如何使用go get导入特定版本的软件包？

我曾经将特定版本的供应商lib安装到项目文件夹中的环境 (node_modules) ，却被告知要安装该版本的 npm 库和package.json。

$ npm install express@4.0.0

所以我把那个版本的包导入到了我的项目中：

var express = require('express');

现在，我想在go中做同样的事情，我该怎么做呢？是否可以安装特定版本的软件包?如果是，要使用集中式 $GOPATH？又该如何导入一个版本而不是另一个版本？

我也许会这样做：

$ go get github.com/wilk/uuid@0.0.1
$ go get github.com/wilk/uuid@0.0.2

但是，我怎样才能在导入期间做出改变呢?

更新18-11-23:从Go 1.11 mod是官方实验。请参照@krish的回答。
更新19-01-01:从Go 1.12 mod仍然是官方实验。 从Go 1.13开始，模块模式将是所有开发的默认模式

旧式回答:

你可以通过官方设置版本 dep

dep ensure --add github.com/gorilla/websocket@1.2.0

从1.5开始 "vendor experiment"这有助于你管理依赖项。从第1.6章开始，这不再是一个实验。在Go wiki上还有一些其他的选择….

编辑：正如在这个答案中提到的gopkg一样。对于1.5之前的Github依赖来说，in是一个不错的选择。

You can use git checkout to get an specific version and build your program using this version.

Example:

export GOPATH=~/
go get github.com/whateveruser/whateverrepo
cd ~/src/github.com/whateveruser/whateverrepo
git tag -l
# supose tag v0.0.2 is correct version
git checkout tags/v0.0.2
go run whateverpackage/main.go

Really surprised nobody has mentioned gopkg.in.

gopkg.in is a service that provides a wrapper (redirect) that lets you express versions as repo urls, without actually creating repos. E.g. gopkg.in/yaml.v1 vs gopkg.in/yaml.v2, even though they both live at https://github.com/go-yaml/yaml

• gopkg.in/yaml.v1 redirects to https://github.com/go-yaml/yaml/tree/v1
• gopkg.in/yaml.v2 redirects to https://github.com/go-yaml/yaml/tree/v2

This isn't perfect if the author is not following proper versioning practices (by incrementing the version number when breaking backwards compatibility), but it does work with branches and tags.

dep is the official experiment for dependency management for Go language. It requires Go 1.8 or newer to compile.

To start managing dependencies using dep, run the following command from your project's root directory:

dep init

After execution two files will be generated: Gopkg.toml ("manifest"), Gopkg.lock and necessary packages will be downloaded into vendor directory.

Let's assume that you have the project which uses github.com/gorilla/websocket package. dep will generate following files:

Gopkg.toml

# Gopkg.toml example
#
# Refer to https://github.com/golang/dep/blob/master/docs/Gopkg.toml.md
# for detailed Gopkg.toml documentation.
#
# required = ["github.com/user/thing/cmd/thing"]
# ignored = ["github.com/user/project/pkgX", "bitbucket.org/user/project/pkgA/pkgY"]
#
# [[constraint]]
#   name = "github.com/user/project"
#   version = "1.0.0"
#
# [[constraint]]
#   name = "github.com/user/project2"
#   branch = "dev"
#   source = "github.com/myfork/project2"
#
# [[override]]
#  name = "github.com/x/y"
#  version = "2.4.0"


[[constraint]]
  name = "github.com/gorilla/websocket"
  version = "1.2.0"

Gopkg.lock

# This file is autogenerated, do not edit; changes may be undone by the next 'dep ensure'.


[[projects]]
  name = "github.com/gorilla/websocket"
  packages = ["."]
  revision = "ea4d1f681babbce9545c9c5f3d5194a789c89f5b"
  version = "v1.2.0"

[solve-meta]
  analyzer-name = "dep"
  analyzer-version = 1
  inputs-digest = "941e8dbe52e16e8a7dff4068b7ba53ae69a5748b29fbf2bcb5df3a063ac52261"
  solver-name = "gps-cdcl"
  solver-version = 1

There are commands which help you to update/delete/etc packages, please find more info on official github repo of dep (dependency management tool for Go).

Go 1.11 will be having a feature called go modules and you can simple add a dependency with a version.

Steps

1. go mod init .
2. go mod edit -require github.com/wilk/uuid@0.0.1
3. go get -v -t ./...
4. go build
5. go install

Here's more info on that topic: https://github.com/golang/go/wiki/Modules

That worked for me

GO111MODULE=on go get -u github.com/segmentio/aws-okta@v0.22.1

Nowadays you can just use go get for it. You can fetch your dependency by the version tag, branch or even the commit.

go get github.com/someone/some_module@master
go get github.com/someone/some_module@v1.1.0
go get github.com/someone/some_module@commit_hash

more details here - How to point Go module dependency in go.mod to a latest commit in a repo?

Go get will also install the binary, like it says in the documentation -

Get downloads the packages named by the import paths, along with their dependencies. It then installs the named packages, like 'go install'.

(from https://golang.org/cmd/go/)