Fix systemd misjudging by sending heartbeats.

systemd_notifier.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+class SystemdNotifier
+  require_relative 'method_executor'
+  public
+
+  @notify_socket = ENV["NOTIFY_SOCKET"]
+  @watchdog_usec = (ENV["WATCHDOG_USEC"] || '0').to_i
+
+  unless @notify_socket && File.socket?(@notify_socket)
+    MethodExecutor.record("error", "heartbeat", "NOTIFY_SOCKET is not set or is not a socket, am I a service?")
+    @enable_heartbeat = false
+  else
+    @enable_heartbeat = true
+    @socket = UNIXSocket.new(@notify_socket)
+  end
+
+  def enabled?
+    @enable_heartbeat
+  end
+
+  def notify_heartbeat(message)
+    return unless @enable_heartbeat
+
+    begin
+      @socket.send(message, 0)
+    rescue => e
+      MethodExecutor.error("heartbeat", "Failed to send heartbeat: #{e}")
+      @enable_heartbeat = false
+    end
+  end
+
+  def self.notify(message)
+    MethodExecutor.record("info", "systemd", message)
+  end
+end