go mod 使用

golang最被诟病的三個問題: module管理機制,泛型,錯誤處理

go mod就是用來解決module管理機制.

首先,把go的版本更新到1.12.x. 可以用go help mod看到go mod的子指令.

Note that support for modules is built into all the go commands,
not just 'go mod'. For example, day-to-day adding, removing, upgrading,
and downgrading of dependencies should be done using 'go get'.
See 'go help modules' for an overview of module functionality.

Usage:

        go mod <command> [arguments]

The commands are:

        download    download modules to local cache
        edit        edit go.mod from tools or scripts
        graph       print module requirement graph
        init        initialize new module in current directory
        tidy        add missing and remove unused modules
        vendor      make vendored copy of dependencies
        verify      verify dependencies have expected content
        why         explain why packages or modules are needed

Use "go help mod <command>" for more information about a command.           

其次,在項目目錄下,一般是main.go(func main()所在的源檔案)所在的目錄下,執行go mod init 項目名(我這裡是go-wikitten).這個指令會在執行指令的目前目錄下,生成一個go.mod 檔案,内容如下:

module go-wikitten   

go 1.12           

最重要的一步來了,因為衆所周知的原因,很多包不能直接下載下傳,可以用proxy,如果找不到proxy,那麼隻能用replace.用文本編輯器打開go.mod,加入如下内容:

module go-wikitten   

go 1.12

replace (
 golang.org/x/text => github.com/golang/text latest

 golang.org/x/net => github.com/golang/net latest

 golang.org/x/crypto => github.com/golang/crypto latest

 golang.org/x/tools => github.com/golang/tools latest

 golang.org/x/sync => github.com/golang/sync latest

 golang.org/x/sys => github.com/golang/sys latest
)           

然後執行 go mod tidy.這個指令會把latest自動替換成最新的版本号.例子:

module go-wikitten   

go 1.12

replace (
golang.org/x/sync => github.com/golang/sync v0.0.0-20190423024810-112230192c58
    golang.org/x/sys => github.com/golang/sys v0.0.0-20190613124609-5ed2794edfdc
    golang.org/x/text => github.com/golang/text v0.3.2
    golang.org/x/tools => github.com/golang/tools v0.0.0-20190613204242-ed0dc450797f
    golang.ort/x/net => github.com/golang/net v0.0.0-20190613194153-d28f0bde5980
)           

如果是老項目,一般不會那麼容易就成功,會提示各種錯誤,比如出現如下錯誤

go: golang.org/x/[email protected]: git fetch -f https://go.googlesource.com/net refs/heads/*:refs/heads/* refs/tags/*:refs/tags/* in D:\workspace\okr\pkg\mod\cache\vcs\4a22365141bc4eea5d5ac4a1395e653f2669485db75ef119e7bbec8e19b12a21: exit status 128:
        fatal: unable to access 'https://go.googlesource.com/net/': Failed to connect to go.googlesource.com port 443: Timed out
go: error loading module requirements           

其實就是提示net包除了最新版之外,還需要其它的版本v0.0.0-20190404232315-eb5bcb51f2a3(出錯資訊@後面的部分),是以我們手工修改go.mod,加入一行:

golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3 => github.com/golang/net v0.0.0-20190404232315-eb5bcb51f2a3           

然後再執行go mod tidy.如果出錯,再把需要的版本加入,反複幾次後,最後應該就會成功了.我最後的go.mod是這樣的:

module go-wikitten

go 1.12

replace (
    golang.org/x/crypto => github.com/golang/crypto v0.0.0-20190611184440-5c40567a22f8
    golang.org/x/net v0.0.0-20181220203305-927f97764cc3 => github.com/golang/net v0.0.0-20181220203305-927f97764cc3
    golang.org/x/net v0.0.0-20190311183353-d8887717615a => github.com/golang/net v0.0.0-20190311183353-d8887717615a
    golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3 => github.com/golang/net v0.0.0-20190404232315-eb5bcb51f2a3
    golang.org/x/net v0.0.0-20190503192946-f4e77d36d62c => github.com/golang/net v0.0.0-20190503192946-f4e77d36d62c
    golang.org/x/sync => github.com/golang/sync v0.0.0-20190423024810-112230192c58
    golang.org/x/sys => github.com/golang/sys v0.0.0-20190613124609-5ed2794edfdc
    golang.org/x/text => github.com/golang/text v0.3.2
    golang.org/x/tools => github.com/golang/tools v0.0.0-20190613204242-ed0dc450797f
    golang.ort/x/net => github.com/golang/net v0.0.0-20190613194153-d28f0bde5980
    gopkg.in/russross/blackfriday.v2 => github.com/russross/blackfriday v2.0.0+incompatible
    gopkg.in/yaml.v2 => github.com/go-yaml/yaml v2.1.0+incompatible
)

