Added basic implementation of GitLab Chatops

The chatops solution is built on top of CI pipelines and essentially
acts as a different UI for scheduling pipelines manually. Pipelines
scheduled via chat have access to an environment variable called
"CHAT_INPUT". This variable stores the arguments that were passed to the
chatops command.

Output is retrieved by reading specific trace sections from the build
output. There are two sections supported (in this order):

1. chat_reply
2. build_script

The "chat_reply" is a trace section that one has to generate themselves,
"build_script" in turn is provided by default. The "build_script" trace
section also includes the output of any commands executed in the
"before_script" list. If one doesn't want to display this output they
should generate the custom "chat_reply" trace section.

Responses are sent back via Sidekiq using the ChatNotificationWorker
class. This ensures that existing CI related jobs won't get slowed down
if Slack (or another chat service) is not responding.

app/models/ci/pipeline.rb

@@ -62,7 +62,8 @@ module Ci
       schedule: 4,
       api: 5,
       external: 6,
-      pipeline: 7
+      pipeline: 7,
+      chat: 8
     }
 
     enum config_source: {

app/models/project_services/slack_slash_commands_service.rb

 class SlackSlashCommandsService < SlashCommandsService
+  prepend EE::SlackSlashCommandsService
   include TriggersHelper
 
   def title

app/services/ci/create_pipeline_service.rb

@@ -3,6 +3,7 @@ module Ci
     attr_reader :pipeline
 
     SEQUENCE = [Gitlab::Ci::Pipeline::Chain::Build,
+                EE::Gitlab::Ci::Pipeline::Chain::RemoveUnwantedChatJobs,
                 Gitlab::Ci::Pipeline::Chain::Validate::Abilities,
                 Gitlab::Ci::Pipeline::Chain::Validate::Repository,
                 Gitlab::Ci::Pipeline::Chain::Validate::Config,
@@ -29,7 +30,8 @@ module Ci
         current_user: current_user,
 
         # EE specific
-        allow_mirror_update: mirror_update
+        allow_mirror_update: mirror_update,
+        chat_data: params[:chat_data]
       )
 
       sequence = Gitlab::Ci::Pipeline::Chain::Sequence

app/workers/all_queues.yml

@@ -144,3 +144,4 @@
 - rebase
 - repository_update_mirror
 - repository_update_remote_mirror
+- chat_notification

app/workers/build_finished_worker.rb

 class BuildFinishedWorker
+  prepend EE::BuildFinishedWorker
   include ApplicationWorker
   include PipelineQueue
 

config/sidekiq_queues.yml

@@ -72,6 +72,7 @@
 
   # EE-specific queues
   - [ldap_group_sync, 2]
+  - [chat_notification, 2]
   - [geo, 1]
   - [repository_remove_remote, 1]
   - [repository_update_mirror, 1]

db/schema.rb

@@ -420,6 +420,14 @@ ActiveRecord::Schema.define(version: 20180301084653) do
   add_index "ci_job_artifacts", ["job_id", "file_type"], name: "index_ci_job_artifacts_on_job_id_and_file_type", unique: true, using: :btree
   add_index "ci_job_artifacts", ["project_id"], name: "index_ci_job_artifacts_on_project_id", using: :btree
 
+  create_table "ci_pipeline_chat_data", id: :bigserial, force: :cascade do |t|
+    t.integer "pipeline_id", null: false
+    t.integer "chat_name_id", null: false
+    t.text "response_url", null: false
+  end
+
+  add_index "ci_pipeline_chat_data", ["pipeline_id"], name: "index_ci_pipeline_chat_data_on_pipeline_id", unique: true, using: :btree
+
   create_table "ci_pipeline_schedule_variables", force: :cascade do |t|
     t.string "key", null: false
     t.text "value"
@@ -2505,6 +2513,8 @@ ActiveRecord::Schema.define(version: 20180301084653) do
   add_foreign_key "ci_group_variables", "namespaces", column: "group_id", name: "fk_33ae4d58d8", on_delete: :cascade
   add_foreign_key "ci_job_artifacts", "ci_builds", column: "job_id", on_delete: :cascade
   add_foreign_key "ci_job_artifacts", "projects", on_delete: :cascade
+  add_foreign_key "ci_pipeline_chat_data", "chat_names", on_delete: :cascade
+  add_foreign_key "ci_pipeline_chat_data", "ci_pipelines", column: "pipeline_id", on_delete: :cascade
   add_foreign_key "ci_pipeline_schedule_variables", "ci_pipeline_schedules", column: "pipeline_schedule_id", name: "fk_41c35fda51", on_delete: :cascade
   add_foreign_key "ci_pipeline_schedules", "projects", name: "fk_8ead60fcc4", on_delete: :cascade
   add_foreign_key "ci_pipeline_schedules", "users", column: "owner_id", name: "fk_9ea99f58d2", on_delete: :nullify

ee/app/models/ci/pipeline_chat_data.rb

+module Ci
+  class PipelineChatData < ActiveRecord::Base
+    self.table_name = 'ci_pipeline_chat_data'
+
+    belongs_to :chat_name
+
+    validates :pipeline_id, presence: true
+    validates :chat_name_id, presence: true
+    validates :response_url, presence: true
+  end
+end

ee/app/models/ee/ci/pipeline.rb

 module EE
   module Ci
     module Pipeline
+      extend ActiveSupport::Concern
+
       EE_FAILURE_REASONS = {
         activity_limit_exceeded: 20,
         size_limit_exceeded: 21
       }.freeze
 
