go | 易学教程

云原生｜KubeVela

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在互联网与云计算技术发展的日新月异过去五年中，应用研发人员对效率与敏捷的极致追求，终于把业界带进了一个崭新的云原生时代。而云原生理念的迅速普及，火了 Docker，红了 Kubernetes ，也间接让一个编程语言成为了如今服务端的“当家花旦”。不消多讲，这位在云原生领域里正红的发紫的“角儿”，就是 Golang。不过，正如同 “PHP 不一定是最好的编程语言”一样，Go 语言本身也不是“万能钥匙”。Go 语言之所以能够乘上云原生这趟高速列车，究其原因，更多是与它如下几个特质密切相关：语法简单，容易上手。云原生社区是一个对开源和贡献者非常看重的生态，这就使得很少需要纠结于语法细节的 Go 语言迅速成为了这个社区的“不二之选”。否则的话，云原生 CNCF 社区里大量项目都得忙着讨论这个指针那个引用，什么 Kubernetes CRD 之类的创新设计估计都得凉。 golang.org 库非常丰富。咱们现代软件开发行业，讲究的就是“面向 library” 编程，谁没事儿都不会手撸一个 HTTP 框架或者并发库。开箱即用的库越多，咱研发效率就越高。在这一点上，Go 语言不仅有先天优势，而且雪球越滚越大，已然是云原生一霸了。部署简单。Go 语言项目开发完了，一个静态文件就可以运行了，特别适合直接扔在 Docker 里跑。大家可以想象一下如果 Kubernetes 是

Catch buffered stdout output of exec.Command

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问题 I'm trying to catch output of external program. Example: #include <stdio.h> #include <unistd.h> #include <stddef.h> int main() { int i = 0; while(i < 10) { printf("i = %i\n", i++); usleep(2000000); } return 0; } And here is my main.go: package main import ( "bufio" "io" "log" "os/exec" ) func reecho(closer io.ReadCloser) { reader := bufio.NewReader(closer) for { s, e := reader.ReadString('\n') if e != nil { log.Println(e) break } log.Println(s) } } func main() { cmd := exec.Command(".

Converting negative numbers

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问题 When converting a negative number to an unsigned integer and later adding that value it results in subtracting. a := (uint8)(10) b := (int8)(-8) fmt.Println(a + (uint8)(b)) // result: 2 Is this an idiomatic approach or should it be done more explicitly? 回答1: Since the type is unsigned it is an overflow: uint8(b) is 248 , so a + uint8(b) is 10+248=258=256+2 => 2 my question is more about how to subtract from unsigned integers when the value (sometimes you want to add and sometimes subtract) is

Remove a field from a struct, transform a struct

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问题 From the Google Drive API I get a struct type File. This struct is almost the same as the struct I would like to insert into BigQuery. The File struct contains an "AppProperties" field that is incompatible with BigQuery: AppProperties map[string]string `json:"appProperties,omitempty"` So the end result that I would like to have is the same struct, with the AppProperties field removed. So basically the question is "how to remove a field from a struct" but that does not make sense as the struct

multiple definition when using cgo

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问题 package main /* int add(int a, int b) { return a + b; } */ import "C" import "fmt" func main() {} func Test1() { fmt.Println(C.add(1, 3)) } //export Test2 func Test2() { } Compile the programe: dingrui@dingrui-PC:~/Projects/gotest/array$ go build -o libtest.so -buildmode=c-shared main.go # command-line-arguments /tmp/go-build043762604/b001/_x002.o: In function `add': ./main.go:5: multiple definition of `add' /tmp/go-build043762604/b001/_x001.o:/tmp/go-build/main.go:5: first defined here

Referencing a Go module that is local [duplicate]

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问题 This question already has answers here : How to use a module that is outside of “GOPATH” in another module? (2 answers) Closed 1 year ago . I've been unsuccessful in importing a package from a local project (a Go module). Here is a brief of what I'm trying: I created a Go module package like so: $ cd $ mkdir mymodule $ cd mymodule $ go mod init github.com/Company/mymodule Then I added hello.go under the mymodule with a little function // mymodule/hello.go package mymodule func sayHello()

如果宁静是Oracle，那万茜，张雨绮，黄圣依是什么？

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和姐姐们浪起来~ 嗯！这两天在看乘风破浪的姐姐（被逼） =_= 。。。好吧，其实我自己也看进去了。于是就有这样一个奇思妙想，如果把姐姐们比作计算机领域的技术 or 工具，会是怎么样？于是自己就 yy 了一番。宁静：Oracle，宁静以致远，江湖地位犹在。在大型企业里，通常拥有庞大的资金能力，所以它们会选择用钱购买解决方案，而不是自己雇佣人员使用 MySQL 去维护。在姐姐中，每人都有一个采访视频。主持人问现在圈内艺人分为一线，二线和三线，你觉得自己是几线？这个问题很犀利，大多数人可能会谦虚一番，宁静直言：我一直是一线。将静姐比作 oracle，当仁不让。张雨绮：PHP，宇宙第一强无敌，舍我其谁。袁隆平曾经感慨：我这辈子最大的遗憾，就是让你们吃饱了撑着。于是，由于 PHP 入门门槛低，上手快，被吃瓜群众公认为语言界的 TOP1。而我们绮绮子，就更牛逼了，整个一个铁憨憨。不过其实呢，绮绮子傻大姐，这次真的改变了我之前对其的印象（额，不对，我好像之前都没印象，毕竟我不咋看综艺）。虽说智商偶尔不在线，但她自己给自己创造一个世界，内心清晰而明朗。如同 PHP，内里乾坤，我自知。万茜：Python，姐姐们的团宠。在一堆美女中，她像个帅气的男孩子，让每个姐姐感觉不到压力和竞争。不管你司是传统开发，大数据，又或者机器学习。嗯，你都会需要我。总而言之 “业务能力很强”。万茜在开始表演时

Type conversion of a string read from stdin to int is giving me a 0

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问题 Code: reader := bufio.NewReader(os.Stdin) fmt.Print("Enter a number") input,_ := reader.ReadString('\n') fmt.Printf("Type of the entered value is %T\n",input) fmt.Println(input) out,_ := strconv.Atoi(input) fmt.Printf("Type now is: %T\n", out) fmt.Printf("Value now is %d\n",out) fmt.Println(out) Complete beginner to Golang. I was trying to solve one of the problems from r/dailyprogrammer. I took the snippet to read the input from SO, as well as the strconv.Atoi function. The examples for this

How to safely load a hash, and convert a value to a boolean if it exists

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问题 I have a redis hash that has a key "has_ended" that I want to convert to a boolean value. someMap, _ := rv.redis.HGetAll(key).Result() // returns map[string]interface{} hasEnded := someMap["has_ended"] If the key "has_ended" isn't present in the map and I try to convert it to a boolean it will crash. How can I write this safely? 回答1: Assuming that you are using the popular github.com/go-redis/redis package, the return value from HGetAll(key).Result() is a map[string]string (doc). The

Go: build error when compiling unit tests (I'm trying to mock influxdb types)

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问题 I'm just starting with go language. My mini-project successfully reads data from InfluxDB. Problem: when I import my package (which uses InfluxDB) into my unit test package, the build fails. "Production" code: package data import client "github.com/influxdata/influxdb1-client/v2" func FunctionToTest() {} // To make import necessary, unused for now func createClient() (client.Client, error) { return client.NewHTTPClient(client.HTTPConfig{Addr: addr}) } Unit test: package data_test import ( "..

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