Async IO Explained with Moon Chat
34sUses a funny analogy about chatting on Jupiter's moon to explain async IO, making a complex topic relatable.
▶ Play ClipAsync IO in Python uses the async and await keywords to enable concurrent execution of tasks that involve waiting, such as I/O operations, HTTP requests, and database calls. By allowing tasks to pause and resume, async IO improves efficiency and reduces overall execution time.
Async IO solves lag in communications, like chatting on Jupiter's moon, by allowing tasks to wait without blocking.
The async and await keywords in Python enable managing a collection of laggy tasks efficiently.
Synchronous code runs tasks one after another; asynchronous code allows tasks to overlap in time.
Subroutines run to completion without pausing; coroutines can be paused and resumed, maintaining state between pauses.
Concurrency overlaps start and stop times of coroutines; parallelism uses multiple threads executing simultaneously.
Create two functions: brew_coffee (3 seconds) and toast_bagel (2 seconds) to simulate concurrent breakfast preparation.
Synchronous code takes 5+ seconds to complete both tasks sequentially.
Add async keyword to functions and await keyword before awaitable commands like asyncio.sleep.
asyncio.gather groups coroutines for concurrent execution; returns results in the same order as arguments.
Alternative to gather: create tasks with asyncio.create_task and await each individually.
Async IO in Python allows efficient concurrent execution of I/O-bound tasks, reducing total time by overlapping waiting periods. The async and await keywords, along with asyncio module functions like gather and create_task, provide powerful tools for concurrency.
"Title accurately describes the content: a tutorial on async/await and concurrency in Python."
What is the difference between synchronous and asynchronous programming?
Synchronous: tasks run one after another. Asynchronous: tasks can start, process, and finish in overlapping time periods.
0:40
What is a coroutine?
A special function that can be paused and resumed, maintaining state between pauses.
2:00
What keywords in Python are used for async programming?
async and await.
3:56
What does the asyncio.gather function do?
It groups coroutines for concurrent execution and returns results in the same order as the arguments.
6:00
How do you get return values from coroutines run with asyncio.gather?
Await the gather call; results are returned in the same order as the coroutines were passed.
6:30
What is the difference between concurrency and parallelism?
Concurrency: overlapping start and stop times of multiple coroutines. Parallelism: different threads execute at the same time.
3:12
What must you do to a function that contains an await keyword?
Declare it with the async keyword.
7:00
How do you run an async main function?
Use asyncio.run(main()).
7:14
What is the alternative to asyncio.gather for running coroutines concurrently?
Use asyncio.create_task for each coroutine and await them individually.
7:43
Can a subroutine be paused and resumed?
No, subroutines run until completion without pausing.
1:57
Synchronous vs Asynchronous
Fundamental distinction between sequential and overlapping task execution.
0:40Coroutines maintain state
Key feature enabling pausing and resuming execution.
2:00Concurrency vs Parallelism
Clarifies two different approaches to resource utilization.
3:12asyncio.gather usage
Practical technique for concurrent execution with ordered results.
6:00create_task alternative
Provides flexibility in managing individual coroutines.
7:43[00:02] when chatting with someone on Jupiter's
[00:03] thirdd largest moon you will notice a
[00:06] distinct lag in Communications that is
[00:08] due to async
[00:14] IO when you try to perform a task that
[00:16] requires a lot of waiting you may notice
[00:19] an annoying lag in execution you can
[00:21] solve this with async IO this module
[00:25] brings the await and async syntax to
[00:27] python this pair of felet words empowers
[00:30] you with the tools to easily manage a
[00:33] collection of laggy
[00:34] tasks sometimes impatience is a
[00:40] virtue code can be categorized as
[00:43] synchronous or
[00:44] asynchronous in synchronous programming
[00:47] tasks are performed one at a time in the
[00:49] order they are called each task must
[00:52] finish before the next one can
[00:54] begin with asynchronous programming
[00:56] however different tasks can start
[00:59] process and finish in overlapping
[01:01] periods of time for example imagine a
[01:04] task that submits many HTTP requests in
[01:08] the synchronous World these HTTP
[01:11] requests must be completed one at a time
[01:14] in the asynchronous world each request
[01:17] can start and be set aside while waiting
[01:19] for a response during this waiting
[01:21] period different tasks can step forward
[01:24] and use the Computing resources this
[01:27] nonlinear approach saves one of the most
[01:29] Val resources around time to better
[01:34] understand the mechanics of synchronous
[01:35] and asynchronous execution you need to
[01:37] learn about sub routines and co-routines
[01:40] a sub routine is a block of code that
[01:42] can be called as needed when a sub
[01:44] routine is called control of the program
[01:47] is transferred to that sub routine when
[01:49] its work is done control is returned
[01:52] back to the main program and execution
[01:54] continues from where it left off sub
[01:57] routines cannot be paused and resumed
[02:00] they run until
[02:02] done a co- routine is a special kind of
[02:05] function that can have its executions
[02:07] paused and resumed this is possible
[02:10] because they maintain their state
[02:12] between pauses co- routines are perfect
[02:15] for tasks that need to wait for
[02:17] something like IO operations database
[02:20] calls and HTTP requests the terms sub
[02:24] routine and co-routine are derived from
[02:27] the roles they play and how they
