… … Stack Traces for Async Code are Unhelpful Threadpool threads: #0 process_file(...) #5 pool.run() #10 __clone … … IO Thread: #0 async_read_some_at(...) #3 ctx Threadpool threads: #0 process_file(...) #5 pool.run() #10 … IO Thread: … #0 async_read_some_at(...) #3 ctx.run() #5 __clone … … Main thread: #0 unifex::sync_wait( … #0 async_read_some_at(...) … #12 unifex::sync_wait(...) #16 main() #19 __libc_start_main() … … Async Stacks are BetterStructured Concurrency Makes Async Stacks Possible

Cheat Sheet - Awaitable 1 struct Awaitable { 2 bool await_ready (); 3 auto await_suspend (std:: coroutine_handle < promise_type >); 4 auto await_resume (); 5 };12/55 Cheat Sheet: Map of Coroutine Land13/55 Task18/55 Threads - A straightforward solution std::future spawn_task () { return std:: async( outer_function ); }18/55 Threads - A straightforward solution main() spawn task()18/55 Threads auto data = co_await async_io (...); co_return IoResult :: from_io_data(data ); }24/55 Suspending nested coroutines Async inner_function () { auto data = co_await async_io (...); co_return

demonstrated to justify switchingCallbacks vs coroutines // read length auto len = make_unique(); async_read(socket, buffer(len.get(), sizeof(int32_t)), [len = move(len)](auto ec, size_t len1){ && len1 == sizeof(int32_t)) { // read data auto buf = make_unique(*len); async_read(socket, buffer(buf.get(), *len), [buf = move(buf), len = *len] (auto // read length int32_t len; co_await async_read(s, buffer(&len, sizeof(len)), use_awaitable); // read data auto buf = make_unique(len); co_await async_read(s, buffer(buf.get(), len)

Reference Router Inspection Information Classes Visitor Classes Utilities URI Date and Time HTTP Status Async Other Testing Helpers Simulating Requests Other Helpers Changelogs 3.0.0 Summary Changes to Supported containers. $ pip install [gunicorn|uwsgi|waitress] ASGI Server Conversely, in order to run an async Falcon ASGI app, you will need an ASGI [https://asgi.readthedocs.io/en/latest/] application server in terms of resources and state # transitions, which map to HTTP verbs. class ThingsResource: async def on_get(self, req, resp): """Handles GET requests""" resp.status = falcon.HTTP_200

Reference Router Inspection Information Classes Visitor Classes Utilities URI Date and Time HTTP Status Async Other Testing Helpers Simulating Requests Other Helpers Changelogs 3.0.1 Summary Fixed Contributors containers. $ pip install [gunicorn|uwsgi|waitress] ASGI Server Conversely, in order to run an async Falcon ASGI app, you will need an ASGI [https://asgi.readthedocs.io/en/latest/] application server in terms of resources and state # transitions, which map to HTTP verbs. class ThingsResource: async def on_get(self, req, resp): """Handles GET requests""" resp.status = falcon.HTTP_200

HTTP error responses Full Unicode support Intuitive request and response objects Works great with async libraries like gevent Minimal attack surface for writing secure APIs 100% code coverage with a comprehensive Reference Router Inspection Information Classes Visitor Classes Utilities URI Date and Time HTTP Status Async Other Testing Helpers Simulating Requests Other Helpers Changelogs 3.0.0 Changes to Supported containers. $ pip install [gunicorn|uwsgi|waitress] ASGI Server Conversely, in order to run an async Falcon ASGI app, you will need an ASGI [https://asgi.readthedocs.io/en/latest/] application server

HTTP error responses Full Unicode support Intuitive request and response objects Works great with async libraries like gevent Minimal attack surface for writing secure APIs 100% code coverage with a comprehensive Reference Router Inspection Information Classes Visitor Classes Utilities URI Date and Time HTTP Status Async Other Testing Helpers Simulating Requests Other Helpers Changelogs 3.0.0 Changes to Supported Falcon on it. $ pip install [gunicorn|uwsgi|waitress] ASGI Server Conversely, in order to run an async Falcon ASGI app, you will need an ASGI [https://asgi.readthedocs.io/en/latest/] application server

import asyncio import websockets async def hello(): uri = "ws://localhost:8765" async with websockets.connect(uri) as websocket: await websocket.send("Hello world!") await websocket.recv() asyncio.get_event_loop() server: #!/usr/bin/env python import asyncio import websockets async def echo(websocket, path): async for message in websocket: await websocket.send(message) start_server = websockets.serve(echo, "localhost" example import asyncio import websockets async def hello(websocket, path): name = await websocket.recv() print(f"< {name}") greeting = f"Hello {name}!" await websocket.send(greeting) print(f"> {greeting}")

”: #!/usr/bin/env python import asyncio import websockets async def hello(uri): async with websockets.connect(uri) as websocket: await websocket.send("Hello world!") asyncio.get_event_loop().run_until_complete( server: #!/usr/bin/env python import asyncio import websockets async def echo(websocket, path): async for message in websocket: await websocket.send(message) asyncio.get_event_loop().run_until_complete( example import asyncio import websockets async def hello(websocket, path): name = await websocket.recv() print(f"< {name}") greeting = f"Hello {name}!" await websocket.send(greeting) print(f"> {greeting}")

”: #!/usr/bin/env python import asyncio import websockets async def hello(uri): async with websockets.connect(uri) as websocket: await websocket.send("Hello world!") asyncio.get_event_loop().run_until_complete( server: #!/usr/bin/env python import asyncio import websockets async def echo(websocket, path): async for message in websocket: await websocket.send(message) asyncio.get_event_loop().run_until_complete( example import asyncio import websockets async def hello(websocket, path): name = await websocket.recv() print(f"< {name}") greeting = f"Hello {name}!" await websocket.send(greeting) print(f"> {greeting}")