vendor: evaluate 'github.com/golang/dep'

[gyuho]

Experiment with official Go's dependency management tool https://github.com/golang/dep

[gyuho]

We can't use this until this is addressed golang/dep#120.
Currently dep would introduce extra >1million lines of vendor code.

[xiang90]

i do not believe this can happen in 3.3 release cycle based on the progress of golang/dep. @gyuho can we move this out of 3.3?

[olivere]

As asked in #8692, here's my very brief summary of checking with dep again, on my fork of etcd on a MBP.

$ uname -a
Darwin violet 17.0.0 Darwin Kernel Version 17.0.0: Thu Aug 24 21:48:19 PDT 2017; root:xnu-4570.1.46~2/RELEASE_X86_64 x86_64
$ glide -v
glide version 0.13.0
$ rm -rf vendor
$ glide i
...
violet master … github.com/olivere/etcd $ du -h vendor | wc -l
     802
violet master … github.com/olivere/etcd $ du -h vendor | tail -1
 74M	vendor

Next up, dep:

$ dep version
dep:
 version     : devel
 build date  :
 git hash    :
 go version  : go1.9.1
 go compiler : gc
 platform    : darwin/amd64
$ rm -rf vendor
$ dep init
Importing configuration from glide. These are only initial constraints, and are further refined during the solve process.
Detected glide configuration files...
Converting from glide.yaml and glide.lock...
  Using ^0.1.0 as initial constraint for imported dep github.com/bgentry/speakeasy
  Trying v0.1.0 (4aabc24) as initial lock for imported dep github.com/bgentry/speakeasy
  Using ^1.3.1-coreos.2 as initial constraint for imported dep github.com/coreos/bbolt
  Trying v1.3.1-coreos.2 (54f6fad) as initial lock for imported dep github.com/coreos/bbolt
...
$ du -h vendor | wc -l
     955
$ du -h vendor | tail -1
 94M	vendor

[gyuho]

I remember we had to add some [[override]] rules.

[olivere]

@gyuho Sorry. I just updated my findings--I forgot to merge from upstream first. The numbers changed a bit, but the end result is basically the same.

[gyuho]

Plan to migrate to dep after 3.3 release. I migrated another project with dep

1. https://github.com/coreos/dbtester/blob/master/scripts/updatedep.sh
2. https://github.com/coreos/dbtester/blob/master/Gopkg.toml
3. https://github.com/coreos/dbtester/blob/master/.gitignore

We need .gitignore updates until dep implements pruning.