Context canceled golang I'm fairly new to Go but I'm struggling to find the root cause of what could be causing the context to be canceled and where exactly it may be being canceled. ctx, cancel := context. Using context in such a way is actually strongly recommended to act as a back-pressure mechanism so that the server doesn’t perform unnecessary tasks when clients cancel the request (for whatever reason). Implementing Context Cancellation: Typically, a parent context is May 2, 2021 · That message usually means that the client went away, before the request was fully processed and therefore the rest of the processing was cancelled. Comments in the thread bring up some very valid concerns with this pattern beyond the caveats I cover below, but ultimately the feature is now part of the Go 1. This tutorial also teaches how to terminate outstanding web requests which were cancelled by the client. 7, the context package provides us a way to deal with context in our application. >95% of context usages should only pass it on to other functions, or wrap it with context. docker: Error response from daemon: network xxx not found. I see the benefits in terms of cancelling from the parent as well as sharing context-specific stuff (loggers, for ex Dec 17, 2024 · 文章浏览阅读3k次。博客讨论了Go语言中Context的使用，特别是在微服务框架中的超时处理。当Context超时时，其Done通道会被关闭，导致协程终止。通过示例代码展示了即使尝试通过WithTimeout延长超时时间，也无法避免协程因父Context超时而被取消。为了解决这个问题，提出了创建不受原Context超时影响的 Feb 6, 2022 · Why does golang concurrent uploading of files to S3 bucket result in canceled, context deadline exceeded Asked 3 years, 6 months ago Modified 3 years ago Viewed 4k times May 10, 2021 · Context cancelation is not magic - it's just a signal mechanism. Millisecond) defer cancel() // Create a channel complete. Canceled error which would unwrap to the cause error to assure that err == context. Jul 30, 2020 · 30 July 2020 Break The Golang Context Chain And enabling a context to be used after cancellation Go 1. Apr 29, 2023 · Learn how to cancel long running tasks in Go using context cancellation and timeout. 7, is a powerful and essential tool for managing and controlling the lifecycle of goroutines and managing request-scoped values, deadlines, and Oct 26, 2023 · I understand that originally ctx. (This is mostly a copy-paste from a golang-sql post, as requested by @ Apr 29, 2023 · Go 1. Mar 23, 2023 · How to handle and send "cancellation signals" using the context package in the standard library. Request and this contains the standard library context. Mar 10, 2025 · This article will show you how to implement timeouts effectively using Go's built-in concurrency primitives Jun 18, 2024 · If you want a context to be cancelled after a certain amount of time, you can always use context. Jul 19, 2018 · We see these a fair amount “http: proxy error: context canceled” This is a golang net lib error, appears to be due to the client prematurely severing the connection prior to the tyk proxy being complete in proxying the request? Could this be related to a simple timeout? Any settings in tyk we could tweak to possibly reduce these? The returned context's Done channel is closed 235// when the returned cancel function is called or when the parent context's 236// Done channel is closed, whichever happens first. Nov 27, 2024 · In Go (Golang), managing timeouts and cancellations in concurrent programming is crucial for creating efficient and responsive applications. go 文件总共不到 500 行，其中还有很多大段的注释，代码可能也就 200 行左右的样子，是一个非常值得研究的代码库。 先看一张整体的图： 类型 名称 作用 Context 接口 定义了 Context 接口的四个方法 emptyCtx 结构体 实现了 Context 接口，它其实是个空的 context CancelFunc 函数 Sep 23, 2024 · Currently this is not the case, so telling apart whether a process was killed because the context was canceled, or because of an external signal, is not possible. If you place a print in that function, you will see it in the terminal, even after the context being cancelled. Nov 8, 2017 · I have this simple code in which I try to check if the request was cancelled. Canceled continues to work. Context for controlling cancellation in Golang HTTP servers. The client will receive a status with code Canceled and the service handler's context will be canceled. When a Context is canceled, all Contexts derived from it are also canceled. Background() function creates a background context, serving as the root of any context tree. 7 sometimes it gives context canceled Nov 27, 2024 · The Go programming language, also known as Golang, is designed for building fast, scalable, and concurrent applications. WithCancel is also useful for canceling redundant requests when using multiple replicas. It also means I have to wait up to a second for it to respond to a context being canceled. Err could not return an context. Does it result in a new HTTP request to the server communicating the context of the previous/ongoing gRPC request is canceled? Jul 10, 2023 · Photo by Ono Kosuki Understanding the Context Package: The context package in Go provides a consistent mechanism for sending signals of cancellation and setting deadlines across API boundaries. agnihotry. Optionally, pass some authentication checks, for example, using Redis AUTH Jul 5, 2020 · The problem with this approach is that despite the request being cancelled, the doSomethingContext will still be executed. g. Do function somewhere, or at least that's the stdlib function that's being called from my own code. Oct 29, 2024 · 背景 我们 项目 中使用 web框架 是gin框架，数据库orm使用的是gorm的框架。