8 files changed, 28 insertions, 9 deletions
diff --git a/app/models/ci/pipeline.rb b/app/models/ci/pipeline.rb
index 53af87a271a..5eb30f4aaa0 100644
--- a/app/models/ci/pipeline.rb
+++ b/app/models/ci/pipeline.rb
@@ -7,12 +7,17 @@ module Ci
     include Presentable
     include Gitlab::OptimisticLocking
     include Gitlab::Utils::StrongMemoize
+    include AtomicInternalId
 
     belongs_to :project, inverse_of: :pipelines
     belongs_to :user
     belongs_to :auto_canceled_by, class_name: 'Ci::Pipeline'
     belongs_to :pipeline_schedule, class_name: 'Ci::PipelineSchedule'
 
+    has_internal_id :iid, scope: :project, presence: false, init: ->(s) do
+      s&.project&.pipelines&.maximum(:iid) || s&.project&.pipelines&.count
+    end
+
     has_many :stages
     has_many :statuses, class_name: 'CommitStatus', foreign_key: :commit_id, inverse_of: :pipeline
     has_many :builds, foreign_key: :commit_id, inverse_of: :pipeline
@@ -531,6 +536,7 @@ module Ci
 
     def predefined_variables
       Gitlab::Ci::Variables::Collection.new
+        .append(key: 'CI_PIPELINE_IID', value: iid.to_s)
         .append(key: 'CI_CONFIG_PATH', value: ci_yaml_file_path)
         .append(key: 'CI_PIPELINE_SOURCE', value: source.to_s)
         .append(key: 'CI_COMMIT_MESSAGE', value: git_commit_message)
diff --git a/app/models/concerns/atomic_internal_id.rb b/app/models/concerns/atomic_internal_id.rb
index 22f516a172f..164c704260e 100644
--- a/app/models/concerns/atomic_internal_id.rb
+++ b/app/models/concerns/atomic_internal_id.rb
@@ -25,9 +25,13 @@ module AtomicInternalId
   extend ActiveSupport::Concern
 
   module ClassMethods
-    def has_internal_id(column, scope:, init:) # rubocop:disable Naming/PredicateName
-      before_validation(on: :create) do
+    def has_internal_id(column, scope:, init:, presence: true) # rubocop:disable Naming/PredicateName
+      before_validation :"ensure_#{scope}_#{column}!", on: :create
+      validates column, presence: presence
+
+      define_method("ensure_#{scope}_#{column}!") do
         scope_value = association(scope).reader
+
         if read_attribute(column).blank? && scope_value
           scope_attrs = { scope_value.class.table_name.singularize.to_sym => scope_value }
           usage = self.class.table_name.to_sym
@@ -35,13 +39,9 @@ module AtomicInternalId
           new_iid = InternalId.generate_next(self, scope_attrs, usage, init)
           write_attribute(column, new_iid)
         end
-      end
 
-      validates column, presence: true, numericality: true
+        read_attribute(column)
+      end
     end
   end
-
-  def to_param
-    iid.to_s
-  end
 end
diff --git a/app/models/concerns/iid_routes.rb b/app/models/concerns/iid_routes.rb
new file mode 100644
index 00000000000..246748cf52c
--- /dev/null
+++ b/app/models/concerns/iid_routes.rb
@@ -0,0 +1,9 @@
+module IidRoutes
+  ##
+  # This automagically enforces all related routes to use `iid` instead of `id`
+  # If you want to use `iid` for some routes and `id` for other routes, this module should not to be included,
+  # instead you should define `iid` or `id` explictly at each route generators. e.g. pipeline_path(project.id, pipeline.iid)
+  def to_param
+    iid.to_s
+  end
+end
diff --git a/app/models/deployment.rb b/app/models/deployment.rb
index 254764eefde..ac86e9e8de0 100644
--- a/app/models/deployment.rb
+++ b/app/models/deployment.rb
@@ -1,5 +1,6 @@
 class Deployment < ActiveRecord::Base
   include AtomicInternalId
+  include IidRoutes
 
   belongs_to :project, required: true
   belongs_to :environment, required: true
diff --git a/app/models/internal_id.rb b/app/models/internal_id.rb
index f7f930e86ed..f50f28deffe 100644
--- a/app/models/internal_id.rb
+++ b/app/models/internal_id.rb
@@ -14,7 +14,7 @@ class InternalId < ActiveRecord::Base
   belongs_to :project
   belongs_to :namespace
 
-  enum usage: { issues: 0, merge_requests: 1, deployments: 2, milestones: 3, epics: 4 }
+  enum usage: { issues: 0, merge_requests: 1, deployments: 2, milestones: 3, epics: 4, ci_pipelines: 5 }
 
   validates :usage, presence: true
 
diff --git a/app/models/issue.rb b/app/models/issue.rb
index 41a290f34b4..d136700836d 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -2,6 +2,7 @@ require 'carrierwave/orm/activerecord'
 
 class Issue < ActiveRecord::Base
   include AtomicInternalId
+  include IidRoutes
   include Issuable
   include Noteable
   include Referable
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 79fc155fd3c..4c1628d2bdb 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -1,5 +1,6 @@
 class MergeRequest < ActiveRecord::Base
   include AtomicInternalId
+  include IidRoutes
   include Issuable
   include Noteable
   include Referable
diff --git a/app/models/milestone.rb b/app/models/milestone.rb
index d14e3a4ded5..d05dcfd083a 100644
--- a/app/models/milestone.rb
+++ b/app/models/milestone.rb
@@ -9,6 +9,7 @@ class Milestone < ActiveRecord::Base
 
   include CacheMarkdownField
   include AtomicInternalId
+  include IidRoutes
   include Sortable
   include Referable
   include StripAttribute