vgo: An experimental go tools with version concept is under proposal and will include in go 1.12.

1. GTG (Golang Taipei Gathering): 30
Introduction vgo
Evan Lin

2. Agenda
● Go vendoring and package management
● Introduce vgo
● vgo features
● vgo tutorial

3. How to write a Go application
1. We write code
2. We use other’s code
3. ow..
Reference: GopherCon 2017: Sam Boyer - The New Era of Go Package Management

4. Need other’s code?
`go get github.com/xxxx/xxx`

5. If you are lucky….

6. But...

7. Vendoring control ...

8. Rise of vendoring tools:
● 2013: godep, gom, et. all - 2013
● 2014: glide, gopkg, et. all - 2014
● 2015: gb, govendor, et. all - 2015
● 2017: dep (official experiment)
Reference: GopherCon 2017: Sam Boyer - The New Era of Go Package Management

9. About Vendoring in Go
● 2015: Go 1.5 vendor/ added, default off
● 2016: Go 1.6 vendor/ on by default
● 2017: Go 1.7 vendor/ always on
Reference: GopherCon 2017: Sam Boyer - The New Era of Go Package Management

10. what is vgo
● Proposed Modification to "go" Tool.
● Provide versioned concept to go tools
● Target to ship on go 1.11, will be offcial on go 1.12
● vgo has lots of features….

11. vgo Features
● The Import Compatibility Rule
● Semantic Import Versioning
● Minimal Version Selection
● Allow run go command outside GOPATH
● Default download code in `vgo build`
● ...

12. 1. The Import Compatibility Rule
● 2017/06 github.com/kkdai/testGo
● 2017/08 github.com/kkdai/testGo
● 2017/12 github.com/kkdai/testGo.v2
Need backward-compatible
Breaking change

13. 2. Semantic Import Versioning

14. 3. Minimal Version Selection
Minimal version selection allows modules to
specify only minimum requirements for their
dependency modules.

15. When you want the update
your software?
● For security concern?
● Faster? Stronger?

16. Update your vendor code ..

17. Update your vendor code until you need it

18. Update your vendor code untill you *REALLY* need it

19. 4. Allow run go command outside GOPATH
Allow running the go command in file trees outside GOPATH, provided there is
a go.mod in the current directory or a parent directory.
That go.mod file defines the mapping from file system to import path as well
as the specific module versions used in the build.
P.S.
● Go 1.10 set default GOPATH
● vgo (1.12?) run go command outside GOPATH

20. 5. Default download without `go get`
● Original build process:
○ Write your own `main.go`
○ `go get` dependency module code
○ `go build`
● vgo build process:
○ Write your own `main.go`
○ `vgo build`

21. vgo tutorial

22. vgo can run go command outside GOPATH..

23. vgo tutorial (1):
● Install vgo
○ go get -u golang.org/x/vgo
● example code (download here)

24. vgo tutorial (2)
● Create go.mod
○ touch go.mod
● Build your code

25. vgo tutorial (3)
● Check go.mod
● Question: How to define your version?
○ It support branch and tag
■ https://github.com/bketelsen/captainhook/blob/master/go.mod#L5:2
■ https://github.com/gorilla/mux/releases/tag/v1.6.0

26. vgo tutorial (4)
● List all modules

27. vgo tutorial (5)
● List all availible version on rsc.io/quote (vgo list)

28. vgo tutorial (6) - Upgrade
● List all module and it latest version

29. vgo tutorial (7) - Upgrade
● Upgrade to latest module

30. vgo tutorial (8) - run test on latest module
● Try to test latest modules

31. vgo tutorial (9) - Downgrading
● Use `vgo get` to downgrading specific version

32. vgo tutorial (10) - Excluding
● Excluding specific version

33. 1. Go & Versioning from Russ Cox
2. Youtube: Building Predictability into Your Pipeline ::
Russ Cox; Jess Frazelle, Sam Boyer, Pete Garcin
3. GopherCon 2017: Sam Boyer - The New Era of Go
Package Management
4. Using vgo for Go Dependency Management
5. Repeatable Builds with vgo
Reference:

34. Youtube: Building Predictability into Your Pipeline :: Russ
Cox; Jess Frazelle, Sam Boyer, Pete Garcin