Extract scoped CI/CD variables to a separate concern

This commits extract code responsible for calculating essential CI/CD
variables to a separate concern. This makes it possible to share this
code between a `Ci::Build` and a `Ci::Bridge`.

We might want to refactor this to use composition instead of
inheritance.

3 files changed, 159 insertions, 142 deletions

diff --git a/app/models/ci/bridge.rb b/app/models/ci/bridge.rb
index f570403615b..0d8d7d95791 100644
--- a/app/models/ci/bridge.rb
+++ b/app/models/ci/bridge.rb
@@ -3,6 +3,7 @@
 module Ci
   class Bridge < CommitStatus
     include Ci::Processable
+    include Ci::Contextable
     include Importable
     include AfterCommitQueue
     include HasRef
@@ -12,6 +13,8 @@ module Ci
     belongs_to :trigger_request
     validates :ref, presence: true
 
+    delegate :merge_request_event?, to: :pipeline
+
     def self.retry(bridge, current_user)
       raise NotImplementedError
     end
@@ -38,11 +41,11 @@ module Ci
       false
     end
 
-    def expanded_environment_name
+    def runnable?
+      false
     end
 
-    def predefined_variables
-      raise NotImplementedError
+    def expanded_environment_name
     end
 
     def execute_hooks
diff --git a/app/models/ci/build.rb b/app/models/ci/build.rb
index f2369191b76..3bfde8d0a77 100644
--- a/app/models/ci/build.rb
+++ b/app/models/ci/build.rb
@@ -5,6 +5,7 @@ module Ci
     prepend ArtifactMigratable
     include Ci::Processable
     include Ci::Metadatable
+    include Ci::Contextable
     include TokenAuthenticatable
     include AfterCommitQueue
     include ObjectStorage::BackgroundMove
@@ -289,6 +290,10 @@ module Ci
         self.name == 'pages'
     end
 
+    def runnable?
+      true
+    end
+
     def archived?
       return true if degenerated?
 
@@ -399,35 +404,6 @@ module Ci
     end
 
     ##
-    # Variables in the environment name scope.
-    #
-    def scoped_variables(environment: expanded_environment_name)
-      Gitlab::Ci::Variables::Collection.new.tap do |variables|
-        variables.concat(predefined_variables)
-        variables.concat(project.predefined_variables)
-        variables.concat(pipeline.predefined_variables)
-        variables.concat(runner.predefined_variables) if runner
-        variables.concat(project.deployment_variables(environment: environment)) if environment
-        variables.concat(yaml_variables)
-        variables.concat(user_variables)
-        variables.concat(secret_group_variables)
-        variables.concat(secret_project_variables(environment: environment))
-        variables.concat(trigger_request.user_variables) if trigger_request
-        variables.concat(pipeline.variables)
-        variables.concat(pipeline.pipeline_schedule.job_variables) if pipeline.pipeline_schedule
-      end
-    end
-
-    ##
-    # Variables that do not depend on the environment name.
-    #
-    def simple_variables
-      strong_memoize(:simple_variables) do
-        scoped_variables(environment: nil).to_runner_variables
-      end
-    end
-
-    ##
     # All variables, including persisted environment variables.
     #
     def variables
@@ -440,12 +416,46 @@ module Ci
       end
     end
 
