Support integration with Koding (online IDE)

Koding: #index: landing page for Koding integration

If enabled it will provide a link to open remote Koding instance url
for now we are also providing the sneak preview video for how
integration works in detail.

Repository: check whether .koding.yml file exists on repository

Projects: landing page: show Run in IDE (Koding) button if repo has stack file

Projects: MR: show Run in IDE Koding button if repo has stack file on active branch

ProjectHelpers: add_koding_stack: stack generator for provided project

With this helper we will auto-generate the required stack template
for a given project. For the feature we can request this base template
from the running Koding instance on integration.

Currently this will provide users to create a t2.nano instance on aws
and it'll automatically configures the instance for basic requirements.

Projects: empty state and landing page provide shortcuts to create stack

projects_helper: use branch on checkout and provide an entry point

This ${var.koding_queryString_branch} will be replaced with the branch
provided in query string which will allow us to use same stack template
for different branches of the same repository.

ref: https://github.com/koding/koding/pull/8597/commits/b8c0e43c4c24bf132670aa8a3cfb0d634acfd09b

projects_helper: provide sha info in query string to use existing vms

With this change we'll be able to query existing vms on Koding side
based on the commit id that they've created.

ref: https://github.com/koding/koding/pull/8597/commits/1d630fadf31963fa6ccd3bed92e526761a30a343

Integration: Docs: Koding documentation added

Disable /koding route if integration is disabled

Use application settings to enable Koding

Projects_helper: better indentation with strip_heredoc usage

Projects_helper: return koding_url as is if there is no project provided

current_settings: set koding_enabled: false by default

Koding_Controller: to render not_found once integration is disabled

Dashboard_specs: update spec for Koding enabled case

Projects_Helper: make repo dynamic

ref: https://github.com/koding/koding/pull/8597/commits/4d615242f45aaea4c4986be84ecc612b0bb1514c

Updated documentation to have right format

14 files changed, 149 insertions, 2 deletions

diff --git a/app/assets/images/koding-logo.svg b/app/assets/images/koding-logo.svg
new file mode 100644
index 00000000000..ad89d684d94
--- /dev/null
+++ b/app/assets/images/koding-logo.svg
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 12 14">
+    <g fill="#d6d7d9">
+        <path d="M8.7 0L5.3.3l3.2 6.8-3.2 6.6 3.5.3L12 6.9z"/>
+        <ellipse cx="1.7" cy="11.1" rx="1.7" ry="1.7"/>
+        <ellipse cx="1.7" cy="5.6" rx="1.7" ry="1.7"/>
+    </g>
+</svg>
\ No newline at end of file
diff --git a/app/controllers/admin/application_settings_controller.rb b/app/controllers/admin/application_settings_controller.rb
index 9e1dc15de84..6ef7cf0bae6 100644
--- a/app/controllers/admin/application_settings_controller.rb
+++ b/app/controllers/admin/application_settings_controller.rb
@@ -109,6 +109,8 @@ class Admin::ApplicationSettingsController < Admin::ApplicationController
       :sentry_dsn,
       :akismet_enabled,
       :akismet_api_key,
+      :koding_enabled,
+      :koding_url,
       :email_author_in_body,
       :repository_checks_enabled,
       :metrics_packet_size,
diff --git a/app/controllers/koding_controller.rb b/app/controllers/koding_controller.rb
new file mode 100644
index 00000000000..bb89f3090f9
--- /dev/null
+++ b/app/controllers/koding_controller.rb
@@ -0,0 +1,15 @@
+class KodingController < ApplicationController
+  before_action :check_integration!, :authenticate_user!, :reject_blocked!
+  layout 'koding'
+
+  def index
+    path = File.join(Rails.root, 'doc/integration/koding-usage.md')
+    @markdown = File.read(path)
+  end
+
+  private
+
+  def check_integration!
+    render_404 unless current_application_settings.koding_enabled?
+  end
+end
diff --git a/app/helpers/application_settings_helper.rb b/app/helpers/application_settings_helper.rb
index 78c0b79d2bd..6de25bea654 100644
--- a/app/helpers/application_settings_helper.rb
+++ b/app/helpers/application_settings_helper.rb
@@ -31,6 +31,10 @@ module ApplicationSettingsHelper
     current_application_settings.akismet_enabled?
   end
 
+  def koding_enabled?
+    current_application_settings.koding_enabled?
+  end
+
   def allowed_protocols_present?
     current_application_settings.enabled_git_access_protocol.present?
   end
diff --git a/app/helpers/projects_helper.rb b/app/helpers/projects_helper.rb
index 505545fbabb..249d18c4486 100644
--- a/app/helpers/projects_helper.rb
+++ b/app/helpers/projects_helper.rb
@@ -236,6 +236,60 @@ module ProjectsHelper
     )
   end
 
+  def add_koding_stack_path(project)
+    namespace_project_new_blob_path(
+      project.namespace,
+      project,
+      project.default_branch || 'master',
+      file_name:      '.koding.yml',
+      commit_message: "Add Koding stack script",
+      content: <<-CONTENT.strip_heredoc
+        provider:
+          aws:
+            access_key: '${var.aws_access_key}'
+            secret_key: '${var.aws_secret_key}'
+        resource:
+          aws_instance:
+            #{project.path}-vm:
+              instance_type: t2.nano
+              user_data: |-
+
+                # Created by GitLab UI for :>
+
+                echo _KD_NOTIFY_@Installing Base packages...@
+
+                apt-get update -y
+                apt-get install git -y
+
+                echo _KD_NOTIFY_@Cloning #{project.name}...@
+
+                export KODING_USER=${var.koding_user_username}
+                export REPO_URL=#{root_url}${var.koding_queryString_repo}.git
+                export BRANCH=${var.koding_queryString_branch}
+
+                sudo -i -u $KODING_USER git clone $REPO_URL -b $BRANCH
+
+                echo _KD_NOTIFY_@#{project.name} cloned.@
+      CONTENT
+    )
+  end
+
+  def koding_project_url(project = nil, branch = nil, sha = nil)
+    if project
+      import_path = "/Home/Stacks/import"
+
+      repo = project.path_with_namespace
+      branch ||= project.default_branch
+      sha ||= project.commit.short_id
+
+      path = "#{import_path}?repo=#{repo}&branch=#{branch}&sha=#{sha}"
+
+      return URI.join(current_application_settings.koding_url, path).to_s
+    end
+
+    current_application_settings.koding_url
+  end
+
   def contribution_guide_path(project)
     if project && contribution_guide = project.repository.contribution_guide
       namespace_project_blob_path(
diff --git a/app/models/application_setting.rb b/app/models/application_setting.rb
index 8c19d9dc9c8..f0bcb2d7cda 100644
--- a/app/models/application_setting.rb
+++ b/app/models/application_setting.rb
@@ -55,6 +55,10 @@ class ApplicationSetting < ActiveRecord::Base
             presence: true,
             if: :akismet_enabled
 
+  validates :koding_url,
+            presence: true,
+            if: :koding_enabled
+
   validates :max_attachment_size,
             presence: true,
             numericality: { only_integer: true, greater_than: 0 }
@@ -149,6 +153,8 @@ class ApplicationSetting < ActiveRecord::Base
       two_factor_grace_period: 48,
       recaptcha_enabled: false,
       akismet_enabled: false,
+      koding_enabled: false,
+      koding_url: nil,
       repository_checks_enabled: true,
       disabled_oauth_sign_in_sources: [],
       send_user_confirmation_email: false,
diff --git a/app/models/repository.rb b/app/models/repository.rb
index 2494c266cd2..bdc3b9d1c1c 100644
--- a/app/models/repository.rb
+++ b/app/models/repository.rb
@@ -277,7 +277,7 @@ class Repository
   def cache_keys
     %i(size commit_count
        readme version contribution_guide changelog
-       license_blob license_key gitignore)
+       license_blob license_key gitignore koding_yml)
   end
 
   # Keys for data on branch/tag operations.
@@ -553,6 +553,14 @@ class Repository
     end
   end
 
+  def koding_yml
+    return nil unless head_exists?
+
+    cache.fetch(:koding_yml) do
+      file_on_head(/\A\.koding\.yml\z/)
+    end
+  end
+
   def gitlab_ci_yml
     return nil unless head_exists?
 
diff --git a/app/views/admin/application_settings/_form.html.haml b/app/views/admin/application_settings/_form.html.haml
index c7fd344eea2..e0878512e62 100644
--- a/app/views/admin/application_settings/_form.html.haml
+++ b/app/views/admin/application_settings/_form.html.haml
@@ -388,6 +388,25 @@
         .help-block
           If you got a lot of false alarms from repository checks you can choose to clear all repository check information from the database.
 
+  %fieldset
+    %legend Koding
+    .form-group
+      .col-sm-offset-2.col-sm-10
+        .checkbox
+          = f.label :koding_enabled do
+            = f.check_box :koding_enabled
+            Enable Koding
+    .form-group
+      = f.label :koding_url, 'Koding URL', class: 'control-label col-sm-2'
+      .col-sm-10
+        = f.text_field :koding_url, class: 'form-control', placeholder: 'http://gitlab.your-koding-instance.com:8090'
+        .help-block
+          Koding has integration enabled out of the box for the
+          %strong gitlab
+          team, and you need to provide that team's URL here. Learn more in the
+          = succeed "." do
+            = link_to "Koding integration documentation", help_page_path("integration/koding")
+
 
   .form-actions
     = f.submit 'Save', class: 'btn btn-save'
diff --git a/app/views/koding/index.html.haml b/app/views/koding/index.html.haml
new file mode 100644
index 00000000000..111cc67336c
--- /dev/null
+++ b/app/views/koding/index.html.haml
@@ -0,0 +1,9 @@
+.row-content-block.second-block.center
+  %p
+    = icon('circle', class: 'cgreen')
+    Integration is active for
+    = link_to koding_project_url, target: '_blank' do
+      #{current_application_settings.koding_url}
+
+.documentation.wiki
+  = markdown @markdown
diff --git a/app/views/layouts/koding.html.haml b/app/views/layouts/koding.html.haml
new file mode 100644
index 00000000000..22319bba745
--- /dev/null
+++ b/app/views/layouts/koding.html.haml
@@ -0,0 +1,5 @@
+- page_title        "Koding"
+- page_description  "Koding Dashboard"
+- header_title      "Koding", koding_path
+
+= render template: "layouts/application"
diff --git a/app/views/layouts/nav/_dashboard.html.haml b/app/views/layouts/nav/_dashboard.html.haml
index 3a14751ea8e..67f558c854b 100644
--- a/app/views/layouts/nav/_dashboard.html.haml
+++ b/app/views/layouts/nav/_dashboard.html.haml
@@ -12,6 +12,11 @@
     = link_to activity_dashboard_path, class: 'dashboard-shortcuts-activity', title: 'Activity' do
       %span
         Activity
+  - if koding_enabled?
+    = nav_link(controller: :koding) do
+      = link_to koding_path, title: 'Koding' do
+        %span
+          Koding
   = nav_link(controller: [:groups, 'groups/milestones', 'groups/group_members']) do
     = link_to dashboard_groups_path, title: 'Groups' do
       %span
diff --git a/app/views/projects/buttons/_koding.html.haml b/app/views/projects/buttons/_koding.html.haml
new file mode 100644
index 00000000000..fdc80d44253
--- /dev/null
+++ b/app/views/projects/buttons/_koding.html.haml
@@ -0,0 +1,7 @@
+- if koding_enabled? && current_user && can_push_branch?(@project, @project.default_branch)
+  - if @repository.koding_yml
+    = link_to koding_project_url(@project), class: 'btn', target: '_blank' do
+      Run in IDE (Koding)
+  - else
+    = link_to add_koding_stack_path(@project), class: 'btn' do
+      Set Up Koding
diff --git a/app/views/projects/merge_requests/_show.html.haml b/app/views/projects/merge_requests/_show.html.haml
index f8025fc1dbe..9d8b4cc56be 100644
--- a/app/views/projects/merge_requests/_show.html.haml
+++ b/app/views/projects/merge_requests/_show.html.haml
@@ -16,6 +16,9 @@
       - if @merge_request.open?
         .pull-right
           - if @merge_request.source_branch_exists?
+            - if koding_enabled? && @repository.koding_yml
+              = link_to koding_project_url(@merge_request.source_project, @merge_request.source_branch, @merge_request.commits.first.short_id), class: "btn inline btn-grouped btn-sm", target: '_blank' do
+                Run in IDE (Koding)
             = link_to "#modal_merge_info", class: "btn inline btn-grouped btn-sm", "data-toggle" => "modal" do
               Check out branch
 
diff --git a/app/views/projects/show.html.haml b/app/views/projects/show.html.haml
index a666d07e9eb..340e159c874 100644
--- a/app/views/projects/show.html.haml
+++ b/app/views/projects/show.html.haml
@@ -64,10 +64,12 @@
         %li.missing
           = link_to add_special_file_path(@project, file_name: '.gitlab-ci.yml') do
             Set Up CI
+
     %li.project-repo-buttons-right
       .project-repo-buttons.project-right-buttons
         - if current_user
           = render 'shared/members/access_request_buttons', source: @project
+          = render "projects/buttons/koding"
 
         .btn-group.project-repo-btn-group
           = render "projects/buttons/download"
@@ -86,4 +88,4 @@
         Archived project! Repository is read-only
 
   %div{class: "project-show-#{default_project_view}"}
-    = render default_project_view
\ No newline at end of file
+    = render default_project_view