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Go学习笔记(十)老项目迁移 go module 大型灾难记录

最近在改造一个比较早期的一个项目,其中就涉及到用将原来 Vendor 管理依赖换成 Go Modules 来管理。 然而过程真是一波三折,在这里总结一下此次 Go Modules 改造中遇到的问题,以及解决方法。

背景

  • go version:

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    $ go version
    go version go1.16.5 darwin/amd64
  • 简化的 demo 如下, 很 “简单” 我们只要把 hello world 输出即可。

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    package main

    import (
    "github.com/coreos/etcd/pkg/transport"
    "github.com/google/certificate-transparency-go/tls"
    "github.com/qiniu/api.v7/auth/qbox"
    "go.etcd.io/etcd/clientv3"
    "google.golang.org/grpc"
    "qiniupkg.com/x/log.v7"
    )

    func main() {

    _ = transport.TLSInfo{}

    _ = clientv3.WatchResponse{}

    _, _ = clientv3.New(clientv3.Config{})

    _ = qbox.NewMac("", "")

    _ = tls.DigitallySigned{}

    _ = grpc.ClientConn{}

    log.Info("hello world")
    }

实战

直接初始化,并 tidy 一下。

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$ go mod init demo-go/gomod
go: creating new go.mod: module demo-go/gomod
go: to add module requirements and sums:
go mod tidy

$ go mod tidy
go: finding module for ...
demo-go/gomod imports
qiniupkg.com/x/log.v7: module qiniupkg.com/[email protected] found (v1.11.5), but does not contain package qiniupkg.com/x/log.v7
demo-go/gomod imports
github.com/qiniu/api.v7/auth/qbox imports
github.com/qiniu/x/bytes.v7/seekable: module github.com/qiniu/[email protected] found (v1.11.5), but does not contain package github.com/qiniu/x/bytes.v7/seekable
demo-go/gomod imports
go.etcd.io/etcd/clientv3 imports
github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context: package github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context provided by github.com/coreos/etcd at latest version v2.3.8+incompatible but not at required version v3.3.10+incompatible
demo-go/gomod imports
go.etcd.io/etcd/clientv3 imports
github.com/coreos/etcd/Godeps/_workspace/src/google.golang.org/grpc: package github.com/coreos/etcd/Godeps/_workspace/src/google.golang.org/grpc provided by github.com/coreos/etcd at latest version v2.3.8+incompatible but not at required version v3.3.10+incompatible
demo-go/gomod imports
go.etcd.io/etcd/clientv3 imports
github.com/coreos/etcd/Godeps/_workspace/src/google.golang.org/grpc/credentials: package github.com/coreos/etcd/Godeps/_workspace/src/google.golang.org/grpc/credentials provided by github.com/coreos/etcd at latest version v2.3.8+incompatible but not at required version v3.3.10+incompatible
demo-go/gomod imports
go.etcd.io/etcd/clientv3 imports
github.com/coreos/etcd/storage/storagepb: package github.com/coreos/etcd/storage/storagepb provided by github.com/coreos/etcd at latest version v2.3.8+incompatible but not at required version v3.3.10+incompatible

好家伙,报错了。我们先看到前两行

  1. qiniupkg.com/[email protected] 中没有 qiniupkg.com/x/log.v7
  2. github.com/qiniu/[email protected] 中没有 github.com/qiniu/x/bytes.v7/seekable

这看起来应该是一个问题, qiniupkg.com/xgithub.com/qiniu/x 应该是同一个包,不同镜像。于是我到 Github 看一下 @lastet 版本的代码,确实没有bytes.v7 包了。人肉查找,最后在 v1.7.8 版本,我们找到了 bytes.v7 包。

于是,我们可以指定一下版本。

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go mod edit -replace qiniupkg.com/x=qiniupkg.com/[email protected]
go mod edit -replace github.com/qiniu/x=github.com/qiniu/[email protected]

继续往下看,接下来的几个问题是一类的,都是etcd导致的。

意思是 go.etcd.io/etcd/clientv3 导入了 github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context, 同时 `github.com/coreos/[email protected]中 提供了github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context。 但是,我们这里需要github.com/coreos/[email protected], 而该版本并不提供github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context` 。

