Implement Event handling

.rubocop_todo.yml

@@ -1,6 +1,6 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2019-07-20 16:07:34 +0200 using RuboCop version 0.73.0.
+# on 2019-07-30 20:31:00 +0200 using RuboCop version 0.73.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -118,7 +118,7 @@ Layout/Tab:
   Exclude:
     - 'config/initializers/omniauth.rb'
 
-# Offense count: 6
+# Offense count: 5
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle.
 # SupportedStyles: final_newline, final_blank_line
@@ -129,7 +129,6 @@ Layout/TrailingBlankLines:
     - 'app/controllers/sessions_controller.rb'
     - 'app/models/user.rb'
     - 'config/initializers/sidekiq.rb'
-    - 'config/initializers/voxpupuli.rb'
 
 # Offense count: 2
 # Cop supports --auto-correct.
@@ -140,7 +139,7 @@ Layout/TrailingWhitespace:
 
 # Offense count: 6
 Metrics/AbcSize:
-  Max: 111
+  Max: 118
 
 # Offense count: 1
 Metrics/CyclomaticComplexity:
@@ -253,11 +252,11 @@ Style/CommentAnnotation:
   Exclude:
     - 'app/workers/repo_status_worker.rb'
 
-# Offense count: 18
+# Offense count: 23
 Style/Documentation:
   Enabled: false
 
-# Offense count: 59
+# Offense count: 64
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle.
 # SupportedStyles: always, never
@@ -333,15 +332,15 @@ Style/TrailingCommaInArguments:
   Exclude:
     - 'config/initializers/semantic_logger.rb'
 
-# Offense count: 3
+# Offense count: 1
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle, MinSize, WordRegex.
 # SupportedStyles: percent, brackets
 Style/WordArray:
   Exclude:
     - 'config/initializers/voxpupuli.rb'
 
-# Offense count: 58
+# Offense count: 69
 # Cop supports --auto-correct.
 # Configuration parameters: AutoCorrect, AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, IgnoredPatterns.
 # URISchemes: http, https

.travis.yml

@@ -4,7 +4,7 @@ dist: xenial
 language: ruby
 cache: bundler
 script:
-  - 'bundle exec rake $CHECK'
+  - 'bundle exec rails $CHECK'
 matrix:
   fast_finish: true
   include:

app/controllers/incoming_controller.rb

@@ -2,10 +2,15 @@ class IncomingController < ApplicationController
   skip_before_action :verify_authenticity_token
   skip_before_action :logged_in
 
+  ##
+  #  Parse the whole payload from Github and hand it over to the GithubEvent handler
   def github
-    # parse the JSON payload, that we get as string, to a hash
     useable_body = JSON.parse(request.body.read).to_h
 
+    # For debug purposes we currently log the requets into Sentry
+    # TODO: Remove this line since the GithubEvent handler reports unknown events.
     Raven.capture_message('Received hook', extra: useable_body)
+
+    GithubEvent.new(useable_body, request.headers['X-GitHub-Event'])
   end
 end

app/lib/github_event.rb

@@ -0,0 +1,19 @@
+class GithubEvent
+  attr_reader :processor
+  delegate :process, to: :processor
+
+  ##
+  # The GithubEvent handler checks which type of event we are dealing with.
+  #
+  # If it is a known event, create a specific handler and let it take care of
+  # the next steps. If not kick off a Sentry error.
+
+  def initialize(payload, type)
+    case type
+    when 'pull_request'
+      @processor = GithubEvent::PullRequest.new(payload)
+    else
+      Raven.capture_message('Unknown Hook Received', extra: payload)
+    end
+  end
+end

app/lib/github_event/base.rb

@@ -0,0 +1,13 @@
+class GithubEvent
+  class Base
+    attr_reader :payload
+
+    ##
+    # Receive the payload and start processing it
+
+    def initialize(payload)
+      @payload = payload
+      process
+    end
+  end
+end

app/lib/github_event/pull_request.rb

@@ -0,0 +1,13 @@
+class GithubEvent
+  class PullRequest < GithubEvent::Base
+    attr_reader :gh_pull_request
+
+    ##
+    # Currently we only care about syncing our database with GitHub as our validation
+    # will take action if necessary.
+
+    def process
+      ::PullRequest.update_with_github(payload['pull_request'])
+    end
+  end
+end