+      included do
+        has_one :chat_data, class_name: 'Ci::PipelineChatData'
+      end
+
       def predefined_variables
         result = super
         result << { key: 'CI_PIPELINE_SOURCE', value: source.to_s, public: true }

ee/app/models/ee/slack_slash_commands_service.rb

+module EE
+  module SlackSlashCommandsService
+    def chat_responder
+      ::Gitlab::Chat::Responder::Slack
+    end
+  end
+end

ee/app/models/license.rb

@@ -62,6 +62,7 @@ class License < ActiveRecord::Base
     dast
     epics
     ide
+    chatops
   ].freeze
 
   # List all features available for early adopters,
@@ -316,6 +317,7 @@ class License < ActiveRecord::Base
 
   def reset_current
     self.class.reset_current
+    Gitlab::Chat.flush_available_cache
   end
 
   def reset_license

ee/app/workers/chat_notification_worker.rb

+# frozen_string_literal: true
+
+class ChatNotificationWorker
+  include ApplicationWorker
+
+  RESCHEDULE_INTERVAL = 2.seconds
+
+  def perform(build_id)
+    Ci::Build.find_by(id: build_id).try do |build|
+      send_response(build)
+    end
+  rescue Gitlab::Chat::Output::MissingBuildSectionError
+    # The creation of traces and sections appears to be eventually consistent.
+    # As a result it's possible for us to run the above code before the trace
+    # sections are present. To better handle such cases we'll just reschedule
+    # the job instead of producing an error.
+    self.class.perform_in(RESCHEDULE_INTERVAL, build_id)
+  end
+
+  def send_response(build)
+    Gitlab::Chat::Responder.responder_for(build).try do |responder|
+      if build.success?
+        output = Gitlab::Chat::Output.new(build)
+
+        responder.success(output.to_s)
+      else
+        responder.failure
+      end
+    end
+  end
+end

ee/app/workers/ee/build_finished_worker.rb

+module EE
+  module BuildFinishedWorker
+    def perform(build_id)
+      super
+
+      ::Ci::Build.find_by(id: build_id).try do |build|
+        ChatNotificationWorker.perform_async(build_id) if build.pipeline.chat?
+      end
+    end
+  end
+end

ee/changelogs/unreleased/chatops.yml

+---
+title: Added basic implementation of GitLab Chatops
+merge_request:
+author:
+type: added

ee/db/migrate/20180209115333_create_chatops_tables.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class CreateChatopsTables < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  def change
+    create_table :ci_pipeline_chat_data, id: :bigserial do |t|
+      t.integer :pipeline_id, null: false
+      t.references :chat_name, foreign_key: { on_delete: :cascade }, null: false
+      t.text :response_url, null: false
+
+      # A pipeline can only contain one row in this table, hence this index is
+      # unique.
+      t.index :pipeline_id, unique: true
+    end
+
+    add_foreign_key :ci_pipeline_chat_data, :ci_pipelines,
+      column: :pipeline_id,
+      on_delete: :cascade
+  end
+end

ee/lib/ee/gitlab/ci/pipeline/chain/remove_unwanted_chat_jobs.rb

+module EE
+  module Gitlab
+    module Ci
+      module Pipeline
+        module Chain
+          class RemoveUnwantedChatJobs < ::Gitlab::Ci::Pipeline::Chain::Base
+            def perform!
+              return unless pipeline.config_processor && pipeline.chat?
+
+              # When scheduling a chat pipeline we only want to run the build
+              # that matches the chat command.
+              pipeline.config_processor.jobs.select! do |name, _|
+                name.to_s == command.chat_data[:command].to_s
+              end
+            end
+
+            def break?
+              false
+            end
+          end
+        end
+      end
+    end
+  end
+end

ee/lib/gitlab/chat.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Chat
+    CACHE_TTL = 1.hour.to_i
+    AVAILABLE_CACHE_KEY = :gitlab_chat_available
+
+    # Returns `true` if Chatops is available for the current instance.
+    def self.available?
+      # We anticipate this code to be called rather frequently, especially on
+      # large instances such as GitLab.com. To reduce database load we cache the
+      # output for a while.
+      Rails.cache.fetch(AVAILABLE_CACHE_KEY, expires_in: CACHE_TTL) do
+        ::License.feature_available?(:chatops)
+      end
+    end
+
+    def self.flush_available_cache
+      Rails.cache.delete(AVAILABLE_CACHE_KEY)
+    end
+  end
+end

