Does not log failed sign-in attempts when database is in read-only mode

app/models/user.rb

@@ -1097,8 +1097,11 @@ class User < ActiveRecord::Base
   #   <https://github.com/plataformatec/devise/blob/v4.0.0/lib/devise/models/lockable.rb#L92>
   #
   def increment_failed_attempts!
+    return if ::Gitlab::Database.read_only?
+
     self.failed_attempts ||= 0
     self.failed_attempts += 1
+
     if attempts_exceeded?
       lock_access! unless access_locked?
     else

spec/models/user_spec.rb

@@ -2755,4 +2755,18 @@ describe User do
       it { is_expected.to be_truthy }
     end
   end
+
+  describe '#increment_failed_attempts!' do
+    subject(:user) { create(:user, failed_attempts: 0) }
+
+    it 'logs failed sign-in attempts' do
+      expect { user.increment_failed_attempts! }.to change(user, :failed_attempts).from(0).to(1)
+    end
+
+    it 'does not log failed sign-in attempts when in a GitLab read-only instance' do
+      allow(Gitlab::Database).to receive(:read_only?) { true }
+
+      expect { user.increment_failed_attempts! }.not_to change(user, :failed_attempts)
+    end
+  end
 end