Add support to connect gitlab-shell to Unicorn via UNIX socket  (v2)

Hello up there.

I'm doing SlapOS port of GitLab, and that means several different services could be running on the same machine, including several GitLabs.

So far all internal GitLab subservices could be glued together via UNIX sockets except gitlab-shell -> Unicorn link, which, when done via local TCP, requires firewall/network namespaces to protect services on one machine from each other.

On the other hand access to UNIX domain sockets is managed via regular UNIX permissions on filesystem, and thus is easier to manage. Besides UNIX domain sockets are well known to be faster compared to TCP over loopback - in particular to have ~ 2 times less latency and ~ 2 times more throughput.

From this point of view it makes sense to teach gitlab-shell to talk to Unicorn via UNIX socket and switch to that mode by default eventually.

I've just made a patch for this. Please apply.

Thanks beforehand,  
Kirill

/cc @dzaporozhets, @jacobvosmaer, @rspeicher 

See merge request !30

Use load path, set ROOT_PATH via ENV

Uses load path instead of require_relative, adds an environment variable to set gitlab-shell ROOT_PATH variable (Fixes #30)

See merge request !28

It is well known that UNIX sockets are faster than TCP over loopback.

E.g. on my machine according to lmbench[1] they have ~ 2 times
lower latency and ~ 2-3 times more throughput compared to TCP over
loopback:

    *Local* Communication latencies in microseconds - smaller is better
    ---------------------------------------------------------------------
    Host                 OS 2p/0K  Pipe AF     UDP  RPC/   TCP  RPC/ TCP
                            ctxsw       UNIX         UDP         TCP conn
    --------- ------------- ----- ----- ---- ----- ----- ----- ----- ----
    teco      Linux 4.2.0-1  13.8  29.2 26.8  45.0  47.9  48.5  55.5  45.

    *Local* Communication bandwidths in MB/s - bigger is better
    -----------------------------------------------------------------------------
    Host                OS  Pipe AF    TCP  File   Mmap  Bcopy  Bcopy  Mem   Mem
                                 UNIX      reread reread (libc) (hand) read write
    --------- ------------- ---- ---- ---- ------ ------ ------ ------ ---- -----
    teco      Linux 4.2.0-1 1084 4353 1493 2329.1 3720.7 1613.8 1109.2 3402 1404.

The same ratio usually holds for servers.

Also UNIX sockets, since they reside on filesystem, besides being faster with
less latency, have one another nice property: access permissions to them are
managed the same way access to files is.

Because of lower latencies and higher throughput - for performance reasons, and
for easier security, it makes sense to interconnect services on one machine via
UNIX sockets and talk via TCP only to outside world.

All internal services inside GitLab can talk to each other via UNIX socket
already and only gitlab-shell was missing support to talk to Unicorn via UNIX
socket.

Let's teach gitlab-shell to talk via UNIX sockets.

[1] http://www.bitmover.com/lmbench/

~~~~

In this patch we

- add URI::HTTPUNIX to handle http+unix:// URI scheme
- add Net::HTTPUNIX to handle "connect via unix socket and then talk http"
- adjust GitlabNet#http_client_for() accordingly
- adjust documentation in config.yml.example

The http+unix:// scheme is not reinvented anew: the idea about its structure is
quite logical an was already established at least in requests-unixsocket python
package:

    http://fixall.online/theres-no-need-to-reinvent-the-wheelhttpsgithubcommsabramorequests-unixsocketurl/241810/
    https://github.com/msabramo/requests-unixsocket

Adapt gitlab-ci.yml for shared runners

After merging this we should disconnect the specific runner on gitlab-org/gitlab-shell.

See merge request !27

Version bump 2.6.6



See merge request !22

Skip 'git annex init' when using 'gcryptsetup'

'gcryptsetup' is a special git-annex feature that does its own
initialization.

See merge request !18

change images to svg

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

When cleaning this environment variable can be problems with the processing of non-ASCII data

Handle broken symlinks in create-hooks

If a repository contained a broken symlink named 'hooks', this would
raise ENOENT in lib/gitlab_projects.rb, which got ignored in
bin/create-hooks. This commit fixes that by making sure we handle
broken symlinks in lib/gitlab_projects.rb.

See merge request !19

If a repository contained a broken symlink named 'hooks', this would
raise ENOENT in lib/gitlab_projects.rb, which got ignored in
bin/create-hooks. This commit fixes that by making sure we handle
broken symlinks in lib/gitlab_projects.rb.

'gcryptsetup' is a special git-annex feature that does its own
initialization.

Version bump 2.6.4



See merge request !17

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Remove keys from authorized_keys in-place

This will speed up the rm-key operation. The downside is that
authorized_keys will not shrink when you remove a key. If this ever
becomes a problem it can be fixed by running 'rake gitlab:shell:setup'.

See merge request !66

This will speed up the rm-key operation. The downside is that
authorized_keys will not shrink when you remove a key. If this ever
becomes a problem it can be fixed by running 'rake gitlab:shell:setup'.

Add git-lfs-authenticate to command white list

Add gitlab-ci yml script
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

cc @vsizov

See merge request !14

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>