app/models/label.rb

@@ -1,3 +1,8 @@
 class Label < ApplicationRecord
   has_and_belongs_to_many :pull_requests
+
+  # TODO: Find out how to manage predefined labels
+  def self.needs_rebase
+    find_or_create_by(name: 'needs-rebase', color: '207de5')
+  end
 end

app/models/pull_request.rb

@@ -1,4 +1,89 @@
 class PullRequest < ApplicationRecord
-  belongs_to :repository
+  # It is easier overall to use the GitHub ID for relation management.
+  # It allows us to maintain, update or the Repository or PullRequest without
+  # the counterpart.
+  belongs_to :repository, primary_key: :github_id, foreign_key: :gh_repository_id, inverse_of: :pull_requests
+
   has_and_belongs_to_many :labels
+  after_save :queue_validation
+
+  ##
+  # This method is used for updating our database with the current state of the PullRequest
+  # in GitHub. Therefore it's used with the payload of the webhook content processed by
+  # GithubEvent handler and by the content from the api fetched by the periodic check.
+
+  def self.update_with_github(gh_pull_request)
+    PullRequest.where(github_id: gh_pull_request['id']).first_or_initialize.tap do |pull_request|
+      pull_request.number           = gh_pull_request['number']
+      pull_request.state            = gh_pull_request['state']
+      pull_request.title            = gh_pull_request['title']
+      pull_request.body             = gh_pull_request['body']
+      pull_request.gh_created_at    = gh_pull_request['created_at']
+      pull_request.gh_updated_at    = gh_pull_request['updated_at']
+      pull_request.gh_repository_id = gh_pull_request['base']['repo']['id']
+      pull_request.closed_at        = gh_pull_request['closed_at']
+      pull_request.merged_at        = gh_pull_request['merged_at']
+      pull_request.mergeable        = gh_pull_request['mergeable']
+      pull_request.save
+
+      gh_pull_request['labels'].each do |label|
+        pull_request.labels << Label.find_or_create_by(name: label['name'], color: label['color'])
+      end
+    end
+  end
+
+  ##
+  #  Ensure that the Label is attached to the PullRequest
+  #
+  #  Therefore ensure that the Label exists for the corresponding repository
+  #
+  #  Then ensure the Label is attached to this PullRequest by checking the list
+  #  of attached Labels. Unfortunately this seems to be the only option
+  #
+  #  If the list does not include the given Label we attach it
+
+  def ensure_label_is_attached(label)
+    repository.ensure_label_exists(label)
+
+    attached_labels = Github.client.labels_for_issue(gh_repository_id, number)
+    return if attached_labels.any? { |attached_label| attached_label['name'] == label.name }
+
+    Github.client.add_labels_to_an_issue(gh_repository_id, number, [label.name])
+  end
+
+  ##
+  #  We simply remove the given Label if it exists
+
+  def ensure_label_is_detached(label)
+    Github.client.remove_label(gh_repository_id, number, label.name)
+  end
+
+  ##
+  #  if the PullRequest is mergeable we need to check if the 'needs-rebase' Label
+  #  is attached. If so, we need to remove it.
+  #
+  #  If the PullRequest is not yet mergeable we need to attach the 'needs-rebase'
+  #  Label. Therefore we also need to check if the Label exists on repository level.
+  #
+  # The saved_changes variable includes all the stuff that has changed.
+  # We currently don't care about them
+
+  def validate(_saved_changes)
+    if mergeable
+      ensure_label_is_detached(Label.needs_rebase)
+    else
+      repository.ensure_label_exists(Label.needs_rebase)
+      ensure_label_is_attached(label)
+    end
+  end
+
+  private
+
+  ##
+  #  Since we want to be a fancy responsive application we to all the validation
+  #  stuff which might result in some new querys and api requests asyncronously.
+
+  def queue_validation
+    ValidatePullRequestWorker.perform_async(id, saved_changes) if saved_changes?
+  end
 end

app/models/repository.rb

@@ -1,6 +1,9 @@
 class Repository < ApplicationRecord
-  has_many :pull_requests
-  has_many :open_pull_requests, -> { where(state: 'open') }, class_name: 'PullRequest'
+  # It is easier overall to use the GitHub ID for relation management.
+  # It allows us to maintain, update or the Repository or PullRequest without
+  # the counterpart.
+  has_many :pull_requests, primary_key: :github_id, foreign_key: :gh_repository_id, inverse_of: :repository
+  has_many :open_pull_requests, -> { where(state: 'open') }, class_name: 'PullRequest', primary_key: :github_id, foreign_key: :gh_repository_id
 
   def actions_needed
     @action_needed ||= begin
@@ -19,25 +22,31 @@ def github_url
     'https://github.com/' + full_name
   end
 
