go | 易学教程

what is the golang equivalent of a Java synchronized() block?

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问题 Java provides a very convenient idiom for synchronizing critical portions of code: synchronized(someObject) { // do something really important all by myself with nobody bothering me } Or public synchronized void doSomething() { // ... } What is the go equivalent? (A quick search reveals: golang.org/pkg/sync/ - which seems (maybe I'm wrong) a bit too low level for general use.) (Example of why I care about this: I need to send a message to multiple listeners via channels. Channels provide a

How to set bool pointer to true in struct literal?

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问题 I have the function below which accepts a bool pointer. I'm wondering if there is any notation which allows me to set the value of the is field to true in the struct literal; basically without to define a new identifier (i.e. var x := true ; handler{is: &x} ) package main import "fmt" func main() { fmt.Println("Hello, playground") check(handler{is: new(bool) }) } type handler struct{ is *bool } func check(is handler){} 回答1: You can do that but it's not optimal: h := handler{is: &[]bool{true}

Zip a byte array in Go

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问题 I am trying to take a chunk of bytes and compress them using the archive/zip package in Go. However, I can't understand it at all. Are there any examples of how it could be done and is there any explanation of that cryptic package? 回答1: Thanks to jamessan I did find the example (which doesn't exactly catch your eye). Here is what I come up with as the result: func (this *Zipnik) zipData() { // Create a buffer to write our archive to. fmt.Println("we are in the zipData function") buf := new

百度分布式配置中心BRCC正式开源

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“ 2021年02月，百度分布式配置中心BRCC，正式开源！” 01. 什么是BRCC BRCC（better remote config center）是一个分布式配置中心，用于统一管理应用服务的配置信息，避免各类资源散落在各个项目中，简化资源配置的维护成本。作为一种轻量级的解决方案，部署简单，同时支持多环境、多版本、多角色的资源管理，可以在不改变应用源码的情况下无缝切换和实时生效配置信息。 02. 技术架构 BRCC由三部分组成：管理端、服务端、SDK，其中： 1）管理端 : 前后端分离，后端基于Spring Boot 2.0开发，支持6个维度（产品、工程、环境、版本、分组、配置项）管理key-value格式的配置；支持细粒度的权限控制层级、操作轨迹等能力。安全易用，支持插件化的扩展轻松集成任何公司/组织的账号管理系统。 2）服务端：基于spring boot 2.0开发，打包后可以直接运行，支持配置的分发、更新推送。 3）SDK：支持java、go等多种开发语言和开发框架集成，支持spring注解、配置变更监听和刷新，零业务侵入性，低门槛集成（提供spring boot starter方式接入）。 03. 特性 1）统一管理不同环境、不同产品线的配置 BRCC提供统一界面集中式管理不同环境、不同产品线、不同工程的配置通过版本的复制，可以高效的完成新业务的配置 2

RTMP协议视频平台EasyDSS编译过程中Go语言异步信息处理设计与实现

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在EasyDSS开发过程中，有此种场景：Go模块通过http请求获取C模块的信息，然后将信息保存到数据库中。基本流程如下：该种模式一般称为同步处理，将收到的结果写入到数据库完毕后才会进行下一次的http请求。但是实际情况下，下一次的http请求，和上一次的结果是可以并发进行的。即以上模型可以优化为： 1.第一步：发送第一次 http 请求 A ，获取 A 的结果 2.第二步：并发执行以下两个步骤： 1）将 A 的结果写入到数据库中 2）发出第二次的 http 请求 B 因为第二步是并发执行，就节省了一段时间，属于异步处理，比最开始的同步执行速度更快，以下介绍如何实现该功能。首先全部创建一个通道，用于处理 http 请求的结果。 var ( // 处理响应的进程 gProcessSpaceChan = make(chan vs.Group, 20) ) 然后编写处理请求结果的函数，该函数是阻塞读取 gProcessSpaceChan 通道中的数据，只要有数据则写入到数据库中。 // 处理收到http结果 func progressSpacesResponse() { // 收到 group 信息, 写入到数据库中 for group := range gProcessSpaceChan { space := &table.Space{} space.CopyData(&group

Break out of select loop?

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问题 I'm trying to use a select in a loop to receive either a message or a timeout signal. If the timeout signal is received, the loop should abort: package main import ("fmt"; "time") func main() { done := time.After(1*time.Millisecond) numbers := make(chan int) go func() {for n:=0;; {numbers <- n; n++}}() for { select { case <-done: break case num := <- numbers: fmt.Println(num) } } } However, it doesn't seem to be stopping: $ go run a.go 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

How do I debug a program written in the Go language?

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问题 How do I debug a Go program? I have been using the Gedit Go IDE, but it doesn't have debugging. Is there a way to step though my code and inspect memory? Or am I stuck with print statements? Can I use OutputDebugString? 回答1: Update : There is now an official page in the docs on Debugging Go Code with GDB. Much has changed since this answer was written, and several of the limitations listed below have been removed. I'm leaving the rest of this answer for posterity, but if you want to debug Go

How do I debug a program written in the Go language?

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Is there an efficient way to concatenate strings

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问题 For example, there is a function like that: func TestFunc(str string) string { return strings.Trim(str," ") } It runs in the example below: {{ $var := printf "%s%s" "x" "y" }} {{ TestFunc $var }} Is there anyway to concatenate strings with operators in template ? {{ $var := "y" }} {{ TestFunc "x" + $var }} or {{ $var := "y" }} {{ TestFunc "x" + {$var} }} It gives unexpected "+" in operand error. I couldnt find it in documentation (https://golang.org/pkg/text/template/) 回答1: There is not a way

Is there an efficient way to concatenate strings

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