Go language study notes - dealing with timeout problems - Context usage | Go language from scratch

Study notes, where to write.

I recently looked at the use of the go language Context and found it very magical and convenient.

Speaking of context, when I was learning golang, I saw that many libraries were used. In short, context can handle the interaction between multiple goroutines.Similar to other languages, you may need to define a thread-safe object yourself, and use thread-safe objects to implement the interaction between multiple threads.Golang directly has a default package context, which can save the process of defining each time, which is very convenient.

I won't go into details about the use of Context, there are many online.

This article mainly uses context to implement the processing of a timeout scenario.

demo1

First use the context.WithTimeout method to implement timeout processing.

The code is as follows:

package mainimport ("context""fmt""time")func handle() {//build timeout context_ctx, _cancel := context.WithTimeout(context.Background(), 5*time.Second)go work(_ctx)time.Sleep(6 * time.Second)_cancel()}//Workfunc work(ctx context.Context) {for {time.Sleep(1 * time.Second)select {case <-ctx.Done():fmt.Println("work done")default:fmt.Println("working")}}}func main() {handle()}

Code Description

1. Build a context with a 5-second timeout and pass it into the goroutine, and the work method polls the context status.

Execution results

demo2

First use the context.WithDeadline method to implement timeout processing.

The code is as follows:

package mainimport ("context""fmt""time")func handle1() {//build timeout context_ctx, _cancel := context.WithDeadline(context.Background(), time.Now().Add(5*time.Second))go work1(_ctx)time.Sleep(6 * time.Second)_cancel()}// job 1func work1(ctx context.Context) {for {time.Sleep(1 * time.Second)if _deadline, _a := ctx.Deadline(); _a {if time.Now().After(_deadline) {fmt.Println("after deadline")break}}select {case <-ctx.Done():fmt.Println("work done")default:fmt.Println("working")}}}func main() {handle1()}

Code Description

1. Pay attention to the time parameter method behind WithDeadline, which is different from WithTimeout.

2. Here, before the rotation training, judge whether the current time has exceeded the deadline, and if it exceeds, it will jump out directly.

Execution results

Summary

There are still many uses of context, which need to be used more in the project and share more feelings in the future.