最近项目中，偶尔会报一些context canceled的错误，这个错误很容易理解，当context取消时，并且监听了上下文的Done信号，并且以error的方式抛出，就会报这样的错误。关于context的这个作用机制，我在《golang中的上下文》这篇文章中 Dec 18, 2024 · http请求如有野生协程，不能使用request context（因为response之后context就会被cancel掉了），应当使用独立的context（比如 context. WithTimeout, but seeing as you're wanting to do some cleanup when the context is cancelled (e. Important Use Cases of Context Request-Scoped Data: An example of request-scoped data would be the body, headers, or params of an API request. com/post/understanding_the_context_package_in_golang/ The article states the following regarding context cancelation functions in go: Sep 25, 2019 · gRpc stream server gets conext canceled rpc error in streamServerInstance. WithTimeout or context. Request options allow you to easily configure and augment how the SDK makes API operation requests to AWS services. Context value or a done channel. Furthermore, it shows you how to implement it if you want to keep the process but want to introduce Timeout in it. But surprisingly, it prints false instead of true in go 1. Context times out, it returns DeadlineExceeded. Background()） Mar 17, 2021 · I'm relatively new to Golang and am trying to incorporate Contexts into my code. Context is cancelled, it returns Canceled. I think the value of context cancellation is, when it's invisible. I recently came across the following article in a blog: http://p. Jun 16, 2025 · Deep-dive into Golang's context package to manage cancellation, timeouts, deadlines, and request-scoped data across goroutines with practical examples and best practices. Here are some common ways: Background Context The context. Dec 13, 2024 · Instead, the context is canceled as soon as we start processing the request. These functions supports propagating the given… Unlock efficient concurrency in Golang applications using the Context package, a fundamental concept for building scalable systems. That is a feature, not a bug. closing some channels or whatever), the answer is simple: yes, you can keep doing things after you've read <-ctx. After which, it blocks all requests to other endpoints as well. Just use it like a normal request afterwards. 21 Update: Apparently alongside me writing this article, the Go project was tracking this very same issue. WithTimeout`创建子Context时，一旦父Context取消或超时，所有基于该Context的 Goroutine 都会收到`context canceled`错误。 Learn how to use context. 0 release adds support for the API operation request functional options, and the Context pattern. Apr 23, 2023 · Is there a reasonable solution to this problem other than setting a low timeout and checking the value of context manually? Seems like we don't have a choice but to poll which defeats the purpose of the blocking pop. Verify that your network connection is stable and there are no issues with internet connectivity to ensure proper network context 包的代码并不长，context. 20 introduced two new functions in the contex package: WithCancelCause and Cause . Context, in *pb. Basically do not create a context tree like below Only the parent goroutine or function should be able to cancel the context. Perform TLS handshake using the new connection. Background as parent. It's not the goroutine that being leaked but the child context. Body after request's context was cancelled and get context cancelled error, but only sometimes and only when response body is long I am making a request with Nov 9, 2023 · failed to solve: Canceled: context canceled I tried: -restarting docker -restarting my computer -reinstalling docker -killed all containers -deleted all containers, images, volumes Apr 26, 2022 · I’ve read other posts (Error : "Context canceled" and "Context deadline exceed" and Error encountered context canceled while in goroutine) explaining that if a client leaves before the request is complete, it will cancel database operations to reduce load. Why not use status. * functions or putting it in an errgroup or a similar abstraction. Consider this simple example: client := re May 7, 2021 · I am guessing checking ctx. WithTimeout and in calls to the CancelFunc returned by context. 5 it worked as expected. Learn essential Golang techniques for managing context cancellation signals, improving concurrency control and resource management in complex Go applications. Oct 21, 2022 · 7 I am trying to understand how Go context cancellation works underneath in client service communication (say, any gRPC API call ). However, when an application is … Feb 7, 2021 · Golang Context is a tool that is used to share request-scoped data, cancellation signals, and timeouts or deadlines across API layers or processes in a program. Context has been introduced, I've understood it such that a canceled context should cause an immediate return from a function. It allows for the propagation of request-scoped values and signals across API boundaries and goroutines. 