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Questions tagged [async]

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How to structure your Python code with asynchronous and synchronous parts

I have a Python FastAPI server application which naturally guides you towards the asynchronous paradigm. For legacy reasons, I have to support two backends, one which is purely synchronous and one ...
user3058865's user avatar
1 vote
0 answers
54 views

golang: pattern for handling message queues? Are named functions anti-idiomatic somehow?

Had a discussion today in how to implement services that work with messages coming in from event queues. We call these services processors. One of us argues for using several functions, while the ...
Albert Balbastre-Morte's user avatar
0 votes
0 answers
51 views

Single-threaded request-response type server architecture

I'm writing an internet service in Rust that works more or less like an HTTP-server, just without the HTTP part, and strictly over UDP. I also have a requirement to build it like an old-school game of ...
laggyfrog's user avatar
0 votes
0 answers
56 views

React Design - Parent / Child Interaction with Async State

I have a situation involving a parent component, children, and async fetch operations, and I am wondering how to best structure it. The current code structure I have is as follows: I have a parent ...
713sean's user avatar
  • 131
0 votes
0 answers
44 views

Synchranization issue in async jobs created and finished before main thread ends

Main execution thread creates asynchronous job (started and executed by different process) that works on same data that the main thread. For example we create some database entries, that we want to ...
Taavi Ilves's user avatar
2 votes
2 answers
336 views

What are the risks in eliminating sync over async?

I'm reviewing changes to a widely used library, which are supposed to be refactorings, and so we want to minimize the risk of introducing any accidental regression. Of course, there are changes from ...
Tim Lovell-Smith's user avatar
5 votes
1 answer
3k views

Should web API controller actions that perform no async work always be declared as async?

I have been going over our app web api and making sure all async work is async all the way - and no artificial asynchronicity is enforced. Say I have the following web api controller: [HttpGet] ...
Veverke's user avatar
  • 451
0 votes
1 answer
162 views

Bubbling errors upstream in async message-based services

Imagine a simple set up of an API and a 2nd service, where the API pushes some msgs to the message queue and the service pulls them and processes them. Now, if an error occurs while processing a msg, ...
Milkncookiez's user avatar
0 votes
1 answer
420 views

How to optimize average rating calculation in a review system?

I'm thinking of a designing a review system (restaurant, hotel etc) where users can drop star reviews. Typically in a such a application, you can see the average rating of an entity along with all ...
Ahmed Sadman Muhib's user avatar
1 vote
1 answer
106 views

How should I handle routine health checks in a Node.js/Nest.js application?

I have a Nest.js application, and lately I've been thinking about how I can ensure that data is synchronized between two sources - my database and an external database. For example - and to my ...
Michael Jay's user avatar
0 votes
1 answer
236 views

Can resource which requires asynchronous cleanup be constructed synchronously?

More specifically this applies only to resources which have asynchronous dependencies themselves (but I think that's majority of them). Concrete example: class Foo : IAsyncDisposable { public ...
Shadow's user avatar
  • 361
45 votes
6 answers
26k views

In JavaScript, how is awaiting the result of an async different than sync calls?

I'm having a hard time wrapping my head around the use of async/await and regular sync function calls in JavaScript. Let's say I have two functions: Function 1: async function doSomething() { ...
noblerare's user avatar
  • 1,321
0 votes
3 answers
187 views

Critical section with two different "rights of way" [closed]

In C#, how do I handle critical section with two different "rights of way"? Theoretical use case: imagine a swimming pool (the resource). Many individual swimmers (worker threads A, B, C, ...
Yann's user avatar
  • 119
4 votes
1 answer
380 views

Share models between AsyncAPI and RESTful APIs?

What I try to solve: Given I run a set of microservices, most of which expose a RESTful API and additionally publish or consume events via messaging broker, and I have decided to go "API first&...
observer's user avatar
  • 157
0 votes
1 answer
82 views

Long-running jobs in an event-driven environment with constrained max-execution-duration

Hello we have an async event-driven system (kotlin, spring cloud stream, rabbitmq) where there might be an event FooPayloadArrived, published by an ingress rest-controller. Processing this ...
hotzen's user avatar
  • 115
4 votes
1 answer
387 views

Could the async keyword be eliminated in a new programming language?