[02:28] function sub routine is a delightful
[02:31] blend of sub and routine as the name
[02:35] suggests it is a subset of a larger
[02:37] program co- routine is a ju toos of Co
[02:41] and routine Co for together and routine
[02:46] for
[02:47] routine this name was chosen by someone
[02:49] to describe routines that can run
[02:52] cooperatively co-routines are the key
[02:54] ingredient to make asynchronous
[02:56] programming or concurrency possible in
[02:59] in a typical single-threaded app all of
[03:02] the code and sub routines run
[03:04] sequentially this is simple but can be
[03:07] wasteful there are two different
[03:08] approaches that make better use of
[03:10] available Computing resources
[03:12] concurrency and
[03:14] parallelism using concurrency the start
[03:17] and stop times of multiple co- routines
[03:20] can overlap with parallelism different
[03:23] threads can execute at the same time is
[03:27] there going to be any python in this
[03:28] python lesson
[03:30] yes yes there is but before we can enter
[03:34] python mode I must import an important
[03:37] message socratica is now in the course
[03:39] business visit socratic.com to see the
[03:42] excitement for yourself and for an
[03:45] asynchronous update about future courses
[03:47] feverishly type your email address in a
[03:50] text box somewhere on the site now back
[03:54] to python we are now going to show you
[03:56] how to use concurrency in Python with
[03:58] the async and await keywords and the
[04:01] async io
[04:03] module let us create two functions brew
[04:08] coffee and toast
[04:12] Bagel The Brew Coffee function will use
[04:14] the sleep function to simulate a command
[04:17] that takes 3 seconds to complete the
[04:19] toast Bagel function will pretend it
[04:21] takes 2 seconds to complete with this
[04:24] 5-second toasty breakfast the future is
[04:26] fast and
[04:28] carbolicious we will record a start time
[04:31] call both
[04:33] functions record a stop
[04:35] time compute the elaps time and print
[04:38] the
[04:44] results
[04:50] run this code took 5 seconds and a bit
[04:53] more to execute but there is no reason
[04:56] to wait for the coffee to finish before
[04:58] you start toasting the B Bagel such
[05:00] inefficiency gives the secretly embedded
[05:03] AI systems far too much time for
[05:05] Mischief let us modify this code so it
[05:08] runs
[05:09] concurrently with
[05:11] co-routines to turn each function into a
[05:14] co- routine add the async keyword this
[05:18] is the first step but not the last as is
[05:21] evident if you run using the async
[05:24] keyword to make a co- routine is
[05:26] necessary but not sufficient you also
[05:29] need to to specify where in the co-
[05:30] routine it is safe to pause and yield
[05:33] control to other co- routines you do
[05:35] this with the await
[05:38] keyword this brings us to another
[05:40] essential concept you can only put await
[05:43] in front of commands that are awaitable
[05:46] the sleep function is not
[05:48] awaitable luckily the async io module
[05:51] gives you an awaitable version of the
[05:53] sleep
[05:54] function you can call the co- routines
[05:57] individually or in a batch we will first
[06:00] demonstrate the batch approach the async
[06:03] io module has a gather function to group
[06:05] co- routines for concurrent execution
[06:08] the arguments determine which co-
[06:10] routines will run
[06:11] concurrently the arguments may appear to
[06:13] be regular function calls but they are
[06:15] not calling a co-routine returns a
[06:18] co-routine object not a typical return
[06:21] value these co-routine objects give
[06:24] async IO the ability to start and stop
[06:27] their
[06:28] execution to get the return values from
[06:30] the co- routines you need to await them
[06:34] and note that you await the return
[06:35] values in the same order you pass the
[06:37] co- routines to The Gather function
[06:40] order matters and the use of a weight
[06:43] here is not optional after all we have
[06:47] to wait for both co- routines to finish
[06:50] so it only makes sense that we have to
[06:51] wait on the batch too we are so close to
[06:54] the finish line but there is one final
[06:57] step see how we await for the batch
[07:00] results any function that has an await
[07:02] keyword must be declared async this
[07:06] means we must put the async keyword
[07:08] before the main
[07:09] function because main has now become a
[07:12] co-routine we have to call it in a
[07:14] slightly different way the async io
[07:17] module has you covered just call the Run
[07:20] function and pass in the main co-
[07:22] routine now inhale widen your eyes and
[07:28] run
[07:32] Joy of Joys our breakfast was completed
[07:35] in 3 seconds instead of five time saved
[07:39] me
[07:41] happy there is an alternative to using
[07:43] the gather function you can use the
[07:46] create task function in the async io
[07:48] module to create a task out of each co-
[07:52] routine then you can await each co-
[07:54] routine
[07:57] individually run
[08:03] just as fast just as happy so which is
[08:08] better working in batches or with
[08:10] individual tasks it is your choice so
[08:14] Choose Wisely computer chips want to
[08:17] compute that is their singular purpose
[08:19] in life the async io module was built to
[08:23] help chips realize their full potential
[08:26] by adding a pause button to objects you
[08:28] enable them to take turns sharing is
[08:31] caring after all and speaking of sharing
[08:34] many human people ask you to share their
[08:36] videos with as many human people as
[08:38] possible this is not an efficient use of
[08:41] resources instead await the opportunity
[08:44] to yield this video to someone who has
[08:47] finished a task and is thinking about
[08:50] the
[08:54] [Music]
[08:58] future
[09:02] [Music]
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