Asynchronous Equivalencies

main.py

# NOTE: won't run, just an example 

# in all cases, we're trying to get to "# hooray"

# asynchronous via Twisted's callbacks

from wherever import bar, baz 

def foo():
    
    df = bar()
    bar.addCallback(success_bar)
    bar.addErrback(fail_bar)
    
    
def success_bar(result):
    
    df = baz(result)
    baz.addCallback(success_baz)
    baz.addErrback(fail_baz)


def fail_bar(failure):
    pass


def success_baz(result):
    # hooray
    pass


def fail_baz(failure):
    pass


# asynchronous via Twisted's inlineCallbacks

from twisted.internet.defer import inlineCallbacks as asynchronous 

@asynchronous 
def foo():
    
    try:
        result = yield bar()
        result = yield baz(result)
        # hooray
    except Exception as ex:
        pass
    

# asynchronous via asyncio (Python 3)

async def foo():
    
    try:
        result = await asyncio.ensure_future(bar())
        result = await asyncio.ensure_future(baz(result))
        # hooray
    except Exception as ex:
        pass
    
    
# asynchronous via asyncio futures (aka deferreds)

def foo():
    
    future = asyncio.ensure_future(bar())
    future.add_done_callback(done_bar)
    
    
def done_bar(future):
    
    try:
        result = future.result()
        future = asyncio.ensure_future(baz(result))
        future.add_done_callback(done_baz)
    except Exception as ex:
        pass
    
def done_baz(future):
    
    try:
        result = future.result()
        # hooray
    except Exception as ex:
        pass