This post implies that the creators of Rust had to add the "async" keyword to make the async/await functionality backward compatible. Why do we need the async keyword? In a new language, ...
phil-daniels's user avatar
0 votes
1 answer
710 views

Asynchronous Server in C++

We are looking to develop an asynchronous server in C++. We are coming from C#, which has built-in support for async-await networking. However, with C++ it appears as if it is basically mandatory to ...
lol's user avatar
  • 113
-3 votes
1 answer
178 views

Why isn't JavaScript always async? [duplicate]

In JS, code runs single-threaded, that's why asynchronicity is necessary. I cannot use code like result = someRequest(), instead I need to give it a callback someRequest(resultCallback) or write a ...
phil294's user avatar
  • 179
2 votes
2 answers
359 views

Should I create two synchronous or a single asynchronous rest APIs?

Here is the situation. System A sends the notification as it completes the work items to System B. System A does not know how many items the project consists of. It's just a pass-through system. ...
user1473349's user avatar
1 vote
1 answer
2k views

Measuring async/await overhead

A while ago I read an article stating that overhead of an async/await call was around 50ms. More recently I read an article that it was around 5ms. I was having a discussion about whether we should ...
Ian's user avatar
  • 415
1 vote
3 answers
1k views

Is it bad practice to do additional work in IAsyncEnumerable generator method?

Imagine you have to process each row in a large table. For every single row you have to download some data from a web service and store it in a different database. Loading all rows at once into the ...
stefan's user avatar
  • 13
-3 votes
1 answer
155 views

How does a site API determine the difference between a user and program request in a browser?

So this is in regards to scraping yes; no language in particular. Some sites allow you to see a JSON modal if you pull it directly from a web browser. But, at any notion a program is used, immediately ...
herboren's user avatar
0 votes
2 answers
385 views

Why/When do we need to call an async method from a sync method?

It is my first question here so I hope I'm not doing a mistake. I see a plethora of questions in SO that people ask "how can I call an async method from a sync method?". Given my little ...
Soner from The Ottoman Empire's user avatar
1 vote
1 answer
242 views

C# design for handling a high rate of async network operations that complete with a callback (hundreds per second)

I am working with a message broker technology, to which events will be published (following an "event carried state transfer" architecture) for consumption by other applications. The vendor ...
allmhuran's user avatar
  • 316
1 vote
1 answer
320 views

C#: Should I define methods as async?

I have a C# (WPF) application which consumes a particular 3rd party API/tool (let's call this Tool A). My colleagues and I are trying to decouple that from our application, so that it is possible to ...
Jai's user avatar
  • 113
2 votes
2 answers
983 views

What are the different messaging patterns for multiple producers to single consumer through a distributed queue?

We have multiple producers that publish messages to the same SQS queue. We have a single consumer that processes the messages. The producers do not care about the response. It is more like a broadcast ...
kashive's user avatar
  • 137
-2 votes
1 answer
281 views

Designing a sqlite component in C++

I work on a small component in an embedded device (sensor). This component : Every 5 seconds, sends requests to other components using sockets (get health check status, operating status etc) and ...
psy's user avatar
  • 137
2 votes
1 answer
2k views

Why no async functions for Utf8JsonReader and ReadOnlySequence

I have used Utf8Json a lot (it is very good) but have since adapted some lower level code and started using Utf8JsonReader directly. Looking into the code of the Utf8Json library, I see ...
morleyc's user avatar
  • 345
-2 votes
2 answers
575 views

Async Value Object Creation (DDD)

Suppose that I have a Value Object representing an Image URL of a Cake. To check that it really is a cake, I make an asynchronous API call to a server that checks whether the image really represents ...
Hillel SAAL's user avatar
3 votes
3 answers
1k views

Issues with an interface treating a synchronous action as async

Let's say I'm trying to write a library that abstracts certain actions. In this example I want to turn a light on or off. There could be hundreds of different kinds of lights that are controlled in ...
cost's user avatar
  • 171
0 votes
1 answer
82 views

Organizing Parallel Arrays of Promises / Async tasks

I'm struggling a bit for a preferred way to organize a sequence of asynchronous tasks that can be applied in parallel. Say, you are parsing data from many files. In my case I'm using javascript and ...
user949300's user avatar
  • 8,859
4 votes
3 answers
1k views

How does an hexagonal architecture help with async/await async-over-sync?

In his book "Concurrency in C# Cookbook", Stephen Cleary writes: If you can, try to organize your code along modern design guidelines, like Ports and Adapters (Hexagonal Architecture), which ...
D.R.'s user avatar
  • 231
4 votes
1 answer
1k views

Difference Between AsyncResult and Task in c#

So, in C#, I understand the historical difference between the two vaguely; a Task is a newer concept and the highest level concurrency native C# offers. AsyncResult is a bit more ambiguous. For ...
gabriel.hayes's user avatar
0 votes
2 answers
148 views

What is the best practice for incorporating asynchronous code in this case?