8. Canceled? Jan 19, 2022 · When the Go driver detects that a context is cancelled, I think it will idle the connection and return it to the pool. Jul 22, 2018 · 1 I get this error when the network doesn't exist. A Context with a deadline is canceled after the deadline passes. 358 // 359 // If the request Context has a nil Done channel (which 360 // means it is either context. WithCancel. Dec 7, 2020 · Your Question While I was running this transaction with gorm@V1. Context was cancelled. Mar 28, 2023 · What's the possibilities of getting context canceled while trying to run multiple tabs in a browser on NewRemoteAllocator inside docker #1290 Jan 25, 2024 · I am trying to create a web admin dashboard, using Typescript with redux-saga fro frontend and for backend Docker, Golang, Postgres as &quot;main&quot; db and Redis to store access tokens; I follow Jul 6, 2024 · In Go, the context package is like a Swiss Army knife for managing cancellation, deadlines, and request-scoped values across API boundaries and goroutines. Incoming requests to a server should create a Context, and outgoing calls to servers should accept a Context. If so, then how can the Err function report the reason for the termination of the operation? The godoc says "Err returns Canceled if the context was canceled" So if cancel must always be called to release resources, Err will always return a value of Canceled. WithCancel`或`context. Context should record a bit of caller information (say, the PC of the immediate calling function) in context. Then we could add a debugging hook to interrogate why a particular context. Nov 26, 2024 · A Guide to Graceful Shutdown in Go with Goroutines and Context In Go (Golang), managing concurrency through goroutines is a fundamental part of many applications. Del when I expect it to complete when I'm interrupting the program #2948 Unanswered NorseGaud asked this question in Q&A 239K subscribers in the golang community. Recv() function which leads to the stram connection getting dropped between the server and Apr 21, 2017 · When clients prematurely abandon a proxied HTTP request, there is no identified cause other than "context canceled". Jun 15, 2020 · If you are using go routines, if the parent go routine finishes but child routine still runs in the background, and the child go routine had a context which is common to the parent go routine this can end up in a context cancelled, if the parent go routine cancels the context before exiting. To abort work, you still need to monitor the state of the context from within your worker goroutine: Nov 9, 2023 · Hello team! Thank you for your work! I have following code which tries to understand whether client is cancelled request and it works well func (s *server) SayHello(ctx context. ERRO[0000] error waiting for container: context canceled It's quite easy to miss the output line after a long docker command and before the red error message. WithContext passing a context with a deadline or that will be canceled otherwise. Hell Jan 9, 2025 · Gist of Go: Context This is a chapter from my book on Go concurrency, which teaches the topic from the ground up through interactive examples. Aug 30, 2022 · Since context. Nov 26, 2024 · The context package in Go is an essential toolkit for managing request-scoped data, cancellations, and deadlines. Dec 23, 2021 · 项目中没有发现 cancel context 的代码，那么 context canceled 的错误是哪里来的？ 特别说明，这里讨论的 context 是指 gin Context 中的 Request Context Jul 12, 2018 · I wonder if context. Context is canceled when we use it within goroutine for doing async task (so this task can be executed after the reply to http client that doing request on gin This doesn't seem to be true anymore? I did some tests, the goroutine will be normally released. Dec 29, 2021 · Context Cancellation in Go Dec 29, 2021 development golang context In Go, we can use context to send cancellation signals to goroutines that is doing some work. Nov 11, 2021 · net/http: setting Timeout in http. Learn how to leverage Golang context for efficient HTTP request management, timeout handling, and request cancellation in modern web applications. Background ()） Jun 29, 2023 · context canceled errors on Go web servers because requests cancelled by the browser Jul 29, 2014 · WithCancel and WithTimeout return derived Context values that can be canceled sooner than the parent Context. Overview of the context Package The context package helps you Jul 4, 2023 · The Complete Guide to Context in Golang: Efficient Concurrency Management Introduction Concurrency is a fundamental aspect of Go programming, and effectively managing concurrent operations is Sep 8, 2024 · 一、背景 在工作中，因报警治理标准提高，在报警治理的过程中，有一类context cancel报警渐渐凸显出来。 目前context cancel日志报警大致可以分为两类。 context deadline exceeded 耗时长 有明确报错原因 context canceled 耗时短 无明确报错原因 分布在各个接口 之前因为不了解原因，所以一遇到这类报警，统一 May 6, 2025 · 在Golang开发中，`context canceled`错误常因父Context被取消或超时导致。 