Add chatops responder for mattermost

app/models/project_services/mattermost_slash_commands_service.rb

@@ -36,6 +36,10 @@ class MattermostSlashCommandsService < SlashCommandsService
     [[], e.message]
   end
 
+  def chat_responder
+    ::Gitlab::Chat::Responder::Mattermost
+  end
+
   private
 
   def command(params)

changelogs/unreleased/mattermost-chat-responder.yml

+---
+title: Add responding to ChatOps jobs triggered in Mattermost
+merge_request: 29366
+author: Brian Kintz
+type: added

lib/gitlab/chat/responder/mattermost.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Chat
+    module Responder
+      class Mattermost < Responder::Base
+        SUCCESS_COLOR = '#00c100'
+        FAILURE_COLOR = '#e40303'
+
+        # 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 Mattermost
+        #
+        # body - The message payload to send back to Mattermost, as a Hash.
+        def send_response(body)
+          Gitlab::HTTP.post(
+            pipeline.chat_data.response_url,
+            {
+              headers: { 'Content-Type': 'application/json' },
+              body: body.to_json
+            }
+          )
+        end
+
+        # Sends the output for a build that completed successfully.
+        #
+        # output - The output produced by the chat command.
+        def success(output)
+          return if output.empty?
+
+          send_response(
+            response_type: :in_channel,
+            attachments: [
+              {
+                color: SUCCESS_COLOR,
+                text: "ChatOps job started by #{user_ref} completed successfully",
+                fields: [
+                  {
+                    short: true,
+                    title: "ID",
+                    value: "#{build_ref}"
+                  },
+                  {
+                    short: true,
+                    title: "Name",
+                    value: build.name
+                  },
+                  {
+                    short: false,
+                    title: "Output",
+                    value: success_message(output)
+                  }
+                ]
+              }
+            ]
+          )
+        end
+
+        # Sends the output for a build that failed.
+        def failure
+          send_response(
+            response_type: :in_channel,
+            attachments: [
+              {
+                color: FAILURE_COLOR,
+                text: "ChatOps job started by #{user_ref} failed!",
+                fields: [
+                  {
+                    short: true,
+                    title: "ID",
+                    value: "#{build_ref}"
+                  },
+                  {
+                    short: true,
+                    title: "Name",
+                    value: build.name
+                  }
+                ]
+              }
+            ]
+          )
+        end
+
+        # Returns the output to send back after a command has been scheduled.
+        def scheduled_output
+          {
+            response_type: :ephemeral,
+            text: "Your ChatOps job #{build_ref} has been created!"
+          }
+        end
+
+        private
+
+        def success_message(output)
+          <<~HEREDOC.chomp
+            ```shell
+            #{strip_ansi_colorcodes(limit_output(output))}
+            ```
+          HEREDOC
+        end
+
+        def limit_output(output)
+          if output.bytesize <= MESSAGE_SIZE_LIMIT
+            output
+          else
+            "The output is too large to be sent back directly!"
+          end
+        end
+
+        def strip_ansi_colorcodes(output)
+          output.gsub(/\x1b\[[0-9;]*m/, '')
+        end
+
+        def user_ref
+          user = pipeline.chat_data.chat_name.user
+          user_url = ::Gitlab::Routing.url_helpers.user_url(user)
+
+          "[#{user.name}](#{user_url})"
+        end
+
+        def build_ref
+          build_url = ::Gitlab::Routing.url_helpers.project_build_url(project, build)
+
+          "[##{build.id}](#{build_url})"
+        end
+      end
+    end
+  end
+end

spec/lib/gitlab/chat/responder/mattermost_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Chat::Responder::Mattermost 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(Gitlab::HTTP).to receive(:post).with(
+        'http://example.com',
+        { headers: { 'Content-Type': '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(
+            response_type: :in_channel,
+            attachments: array_including(
+              a_hash_including(
+                text: /#{pipeline.chat_data.chat_name.user.name}.*completed successfully/,
+                fields: array_including(
+                  a_hash_including(value: /##{build.id}/),
+                  a_hash_including(value: build.name),
+                  a_hash_including(value: "```shell\nscript output\n```")
+                )
+              )
+            )
+          )
+        )
+
+      responder.success('script output')
+    end
+
+    it 'limits the output to a fixed size' do
+      expect(responder)
+        .to receive(:send_response)
+        .with(
+          hash_including(
+            response_type: :in_channel,
+            attachments: array_including(
+              a_hash_including(
+                fields: array_including(
+                  a_hash_including(value: /The output is too large/)
+                )
+              )
+            )
+          )
+        )
+
+      responder.success('a' * 4000)
+    end
+
+    it 'does not send a response if the output is empty' do
+      expect(responder).not_to receive(:send_response)
+
+      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(
+            response_type: :in_channel,
+            attachments: array_including(
+              a_hash_including(
+                text: /#{pipeline.chat_data.chat_name.user.name}.*failed/,
+                fields: array_including(
+                  a_hash_including(value: /##{build.id}/),
+                  a_hash_including(value: build.name)
+                )
+              )
+            )
+          )
+        )
+
+      responder.failure
+    end
+  end
+
+  describe '#scheduled_output' do
+    it 'returns the output for a scheduled build' do
+      output = responder.scheduled_output
+
+      expect(output).to match(
+        hash_including(
+          response_type: :ephemeral,
+          text: /##{build.id}/
+        )
+      )
+    end
+  end
+end

spec/models/project_services/mattermost_slash_commands_service_spec.rb

@@ -121,5 +121,12 @@ describe MattermostSlashCommandsService do
         end
       end
     end
+
+    describe '#chat_responder' do
+      it 'returns the responder to use for Mattermost' do
+        expect(described_class.new.chat_responder)
+          .to eq(Gitlab::Chat::Responder::Mattermost)
+      end
+    end
   end
 end