Context: I'm building a popup widget. The html and css files are stored in S3. I need to get those files asynchronously and then continue with the rest of the logic. In the code below, I'm getting ...
EnterPassword's user avatar
5 votes
1 answer
1k views

Implementing both Sync and Async clients with DRY

I'm developing a client library. I'd like to provide both Sync and Async interfaces to endpoints on a server. They would be rather easy to implement as completely separate entities, but I would like ...
Felix's user avatar
  • 377
0 votes
1 answer
2k views

Unit testing async tcp server

I built an async multi-client TCP server for RPC usage. It's working well but I've found it difficult to unit test certain functionality: Connect 2x clients, is client count 2 Connect 1x ...
Naxin's user avatar
  • 111
5 votes
2 answers
4k views

How do JavaScript engines convert async/await to promises under the hood?

I'm curious how the async/await syntax is converted to Promises. Maybe I'm just not thinking about it properly, but I don't know how this code would be converted to a Promise: async function myFunc(...
dx_over_dt's user avatar
1 vote
1 answer
285 views

How is an async stack implemented?

I am working on creating a simple VM sort of thing in JS: let sp = 0 // stack pointer let m = [] // memory initialize: sp = 0 invoke: m[sp] = m[sp - 1] // position in stack m[sp + 1] = input[m[...
Lance's user avatar
  • 2,611
0 votes
0 answers
66 views

Streaming Promises in NodeJS

Imagine a typical HTTP service that does async db queries. If HTTP requests are received more quickly than the db can complete queries (such as because the db disk or network is slow), the Promises ...
squarewav's user avatar
  • 206
1 vote
0 answers
39 views

Using TPL to manage hundreds of contexts

Overview of application: A chat bot that connects via IRC, using TPL. As messages come from the socket (from .ReadAsync()), they are ultimately parsed and passed to a handler within the bot itself (...
Blue's user avatar
  • 89
18 votes
3 answers
32k views

How to justify using await instead of .Result() or .Wait() in .NET Core?

Since the inception of .NET Core, console apps, function apps, ASP.NET etc. are not using synchronization context in async methods (so they're synchronizing straight to Thread Pool). This means that ...
kor_'s user avatar
  • 289
3 votes
1 answer
450 views

Isn't asynchronicity an implementation detail?

Consider a simple — and fake — interface: interface ISuperGetter { Super Get(); } An implementation would get some Super from RAM. One would store what it needs on disk. Yet another could fetch the ...
user avatar
2 votes
2 answers
145 views

Name of locking approach

I've seen this approach several times, both in async and multithreaded code. A counter is used to track asynchronous behavior or thread behavior - whenever a new action is started, the counter is ...
Dan Monego's user avatar
6 votes
3 answers
4k views

Why is it necessary for every new api to be async?

I'm expressing my frustration here somewhat, but why do many new libraries only have asynchronous APIs? For example I'm creating a small utility to fetch a web page and parse some data from it. ...
spirc's user avatar
  • 280
6 votes
2 answers
823 views

balance between UI responsiveness and avoiding race conditions

To keep scope small I will talk about UI race conditions initiated by the same user in the same app sessions. The question is general and not specific to mobile, web or desktop UI. The issue Modern ...
KolA's user avatar
  • 615
0 votes
1 answer
162 views

I'm writing an application that needs to log error/ exception messages but should still continue execution if it not a fatal error

I'm writing an application that needs to log error/ exception messages but should still continue execution if the error is not a fatal error. I was thinking of making a method that returns a Task but ...
BipinR's user avatar
  • 163
13 votes
1 answer
8k views

Is the C# async/Task construct equivalent to Java's Executor/Future?

I'm a long time Java developer, but with so little traffic on SE, I don't limit my viewing to any single tags. I've noticed that C# questions with async/await come up a lot, and as far as I've read it'...
Kayaman's user avatar
  • 1,960
0 votes
1 answer
3k views

Async - why have an async for a login?

C# web scaffolding has an async call for every member. Why? For example: Async for a login call makes no sense. User has to wait for validation. What else would the app do until the application ...
J Armbruster's user avatar
2 votes
1 answer
491 views

Must we define methods and async when we don't know whether the implementation is synchronous or asynchronous?

I think I know the answer to this, but it's particular enough that I don't want to go telling other people stuff until I'm 100% certain. Suppose I have a class with some dependency: public interface ...
Scott Hannen's user avatar
  • 1,034
0 votes
0 answers
754 views

Using signalR for streaming alongside a microservice architecture

I have a cluster of micro services with an exposed search API serving a client app. I want to "stream" in real time the aggregated results of a complex search. The search will be kicked of by the ...
cookee89's user avatar