+  ##
+  #  Check if the Label exists in the Repository
+  #  If we get a 404 create the Label.
+
+  def ensure_label_exists(label)
+    GitHub.client.label(github_id, label.name)
+  rescue Octokit::NotFound
+    Github.client.add_label(github_id, label.name, label.color)
+  end
+
+  ##
+  #  Delete the given Label from the Repository
+  #
+  def ensure_label_missing(label)
+    GitHub.client.delete_label!(github_id, label.name)
+  end
+
+  ##
+  #  Fetch all open and closed PullRequests and sync our database with them
+  #
   def update_pull_requests
     open_pull_requests = Github.client.pull_requests("voxpupuli/#{name}")
     closed_pull_requests = Github.client.pull_requests("voxpupuli/#{name}", state: :closed)
     (open_pull_requests + closed_pull_requests).each do |gh_pull_request|
-      PullRequest.where(repository_id: id, number: gh_pull_request.number).first_or_initialize.tap do |pull_request|
-        pull_request.number = gh_pull_request.number
-        pull_request.state = gh_pull_request.state
-        pull_request.title = gh_pull_request.title
-        pull_request.body = gh_pull_request.body
-        pull_request.gh_created_at = gh_pull_request.created_at
-        pull_request.gh_updated_at = gh_pull_request.updated_at
-        pull_request.closed_at = gh_pull_request.closed_at
-        pull_request.merged_at = gh_pull_request.merged_at
-        pull_request.save
-
-        gh_pull_request.labels.each do |label|
-          pull_request.labels << Label.find_or_create_by(name: label.name, color: label.color)
-        end
-      end
+      PullRequest.update_with_github(gh_pull_request)
     end
 
     pull_requests.count

app/workers/repo_status_worker.rb

@@ -11,7 +11,6 @@ def save_data_to_redis(data)
   # Categorizes repository based on their locally cached information
   # implements https://github.com/voxpupuli/modulesync_config/blob/master/bin/get_all_the_diffs
   # TODO: clean up stuff and make it less shitty
-  # rubocop:disable Metrics/AbcSize
   def perform
     repos = Repository.pluck(:name)
     data = OpenStruct.new
@@ -144,5 +143,4 @@ def perform
 
     save_data_to_redis(data)
   end
-  # rubocop:enable Metrics/AbcSize
 end

app/workers/validate_pull_request_worker.rb

@@ -0,0 +1,12 @@
+class ValidatePullRequestWorker
+  include Sidekiq::Worker
+
+  ##
+  # As validation may take a bit more time we do it async.
+  # This worker is not meant to hold any logic but only trigger the
+  # validation in its asyncronous context.
+
+  def perform(id, saved_changes)
+    PullRequest.find(id).validate(saved_changes)
+  end
+end

db/migrate/20190730094710_add_mergeable_and_gh_repo_id_to_pull_requests.rb

@@ -0,0 +1,7 @@
+class AddMergeableAndGhRepoIdToPullRequests < ActiveRecord::Migration[5.2]
+  def change
+    add_column :pull_requests, :mergeable, :boolean
+    add_column :pull_requests, :gh_repository_id, :integer
+    add_column :pull_requests, :github_id, :integer
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2019_06_20_115024) do
+ActiveRecord::Schema.define(version: 2019_07_30_094710) do
 
   create_table "labels", force: :cascade do |t|
     t.string "name"
@@ -38,6 +38,9 @@
     t.integer "repository_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.boolean "mergeable"
+    t.integer "gh_repository_id"
+    t.integer "github_id"
     t.index ["repository_id"], name: "index_pull_requests_on_repository_id"
   end