Gitlab integration support

[fudanchii]

This is the preliminary version of GitLab integration

Current features:

• Drone may use either gitlab.com or self-hosted repo with custom domain
• Paste GitLab user's private_token to link drone's user with gitlab's.
• User may change this private_token later (re-link account)
• Add private or public repository
• Add deploy key on private repository, use ssh to clone at build.
• Add post commit hook, and merge_request hook
• Build on post-commit and merge-request

Known glitch (wip/open for contribution):

• Re-registering repository may adds duplicated hooks and deploy key
  This may be fixed at go-gitlab-client ( Currently there's no function similar to go-github's CreateUpdate)
• Building branch with / on its name may be broken,
  Need to encode / to %2F when calling GitLab API
• merge_request build from forked repository doesn't work, it works if merge request came from the same repository.
  Unlike GitHub, GitLab doesn't provide MR/PR refs at parent repository,
  This should be fetched and merged manually at build which require Drone to also save source repository url from which the MR/PR came from, and this may bump into another problem when the source repository is marked as private. Possible fix is to propose a patch to GitLab to add refs at parent repository for each PR/MR, similar to how GitHub PR works. (I just noticed that we don't have this feature too for bitbucket, so nvm I guess?)
• Build still trying to trigger notification to GitHub, this should get decoupled.
• Some other unknown glitches, etc...

@bradrydzewski
I'd like to propose to vendorize go-gitlab-client for now and push back to upstream when things get stable here, or maybe a fork? What do you think?

Any inputs will be much appreciated,
Thanks!

(edit: s/private_key/private_token/g)

[bradrydzewski]

Looks like a really solid implementation! Great job!

There was an issue with the build related to the go-gitlab client. Take a look and let me know how to proceed. Thanks!

[fudanchii]

This should be built with plouc/go-gitlab-client#8 applied.
Related to my proposal above.

To build it manually:

go get github.com/plouc/go-gitlab-client
cd $GOPATH/src/github.com/plouc/go-gitlab-client
git remote add fudanchii https://github.com/fudanchii/go-gitlab-client
git fetch fudanchii
git checkout -b raw-request fudanchii/raw-request
cd $GOPATH/src/github.com/drone/drone
make

Since this is temporary,
I don't think we want to edit our .drone.yml or Makefile to accomodate this. Another reason why I propose to vendorize the package. ;D

[bradrydzewski]

sorry, I should have read your comments more closely :)

vendoring packages
There are currently three different options: godep, goven and gom. I'm leaning toward gom but haven't had the chance to play around to determine pros and cons. Have you tried gom yet?

merge requests
Bitbucket's implementation is quite new and wasn't as polished as GitHub so I decided to omit the feature for now. I recommend the same for GitLab if it isn't quite ready. I'll leave this up to you, since I don't have much experience with the platform.

We should add issues for any known issues / glitches so that we can track going forward.

Again, great work on this!

[bradrydzewski]

I also forgot to mention this package manager:
https://github.com/gpmgo/docs/blob/master/en-US/Quickstart.md

[fudanchii]

I pushed some workaround for this. Refer to my last commit message.
discussion regarding which dependency management to use at #177

[kzaitsev]

@fudanchii i send small PR, to add support self-signed certificates fudanchii/go-gitlab-client#1

[fudanchii]

@Bugagazavr It's been merged. Thank you!

[bradrydzewski]

Merged! Thanks again and feel free to add issues for any outstanding items

[dosire]

Thanks for supporting GitLab @fudanchii and @bradrydzewski !

[fudanchii]

@dosire You're welcome! We've just started, so it might still rough at the edges. :D
It's an effort of the community, this support could not even started without @plouc's go-gitlab-client and awesome contributions from @arrowcircle, @luxifer and all fine folks at #53!

Kudos for all of them!

[luxifer]

thanks @fudanchii ;)

[swistaczek]

Great work folks!

[cindoum]

When will this feature be live? (on https://drone.io/)