kandi X-RAY | awaitables Summary
kandi X-RAY | awaitables Summary
awaitables
Support
Quality
Security
License
Reuse
Top functions reviewed by kandi - BETA
Currently covering the most popular Java, JavaScript and Python libraries. See a Sample of awaitables
awaitables Key Features
awaitables Examples and Code Snippets
Community Discussions
Trending Discussions on awaitables
QUESTION
I'm very new to python and I'm trying to implement an API for requesting some data from Interactive Brokers Trader Workstation. I'm using Flask and ib_insync.
Here is my code:
...ANSWER
Answered 2021-Apr-26 at 09:24It appears Flask uses its own internal blocking/callback/threaded model and isn't compatible with Asyncio which this project is built on. Source: https://github.com/erdewit/ib_insync/issues/266
Required behaviour could be implemented using another framework instead of Flask. E.g. Quart.
In the case of using Quart, this code could be rewritten:
QUESTION
using: python 3.8 on windows 10
I am working on a script that runs in a while loop. At the end of the loop I want it to wait for 5 seconds for the user to give input and then restart, or exit if they do not give input.
I've never actually used it before but I assumed asyncio would be useful because it allows for the definition of awaitables. However bringing things together is proving more difficult than I'd anticipated.
...ANSWER
Answered 2021-Feb-10 at 04:58If you look in the docs for keyboard.record it says:
Note: this is a blocking function.
This is why your process didn't end after 5 seconds. It was blocking at keyboard.record('enter', True). If you are going to stick with the keyboard module, what you need to do is create a hook on the 'enter' key. I put a quick demo together with your code:
QUESTION
I have inherited the following:
...ANSWER
Answered 2020-Sep-08 at 18:45std::conjunction is for type traits. std::conjunction...> is a type with a member static bool value = (IsAwaiter::value && ...), where each IsAwaiter is itself expected to be a type trait with its own static bool member value. This is nonsensical when IsAwaiter is a concept, because concepts are not type traits. They are "just" booleans. Use a fold expression.
QUESTION
I am new to asynchronous programming.
My understanding is that it is useful for tasks that run in parallel but have a lot of waiting involved. For example, downloading 10 zip archives and decompressing them can be done in parallel but since the "downloading" part is just waiting time for the CPU, asyncio is a useful concept here. Please correct me if I'm wrong.
All tutorials I have seen follow a similar examplary problem as described above and solve it by creating a bunch of awaitables and then await all of them together. (e.g. by gather)
However, it seems a common requirement to me to start such an async operation, e.g. the download of a file, continue to do other work in parallel until the file is actually needed and then retrieve it. This is basically what "futures" represent.
I don't see how this could be implemented with async functions though. If I wouldn't "await" the call to download_file, then it would not even perform the initial setup and the download would not be started. If I would "await" the call immediately, it would wait for the entire download to finish and I wouldn't be able to do any work in parallel.
The only solution I came up with is to have download_file return an awaitable future. Is that truly the best way? If so, what even is the point of async, if we still have to use objects like futures like we had to before "async" keywords were introduced?
ANSWER
Answered 2020-Aug-26 at 13:53The solution (in asyncio) is to use something like:
QUESTION
I have some code that runs multiple tasks in a loop like this:
...ANSWER
Answered 2020-Aug-25 at 18:34Your can try that tricks, probably it is not good solution:
QUESTION
How to keep a console application open even if all the awaitables finished, but without interrupting other possible awaitables?
I know my question sounds strange but just to explain:
I'm using the Telegram.Bot library and I need to listen to all the incoming updates from telegram. The problem is that as soon as I set the Update Handler the console just closes.
Another thing I have is a request using RestSharp that gets a json from API every x minutes, that does the job done keeping the console alive because I'm using a way to detect console cancelation before interrupting the loop.
Is there another better way of doing what I want?
This is what I'm using for console close listening https://stackoverflow.com/a/22996661/12420972
And I have the exitSystem as a variable for a while loop
...ANSWER
Answered 2020-Apr-28 at 17:28Using while loop will unnecessary waste the CPU cycles, because all you want to do is wait for exit signal. You can wait for a task completion event asynchronously using the the TaskCompletionSource. Below is the code which gives you an idea how to implement it.
QUESTION
import asyncio
import time
async def func():
print('task start')
await asyncio.sleep(10)
print('task end')
async def main():
task1 = asyncio.create_task(func())
task2 = asyncio.create_task(func())
task3 = asyncio.create_task(func())
task4 = asyncio.create_task(func())
s = time.monotonic()
print('main start', time.monotonic() - s)
await task1
print('main continue', time.monotonic() - s)
await task2
print('main continue', time.monotonic() - s)
await task3
print('main continue', time.monotonic() - s)
await task4
print('main end', time.monotonic() - s)
asyncio.run(main())
ANSWER
Answered 2020-Mar-11 at 12:01Your code does what it is supposed to do according to the specification of asyncio, but perhaps you are misunderstanding what a "task" is.