-    ##
-    # Regular Ruby hash of scoped variables, without duplicates that are
-    # possible to be present in an array of hashes returned from `variables`.
-    #
-    def scoped_variables_hash
-      scoped_variables.to_hash
+    CI_REGISTRY_USER = 'gitlab-ci-token'.freeze
+
+    def persisted_variables
+      Gitlab::Ci::Variables::Collection.new.tap do |variables|
+        break variables unless persisted?
+
+        variables
+          .concat(pipeline.persisted_variables)
+          .append(key: 'CI_JOB_ID', value: id.to_s)
+          .append(key: 'CI_JOB_URL', value: Gitlab::Routing.url_helpers.project_job_url(project, self))
+          .append(key: 'CI_JOB_TOKEN', value: token.to_s, public: false)
+          .append(key: 'CI_BUILD_ID', value: id.to_s)
+          .append(key: 'CI_BUILD_TOKEN', value: token.to_s, public: false)
+          .append(key: 'CI_REGISTRY_USER', value: CI_REGISTRY_USER)
+          .append(key: 'CI_REGISTRY_PASSWORD', value: token.to_s, public: false)
+          .append(key: 'CI_REPOSITORY_URL', value: repo_url.to_s, public: false)
+          .concat(deploy_token_variables)
+      end
+    end
+
+    def persisted_environment_variables
+      Gitlab::Ci::Variables::Collection.new.tap do |variables|
+        break variables unless persisted? && persisted_environment.present?
+
+        variables.concat(persisted_environment.predefined_variables)
+
+        # Here we're passing unexpanded environment_url for runner to expand,
+        # and we need to make sure that CI_ENVIRONMENT_NAME and
+        # CI_ENVIRONMENT_SLUG so on are available for the URL be expanded.
+        variables.append(key: 'CI_ENVIRONMENT_URL', value: environment_url) if environment_url
+      end
+    end
+
+    def deploy_token_variables
+      Gitlab::Ci::Variables::Collection.new.tap do |variables|
+        break variables unless gitlab_deploy_token
+
+        variables.append(key: 'CI_DEPLOY_USER', value: gitlab_deploy_token.username)
+        variables.append(key: 'CI_DEPLOY_PASSWORD', value: gitlab_deploy_token.token, public: false)
+      end
     end
 
     def features
@@ -623,27 +633,6 @@ module Ci
       super || project.try(:build_coverage_regex)
     end
 
-    def user_variables
-      Gitlab::Ci::Variables::Collection.new.tap do |variables|
-        break variables if user.blank?
-
-        variables.append(key: 'GITLAB_USER_ID', value: user.id.to_s)
-        variables.append(key: 'GITLAB_USER_EMAIL', value: user.email)
-        variables.append(key: 'GITLAB_USER_LOGIN', value: user.username)
-        variables.append(key: 'GITLAB_USER_NAME', value: user.name)
-      end
-    end
-
-    def secret_group_variables
-      return [] unless project.group
-
-      project.group.ci_variables_for(git_ref, project)
-    end
-
-    def secret_project_variables(environment: persisted_environment)
-      project.ci_variables_for(ref: git_ref, environment: environment)
-    end
-
     def steps
       [Gitlab::Ci::Build::Step.from_commands(self),
        Gitlab::Ci::Build::Step.from_after_script(self)].compact
@@ -803,89 +792,6 @@ module Ci
       @unscoped_project ||= Project.unscoped.find_by(id: project_id)
     end
 