require (
    github.com/davidrjenni/reftools v0.0.0-20190411195930-981bbac422f8
    github.com/dchest/captcha v0.0.0-20170622155422-6a29415a8364
    github.com/fatih/motion v0.0.0-20190527122956-41470362fad4
    github.com/fsnotify/fsnotify v1.4.7
    github.com/gin-gonic/gin v1.4.0
    github.com/gorilla/context v1.1.1
    github.com/gorilla/securecookie v1.1.1
    github.com/gorilla/sessions v1.1.3
    github.com/keegancsmith/rpc v1.1.0
    github.com/kisielk/errcheck v1.2.0
    github.com/kisielk/gotool v1.0.0
    github.com/kr/pretty v0.1.0 // indirect
    github.com/lib/pq v1.1.1
    github.com/lxmgo/config v0.0.0-20180313024057-8db99aca0f7e
    github.com/mattn/go-isatty v0.0.8
    github.com/mdempsky/gocode v0.0.0-20190203001940-7fb65232883f
    github.com/microcosm-cc/bluemonday v1.0.2
    github.com/mozillazg/go-pinyin v0.15.0
    github.com/pkg/errors v0.8.1
    github.com/shurcooL/sanitized_anchor_name v1.0.0 // indirect
    github.com/sqs/goreturns v0.0.0-20181028201513-538ac6014518
    github.com/stamblerre/gocode v0.0.0-20190327203809-810592086997
    github.com/stretchr/testify v1.3.0
    go4.org v0.0.0-20190313082347-94abd6928b1d
    golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2
    golang.org/x/net v0.0.0-20190503192946-f4e77d36d62c
    golang.org/x/sys v0.0.0-20190412213103-97732733099d
    golang.org/x/text v0.3.0
    golang.org/x/tools v0.0.0-20190408220357-e5b8258f4918
    gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
    gopkg.in/go-playground/assert.v1 v1.2.1
    gopkg.in/go-playground/validator.v8 v8.18.2
    gopkg.in/russross/blackfriday.v2 v2.0.0-00010101000000-000000000000
)           

最後,附上常用的replace清單:

golang.org/x/text => github.com/golang/text latest

 golang.org/x/net => github.com/golang/net latest

 golang.org/x/crypto => github.com/golang/crypto latest

 golang.org/x/tools => github.com/golang/tools latest

 golang.org/x/sync => github.com/golang/sync latest

 golang.org/x/sys => github.com/golang/sys latest

 cloud.google.com/go => github.com/googleapis/google-cloud-go latest

 google.golang.org/genproto => github.com/google/go-genproto latest

 golang.org/x/exp => github.com/golang/exp latest

 golang.org/x/time => github.com/golang/time latest

 golang.org/x/oauth2 => github.com/golang/oauth2 latest

 golang.org/x/lint => github.com/golang/lint latest

 google.golang.org/grpc => github.com/grpc/grpc-go latest

 google.golang.org/api => github.com/googleapis/google-api-go-client latest

 google.golang.org/appengine => github.com/golang/appengine latest

 golang.org/x/mobile => github.com/golang/mobile latest

 golang.org/x/image => github.com/golang/image latest
 
 cloud.google.com/go => github.com/googleapis/google-cloud-go v0.34.0

 github.com/go-tomb/tomb => gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7

 go.opencensus.io => github.com/census-instrumentation/opencensus-go v0.19.0

 go.uber.org/atomic => github.com/uber-go/atomic v1.3.2

 go.uber.org/multierr => github.com/uber-go/multierr v1.1.0

 go.uber.org/zap => github.com/uber-go/zap v1.9.1
 
 google.golang.org/api => github.com/googleapis/google-api-go-client v0.0.0-20181220000619-583d854617af

 google.golang.org/appengine => github.com/golang/appengine v1.3.0

 google.golang.org/genproto => github.com/google/go-genproto v0.0.0-20181219182458-5a97ab628bfb

 google.golang.org/grpc => github.com/grpc/grpc-go v1.17.0

 gopkg.in/alecthomas/kingpin.v2 => github.com/alecthomas/kingpin v2.2.6+incompatible

 gopkg.in/mgo.v2 => github.com/go-mgo/mgo v0.0.0-20180705113604-9856a29383ce

 gopkg.in/vmihailenco/msgpack.v2 => github.com/vmihailenco/msgpack v2.9.1+incompatible

 gopkg.in/yaml.v2 => github.com/go-yaml/yaml v0.0.0-20181115110504-51d6538a90f8

 labix.org/v2/mgo => github.com/go-mgo/mgo v0.0.0-20160801194620-b6121c6199b7

 launchpad.net/gocheck => github.com/go-check/check v0.0.0-20180628173108-788fd7840127           

國内可以使用的proxy

• https://goproxy.io
• https://athens.azurefd.net
• https://goproxy.cn
• https://gocenter.io
• https://mirrors.aliyun.com/goproxy/

  linux下使用

  export GOPROXY=

  windows下直接設定環境變量GOPROXY