1 files changed, 63 insertions, 0 deletions
diff --git a/lib/gitlab/database/health_status/signals.rb b/lib/gitlab/database/health_status/signals.rb
new file mode 100644
index 00000000000..e1bcdcae9c7
--- /dev/null
+++ b/lib/gitlab/database/health_status/signals.rb
@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Database
+    module HealthStatus
+      module Signals
+        # Base class for a signal
+        class Base
+          attr_reader :indicator_class, :reason
+
+          def initialize(indicator_class, reason:)
+            @indicator_class = indicator_class
+            @reason = reason
+          end
+
+          def to_s
+            "#{short_name} (indicator: #{indicator_class}; reason: #{reason})"
+          end
+
+          def log_info?
+            false
+          end
+
+          def stop?
+            false
+          end
+
+          def short_name
+            self.class.name.demodulize
+          end
+        end
+
+        # A Signals::Stop is an indication to put a migration on hold or stop it entirely:
+        # In general, we want to slow down or pause the migration.
+        class Stop < Base
+          def log_info?
+            true
+          end
+
+          def stop?
+            true
+          end
+        end
+
+        # A Signals::Normal indicates normal system state: We carry on with the migration
+        # and may even attempt to optimize its throughput etc.
+        class Normal < Base; end
+
+        # When given an Signals::Unknown, something unexpected happened while
+        # we evaluated system indicators.
+        class Unknown < Base
+          def log_info?
+            true
+          end
+        end
+
+        # No signal could be determined, e.g. because the indicator
+        # was disabled.
+        class NotAvailable < Base; end
+      end
+    end
+  end
+end