-    CI_REGISTRY_USER = 'gitlab-ci-token'.freeze
-
-    def persisted_variables
-      Gitlab::Ci::Variables::Collection.new.tap do |variables|
-        break variables unless persisted?
-
-        variables
-          .concat(pipeline.persisted_variables)
-          .append(key: 'CI_JOB_ID', value: id.to_s)
-          .append(key: 'CI_JOB_URL', value: Gitlab::Routing.url_helpers.project_job_url(project, self))
-          .append(key: 'CI_JOB_TOKEN', value: token.to_s, public: false)
-          .append(key: 'CI_BUILD_ID', value: id.to_s)
-          .append(key: 'CI_BUILD_TOKEN', value: token.to_s, public: false)
-          .append(key: 'CI_REGISTRY_USER', value: CI_REGISTRY_USER)
-          .append(key: 'CI_REGISTRY_PASSWORD', value: token.to_s, public: false)
-          .append(key: 'CI_REPOSITORY_URL', value: repo_url.to_s, public: false)
-          .concat(deploy_token_variables)
-      end
-    end
-
-    def predefined_variables # rubocop:disable Metrics/AbcSize
-      Gitlab::Ci::Variables::Collection.new.tap do |variables|
-        variables.append(key: 'CI', value: 'true')
-        variables.append(key: 'GITLAB_CI', value: 'true')
-        variables.append(key: 'GITLAB_FEATURES', value: project.licensed_features.join(','))
-        variables.append(key: 'CI_SERVER_NAME', value: 'GitLab')
-        variables.append(key: 'CI_SERVER_VERSION', value: Gitlab::VERSION)
-        variables.append(key: 'CI_SERVER_VERSION_MAJOR', value: Gitlab.version_info.major.to_s)
-        variables.append(key: 'CI_SERVER_VERSION_MINOR', value: Gitlab.version_info.minor.to_s)
-        variables.append(key: 'CI_SERVER_VERSION_PATCH', value: Gitlab.version_info.patch.to_s)
-        variables.append(key: 'CI_SERVER_REVISION', value: Gitlab.revision)
-        variables.append(key: 'CI_JOB_NAME', value: name)
-        variables.append(key: 'CI_JOB_STAGE', value: stage)
-        variables.append(key: 'CI_COMMIT_SHA', value: sha)
-        variables.append(key: 'CI_COMMIT_SHORT_SHA', value: short_sha)
-        variables.append(key: 'CI_COMMIT_BEFORE_SHA', value: before_sha)
-        variables.append(key: 'CI_COMMIT_REF_NAME', value: ref)
-        variables.append(key: 'CI_COMMIT_REF_SLUG', value: ref_slug)
-        variables.append(key: "CI_COMMIT_TAG", value: ref) if tag?
-        variables.append(key: "CI_PIPELINE_TRIGGERED", value: 'true') if trigger_request
-        variables.append(key: "CI_JOB_MANUAL", value: 'true') if action?
-        variables.append(key: "CI_NODE_INDEX", value: self.options[:instance].to_s) if self.options&.include?(:instance)
-        variables.append(key: "CI_NODE_TOTAL", value: (self.options&.dig(:parallel) || 1).to_s)
-        variables.concat(legacy_variables)
-      end
-    end
-
-    def legacy_variables
-      Gitlab::Ci::Variables::Collection.new.tap do |variables|
-        variables.append(key: 'CI_BUILD_REF', value: sha)
-        variables.append(key: 'CI_BUILD_BEFORE_SHA', value: before_sha)
-        variables.append(key: 'CI_BUILD_REF_NAME', value: ref)
-        variables.append(key: 'CI_BUILD_REF_SLUG', value: ref_slug)
-        variables.append(key: 'CI_BUILD_NAME', value: name)
-        variables.append(key: 'CI_BUILD_STAGE', value: stage)
-        variables.append(key: "CI_BUILD_TAG", value: ref) if tag?
-        variables.append(key: "CI_BUILD_TRIGGERED", value: 'true') if trigger_request
-        variables.append(key: "CI_BUILD_MANUAL", value: 'true') if action?
-      end
-    end
-
-    def persisted_environment_variables
-      Gitlab::Ci::Variables::Collection.new.tap do |variables|
-        break variables unless persisted? && persisted_environment.present?
-
-        variables.concat(persisted_environment.predefined_variables)
-
-        # Here we're passing unexpanded environment_url for runner to expand,
-        # and we need to make sure that CI_ENVIRONMENT_NAME and
-        # CI_ENVIRONMENT_SLUG so on are available for the URL be expanded.
-        variables.append(key: 'CI_ENVIRONMENT_URL', value: environment_url) if environment_url
-      end
-    end
-
-    def deploy_token_variables
-      Gitlab::Ci::Variables::Collection.new.tap do |variables|
-        break variables unless gitlab_deploy_token
-
-        variables.append(key: 'CI_DEPLOY_USER', value: gitlab_deploy_token.username)
-        variables.append(key: 'CI_DEPLOY_PASSWORD', value: gitlab_deploy_token.token, public: false)
-      end
-    end
-
     def environment_url
       options&.dig(:environment, :url) || persisted_environment&.external_url
     end
diff --git a/app/models/concerns/ci/contextable.rb b/app/models/concerns/ci/contextable.rb
new file mode 100644
index 00000000000..4986a42dbd2
--- /dev/null
+++ b/app/models/concerns/ci/contextable.rb
@@ -0,0 +1,108 @@
+# frozen_string_literal: true
+
+module Ci
+  ##
+  # This module implements methods that provide context in form of