我们直接更新 etcd 到的 v3.3.10 试试。

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go mod edit -replace go.etcd.io/etcd=go.etcd.io/[email protected]+incompatible

我们再 go mod tidy 下。

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$ go mod tidy
go: demo-go/gomod imports
go.etcd.io/etcd/clientv3 tested by
go.etcd.io/etcd/clientv3.test imports
github.com/coreos/etcd/auth imports
github.com/coreos/etcd/mvcc/backend imports
github.com/coreos/bbolt: github.com/coreos/[email protected]: parsing go.mod:
module declares its path as: go.etcd.io/bbolt
but was required as: github.com/coreos/bbolt

这个错误和鸟窝这篇 Etcd使用go module的灾难一致,go.etcd.io/bboltgithub.com/coreos/bbolt 包名不一致,我们替换一下。

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go mod edit -replace github.com/coreos/[email protected]=go.etcd.io/[email protected]

继续,go mod tidy 一下。

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$ go mod tidy
...
demo-go/gomod imports
go.etcd.io/etcd/clientv3 imports
github.com/coreos/etcd/clientv3/balancer: module github.com/coreos/[email protected] found (v2.3.8+incompatible), but does not contain package github.com/coreos/etcd/clientv3/balancer
demo-go/gomod imports
go.etcd.io/etcd/clientv3 imports
github.com/coreos/etcd/clientv3/balancer/picker: module github.com/coreos/[email protected] found (v2.3.8+incompatible), but does not contain package github.com/coreos/etcd/clientv3/balancer/picker
demo-go/gomod imports
go.etcd.io/etcd/clientv3 imports
github.com/coreos/etcd/clientv3/balancer/resolver/endpoint: module github.com/coreos/[email protected] found (v2.3.8+incompatible), but does not contain package github.com/coreos/etcd/clientv3/balancer/resolver/endpoint
demo-go/gomod imports
go.etcd.io/etcd/clientv3 imports
github.com/coreos/etcd/clientv3/credentials: module github.com/coreos/[email protected] found (v2.3.8+incompatible), but does not contain package github.com/coreos/etcd/clientv3/credentials
demo-go/gomod imports
go.etcd.io/etcd/clientv3 tested by
go.etcd.io/etcd/clientv3.test imports
github.com/coreos/etcd/integration imports
github.com/coreos/etcd/proxy/grpcproxy imports
google.golang.org/grpc/naming: module google.golang.org/[email protected] found (v1.39.0), but does not contain package google.golang.org/grpc/naming

好家伙,又是etcd。 仔细一看,我们导入了github.com/coreos/etcdgo.etcd.io/etcd 两个版本etcd, 我们前面只替换了一个。现在我们把另外一个也替换了。

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go mod edit -replace github.com/coreos/etcd=github.com/coreos/[email protected]+incompatible

go mod tidy下,这个错误没有了,但还有个grpc的错误,继续找原因。原来是google.golang.org/grpc v1.39.0 版本没有google.golang.org/grpc/naming 包。 上 Github 仓库, 找了一下历史版本,v1.29.1上是有这个包的,我们继续替换。

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go mod edit -replace google.golang.org/grpc=google.golang.org/[email protected]

这下,终于,go mod tidy通过了,可以开心的输出hello world 了。

然而,

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$ go run main.go
# github.com/coreos/etcd/clientv3/balancer/resolver/endpoint
../../../go/pkg/mod/github.com/coreos/[email protected]+incompatible/clientv3/balancer/resolver/endpoint/endpoint.go:114:78: undefined: resolver.BuildOption
../../../go/pkg/mod/github.com/coreos/[email protected]+incompatible/clientv3/balancer/resolver/endpoint/endpoint.go:182:31: undefined: resolver.ResolveNowOption
# github.com/coreos/etcd/clientv3/balancer/picker
../../../go/pkg/mod/github.com/coreos/[email protected]+incompatible/clientv3/balancer/picker/err.go:37:44: undefined: balancer.PickOptions
../../../go/pkg/mod/github.com/coreos/[email protected]+incompatible/clientv3/balancer/picker/roundrobin_balanced.go:55:54: undefined: balancer.PickOptions

意不意外,惊不惊喜!!