例如，当使用`context. Ask questions and post articles about the Go programming language and related tools, events etc. org/src/context/context. I'm quite certain it's within the httpclient. What version of Go are you using (go version)? go version go1. May 31, 2022 · Description With gin v1. Dec 2, 2024 · Learn how to implement cancelable functions in Golang using the Context package for more efficient and scalable programming practices. Context is canceled when we use it within goroutine for doing async task (so this task can be executed after the reply to http client that doing request on gin Feb 4, 2025 · If the context. It was originally designed to make working with HTTP Feb 25, 2022 · This proposal addresses issue #26356 by extending package context with new functions for writing and reading the "cause" of the context's cancelation. To troubleshoot and address this issue, follow these steps: Check Network Connectivity. Body after request's context was cancelled and get context cancelled error, but only sometimes and only when response body is long I am making a request with Oct 28, 2025 · Cancellation This example shows how clients can cancel in-flight RPCs by canceling the context passed to the RPC call. go Dec 23, 2019 · Make sure in mind that context can only be canceled once, hence, therefore, deriving from already cancellation context using WithCancel (), WithTimeout () and WithDeadline () should be avoided. It is one of the most important tools while working with concurrent programming in Go. Learn practical implementation, best practices, and real-world examples. I'd probably default to StatusBadRequest, or make one up in the 4xx range. Background or a new context with context. go#L370 so they seem identical, given a closed context will always have Err set. This Request field is of the type *http. A problem here is that the context may have been canceled by something other than the client, though that's uncommon. The Context associated with an incoming request is typically canceled when the request handler returns. The following snippet would Nov 22, 2024 · In Go programming, the context package is widely used to manage deadlines, cancellations, and other request-scoped values across API boundaries and go-routines. Can you check if there is some timeout configured for those requests and if that can be increased? Jun 6, 2022 · TLDR: Using r. If that is the case base the background task either on context. Carry cancellation information: e. kubernetes, docker, prometheus, containerd - from eyeballing it, some are checking the error from the http client call - so maybe it's worth it to provide compatibility in this sense 🤔 - Or mention this change in the release note. This Code below (taken from Ardan labs) gives an example of cancelling a context: package main import ( "context" "fmt" "time" ) type data struct { UserID string } func main() { // Create a context that is both manually cancellable and will signal // a cancel at the specified duration. Apr 3, 2017 · The AWS SDK for Go v1. Client produces unexpected "context canceled" on body. I wonder what's the correct way to check that? package m Oct 17, 2024 · Dive deep into Go's context package, exploring its core components, key use cases, and best practices. Cause(sleep) which returns context deadline exceeded in case of timeout or context canceled if the sleep/parent context is canceled with cancel(). If the context. Mar 3, 2022 · Introduction ⌗ The context package in Go provides a mechanism to prevent the application from doing unnecessary work, hence preserving resources. Nov 20, 2021 · 7 I have been reading some articles on the use of the context package from golang. (in other words, it isn't blocking/waiting for your context to cancel) You can use a Context to set a timeout or deadline after which an operation will be canceled. In Go, context usually refers to the Context interface from the context package. Both of these features were high demand requests from our users. The context in go it used for following purposes: Carry deadline information: e. Without canceling the context, all child contexts will remain in memory until the parent context is canceled. An HTTP request gets its own context that is cancelled when the request is finished. Context, similar to the get method of a map. In programming, context refers to information about the environment in which an object exists or a function executes. The package provides background information. Aug 10, 2024 · I have a service that uses context cancelation by design to stop any previous process if the other/newest one is coming. It provides a standardised way to pass contextual information and control the lifecycle of operations, especially when dealing with concurrency and long-running tasks. The way I make a span is exactly similar to the any example from the instrum If the request contains 355 // a Context that carries a cancellation signal, don't 356 // bother spinning up a goroutine to watch the CloseNotify 357 // channel (if any). Does that imply the running DB operation that it started will also be killed o Nov 11, 2021 · net/http: setting Timeout in http. Err () is safe for concurrent-access https://golang. The chain of function calls between them must propagate the Context, optionally replacing it with a derived Context created using WithCancel, WithDeadline, WithTimeout, or WithValue. go run server/main. As part of Mar 27, 2024 · Getting context canceled from Client. Mar 30, 2022 · Context deadline exceeded When context is cancelled, go-redis and most other database clients (including database/sql) must do the following: Close the connection, because it can't be safely reused. Oct 21, 2025 · From Go 1. I see this same expectation in almost all source code I Nov 30, 2022 · I want to prevent iterations from continuing if the context was cancelled to prevent memory leaks. WithTimeout(context. Type of Context that stands in for a Context that can be canceled and has a Deadline. 