Question

下面的代码：

// Sample program to show how to use the WithDeadline function
// of the Context package.
package main

import (
    "context"
    "fmt"
    "time"
)

type data struct {
    UserID string
}

func main() {

    // Set a duration.
    // duration := 150 * time.Millisecond
    duration := time.Now().Add(3 * time.Second)

    // Create a context that is both manually cancellable and will signal
    // a cancel at the specified duration.
    ctx, cancel := context.WithDeadline(context.Background(), duration)
    defer cancel()

    // Create a channel to received a signal that work is done.
    ch := make(chan data, 1)
    // Ask the goroutine to do some work for us.
    go func() {

        // Simulate work.
        time.Sleep(50 * time.Millisecond)

        // Report the work is done.
        ch <- data{"123"}
    }()

    // Wait for the work to finish. If it takes too long move on.
    select {
    case d := <-ch:
        fmt.Println("work complete", d)
    case <-ctx.Done():
        fmt.Println("work cancelled")
    }
}

正在使用WithDeadline发送计时器发送的cancel()。可以使用以下方法完成：

duration := 150 * time.Millisecond

// Create a context that is both manually cancellable and will signal
// a cancel at the specified duration.
ctx, cancel := context.WithTimeout(context.Background(), duration)

在内部，context.WithTimeout调用context.WithDeadline函数并通过将超时添加到当前时间来生成截止日期。

context.WithTimeout()与context.WithDeadline()的区别

Answer 1

WithTimeout是执行WithDeadline(parent, time.Now().Add(timeout))的便捷功能。

功能在应用程序指定截止日期的方式方面有所不同。否则它们是相同的。

调用适合您现有值的函数。

Answer 2

context.WithTimeout（）与context.WithDeadline（）有何不同

第一个需要一段时间才能从现在开始取消，第二个是调用取消的绝对时间，如文档中所述，值得照常阅读。

上下文-WithDeadline（）vs WithTimeout（）

2 个答案: