GO语言 VSCode开发环境搭建 [Mac]

Go是一个由Google团队和开源社区的许多贡献者开发的开源项目. 本文详细记录了Go开发环境搭建过程，包括Go安装，IDE配置等。

系统环境配置

MacOS High Sierra
版本10.13.5

MacBook Pro (Retina, 15-inch, Mid 2015)
处理器 2.2 GHz Intel Core i7
内存 16 GB 1600 MHz DDR3
图形卡 Intel Iris Pro 1536 MB

一、GO 安装

Go官网提供了可用的Go列表，可以直接下载安装。本文主要采用了homebrew工具进行安装，其优点是简单同时也能够在需要的时候利用homebrew进行升级。(HomeBrew安装教程参见 https://brew.sh/)

zhongxiao.yzx@MacBook-Pro:~/Workspace/ $brew info go

go: stable 1.10.3 (bottled), HEAD
Open source programming language to build simple/reliable/efficient software
https://golang.org
Not installed
From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/go.rb
==> Requirements
Required: macOS >= 10.8 ✔
==> Options
--without-cgo
	Build without cgo (also disables race detector)
--without-race
	Build without race detector
--HEAD
	Install HEAD version
==> Caveats
A valid GOPATH is required to use the `go get` command.
If $GOPATH is not specified, $HOME/go will be used by default:
  https://golang.org/doc/code.html#GOPATH
You may wish to add the GOROOT-based install location to your PATH:
  export PATH=$PATH:/usr/local/opt/go/libexec/bin

zhongxiao.yzx@MacBook-Pro:~/Workspace $brew install go

Updating Homebrew...
warning: unable to access '/Users/zhongxiao.yzx/.config/git/ignore': Permission denied
warning: unable to access '/Users/zhongxiao.yzx/.config/git/attributes': Permission denied
==> Auto-updated Homebrew!
Updated 1 tap (homebrew/core).
==> Renamed Formulae
cdiff -> ydiff
==> Downloading https://homebrew.bintray.com/bottles/go-1.10.3.high_sierra.bottle.tar.gz
######################################################################## 100.0%
==> Pouring go-1.10.3.high_sierra.bottle.tar.gz
==> Caveats
A valid GOPATH is required to use the `go get` command.
If $GOPATH is not specified, $HOME/go will be used by default:
  https://golang.org/doc/code.html#GOPATH
You may wish to add the GOROOT-based install location to your PATH:
  export PATH=$PATH:/usr/local/opt/go/libexec/bin
==> Summary

二、Go环境变量配置

Go安装完成后，可以工作go env查看环境Go相关的环境变量

zhongxiao.yzx@MacBook-Pro:~/Workspace $go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/zhongxiao.yzx/Library/Caches/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/zhongxiao.yzx/go"
GORACE=""
GOROOT="/usr/local/Cellar/go/1.10.3/libexec"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.10.3/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/3l/nr_rmq_x0wd1nmg84kl9cfj00000gn/T/go-build353988632=/tmp/go-build -gno-record-gcc-switches -fno-common"

其中GOROOT,GOPATH是3个重要的环境变量

• GOROOT: 安装目录
• GOPATH: 日常开发的根目录，该目录在Go开发，编译，安装过程中起着重要的作用，例如 go get， go install等命令都会根据GOPATH来保存相关的插件，文件等。该目录不能和Go的安装目录一样，这个目录下面有三个子目录: src、bin、pkg

1. src 存放源代码（比如：.go .c .h .s等）
2. pkg 编译后生成的文件（比如：.a）
3. bin 编译后生成的可执行文件（为了方便，可以把此目录加入到$PATH变量中，如果有多个gopath,那么使用${GOPATH//://bin:}/bin） 