ee/lib/gitlab/chat/command.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Chat
+    # Class for scheduling chat pipelines.
+    #
+    # A Command takes care of creating a `Ci::Pipeline` with all the data
+    # necessary to execute a chat command. This includes data such as the chat
+    # data (e.g. the response URL) and any environment variables that should be
+    # exposed to the chat command.
+    class Command
+      include Utils::StrongMemoize
+
+      attr_reader :project, :chat_name, :name, :arguments, :response_url,
+                  :channel
+
+      # project - The Project to schedule the command for.
+      # chat_name - The ChatName belonging to the user that scheduled the
+      #             command.
+      # name - The name of the chat command to run.
+      # arguments - The arguments (as a String) to pass to the command.
+      # channel - The channel the message was sent from.
+      # response_url - The URL to send the response back to.
+      def initialize(project:, chat_name:, name:, arguments:, channel:, response_url:)
+        @project = project
+        @chat_name = chat_name
+        @name = name
+        @arguments = arguments
+        @channel = channel
+        @response_url = response_url
+      end
+
+      # Tries to create a new pipeline.
+      #
+      # This method will return a pipeline that _may_ be persisted, or `nil` if
+      # the pipeline could not be created.
+      def try_create_pipeline
+        return unless valid?
+
+        create_pipeline
+      end
+
+      def create_pipeline
+        service = ::Ci::CreatePipelineService.new(
+          project,
+          chat_name.user,
+          ref: branch,
+          sha: commit,
+          chat_data: {
+            chat_name_id: chat_name.id,
+            command: name,
+            arguments: arguments,
+            response_url: response_url
+          }
+        )
+
+        service.execute(:chat) do |pipeline|
+          create_environment_variables(pipeline)
+          create_chat_data(pipeline)
+        end
+      end
+
+      # pipeline - The `Ci::Pipeline` to create the environment variables for.
+      def create_environment_variables(pipeline)
+        pipeline.variables.create!(
+          [
+            { key: 'CHAT_INPUT', value: arguments },
+            { key: 'CHAT_CHANNEL', value: channel }
+          ]
+        )
+      end
+
+      # pipeline - The `Ci::Pipeline` to create the chat data for.
+      def create_chat_data(pipeline)
+        pipeline.create_chat_data!(
+          chat_name_id: chat_name.id,
+          response_url: response_url
+        )
+      end
+
+      def valid?
+        branch && commit
+      end
+
+      def branch
+        strong_memoize(:branch) { project.default_branch }
+      end
+
+      def commit
+        strong_memoize(:commit) do
+          project.commit(branch)&.id if branch
+        end
+      end
+    end
+  end
+end

ee/lib/gitlab/chat/output.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Chat
+    # Class for gathering and formatting the output of a `Ci::Build`.
+    class Output
+      attr_reader :build
+
+      MissingBuildSectionError = Class.new(StandardError)
+
+      # The primary trace section to look for.
+      PRIMARY_SECTION = 'chat_reply'
+
+      # The backup trace section in case the primary one could not be found.
+      FALLBACK_SECTION = 'build_script'
+
+      # build - The `Ci::Build` to obtain the output from.
+      def initialize(build)
+        @build = build
+      end
+
+      # Returns a `String` containing the output of the build.
+      #
+      # The output _does not_ include the command that was executed.
+      def to_s
+        offset, length = read_offset_and_length
+
+        trace.read do |stream|
+          stream.seek(offset)
+
+          output = stream
+            .stream
+            .read(length)
+            .force_encoding(Encoding.default_external)
+
+          without_executed_command_line(output)
+        end
+      end
+
+      # Returns the offset to seek to and the number of bytes to read relative
+      # to the offset.
+      def read_offset_and_length
+        section = find_build_trace_section(PRIMARY_SECTION) ||
+          find_build_trace_section(FALLBACK_SECTION)
+
+        unless section
+          raise(
+            MissingBuildSectionError,
+            "The build_script trace section could not be found for build #{build.id}"
+          )
+        end
+
+        length = section[:byte_end] - section[:byte_start]
+
+        [section[:byte_start], length]
+      end
+
+      # Removes the line containing the executed command from the build output.
+      #
+      # output - A `String` containing the output of a trace section.
+      def without_executed_command_line(output)
+        output.split("\n")[1..-1].join("\n")
+      end
+
+      # Returns the trace section for the given name, or `nil` if the section
+      # could not be found.
+      #
+      # name - The name of the trace section to find.
+      def find_build_trace_section(name)
+        trace_sections.find { |s| s[:name] == name }
+      end
+
+      def trace_sections
+        @trace_sections ||= trace.extract_sections
+      end
+
+      def trace
+        @trace ||= build.trace
+      end
+    end
+  end
+end

ee/lib/gitlab/chat/responder.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Chat
+    module Responder
+      # Returns an instance of the responder to use for generating chat
+      # responses.
+      #
+      # This method will return `nil` if no formatter is available for the given
+      # build.
+      #
+      # build - A `Ci::Build` that executed a chat command.
+      def self.responder_for(build)
+        service = build.pipeline.chat_data&.chat_name&.service
+
+        if (responder = service.try(:chat_responder))
+          responder.new(build)
+        end
+      end
+    end
+  end
+end

ee/lib/gitlab/chat/responder/base.rb

+module Gitlab
+  module Chat
+    module Responder
+      class Base
+        attr_reader :build
+
+        # build - The `Ci::Build` that was executed.
+        def initialize(build)
+          @build = build
+        end
+
+        def pipeline
+          build.pipeline
+        end
+
+        def project
+          pipeline.project
+        end
+
+        def success(*)
+          raise NotImplementedError, 'You must implement #success(output)'
+        end
+
+        def failure
+          raise NotImplementedError, 'You must implement #failure'
+        end
+
+        def send_response(output)
+          raise NotImplementedError, 'You must implement #send_response(output)'
+        end
+
+        def scheduled_output
+          raise NotImplementedError, 'You must implement #scheduled_output'
+        end
+      end
+    end
+  end
+end