原来etcd包依赖了grpcresolver包,但我导入的v1.29.1版本的grpc是没有这个包的。到 grpc仓库 挨个版本看了一下,确实只有v1.26.0版本才声明了type BuildOption 。于是,我们再次使用替换大法。

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go mod edit -replace google.golang.org/grpc=google.golang.org/[email protected]

再次tidy, 运行! 终于,看到了久违的hello world!

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$ go run main.go
2021/07/20 12:27:09.642431 [INFO] /Users/razeen/wspace/github/demo-go/gomod/main.go:26: hello world

总结

项目规范

现在我们回过头看下这个 demo 项目,其实很有问题。

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"github.com/coreos/etcd/pkg/transport"
"github.com/google/certificate-transparency-go/tls"
"github.com/qiniu/api.v7/auth/qbox"
"go.etcd.io/etcd/clientv3"
"google.golang.org/grpc"
"qiniupkg.com/x/log.v7"

etcdqiniupkg的包完全可以统一,只导入一种!而且,后来我们发现log.v7这包也是意外导入的….

这也是在改造我们一些老的项目时遇到的问题,以前用vendor go get 没有注意到这些问题,这是需要提前规范的。

看懂 go.mod

我们来简单看一下,经历各种坎坷后,得出的go.mod 文件。

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module demo-go/gomod

go 1.16

replace qiniupkg.com/x => qiniupkg.com/x v1.7.8

replace github.com/qiniu/x => github.com/qiniu/x v1.7.8

replace go.etcd.io/etcd => go.etcd.io/etcd v3.3.20+incompatible

replace github.com/coreos/bbolt v1.3.6 => go.etcd.io/bbolt v1.3.6

replace github.com/coreos/etcd => github.com/coreos/etcd v3.3.20+incompatible

replace google.golang.org/grpc => google.golang.org/grpc v1.26.0

require (
github.com/coreos/bbolt v1.3.6 // indirect
github.com/coreos/etcd v3.3.10+incompatible
github.com/dgrijalva/jwt-go v3.2.0+incompatible // indirect
github.com/google/certificate-transparency-go v1.1.1
github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0 // indirect
github.com/qiniu/api.v7 v7.2.5+incompatible
github.com/qiniu/x v0.0.0-00010101000000-000000000000 // indirect
github.com/soheilhy/cmux v0.1.5 // indirect
github.com/xiang90/probing v0.0.0-20190116061207-43a291ad63a2 // indirect
go.etcd.io/etcd v0.0.0-20200513171258-e048e166ab9c
google.golang.org/grpc v1.29.1
qiniupkg.com/x v0.0.0-00010101000000-000000000000
sigs.k8s.io/yaml v1.2.0 // indirect
)

我们先看一个常见的这几个指令

  • module 定义主模块的路径;
  • go 编写该mod文件时的go版本;
  • require 声明给定模块依赖项的最低要求版本;
  • replace 手动指定的依赖模块 (可以替换全部的版本、指定的版本、本地的版本等等 );

还有就是 v3.3.20+incompatible 后面的 +incompatible , 这是指兼容的版本,指依赖库的版本是v2 或以上,但go.mod和 依赖库路径 没有按照官方指定的方式命名,会加上这个。

v0.0.0-00010101000000-000000000000 这是一个伪版本,在和 不兼容 module 或 标记的版本不可用的时候,回打上这个伪版本。

// indirect 这指明这些不是我们直接引用的依赖。

除此之外,以下指令也可了解一下。

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# 查看当前模块以及所有的依赖模块
go list -m all

# 查看某个模块的以及打标签的版本
go list -m -versions go.etcd.io/etcd

# 升级特定的包
go get [email protected] 升级特定的包

# 了解为什么需要模块
go mod why -m all

# 为什么需要指定(google.golang.org/grpc)的模块
go mod why -m google.golang.org/grpc

更多可以细读官方文档,感谢阅读。

参考

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