• GOBIN：是GOPATH下的bin目录,该环境变量影响到go install命令

    在未设置GOBIN情况下
    zhongxiao.yzx@MacBook-Pro:~/Workspace/dev/golang/src$go install -x main.go
    go install: no install location for .go files listed on command line (GOBIN not set)
    在设置了GOBIN环境变量的情况下
    zhongxiao.yzx@MacBook-Pro:~/Workspace/dev/golang/src$go install -x main.go
    cd .
    /usr/local/Cellar/go/1.10.3/libexec/pkg/tool/darwin_amd64/link -o $WORK/b001/exe/a.out -importcfg $WORK/b001/importcfg.link -buildmode=exe -buildid=m26dg2-o1fDEe4lb1JZs/pcntLKDV1KQrpUm8zrkQ/FVueuXxUB9G0toBnk0P2/m26dg2-o1fDEe4lb1JZs -extld=clang $WORK/b001/_pkg_.a
    /usr/local/Cellar/go/1.10.3/libexec/pkg/tool/darwin_amd64/buildid -w $WORK/b001/exe/a.out # internal
    mkdir -p /Users/zhongxiao.yzx/Workspace/dev/golang/bin/
    mv $WORK/b001/exe/a.out /Users/zhongxiao.yzx/Workspace/dev/golang/bin/main
    rm -r $WORK/b001/

GOPATH在没有配置环境变量的情况下，Go开发环境采用默认的配置
GOROOT="/usr/local/Cellar/go/1.10.3/libexec"
GOPATH="/Users/zhongxiao.yzx/go"

其中${HOME}是"/Users/zhongxiao.yzx/

zhongxiao.yzx@MacBook-Pro:~/Workspace $which go
/usr/local/bin/go

那么为什么GOROOT="/usr/local/Cellar/go/1.10.3/libexec"呢？

zhongxiao.yzx@MacBook-Pro:~/Workspace $ls -la /usr/local/bin/go
lrwxr-xr-x  1 zhongxiao.yzx  admin  26  6 28 09:13 /usr/local/bin/go -> ../Cellar/go/1.10.3/bin/go
zhongxiao.yzx@MacBook-Pro:~/Workspace $ls -la /usr/local/Cellar/go/1.10.3/bin/go
lrwxr-xr-x  1 zhongxiao.yzx  admin  17  6  7 07:50 /usr/local/Cellar/go/1.10.3/bin/go -> ../libexec/bin/go

可见/usr/local/bin/go实际上是对/usr/local/Cellar/go/1.10.3/ libexec/bin/go的引用

虽然go env以有默认的环境变量但是在终端中没有默认Go环境变量的设置，因此在.bash_profile中设置如下

 #--------------------------------------------------
 # go environment variable
 export GOROOT="/usr/local/Cellar/go/1.10.3/libexec"
 export GOPATH="${HOME}/Workspace/dev/golang"
 export GOPATH="${GOPATH}/bin"
 export PATH="${PATH}:${GOPATH}:${GOPATH}/bin"

至此我们可以构建如下的Go程序，并在终端环境采用go build, go run等命令编译运行Go程序
zhongxiao.yzx@MacBook-Pro:~/Workspace/dev/golang$tree -L 2
.
├── bin
├── pkg
└── src

    ├── main.go

// main.go
package main
import (
    "fmt"
)
func main() {
    fmt.Println("hello world")
}

zhongxiao.yzx@MacBook-Pro:~/Workspace/dev/golang/src$go -h
Go is a tool for managing Go source code.
Usage:
        go command [arguments]
The commands are:
        build       compile packages and dependencies
        clean       remove object files and cached files
        doc         show documentation for package or symbol
        env         print Go environment information
        bug         start a bug report
        fix         update packages to use new APIs
        fmt         gofmt (reformat) package sources
        generate    generate Go files by processing source
        get         download and install packages and dependencies
        install     compile and install packages and dependencies
        list        list packages
        run         compile and run Go program
        test        test packages
        tool        run specified go tool
        version     print Go version
        vet         report likely mistakes in packages
Use "go help [command]" for more information about a command.