0, the gin. Dec 18, 2024 · 问题描述 生产环境数据库日志有大量报错内容为 context canceled 的记录。 排查步骤 根据报错日志，定位到报错 context canceled 发生在集中在ORM提交事务之前的DDL方法； 报错处业务场景: 服务为B/S架构，数据同步页面后端服务使用golang-Goframe框架开发，数据库为PostgreSQL，服务业务逻辑为首次进入数据同步 Aug 2, 2021 · How to know if a context has been cancelled? In a following sample code, There are 2 tasks. Context (as long as cancellation Jan 2, 2023 · This post explains how to use Context for the process cancellation or timeout. . The way I make a span is exactly similar to the any example from the instrum Apr 29, 2021 · The server returning a codes. Nov 5, 2025 · Package context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes. Developers are expected to use it and gracefully shutdown execution when the request is interrupted by client or timeout. Context. It is this context. Because reading off a channel that isn't cancelled is blocking, how do I add this where the comment lives? Mar 13, 2019 · You can use context. Canceled status is not the same as context cancelation, and we can't distinguish the two from the status package. 20 onwards, the context package provides a new function to create cancellable contexts with explicit causes: We should take advantage of this improvement to be polite and provide an explicit cause when cancelling a context. 20. Context() works fine in production, testing using Browser is a problem. Code(err) == codes. For example, a cancelled request can mean that client never see the Jun 11, 2018 · FrozenDueToAge NeedsInvestigationSomeone must examine and confirm this is a valid issue and not a duplicate of an existing one. Nov 20, 2024 · A comprehensive guide to Efficient Error Handling with Golang's Context Package. This tutorial will walk you through how to effectively use the context package to level up your Go applications. If any of these tasks completes first, I want to know in other tasks through context cancel. The SDK’s support for the Context pattern […] May 7, 2023 · The context deadline exceeded error appears around the 9th request and will appear 1 second later. Does it result in a new HTTP request to the server communicating the context of the previous/ongoing gRPC request is canceled? Nov 26, 2024 · The context package in Go is an essential toolkit for managing request-scoped data, cancellations, and deadlines. 21 changeset as context Feb 4, 2025 · If the context. This is even worse than not having the timeout at all, because when the request is cancelled, the app answers back to the user saying it did nothing, but in fact The current strategy is to use http. Perhaps something along the lines of: Nov 23, 2024 · Learn Golang's Context package with real-world examples, use cases, and practical implementations Go by Example: ContextNext example: . This context is never canceled, making it suitable for the main execution flow. Let's say a client canceled the context on its end. And also bear in mind what I quoted earlier about request context cancellation: For incoming server requests, the [request] context is canceled when the ServeHTTP method returns. Anyone have a nicer solution? May 25, 2020 · 7 Function calls and goroutines cannot be terminated from the caller, the functions and goroutines have to support the cancellation, often via a context. Oct 14, 2018 · When your code reaches the select, it enters the default case because the context is not yet cancelled, where it sleeps for 15 seconds and then returns, breaking your loop. Close #49521 Closed tim-oster opened this issue on Nov 11, 2021 · 1 comment Jan 10, 2019 · How can I create a copy (a clone if you will) of a Go context that contains all of the values stored in the original, but does not get canceled when the original does? It does seem like a valid us Jan 16, 2023 · How to terminate database query using context in Go One of Go’s best features is the ability to cancel database queries while they are still running via context. Context is a type that has a field called Request. Oct 21, 2022 · I was receiving a “context canceled” error is received in go when there is a timeout from client side/client cancels request before its completed. Jan 25, 2024 · I am trying to create a web admin dashboard, using Typescript with redux-saga fro frontend and for backend Docker, Golang, Postgres as &quot;main&quot; db and Redis to store access tokens; I follow Jul 6, 2024 · In Go, the context package is like a Swiss Army knife for managing cancellation, deadlines, and request-scoped values across API boundaries and goroutines. Context and checking