controllers\articleController.go:6:2: cannot find package "github.com/gin-gonic/gin" in any of:

        E:\gocode\src\gin_demo\vendor\github.com\gin-gonic\gin (vendor tree)

        C:\Go\src\github.com\gin-gonic\gin (from $GOROOT)

        E:\gocode\src\github.com\gin-gonic\gin (from $GOPATH)

go vendor 是go 1.5 官方引入管理包依赖的方式，1.6正式引入

其基本思路是，将引用的外部包的源代码放在当前工程的vendor目录下面，go 1.6以后编译go代码会优先从vendor目录先寻找依赖包；

1.解决的问题：

将源码拷贝到当前工程的vendor目录下，这样打包当前的工程代码到任意机器的$GOPATH/src下都可以通过编译，避免项目代码外部依赖过多，迁移后，

需要多次go get 外包依赖包；而且通过go get 重新拉去的外部依赖包的版本可能和工程开发时使用的不一致，导致编译错误问题。

2.未解决的问题：

无法精确的引用外部包进行版本控制，不能指定引用某个特定版本的外部包；只是在开发时，将其拷贝过来，但是一旦外部包升级,vendor下的代码不会跟着升级，

而且vendor下面并没有元文件记录引用包的版本信息，这个引用外部包升级产生很大的问题，无法评估升级带来的风险；

3.解决go vendor未解决的问题 使用govendor ,其有如下好处：

https://github.com/kardianos/govendor

1>.可以平滑的将现有非vendor项目转换为vendor项目

  govendor add  inport_out_packagename

2>会生成一个元数据文件，记录项目工程依赖的外部包，以及其版本信息

 vendor/vendor.json

3>提供命令查看整个工程的依赖关系

goverdor --list

goverdor --list -v

project:

https://github.com/kardianos/govendor

Sub-commands

    init     Create the "vendor" folder and the "vendor.json" file.                 #创建一个vendor目录并生成个空的verdor.json文件

    list     List and filter existing dependencies and packages.                    #查看已经存在的依赖包

    add      Add packages from $GOPATH.                                             #把$GOPATH中的包拷贝到vendor目录下

    update   Update packages from $GOPATH.                                          #把$GOPATH中的包更新到vendor目录下

    remove   Remove packages from the vendor folder.                                #从vendor目录下移除外部依赖包

    status   Lists any packages missing, out-of-date, or modified locally.          #查看缺失的或者本地修改的包

    fetch    Add new or update vendor folder packages from remote repository.       #从远程代码库拉取依赖包到vendor目录

    sync     Pull packages into vendor folder from remote repository with revisions #一句本地vendor/verdor.json文件指定的包机器版本信息从远程资源库拉取资源

                 from vendor.json file.

    migrate  Move packages from a legacy tool to the vendor folder with metadata.

    get      Like "go get" but copies dependencies into a "vendor" folder.          #等于go get 但是同步外部依赖包到vendor目录，而不是$GOPATH/src

    license  List discovered licenses for the given status or import paths.

    shell    Run a "shell" to make multiple sub-commands more efficient for large

                 projects.

    go tool commands that are wrapped:

      `+<status>` package selection may be used with them

    fmt, build, install, clean, test, vet, generate, tool

Status

Packages can be specified by their "status".

    +local    (l) packages in your project

    +external (e) referenced packages in GOPATH but not in current project

    +vendor   (v) packages in the vendor folder

    +std      (s) packages in the standard library

    +excluded (x) external packages explicitely excluded from vendoring

    +unused   (u) packages in the vendor folder, but unused

    +missing  (m) referenced packages but not found

    +program  (p) package is a main package

    +outside  +external +missing

    +all      +all packages