三、VSCode Go开发环境配置

按照以上的步骤，我们已经建立了最原始的终端Go程序开发环境，但为了更加高效的进行大型Go程序的开发，需要搭建适合开发者的Go编程环境。
VSCode是流行的开源IDE，支持Go语言开发插件(VSCode安装参见 https://code.visualstudio.com)

点击VSCode Extensions图标，搜索Go插件，选择Go进行安装并重新加载Visual Studio Code。

VSCode插件安装依赖依赖GOPATH环境变量，虽然在第二部分已经配置了Go语言环境变量，但是在VSCode中GOPATH依然采用了默认值，因此需要在User Settings中设置go.gopath属性。

设置完Go环境变量，可以在Go工程中创建main.go文件，这时后VSCode会提示依赖缺失，提示安装

Installing 9 tools at /Users/zhongxiao.yzx/Workspace/dev/golang/bin
  gocode
  gopkgs
  go-outline
  go-symbols
  guru
  gorename
  godef
  goreturns
  golint

Installing github.com/mdempsky/gocode SUCCEEDED
Installing github.com/uudashr/gopkgs/cmd/gopkgs SUCCEEDED
Installing github.com/ramya-rao-a/go-outline SUCCEEDED
Installing github.com/acroca/go-symbols SUCCEEDED
Installing golang.org/x/tools/cmd/guru SUCCEEDED
Installing golang.org/x/tools/cmd/gorename SUCCEEDED
Installing github.com/rogpeppe/godef SUCCEEDED
Installing github.com/sqs/goreturns SUCCEEDED
Installing github.com/golang/lint/golint SUCCEEDED

All tools successfully installed. You're ready to Go :).

当然也可以通过手动执行如下命令安装依赖插件

go get -u -v github.com/nsf/gocode
go get -u -v github.com/rogpeppe/godef
go get -u -v github.com/zmb3/gogetdoc
go get -u -v github.com/golang/lint/golint
go get -u -v github.com/lukehoban/go-outline
go get -u -v sourcegraph.com/sqs/goreturns
go get -u -v golang.org/x/tools/cmd/gorename
go get -u -v github.com/tpng/gopkgs
go get -u -v github.com/newhook/go-symbols
go get -u -v golang.org/x/tools/cmd/guru
go get -u -v github.com/cweill/gotests/...

VSCode IDE要支持Go语言开发，执行以下命令安装Go编译调试插件。

go get -v -u github.com/peterh/liner github.com/derekparker/delve/cmd/dlv
brew install go-delve/delve/delve
go get -v -u github.com/peterh/liner github.com/derekparker/delve/cmd/dlv

Go编译调试插件dlv需要证书的支持，按照以下步骤可以为dlv创建和修改证书
1.打开“钥匙串访问”
2.打开菜单->钥匙串访问->证书助理->创建证书

3.设置代码证书信息
 
4.单击“继续”，有限期（天数）：365，可以自己修改，3650
5.一直继续，直到看到“指定用于该证书的位置”钥匙串，选择“系统”并单击“创建”按钮(必须选择“系统”类别，否则最后重新编译带代码签名dlv会失败)
 
6.重启Finder，再打开“钥匙串访问”，选择“系统”，就会看到创建好的“dlv”证书
7.右键"dlv"证书，选择“显示简介->信任->代码签名”修改为：始终信任
 
8.打开terminal,进入到之前安装好的$GOPATH/src目录下的dlv源码文件目录:github.com/derekparker/delve；输入如下命令就可以重新编译出一个带代码签名的dlv执行程序(CERT指定的证书名需要和创建名保持一致)

GO15VENDOREXPERIMENT=1 CERT=dlv make install

最后，退出重新打开VSCode就可以进行Go程序的开发和调试了

参考资料

[1]. The Go Programming Language: https://golang.org/project/
[2]. Editor plugins and IDEs: https://golang.org/doc/editors.html
[3]. vscode-go: https://github.com/Microsoft/vscode-go