ee/lib/gitlab/chat/responder/slack.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Chat
+    module Responder
+      class Slack < Responder::Base
+        SUCCESS_COLOR = '#B3ED8E'
+        FAILURE_COLOR = '#FF5640'
+        RESPONSE_TYPE = :in_channel
+
+        # Slack breaks messages apart if they're around 4 KB in size. We use a
+        # slightly smaller limit here to account for user mentions.
+        MESSAGE_SIZE_LIMIT = 3.5.kilobytes
+
+        # Sends a response back to Slack
+        #
+        # output - The output to send back to Slack, as a Hash.
+        def send_response(output)
+          HTTParty.post(
+            pipeline.chat_data.response_url,
+            {
+              headers: { Accept: 'application/json' },
+              body: output.to_json
+            }
+          )
+        end
+
+        # Sends the output for a build that completed successfully.
+        #
+        # output - The output produced by the chat command.
+        def success(output)
+          output =
+            if output.empty?
+              'The command successfully completed but did not ' \
+                'write any data to STDOUT or STDERR.'
+            else
+              limit_output(output)
+            end
+
+          send_response(
+            text: message_text(output),
+            response_type: RESPONSE_TYPE,
+            attachments: [
+              {
+                color: SUCCESS_COLOR,
+                actions: [
+                  view_project_button,
+                  view_pipeline_button,
+                  view_build_button
+                ]
+              }
+            ]
+          )
+        end
+
+        # Sends the output for a build that failed.
+        def failure
+          send_response(
+            text: message_text('Sorry, the build failed!'),
+            response_type: RESPONSE_TYPE,
+            attachments: [
+              {
+                color: FAILURE_COLOR,
+                actions: [
+                  view_project_button,
+                  view_pipeline_button,
+                  view_build_button
+                ]
+              }
+            ]
+          )
+        end
+
+        # Returns the output to send back after a command has been scheduled.
+        def scheduled_output
+          {
+            text: message_text('The command has been scheduled!'),
+            attachments: [
+              {
+                actions: [
+                  view_project_button,
+                  view_pipeline_button,
+                  view_build_button
+                ]
+              }
+            ]
+          }
+        end
+
+        private
+
+        def limit_output(output)
+          if output.bytesize <= MESSAGE_SIZE_LIMIT
+            output
+          else
+            'The command output is too large to be sent back directly. ' \
+              "The full output can be found at #{build_url}"
+          end
+        end
+
+        def mention_user
+          "<@#{pipeline.chat_data.chat_name.chat_id}>"
+        end
+
+        def message_text(output)
+          "#{mention_user}: #{output}"
+        end
+
+        def view_project_button
+          {
+            type: :button,
+            text: 'View Project',
+            url: url_helpers.project_url(project)
+          }
+        end
+
+        def view_pipeline_button
+          {
+            type: :button,
+            text: 'View Pipeline',
+            url: url_helpers.project_pipeline_url(project, pipeline)
+          }
+        end
+
+        def view_build_button
+          {
+            type: :button,
+            text: 'View Build',
+            url: build_url
+          }
+        end
+
+        def build_url
+          url_helpers.project_build_url(project, build)
+        end
+
+        def url_helpers
+          ::Gitlab::Routing.url_helpers
+        end
+      end
+    end
+  end
+end

ee/lib/gitlab/slash_commands/presenters/run.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module SlashCommands
+    module Presenters
+      class Run < Presenters::Base
+        def present(pipeline)
+          build = pipeline.builds.take
+
+          if build && (responder = Chat::Responder.responder_for(build))
+            in_channel_response(responder.scheduled_output)
+          else
+            unsupported_chat_service
+          end
+        end
+
+        def unsupported_chat_service
+          ephemeral_response(text: 'Sorry, this chat service is currently not supported by GitLab ChatOps.')
+        end
+
+        def failed_to_schedule(command)
+          ephemeral_response(
+            text: 'The command could not be scheduled. Make sure that your ' \
+              'project has a .gitlab-ci.yml that defines a job with the ' \
+              "name #{command.inspect}"
+          )
+        end
+      end
+    end
+  end
+end

ee/lib/gitlab/slash_commands/run.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module SlashCommands
+    # Slash command for triggering chatops jobs.
+    class Run < BaseCommand
+      def self.match(text)
+        /\Arun\s+(?<command>\S+)(\s+(?<arguments>.+))?\z/.match(text)
+      end
+
+      def self.help_message
+        'run <command> <arguments>'
+      end
+
+      def self.available?(project)
+        Chat.available? && project.builds_enabled?
+      end
+
+      def self.allowed?(project, user)
+        can?(user, :create_pipeline, project)
+      end
+
+      def execute(match)
+        command = Chat::Command.new(
+          project: project,
+          chat_name: chat_name,
+          name: match[:command],
+          arguments: match[:arguments],
+          channel: params[:channel_id],
+          response_url: params[:response_url]
+        )
+
+        presenter = Gitlab::SlashCommands::Presenters::Run.new
+        pipeline = command.try_create_pipeline
+
+        if pipeline&.persisted?
+          presenter.present(pipeline)
+        else
+          presenter.failed_to_schedule(command.name)
+        end
+      end
+    end
+  end
+end

