Introduce build pending states table and model

This commits adds a new database table with model and corresponding
migration. We are going to store a final build state upon a final build
update sent from a Runner.

app/models/ci/build_pending_state.rb

+# frozen_string_literal: true
+
+class Ci::BuildPendingState < ApplicationRecord
+  extend Gitlab::Ci::Model
+
+  belongs_to :build, class_name: 'Ci::Build', foreign_key: :build_id
+
+  validates :build, presence: true
+end

changelogs/unreleased/feature-gb-add-ci-build-state-table.yml

+---
+title: Introduce build states table / model / migration
+merge_request: 41585
+author:
+type: added

db/migrate/20200904131544_create_ci_build_pending_states.rb

+# frozen_string_literal: true
+
+class CreateCiBuildPendingStates < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    with_lock_retries do
+      create_table :ci_build_pending_states do |t|
+        t.timestamps_with_timezone
+        t.references :build, index: { unique: true }, null: false, foreign_key: { to_table: :ci_builds, on_delete: :cascade }, type: :bigint
+        t.integer :state
+        t.integer :failure_reason
+        t.binary :trace_checksum
+      end
+    end
+  end
+
+  def down
+    with_lock_retries do
+      drop_table :ci_build_pending_states
+    end
+  end
+end

db/schema_migrations/20200904131544

+08c9c6e5cd19aac17de7fc639eaca5ddba3e8280452821b8a72f05dcde790feb
\ No newline at end of file

db/structure.sql

@@ -9779,6 +9779,25 @@ CREATE SEQUENCE public.ci_build_needs_id_seq
 
 ALTER SEQUENCE public.ci_build_needs_id_seq OWNED BY public.ci_build_needs.id;
 
+CREATE TABLE public.ci_build_pending_states (
+    id bigint NOT NULL,
+    created_at timestamp with time zone NOT NULL,
+    updated_at timestamp with time zone NOT NULL,
+    build_id bigint NOT NULL,
+    state integer,
+    failure_reason integer,
+    trace_checksum bytea
+);
+
+CREATE SEQUENCE public.ci_build_pending_states_id_seq
+    START WITH 1
+    INCREMENT BY 1
+    NO MINVALUE
+    NO MAXVALUE
+    CACHE 1;
+
+ALTER SEQUENCE public.ci_build_pending_states_id_seq OWNED BY public.ci_build_pending_states.id;
+
 CREATE TABLE public.ci_build_report_results (
     build_id bigint NOT NULL,
     project_id bigint NOT NULL,
@@ -16872,6 +16891,8 @@ ALTER TABLE ONLY public.chat_teams ALTER COLUMN id SET DEFAULT nextval('public.c
 
 ALTER TABLE ONLY public.ci_build_needs ALTER COLUMN id SET DEFAULT nextval('public.ci_build_needs_id_seq'::regclass);
 
+ALTER TABLE ONLY public.ci_build_pending_states ALTER COLUMN id SET DEFAULT nextval('public.ci_build_pending_states_id_seq'::regclass);
+
 ALTER TABLE ONLY public.ci_build_report_results ALTER COLUMN build_id SET DEFAULT nextval('public.ci_build_report_results_build_id_seq'::regclass);
 
 ALTER TABLE ONLY public.ci_build_trace_chunks ALTER COLUMN id SET DEFAULT nextval('public.ci_build_trace_chunks_id_seq'::regclass);
@@ -17823,6 +17844,9 @@ ALTER TABLE public.merge_request_diffs
 ALTER TABLE ONLY public.ci_build_needs
     ADD CONSTRAINT ci_build_needs_pkey PRIMARY KEY (id);
 
+ALTER TABLE ONLY public.ci_build_pending_states
+    ADD CONSTRAINT ci_build_pending_states_pkey PRIMARY KEY (id);
+
 ALTER TABLE ONLY public.ci_build_report_results
     ADD CONSTRAINT ci_build_report_results_pkey PRIMARY KEY (build_id);
 
@@ -19265,6 +19289,8 @@ CREATE UNIQUE INDEX index_chat_teams_on_namespace_id ON public.chat_teams USING
 
 CREATE UNIQUE INDEX index_ci_build_needs_on_build_id_and_name ON public.ci_build_needs USING btree (build_id, name);
 
+CREATE UNIQUE INDEX index_ci_build_pending_states_on_build_id ON public.ci_build_pending_states USING btree (build_id);
+
 CREATE INDEX index_ci_build_report_results_on_project_id ON public.ci_build_report_results USING btree (project_id);
 
 CREATE UNIQUE INDEX index_ci_build_trace_chunks_on_build_id_and_chunk_index ON public.ci_build_trace_chunks USING btree (build_id, chunk_index);
@@ -22149,6 +22175,9 @@ ALTER TABLE ONLY public.project_deploy_tokens
 ALTER TABLE ONLY public.packages_conan_file_metadata
     ADD CONSTRAINT fk_rails_0afabd9328 FOREIGN KEY (package_file_id) REFERENCES public.packages_package_files(id) ON DELETE CASCADE;
 
+ALTER TABLE ONLY public.ci_build_pending_states
+    ADD CONSTRAINT fk_rails_0bbbfeaf9d FOREIGN KEY (build_id) REFERENCES public.ci_builds(id) ON DELETE CASCADE;
+
 ALTER TABLE ONLY public.operations_user_lists
     ADD CONSTRAINT fk_rails_0c716e079b FOREIGN KEY (project_id) REFERENCES public.projects(id) ON DELETE CASCADE;