Move ChatOps to Core

ChatOps used to be in the Ultimate tier.

5 files changed, 329 insertions, 0 deletions

diff --git a/lib/gitlab/chat/command.rb b/lib/gitlab/chat/command.rb
new file mode 100644
index 00000000000..49b7dcf4bbe
--- /dev/null
+++ b/lib/gitlab/chat/command.rb
@@ -0,0 +1,94 @@
+# 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|
+          build_environment_variables(pipeline)
+          build_chat_data(pipeline)
+        end
+      end
+
+      # pipeline - The `Ci::Pipeline` to create the environment variables for.
+      def build_environment_variables(pipeline)
+        pipeline.variables.build(
+          [{ key: 'CHAT_INPUT', value: arguments },
+           { key: 'CHAT_CHANNEL', value: channel }]
+        )
+      end
+
+      # pipeline - The `Ci::Pipeline` to create the chat data for.
+      def build_chat_data(pipeline)
+        pipeline.build_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
diff --git a/lib/gitlab/chat/output.rb b/lib/gitlab/chat/output.rb
new file mode 100644
index 00000000000..411b1555a7d
--- /dev/null
+++ b/lib/gitlab/chat/output.rb
@@ -0,0 +1,93 @@
+# 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)
+        # If `output.split("\n")` produces an empty Array then the slicing that
+        # follows it will produce a nil. For example:
+        #
+        #     "\n".split("\n")        # => []
+        #     "\n".split("\n")[1..-1] # => nil
+        #
+        # To work around this we only "join" if we're given an Array.
+        if (converted = output.split("\n")[1..-1])
+          converted.join("\n")
+        else
+          ''
+        end
+      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
diff --git a/lib/gitlab/chat/responder.rb b/lib/gitlab/chat/responder.rb
new file mode 100644
index 00000000000..6267fbc20e2
--- /dev/null
+++ b/lib/gitlab/chat/responder.rb
@@ -0,0 +1,22 @@
+# 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
diff --git a/lib/gitlab/chat/responder/base.rb b/lib/gitlab/chat/responder/base.rb
new file mode 100644
index 00000000000..f1ad0e36793
--- /dev/null
+++ b/lib/gitlab/chat/responder/base.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+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
diff --git a/lib/gitlab/chat/responder/slack.rb b/lib/gitlab/chat/responder/slack.rb
new file mode 100644
index 00000000000..0cf02c92a67
--- /dev/null
+++ b/lib/gitlab/chat/responder/slack.rb
@@ -0,0 +1,80 @@
+# 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)
+          Gitlab::HTTP.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)
+          return if output.empty?
+
+          send_response(
+            text: message_text(limit_output(output)),
+            response_type: RESPONSE_TYPE
+          )
+        end
+
+        # Sends the output for a build that failed.
+        def failure
+          send_response(
+            text: message_text("<#{build_url}|Sorry, the build failed!>"),
+            response_type: RESPONSE_TYPE
+          )
+        end
+
+        # Returns the output to send back after a command has been scheduled.
+        def scheduled_output
+          # We return an empty message so that Slack still shows the input
+          # command, without polluting the channel with standard "The job has
+          # been scheduled" (or similar) responses.
+          { text: '' }
+        end
+
+        private
+
+        def limit_output(output)
+          if output.bytesize <= MESSAGE_SIZE_LIMIT
+            output
+          else
+            "<#{build_url}|The output is too large to be sent back directly!>"
+          end
+        end
+
+        def mention_user
+          "<@#{pipeline.chat_data.chat_name.chat_id}>"
+        end
+
+        def message_text(output)
+          "#{mention_user}: #{output}"
+        end
+
+        def build_url
+          ::Gitlab::Routing.url_helpers.project_build_url(project, build)
+        end
+      end
+    end
+  end
+end