ee/spec/lib/ee/gitlab/ci/pipeline/chain/remove_unwanted_chat_jobs_spec.rb

+require 'spec_helper'
+
+describe EE::Gitlab::Ci::Pipeline::Chain::RemoveUnwantedChatJobs do
+  let(:project) { create(:project) }
+
+  let(:pipeline) do
+    build(:ci_pipeline_with_one_job, project: project, ref: 'master')
+  end
+
+  let(:command) do
+    double(:command, project: project, chat_data: { command: 'echo' })
+  end
+
+  describe '#perform!' do
+    it 'removes unwanted jobs for chat pipelines' do
+      allow(pipeline).to receive(:chat?).and_return(true)
+
+      pipeline.config_processor.jobs[:echo] = double(:job)
+
+      described_class.new(pipeline, command).perform!
+
+      expect(pipeline.config_processor.jobs.keys).to eq([:echo])
+    end
+  end
+
+  it 'does not remove any jobs for non-chat pipelines' do
+    described_class.new(pipeline, command).perform!
+
+    expect(pipeline.config_processor.jobs.keys).to eq([:rspec])
+  end
+end

ee/spec/lib/gitlab/chat/command_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Chat::Command do
+  let(:chat_name) { create(:chat_name) }
+
+  let(:command) do
+    described_class.new(
+      project: project,
+      chat_name: chat_name,
+      name: 'spinach',
+      arguments: 'foo',
+      channel: '123',
+      response_url: 'http://example.com'
+    )
+  end
+
+  describe '#try_create_pipeline' do
+    let(:project) { create(:project) }
+
+    it 'returns nil when the command is not valid' do
+      expect(command)
+        .to receive(:valid?)
+        .and_return(false)
+
+      expect(command.try_create_pipeline).to be_nil
+    end
+
+    it 'tries to create the pipeline when a command is valid' do
+      expect(command)
+        .to receive(:valid?)
+        .and_return(true)
+
+      expect(command)
+        .to receive(:create_pipeline)
+
+      command.try_create_pipeline
+    end
+  end
+
+  describe '#create_pipeline' do
+    let(:project) { create(:project, :test_repo) }
+    let(:pipeline) { command.create_pipeline }
+
+    before do
+      stub_repository_ci_yaml_file(sha: project.commit.id)
+
+      project.add_developer(chat_name.user)
+    end
+
+    it 'creates the pipeline' do
+      expect(pipeline).to be_persisted
+    end
+
+    it 'creates the chat data for the pipeline' do
+      expect(pipeline.chat_data).to be_an_instance_of(Ci::PipelineChatData)
+    end
+
+    it 'stores the chat name ID in the chat data' do
+      expect(pipeline.chat_data.chat_name_id).to eq(chat_name.id)
+    end
+
+    it 'stores the response URL in the chat data' do
+      expect(pipeline.chat_data.response_url).to eq('http://example.com')
+    end
+
+    it 'creates the environment variables for the pipeline' do
+      vars = pipeline.variables.each_with_object({}) do |row, hash|
+        hash[row.key] = row.value
+      end
+
+      expect(vars['CHAT_INPUT']).to eq('foo')
+      expect(vars['CHAT_CHANNEL']).to eq('123')
+    end
+  end
+end

ee/spec/lib/gitlab/chat/output_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Chat::Output do
+  let(:build) do
+    create(:ci_build, pipeline: create(:ci_pipeline, source: :chat))
+  end
+
+  let(:output) { described_class.new(build) }
+
+  describe '#to_s' do
+    it 'returns the build output as a String' do
+      trace = Gitlab::Ci::Trace.new(build)
+
+      trace.set("echo hello\nhello")
+
+      allow(build)
+        .to receive(:trace)
+        .and_return(trace)
+
+      allow(output)
+        .to receive(:read_offset_and_length)
+        .and_return([0, 13])
+
+      expect(output.to_s).to eq('he')
+    end
+  end
+
+  describe '#read_offset_and_length' do
+    context 'without the chat_reply trace section' do
+      it 'falls back to using the build_script trace section' do
+        expect(output)
+          .to receive(:find_build_trace_section)
+          .with('chat_reply')
+          .and_return(nil)
+
+        expect(output)
+          .to receive(:find_build_trace_section)
+          .with('build_script')
+          .and_return({ name: 'build_script', byte_start: 1, byte_end: 4 })
+
+        expect(output.read_offset_and_length).to eq([1, 3])
+      end
+    end
+
+    context 'without the build_script trace section' do
+      it 'raises MissingBuildSectionError' do
+        expect { output.read_offset_and_length }
+          .to raise_error(described_class::MissingBuildSectionError)
+      end
+    end
+
+    context 'with the chat_reply trace section' do
+      it 'returns the read offset and length as an Array' do
+        trace = Gitlab::Ci::Trace.new(build)
+
+        allow(build)
+          .to receive(:trace)
+          .and_return(trace)
+
+        allow(trace)
+          .to receive(:extract_sections)
+          .and_return([{ name: 'chat_reply', byte_start: 1, byte_end: 4 }])
+
+        expect(output.read_offset_and_length).to eq([1, 3])
+      end
+    end
+  end
+
+  describe '#without_executed_command_line' do
+    it 'returns the input without the first line' do
+      expect(output.without_executed_command_line("hello\nworld"))
+        .to eq('world')
+    end
+  end
+
+  describe '#find_build_trace_section' do
+    it 'returns nil when no section could be found' do
+      expect(output.find_build_trace_section('foo')).to be_nil
+    end
+
+    it 'returns the trace section when it could be found' do
+      section = { name: 'chat_reply', byte_start: 1, byte_end: 4 }
+
+      allow(output)
+        .to receive(:trace_sections)
+        .and_return([section])
+
+      expect(output.find_build_trace_section('chat_reply')).to eq(section)
+    end
+  end
+end

