00 2001
From: Tyler Goodlet <jgbt@protonmail.com>
Date: Fri, 10 Dec 2021 13:48:41 -0500
Subject: [PATCH] Add infected `asyncio` echo server example

---
 examples/infected_asyncio_echo_server.py | 90 ++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 examples/infected_asyncio_echo_server.py

diff --git a/examples/infected_asyncio_echo_server.py b/examples/infected_asyncio_echo_server.py
new file mode 100644
index 0000000..aeda42c
--- /dev/null
+++ b/examples/infected_asyncio_echo_server.py
@@ -0,0 +1,90 @@
+'''
+An SC compliant infected ``asyncio`` echo server.
+
+'''
+import asyncio
+from statistics import mean
+import time
+
+import trio
+import tractor
+
+
+async def aio_echo_server(
+    to_trio: trio.MemorySendChannel,
+    from_trio: asyncio.Queue,
+) -> None:
+
+    # a first message must be sent **from** this ``asyncio``
+    # task or the ``trio`` side will never unblock from
+    # ``tractor.to_asyncio.open_channel_from():``
+    to_trio.send_nowait('start')
+
+    # XXX: this uses an ``from_trio: asyncio.Queue`` currently but we
+    # should probably offer something better.
+    while True:
+        # echo the msg back
+        to_trio.send_nowait(await from_trio.get())
+
+
+@tractor.context
+async def trio_to_aio_echo_server(
+    ctx: tractor.Context,
+):
+    # this will block until the ``asyncio`` task sends a "first"
+    # message.
+    async with tractor.to_asyncio.open_channel_from(
+        aio_echo_server,
+    ) as (first, chan):
+
+        assert first == 'start'
+        await ctx.started(first)
+
+        async with ctx.open_stream() as stream:
+
+            async for msg in stream:
+                await chan.send(msg)
+
+                out = await chan.receive()
+                # echo back to parent actor-task
+                await stream.send(out)
+
+
+async def main():
+
+    async with tractor.open_nursery() as n:
+        p = await n.start_actor(
+            'aio_server',
+            enable_modules=[__name__],
+            infect_asyncio=True,
+        )
+        async with p.open_context(
+            trio_to_aio_echo_server,
+        ) as (ctx, first):
+
+            assert first == 'start'
+
+            count = 0
+            async with ctx.open_stream() as stream:
+
+                delays = []
+                send = time.time()
+
+                await stream.send(count)
+                async for msg in stream:
+                    recv = time.time()
+                    delays.append(recv - send)
+                    assert msg == count
+                    count += 1
+                    send = time.time()
+                    await stream.send(count)
+
+                    if count >= 1e3:
+                        break
+
+        print(f'mean round trip rate (Hz): {1/mean(delays)}')
+        await p.cancel_actor()
+
+
+if __name__ == '__main__':
+    trio.run(main)