The Incredible Growth of Python (stackoverflow.blog)

[Michael Torrie]

On 09/11/2017 02:35 AM, Chris Angelico wrote:
> Do a quick poll here on the list. Who sees async functions as an
> alternative to Twisted? Who here has even *used* Twisted? (How many
> even know what it is?)

/me raises hand, slowly, cautiously looking around.  I don't think of
twisted so much as an alternative to threading, but rather a way of
doing event-driven programming with I/O, which does work well as an
alternative to threading.  This model actually fits really well with
protocol implementations. For example in http, each request can be an
"event" that the Twisted stack can process.  When using the LDAP
protocol adapter, each request type can be an event (ADD, MODIFY,
DELETE, etc).

As I understand it, Twisted now runs in conjunction with the new async
stuff.  Apparently you can use both traditional callback style Twisted
programming and the new async stuff together in one program.  And rather
than replace Twisted, the new async core in Python can actually drive
Twisted.

The problem with Twisted is it's really, really hard for a beginner to
mentally trace the execution of code, particularly when you're using an
existing protocol adapter class as your base.  Took me about two weeks
to fully understand the Twisted LDAP server example.

Does the new Async facility in Python make it easier to trace program
flow and logic?

> Personally, I think of them as an alternative to threading. Basically
> they're a way to use the code style of threaded I/O (functions that
> block when they need to read from a socket etc) with the light-weight
> efficiency of doing everything in one thread. I have never used
> Twisted.

If you ever want to do I/O and run a GUI at the same time, Twisted is
probably going to remain your best bet since it integrates tightly with
the major GUIs' event loops.