ee/spec/lib/gitlab/chat/responder/base_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Chat::Responder::Base do
+  let(:project) { double(:project) }
+  let(:pipeline) { double(:pipeline, project: project) }
+  let(:build) { double(:build, pipeline: pipeline) }
+  let(:responder) { described_class.new(build) }
+
+  describe '#pipeline' do
+    it 'returns the pipeline' do
+      expect(responder.pipeline).to eq(pipeline)
+    end
+  end
+
+  describe '#project' do
+    it 'returns the project' do
+      expect(responder.project).to eq(project)
+    end
+  end
+
+  describe '#success' do
+    it 'raises NotImplementedError' do
+      expect { responder.success }.to raise_error(NotImplementedError)
+    end
+  end
+
+  describe '#failure' do
+    it 'raises NotImplementedError' do
+      expect { responder.failure }.to raise_error(NotImplementedError)
+    end
+  end
+
+  describe '#send_response' do
+    it 'raises NotImplementedError' do
+      expect { responder.send_response('hello') }
+        .to raise_error(NotImplementedError)
+    end
+  end
+
+  describe '#scheduled_output' do
+    it 'raises NotImplementedError' do
+      expect { responder.scheduled_output }
+        .to raise_error(NotImplementedError)
+    end
+  end
+end

ee/spec/lib/gitlab/chat/responder/slack_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Chat::Responder::Slack do
+  let(:chat_name) { create(:chat_name, chat_id: 'U123') }
+
+  let(:pipeline) do
+    pipeline = create(:ci_pipeline)
+
+    pipeline.create_chat_data!(
+      response_url: 'http://example.com',
+      chat_name_id: chat_name.id
+    )
+
+    pipeline
+  end
+
+  let(:build) { create(:ci_build, pipeline: pipeline) }
+  let(:responder) { described_class.new(build) }
+
+  describe '#send_response' do
+    it 'sends a response back to Slack' do
+      expect(HTTParty).to receive(:post).with(
+        'http://example.com',
+        { headers: { Accept: 'application/json' }, body: 'hello'.to_json }
+      )
+
+      responder.send_response('hello')
+    end
+  end
+
+  describe '#success' do
+    it 'returns the output for a successful build' do
+      expect(responder)
+        .to receive(:send_response)
+        .with(hash_including(text: '<@U123>: hello', response_type: :in_channel))
+
+      responder.success('hello')
+    end
+
+    it 'limits the output to a fixed size' do
+      expect(responder)
+        .to receive(:send_response)
+        .with(hash_including(text: /The command output is too large/))
+
+      responder.success('a' * 4000)
+    end
+
+    it 'returns a generic message when the build did not produce any output' do
+      expect(responder)
+        .to receive(:send_response)
+        .with(hash_including(text: /did not write any data to STDOUT/))
+
+      responder.success('')
+    end
+  end
+
+  describe '#failure' do
+    it 'returns the output for a failed build' do
+      expect(responder).to receive(:send_response).with(
+        hash_including(
+          text: '<@U123>: Sorry, the build failed!',
+          response_type: :in_channel
+        )
+      )
+
+      responder.failure
+    end
+  end
+
+  describe '#scheduled_output' do
+    it 'returns the output for a scheduled build' do
+      output = responder.scheduled_output
+
+      expect(output[:text]).to eq('<@U123>: The command has been scheduled!')
+    end
+  end
+end

ee/spec/lib/gitlab/chat/responder_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Chat::Responder do
+  describe '.responder_for' do
+    context 'using a regular build' do
+      it 'returns nil' do
+        build = create(:ci_build)
+
+        expect(described_class.responder_for(build)).to be_nil
+      end
+    end
+
+    context 'using a chat build' do
+      it 'returns the responder for the build' do
+        pipeline = create(:ci_pipeline)
+        build = create(:ci_build, pipeline: pipeline)
+        service = double(:service, chat_responder: Gitlab::Chat::Responder::Slack)
+        chat_name = double(:chat_name, service: service)
+        chat_data = double(:chat_data, chat_name: chat_name)
+
+        allow(pipeline)
+          .to receive(:chat_data)
+          .and_return(chat_data)
+
+        expect(described_class.responder_for(build))
+          .to be_an_instance_of(Gitlab::Chat::Responder::Slack)
+      end
+    end
+  end
+end

ee/spec/lib/gitlab/chat_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Chat, :use_clean_rails_memory_store_caching do
+  describe '.available?' do
+    it 'returns true when the chatops feature is available' do
+      allow(License)
+        .to receive(:feature_available?)
+        .with(:chatops)
+        .and_return(true)
+
+      expect(described_class).to be_available
+    end
+
+    it 'returns false when the chatops feature is not available' do
+      allow(License)
+        .to receive(:feature_available?)
+        .with(:chatops)
+        .and_return(false)
+
+      expect(described_class).not_to be_available
+    end
+
+    it 'caches the feature availability' do
+      expect(License)
+        .to receive(:feature_available?)
+        .once
+        .with(:chatops)
+        .and_return(true)
+
+      2.times do
+        described_class.available?
+      end
+    end
+  end
+
+  describe '.flush_available_cache' do
+    it 'flushes the feature availability cache' do
+      expect(License)
+        .to receive(:feature_available?)
+        .twice
+        .with(:chatops)
+        .and_return(true)
+
+      described_class.available?
+      described_class.flush_available_cache
+      described_class.available?
+    end
+  end
+end

