上下文 - WithDeadline() 与 WithTimeout()

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")
    }
}

---

是利用WithDeadline发送timer'd cancel()。这可以使用：

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

有什么context.WithTimeout()不同context.WithDeadline()

Answer 1

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

第一个需要一段时间，之后从现在开始取消，第二个是调用取消的绝对时间，如文档中所述，该文档值得像往常一样阅读。

Answer 2

WithTimeout是一个方便的函数，用于执行WithDeadline(parent, time.Now().Add(timeout)).

这些功能在应用程序指定截止日期的方式上有所不同。否则它们是相同的。

调用适合您手头价值的函数。