if it is cancelled is one of the best way to handle the goroutines. Is(err, context. Done(). Apr 11, 2021 · In testcase-2 when sum func sleeps for 4 secs, context is already cancelled by timeout after 2secs, why is it still executing the sum func in diff go-routine and printing print from sum fn: 1 ? Aug 18, 2023 · I try to read from response. Go's context package provides a way to manage these gracefully through a unified interface for Not just that the request context actually has a timeout and you're trying to use it for a background task spawned by the request? If so that would get cancelled once the request context times out / deadline is reached. " This implies to me that it must always be called. But when I upgraded it to gorm@V1. Context that is responsible for propagating cancellations through your code. 1 darwin/amd64 W Nov 24, 2023 · In golang, the best practice for goroutines is to know when they should exit and passing context. One of its most effective tools for handling concurrency is the context package, which allows you to manage deadlines, Nov 15, 2025 · GORM’s context support is a powerful feature that enhances the flexibility and control of database operations in Go applications. Background, or a custom 361 // Context implementation with no cancellation Apr 29, 2021 · The server returning a codes. cancel the current task after a given timestamp. Close #49521 Closed tim-oster opened this issue on Nov 11, 2021 · 1 comment Nov 22, 2019 · After eagerly testing out the newest v7 Beta, I stumbled across an odd issue, when using contexts in conjunction with blocking operations (such as BRPop). Apr 16, 2024 · The *gin. 9. None of the conditions listed under the docs for func (*Request) Context are true: For incoming server requests, the context is canceled when the client's connection closes, the request is canceled (with HTTP/2), or when the ServeHTTP method returns. Therefore do not pass the cancelFunc to downstream goroutines or functions Jun 30, 2024 · The context package in Go, introduced in Go 1. WithDeadline. Value: Retrieves the value corresponding to the key from the context. In either case, the functions are responsible to check / monitor the context, and if cancel is requested (when the Context's done channel is closed), return early. Aug 13, 2025 · When a context is canceled, either through a direct cancel function or by reaching a deadline, that signal moves through a chain of linked contexts to reach every goroutine that is listening. The Done method in context returns a channel that acts as a cancellation signal to goroutines using the given context. Any thoughts on this? Mar 17, 2025 · Though I think the checking of errors. Jul 5, 2023 · How to use Go's context package to make faster and more robust applications. Explore request-scoped values, deadlines, and cancellation signals across API boundaries and goroutines. Learn how to effectively manage cancellation, deadlines, and request-scoped values in your Go applications, while avoiding common pitfalls and misconceptions. go go run client/main. This approach is similar to what was proposed Jan 4, 2025 · Typical causes The "context deadline exceeded" typically indicates that a network operation or a request to an external service took longer than the expected deadline to complete. Jan 10, 2019 · How can I create a copy (a clone if you will) of a Go context that contains all of the values stored in the original, but does not get canceled when the original does? It does seem like a valid us Jan 16, 2023 · How to terminate database query using context in Go One of Go’s best features is the ability to cancel database queries while they are still running via context. It allows for context management across different operational modes, t Jan 6, 2024 · Creating a Context Contexts in Golang are created using various functions from the context package. Open a new connection. 237// 238// Canceling this context releases resources associated with it, so code should 239// call cancel as soon as the operations running in this [Context Jun 20, 2019 · Go: Context and Cancellation by Propagation Introduced in 1. Apr 20, 2020 · When doing background-processing in a different goroutine, bear in mind that if a parent context is canceled, the cancellation signal 'bubbles down' to its children. Canceled? A Context may be canceled to indicate that work done on its behalf should stop. when a user has exited the website, stop any operations that were initiated http请求中如果启动了协程，并且在 response 之前不能结束的，不能使用 request context （因为 response 之后 context 就会被 cancel 掉了），应当使用独立的 context （比如 context. Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. Therefore, if we want to change how these cancellations propagate, we need to modify this context. Request. Canceled) is quite common, e. For the same context, multiple calls to Value with the same key will return the same result. Background(), 150*time. To derive a Context with a timeout or deadline, call context. Learn how to use Go’s context for cancellation: propagate cancel signals across goroutines, avoid leaks with defer cancel, and write resilient handlers.