ee/spec/lib/gitlab/slash_commands/presenters/run_spec.rb

+require 'spec_helper'
+
+describe Gitlab::SlashCommands::Presenters::Run do
+  let(:presenter) { described_class.new }
+
+  describe '#present' do
+    context 'when no builds are present' do
+      it 'returns an error' do
+        builds = double(:builds, take: nil)
+        pipeline = double(:pipeline, builds: builds)
+
+        expect(presenter)
+          .to receive(:unsupported_chat_service)
+
+        presenter.present(pipeline)
+      end
+    end
+
+    context 'when a responder could be found' do
+      it 'returns the output for a scheduled pipeline' do
+        responder = double(:responder, scheduled_output: 'hello')
+        build = double(:build)
+        builds = double(:builds, take: build)
+        pipeline = double(:pipeline, builds: builds)
+
+        allow(Gitlab::Chat::Responder)
+          .to receive(:responder_for)
+          .with(build)
+          .and_return(responder)
+
+        expect(presenter)
+          .to receive(:in_channel_response)
+          .with('hello')
+
+        presenter.present(pipeline)
+      end
+    end
+
+    context 'when a responder could not be found' do
+      it 'returns an error' do
+        build = double(:build)
+        builds = double(:builds, take: build)
+        pipeline = double(:pipeline, builds: builds)
+
+        allow(Gitlab::Chat::Responder)
+          .to receive(:responder_for)
+          .with(build)
+          .and_return(nil)
+
+        expect(presenter)
+          .to receive(:unsupported_chat_service)
+
+        presenter.present(pipeline)
+      end
+    end
+  end
+
+  describe '#unsupported_chat_service' do
+    it 'returns an ephemeral response' do
+      expect(presenter)
+        .to receive(:ephemeral_response)
+        .with(text: /Sorry, this chat service is currently not supported/)
+
+      presenter.unsupported_chat_service
+    end
+  end
+
+  describe '#failed_to_schedule' do
+    it 'returns an ephemeral response' do
+      expect(presenter)
+        .to receive(:ephemeral_response)
+        .with(text: /The command could not be scheduled/)
+
+      presenter.failed_to_schedule('foo')
+    end
+  end
+end

ee/spec/lib/gitlab/slash_commands/run_spec.rb

+require 'spec_helper'
+
+describe Gitlab::SlashCommands::Run do
+  describe '.available?' do
+    it 'returns true when builds are enabled for the project' do
+      project = double(:project, builds_enabled?: true)
+
+      allow(Gitlab::Chat)
+        .to receive(:available?)
+        .and_return(true)
+
+      expect(described_class.available?(project)).to eq(true)
+    end
+
+    it 'returns false when builds are disabled for the project' do
+      project = double(:project, builds_enabled?: false)
+
+      expect(described_class.available?(project)).to eq(false)
+    end
+
+    it 'returns false when chatops is not available' do
+      allow(Gitlab::Chat)
+        .to receive(:available?)
+        .and_return(false)
+
+      project = double(:project, builds_enabled?: true)
+
+      expect(described_class.available?(project)).to eq(false)
+    end
+  end
+
+  describe '.allowed?' do
+    it 'returns true when the user can create a pipeline' do
+      project = create(:project)
+
+      expect(described_class.allowed?(project, project.creator)).to eq(true)
+    end
+
+    it 'returns false when the user can not create a pipeline' do
+      project = create(:project)
+      user = create(:user)
+
+      expect(described_class.allowed?(project, user)).to eq(false)
+    end
+  end
+
+  describe '#execute' do
+    let(:chat_name) { create(:chat_name) }
+    let(:project) { create(:project) }
+
+    let(:command) do
+      described_class.new(project, chat_name, response_url: 'http://example.com')
+    end
+
+    context 'when a pipeline could not be scheduled' do
+      it 'returns an error' do
+        expect_any_instance_of(Gitlab::Chat::Command)
+          .to receive(:try_create_pipeline)
+          .and_return(nil)
+
+        expect_any_instance_of(Gitlab::SlashCommands::Presenters::Run)
+          .to receive(:failed_to_schedule)
+          .with('foo')
+
+        command.execute(command: 'foo', arguments: '')
+      end
+    end
+
+    context 'when a pipeline could be created but the chat service was not supported' do
+      it 'returns an error' do
+        build = double(:build)
+        pipeline = double(
+          :pipeline,
+          builds: double(:relation, take: build),
+          persisted?: true
+        )
+
+        expect_any_instance_of(Gitlab::Chat::Command)
+          .to receive(:try_create_pipeline)
+          .and_return(pipeline)
+
+        expect(Gitlab::Chat::Responder)
+          .to receive(:responder_for)
+          .with(build)
+          .and_return(nil)
+
+        expect_any_instance_of(Gitlab::SlashCommands::Presenters::Run)
+          .to receive(:unsupported_chat_service)
+
+        command.execute(command: 'foo', arguments: '')
+      end
+    end
+
+    context 'using a valid pipeline' do
+      it 'schedules the pipeline' do
+        responder = double(:responder, scheduled_output: 'hello')
+        build = double(:build)
+        pipeline = double(
+          :pipeline,
+          builds: double(:relation, take: build),
+          persisted?: true
+        )
+
+        expect_any_instance_of(Gitlab::Chat::Command)
+          .to receive(:try_create_pipeline)
+          .and_return(pipeline)
+
+        expect(Gitlab::Chat::Responder)
+          .to receive(:responder_for)
+          .with(build)
+          .and_return(responder)
+
+        expect_any_instance_of(Gitlab::SlashCommands::Presenters::Run)
+          .to receive(:in_channel_response)
+          .with(responder.scheduled_output)
+
+        command.execute(command: 'foo', arguments: '')
+      end
+    end
+  end
+end

ee/spec/models/ci/pipeline_spec.rb

@@ -8,6 +8,8 @@ describe Ci::Pipeline do
     create(:ci_empty_pipeline, status: :created, project: project)
   end
 