+  # essential CI/CD variables that can be used by a build / bridge job.
+  #
+  module Contextable
+    ##
+    # Variables in the environment name scope.
+    #
+    def scoped_variables(environment: expanded_environment_name)
+      Gitlab::Ci::Variables::Collection.new.tap do |variables|
+        variables.concat(predefined_variables)
+        variables.concat(project.predefined_variables)
+        variables.concat(pipeline.predefined_variables)
+        variables.concat(runner.predefined_variables) if runnable? && runner
+        variables.concat(project.deployment_variables(environment: environment)) if environment
+        variables.concat(yaml_variables)
+        variables.concat(user_variables)
+        variables.concat(secret_group_variables)
+        variables.concat(secret_project_variables(environment: environment))
+        variables.concat(trigger_request.user_variables) if trigger_request
+        variables.concat(pipeline.variables)
+        variables.concat(pipeline.pipeline_schedule.job_variables) if pipeline.pipeline_schedule
+      end
+    end
+
+    ##
+    # Regular Ruby hash of scoped variables, without duplicates that are
+    # possible to be present in an array of hashes returned from `variables`.
+    #
+    def scoped_variables_hash
+      scoped_variables.to_hash
+    end
+
+    ##
+    # Variables that do not depend on the environment name.
+    #
+    def simple_variables
+      strong_memoize(:simple_variables) do
+        scoped_variables(environment: nil).to_runner_variables
+      end
+    end
+
+    def user_variables
+      Gitlab::Ci::Variables::Collection.new.tap do |variables|
+        break variables if user.blank?
+
+        variables.append(key: 'GITLAB_USER_ID', value: user.id.to_s)
+        variables.append(key: 'GITLAB_USER_EMAIL', value: user.email)
+        variables.append(key: 'GITLAB_USER_LOGIN', value: user.username)
+        variables.append(key: 'GITLAB_USER_NAME', value: user.name)
+      end
+    end
+
+    def predefined_variables # rubocop:disable Metrics/AbcSize
+      Gitlab::Ci::Variables::Collection.new.tap do |variables|
+        variables.append(key: 'CI', value: 'true')
+        variables.append(key: 'GITLAB_CI', value: 'true')
+        variables.append(key: 'GITLAB_FEATURES', value: project.licensed_features.join(','))
+        variables.append(key: 'CI_SERVER_NAME', value: 'GitLab')
+        variables.append(key: 'CI_SERVER_VERSION', value: Gitlab::VERSION)
+        variables.append(key: 'CI_SERVER_VERSION_MAJOR', value: Gitlab.version_info.major.to_s)
+        variables.append(key: 'CI_SERVER_VERSION_MINOR', value: Gitlab.version_info.minor.to_s)
+        variables.append(key: 'CI_SERVER_VERSION_PATCH', value: Gitlab.version_info.patch.to_s)
+        variables.append(key: 'CI_SERVER_REVISION', value: Gitlab.revision)
+        variables.append(key: 'CI_JOB_NAME', value: name)
+        variables.append(key: 'CI_JOB_STAGE', value: stage)
+        variables.append(key: 'CI_COMMIT_SHA', value: sha)
+        variables.append(key: 'CI_COMMIT_SHORT_SHA', value: short_sha)
+        variables.append(key: 'CI_COMMIT_BEFORE_SHA', value: before_sha)
+        variables.append(key: 'CI_COMMIT_REF_NAME', value: ref)
+        variables.append(key: 'CI_COMMIT_REF_SLUG', value: ref_slug)
+        variables.append(key: "CI_COMMIT_TAG", value: ref) if tag?
+        variables.append(key: "CI_PIPELINE_TRIGGERED", value: 'true') if trigger_request
+        variables.append(key: "CI_JOB_MANUAL", value: 'true') if action?
+        variables.append(key: "CI_NODE_INDEX", value: self.options[:instance].to_s) if self.options&.include?(:instance)
+        variables.append(key: "CI_NODE_TOTAL", value: (self.options&.dig(:parallel) || 1).to_s)
+        variables.concat(legacy_variables)
+      end
+    end
+
+    def legacy_variables
+      Gitlab::Ci::Variables::Collection.new.tap do |variables|
+        variables.append(key: 'CI_BUILD_REF', value: sha)
+        variables.append(key: 'CI_BUILD_BEFORE_SHA', value: before_sha)
+        variables.append(key: 'CI_BUILD_REF_NAME', value: ref)
+        variables.append(key: 'CI_BUILD_REF_SLUG', value: ref_slug)
+        variables.append(key: 'CI_BUILD_NAME', value: name)
+        variables.append(key: 'CI_BUILD_STAGE', value: stage)
+        variables.append(key: "CI_BUILD_TAG", value: ref) if tag?
+        variables.append(key: "CI_BUILD_TRIGGERED", value: 'true') if trigger_request
+        variables.append(key: "CI_BUILD_MANUAL", value: 'true') if action?
+      end
+    end
+
+    def secret_group_variables
+      return [] unless project.group
+
+      project.group.ci_variables_for(git_ref, project)
+    end
+
+    def secret_project_variables(environment: persisted_environment)
+      project.ci_variables_for(ref: git_ref, environment: environment)
+    end
+  end
+end