context - WithDeadline() vs WithTimeout()

Question

以下代码：

// 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来发送定时器的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()有何不同

Answer 1

WithTimeout是执行WithDeadline(parent, time.Now().Add(timeout))的一个方便函数。

这些功能在应用程序指定截止日期的方式上有所不同。否则它们是一样的。

调用适用于手头值的函数。

Answer 2

How上下文。WithTimeout((与上下文不同。带截止日期((

第一个需要一段时间才能从现在开始取消，第二个需要一个绝对的时间才能调用取消，如文档中所述，值得像往常一样阅读。