From the docs:
asyncio.create_task(coro, *, name=None)Wrap the coro coroutine into a Task and schedule its execution. Return the Task object.
This means that as you've created 4 tasks at the beginning of your main, they are all scheduled to execute starting at the same time. And so they all print task start together, then print task end together, at which point, all of your awaits instantly fall through as all tasks have completed at the same time (10 seconds later). So finally you see main continue 10.0 3 times.
Try this code, I believe it will have the behavior you are expecting.
QUESTION
I have a list of awaitables that I want to pass to the asyncio.AbstractEventLoop but I need to throttle the requests to a third party API.
I would like to avoid something that waits to pass the future to the loop because in the meantime I block my loop waiting. What options do I have? Semaphores and ThreadPools will limit how many are running concurrently, but that's not my problem. I need to throttle my requests to 100/sec, but it doesn't matter how long it takes to complete the request.
This is a very concise (non)working example using the standard library, that demonstrates the problem. This is supposed to throttle at 100/sec but throttles at 116.651/sec. What's the best way to throttle the scheduling of an asynchronous request in asyncio?
Working code:
...ANSWER
Answered 2019-Nov-30 at 22:34You can do this by implementing the leaky bucket algorithm:
QUESTION
I'm trying to asynchronously get() a list of URLs using python package resuqests_html, similar to the async example in the README using Python 3.6.5 and requests_html 0.10.0.
My understanding is that AsyncHTMLSession.run() is supposed work very much the same as asyncio.gather(): You give it a bunch of awaitables, and it runs all of them. Is that incorrect?
Here's the code I'm trying, which I expect should get the pages and store the responses:
...ANSWER
Answered 2019-Nov-14 at 08:42Am I doing something wrong?
You are not calling asession.run correctly.
asyncio.gather accepts awaitable objects, such as coroutine objects obtained by just calling a coroutine (async) function. asession.run, on the other hand, accepts callables, such as async functions, which it will invoke to produce awaitables. The difference is like between one function that accepts an iterable, and which you could pass e.g. an instantiated generator, and another that accepts a callable that will return an iterable, and which you could pass a generator function itself.
Since your async functions have arguments, you cannot just pass get_link to asession.run; you must use functools.partial or a lambda itself:
QUESTION
I'm new to asyncio. I came across AIOFiles (https://github.com/Tinche/aiofiles) recently and saw in the documentation that it supports 'async with' and 'async for.' I wanted to learn about it but there isn't much good coverage on it besides PEP 492 which doesn't go into too much detail.
Shortcuts to the relevant sections of PEP 492:
https://www.python.org/dev/peps/pep-0492/#asynchronous-context-managers-and-async-with
https://www.python.org/dev/peps/pep-0492/#asynchronous-iterators-and-async-for
I have a number of questions if somebody wouldn't mind answering:
The only discernible benefit of async iterators / context managers I am picking up on is that you can use awaitables in the implementations of their required magic methods. Am I missing something or is that it?
In PEP 492 regarding async context manager, it says "An asynchronous context manager is a context manager that is able to suspend execution in its enter and exit methods." Is this referring to calling coroutines using await?
ANSWER
Answered 2019-Nov-06 at 08:56The only discernible benefit of async iterators / context managers I am picking up on is that you can use awaitables in the implementations of their required magic methods. Am I missing something or is that it?
You're not missing anything, except perhaps the significance of the ability to suspend. Without suspendable magic methods, context managers and iterators would be useless for async work. For example, a regular file object serves as an iterator that produces the lines from the file. For an async file object (or a stream) to provide equivalent functionality, it must be able to await the line to come, and thereby suspend the coroutine that iterates over it. The same applies to a context manager whose entering must establish an async network connection, and so on.
Is [being able to suspend execution] referring to calling coroutines using await?
Using await in an async def is one way to suspend execution. Another option is for __aenter__ etc. to be normal functions that return a custom awaitable that implements its own __await__. PEP 492 describes the functionality from the vantage point of the code that uses the context manager, which must be ready for its magic methods to suspend -- async with must be inside an async def and it will desugar to code that awaits in the appropriate places.
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
Vulnerabilities
No vulnerabilities reported
Install awaitables
Support
Reuse Trending Solutions
Find, review, and download reusable Libraries, Code Snippets, Cloud APIs from over 650 million Knowledge Items
Find more librariesStay Updated
Subscribe to our newsletter for trending solutions and developer bootcamps
Share this Page
