LB feature is available in FOSS but is not ready

As we have some code in ee/ uses LB, in overriden methods
and may have the (incorrect) assumption that LB is not present in FOSS

lib/gitlab/database/load_balancing.rb

@@ -102,23 +102,9 @@ module Gitlab
         hosts.any? || service_discovery_enabled?
       end
 
+      # Temporarily disabled for FOSS until move from EE to FOSS is complete
       def self.feature_available?
-        # If this method is called in any subscribers listening to
-        # sql.active_record, the SQL call below may cause infinite recursion.
-        # So, the memoization variable must have 3 states
-        # - First call: @feature_available is undefined
-        #   -> Set @feature_available to false
-        #   -> Trigger SQL
-        #   -> SQL subscriber triggers this method again
-        #     -> return false
-        #   -> Set @feature_available  to true
-        #   -> return true
-        # - Second call: return @feature_available right away
-        return @feature_available if defined?(@feature_available)
-
-        @feature_available = false
-        @feature_available = Gitlab::Database.cached_table_exists?('licenses') &&
-                             ::License.feature_available?(:db_load_balancing)
+        Gitlab.ee? || Gitlab::Utils.to_boolean(ENV['ENABLE_LOAD_BALANCING_FOR_FOSS'], default: false)
       end
 
       def self.start_service_discovery

spec/lib/gitlab/database/load_balancing_spec.rb

@@ -5,6 +5,10 @@ require 'spec_helper'
 RSpec.describe Gitlab::Database::LoadBalancing do
   include_context 'clear DB Load Balancing configuration'
 
+  before do
+    stub_env('ENABLE_LOAD_BALANCING_FOR_FOSS', 'true')
+  end
+
   describe '.proxy' do
     context 'when configured' do
       before do
@@ -127,8 +131,6 @@ RSpec.describe Gitlab::Database::LoadBalancing do
   end
 
   describe '.enable?' do
-    let!(:license) { create(:license, plan: ::License::PREMIUM_PLAN) }
-
     before do
       clear_load_balancing_configuration
       allow(described_class).to receive(:hosts).and_return(%w(foo))
@@ -181,27 +183,22 @@ RSpec.describe Gitlab::Database::LoadBalancing do
       end
     end
 
-    context 'without a license' do
+    context 'FOSS' do
       before do
-        License.destroy_all # rubocop: disable Cop/DestroyAll
-        clear_load_balancing_configuration
-      end
+        allow(Gitlab).to receive(:ee?).and_return(false)
 
-      it 'is disabled' do
-        expect(described_class.enable?).to eq(false)
+        stub_env('ENABLE_LOAD_BALANCING_FOR_FOSS', 'false')
       end
-    end
-
-    context 'with an EES license' do
-      let!(:license) { create(:license, plan: ::License::STARTER_PLAN) }
 
       it 'is disabled' do
         expect(described_class.enable?).to eq(false)
       end
     end
 
-    context 'with an EEP license' do
-      let!(:license) { create(:license, plan: ::License::PREMIUM_PLAN) }
+    context 'EE' do
+      before do
+        allow(Gitlab).to receive(:ee?).and_return(true)
+      end
 
       it 'is enabled' do
         allow(described_class).to receive(:hosts).and_return(%w(foo))
@@ -213,8 +210,6 @@ RSpec.describe Gitlab::Database::LoadBalancing do
   end
 
   describe '.configured?' do
-    let!(:license) { create(:license, plan: ::License::PREMIUM_PLAN) }
-
     before do
       clear_load_balancing_configuration
     end
@@ -245,17 +240,6 @@ RSpec.describe Gitlab::Database::LoadBalancing do
 
       expect(described_class.configured?).to eq(false)
     end
-
-    context 'without a license' do
-      before do
-        License.destroy_all # rubocop: disable Cop/DestroyAll
-        clear_load_balancing_configuration
-      end
-
-      it 'is not configured' do
-        expect(described_class.configured?).to eq(false)
-      end
-    end
   end
 
   describe '.configure_proxy' do
@@ -444,7 +428,6 @@ RSpec.describe Gitlab::Database::LoadBalancing do
       end
 
       before do
-        stub_licensed_features(db_load_balancing: true)
         # Preloading testing class
         model.singleton_class.prepend ::Gitlab::Database::LoadBalancing::ActiveRecordProxy