Merge branch 'always_set_env_var_use_model_load_balancing' into 'master'

Always set GITLAB_USE_MODEL_LOAD_BALANCING in test env

See merge request gitlab-org/gitlab!82562

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

@@ -24,10 +24,6 @@
 
 .decomposed-database-rspec:
   extends: .decomposed-database
-  variables:
-    # For decomposition phase 3, uncomment line below:
-    # GITLAB_LOAD_BALANCING_REUSE_PRIMARY_ci: "main"
-    GITLAB_USE_MODEL_LOAD_BALANCING: "true"
 
 .rspec-base:
   extends:
@@ -381,6 +377,8 @@ db:migrate:reset decomposed:
     - db:migrate:reset
     - .decomposed-database
     - .rails:rules:decomposed-databases
+  variables:
+    GITLAB_USE_MODEL_LOAD_BALANCING: "false"
 
 db:migrate-from-previous-major-version:
   extends: .db-job-base
@@ -389,6 +387,7 @@ db:migrate-from-previous-major-version:
     SETUP_DB: "false"
     PROJECT_TO_CHECKOUT: "gitlab-foss"
     TAG_TO_CHECKOUT: "v13.12.9"
+    GITLAB_USE_MODEL_LOAD_BALANCING: "false"
   before_script:
     - !reference [.default-before_script, before_script]
     - '[[ -d "ee/" ]] || export PROJECT_TO_CHECKOUT="gitlab"'

lib/gitlab/database/load_balancing/setup.rb

@@ -90,7 +90,8 @@ module Gitlab
 
           def use_model_load_balancing?
             # Cache environment variable and return env variable first if defined
-            use_model_load_balancing_env = Gitlab::Utils.to_boolean(ENV["GITLAB_USE_MODEL_LOAD_BALANCING"])
+            default_use_model_load_balancing_env = Gitlab.dev_or_test_env? || nil
+            use_model_load_balancing_env = Gitlab::Utils.to_boolean(ENV.fetch('GITLAB_USE_MODEL_LOAD_BALANCING', default_use_model_load_balancing_env))
 
             unless use_model_load_balancing_env.nil?
               return use_model_load_balancing_env

spec/lib/gitlab/database/load_balancing/setup_spec.rb

@@ -274,6 +274,8 @@ RSpec.describe Gitlab::Database::LoadBalancing::Setup do
       end
 
       before do
+        allow(Gitlab).to receive(:dev_or_test_env?).and_return(false)
+
         # Rewrite `class_attribute` to use rspec mocking and prevent modifying the objects
         allow_next_instance_of(described_class) do |setup|
           allow(setup).to receive(:configure_connection)