+  it { is_expected.to have_one(:chat_data) }
+
   describe '.failure_reasons' do
     it 'contains failure reasons about exceeded limits' do
       expect(described_class.failure_reasons)

ee/spec/models/ee/slack_slash_commands_service_spec.rb

+require 'spec_helper'
+
+describe SlackSlashCommandsService do
+  describe '#chat_responder' do
+    it 'returns the responder to use for Slack' do
+      expect(described_class.new.chat_responder)
+        .to eq(Gitlab::Chat::Responder::Slack)
+    end
+  end
+end

ee/spec/workers/build_finished_worker_spec.rb

+require 'spec_helper'
+
+describe BuildFinishedWorker do
+  describe '#perform' do
+    it 'schedules a ChatNotification job for a chat build' do
+      build = create(:ci_build, pipeline: create(:ci_pipeline, source: :chat))
+
+      expect(ChatNotificationWorker)
+        .to receive(:perform_async)
+        .with(build.id)
+
+      described_class.new.perform(build.id)
+    end
+
+    it 'does not schedule a ChatNotification job for a regular build' do
+      build = create(:ci_build, pipeline: create(:ci_pipeline))
+
+      expect(ChatNotificationWorker)
+        .not_to receive(:perform_async)
+
+      described_class.new.perform(build.id)
+    end
+  end
+end

ee/spec/workers/chat_notification_worker_spec.rb

+require 'spec_helper'
+
+describe ChatNotificationWorker do
+  let(:worker) { described_class.new }
+  let(:chat_build) do
+    create(:ci_build, pipeline: create(:ci_pipeline, source: :chat))
+  end
+
+  describe '#perform' do
+    it 'does nothing when the build no longer exists' do
+      expect(worker).not_to receive(:send_response)
+
+      worker.perform(-1)
+    end
+
+    it 'sends a response for an existing build' do
+      expect(worker)
+        .to receive(:send_response)
+        .with(an_instance_of(Ci::Build))
+
+      worker.perform(chat_build.id)
+    end
+
+    it 'reschedules the job if the trace sections could not be found' do
+      expect(worker)
+        .to receive(:send_response)
+        .and_raise(Gitlab::Chat::Output::MissingBuildSectionError)
+
+      expect(described_class)
+        .to receive(:perform_in)
+        .with(described_class::RESCHEDULE_INTERVAL, chat_build.id)
+
+      worker.perform(chat_build.id)
+    end
+  end
+
+  describe '#send_response' do
+    context 'when a responder could not be found' do
+      it 'does nothing' do
+        expect(Gitlab::Chat::Responder)
+          .to receive(:responder_for)
+          .with(chat_build)
+          .and_return(nil)
+
+        expect(worker.send_response(chat_build)).to be_nil
+      end
+    end
+
+    context 'when a responder could be found' do
+      let(:responder) { double(:responder) }
+
+      before do
+        allow(Gitlab::Chat::Responder)
+          .to receive(:responder_for)
+          .with(chat_build)
+          .and_return(responder)
+      end
+
+      it 'sends the response for a succeeded build' do
+        output = double(:output, to_s: 'this is the build output')
+
+        expect(chat_build)
+          .to receive(:success?)
+          .and_return(true)
+
+        expect(responder)
+          .to receive(:success)
+          .with(an_instance_of(String))
+
+        expect(Gitlab::Chat::Output)
+          .to receive(:new)
+          .with(chat_build)
+          .and_return(output)
+
+        worker.send_response(chat_build)
+      end
+
+      it 'sends the response for a failed build' do
+        expect(chat_build)
+          .to receive(:success?)
+          .and_return(false)
+
+        expect(responder).to receive(:failure)
+
+        worker.send_response(chat_build)
+      end
+    end
+  end
+end

lib/gitlab/ci/pipeline/chain/command.rb

@@ -10,7 +10,8 @@ module Gitlab
           :seeds_block,
 
           # EE specific
-          :allow_mirror_update
+          :allow_mirror_update,
+          :chat_data
         ) do
           include Gitlab::Utils::StrongMemoize
 

lib/gitlab/slash_commands/command.rb

@@ -5,7 +5,8 @@ module Gitlab
         Gitlab::SlashCommands::IssueShow,
         Gitlab::SlashCommands::IssueNew,
         Gitlab::SlashCommands::IssueSearch,
-        Gitlab::SlashCommands::Deploy
+        Gitlab::SlashCommands::Deploy,
+        Gitlab::SlashCommands::Run
       ].freeze
 
       def execute

spec/lib/gitlab/import_export/all_models.yml

@@ -126,6 +126,7 @@ pipelines:
 - sourced_pipelines
 - triggered_by_pipeline
 - triggered_pipelines
+- chat_data # EE only
 pipeline_variables:
 - pipeline
 stages: