Update db:check-migrations for decomposed CI

Add a new version of the db:check-migrations job that runs in a
decomposed pipeline, and tests migrations appropriately in that
environment.

.gitlab/ci/rails.gitlab-ci.yml

@@ -346,8 +346,8 @@ rspec fast_spec_helper minimal:
 db:rollback:
   extends: .db-job-base
   script:
-    - scripts/db_migrate VERSION=20181228175414
-    - scripts/db_migrate SKIP_SCHEMA_VERSION_CHECK=true
+    - scripts/db_tasks db:migrate VERSION=20181228175414
+    - scripts/db_tasks db:migrate SKIP_SCHEMA_VERSION_CHECK=true
 
 db:migrate:reset:
   extends: .db-job-base
@@ -372,15 +372,13 @@ db:migrate-from-previous-major-version:
     - git checkout -f $CI_COMMIT_SHA
     - SETUP_DB=false USE_BUNDLE_INSTALL=true bash scripts/prepare_build.sh
   script:
-    - run_timed_command "scripts/db_migrate"
+    - run_timed_command "scripts/db_tasks db:migrate"
 
 db:migrate-from-previous-major-version-decomposed:
   extends:
     - db:migrate-from-previous-major-version
     - .decomposed-database
     - .rails:rules:decomposed-databases
-  variables:
-    GITLAB_MIGRATE_MAIN_ONLY: "true"
 
 .db:check-schema-base:
   extends:
@@ -388,7 +386,7 @@ db:migrate-from-previous-major-version-decomposed:
   variables:
     TAG_TO_CHECKOUT: "v14.4.0"
   script:
-    - run_timed_command "scripts/db_migrate"
+    - run_timed_command "scripts/db_tasks db:migrate"
     - scripts/schema_changed.sh
     - scripts/validate_migration_timestamps
 
@@ -411,6 +409,12 @@ db:check-migrations:
     - scripts/validate_migration_schema
   allow_failure: true
 
+db:check-migrations-decomposed:
+  extends:
+    - db:check-migrations
+    - .decomposed-database
+    - .rails:rules:decomposed-databases
+
 db:gitlabcom-database-testing:
   extends: .rails:rules:db:gitlabcom-database-testing
   stage: test

scripts/db_migrate → scripts/db_tasks

 #!/bin/bash
 
 root_path="$(cd "$(dirname "$0")/.." || exit ; pwd -P)"
+task=$1
 
-if [[ -d "${root_path}/ee/" || "${GITLAB_MIGRATE_MAIN_ONLY}" == "true" ]]; then
-	task="db:migrate:main"
-else
-	task="db:migrate"
+shift
+
+if [[ -d "${root_path}/ee/" || "${DECOMPOSED_DB}" == "true" ]]; then
+	task="${task}:main"
 fi
 
 eval "bundle exec rake ${task} ${*}"

scripts/validate_migration_schema

@@ -30,7 +30,8 @@ class MigrationSchemaValidator
     committed_migrations.reverse_each do |filename|
       version = find_migration_version(filename)
 
-      run("bin/rails db:migrate:down VERSION=#{version}")
+      run("scripts/db_tasks db:migrate:down VERSION=#{version}")
+      run("scripts/db_tasks db:schema:dump")
     end
 
     git_command = "git diff #{diff_target} -- #{FILENAME}"
@@ -40,7 +41,8 @@ class MigrationSchemaValidator
   end
 
   def validate_schema_on_migrate!
-    run('bin/rails db:migrate')
+    run("scripts/db_tasks db:migrate")
+    run("scripts/db_tasks db:schema:dump")
 
     git_command = "git diff -- #{FILENAME}"
     base_message = "the committed #{FILENAME} does not match the one generated by running added migrations"