ceph/src/rgw/rgw_realm_reloader.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #ifndef RGW_REALM_RELOADER_H
   5 #define RGW_REALM_RELOADER_H
   6
   7 #include "rgw_realm_watcher.h"
   8 #include "common/Cond.h"
   9
  10 class RGWRados;
  11
  12 /**
  13  * RGWRealmReloader responds to new period notifications by recreating RGWRados
  14  * with the updated realm configuration.
  15  */
  16 class RGWRealmReloader : public RGWRealmWatcher::Watcher {
  17  public:
  18   /**
  19    * Pauser is an interface to pause/resume frontends. Frontend cooperation
  20    * is required to ensure that they stop issuing requests on the old
  21    * RGWRados instance, and restart with the updated configuration.
  22    *
  23    * This abstraction avoids a depency on class RGWFrontend.
  24    */
  25   class Pauser {
  26    public:
  27     virtual ~Pauser() = default;
  28
  29     /// pause all frontends while realm reconfiguration is in progress
  30     virtual void pause() = 0;
  31     /// resume all frontends with the given RGWRados instance
  32     virtual void resume(RGWRados* store) = 0;
  33   };
  34
  35   RGWRealmReloader(RGWRados*& store, Pauser* frontends);
  36   ~RGWRealmReloader() override;
  37
  38   /// respond to realm notifications by scheduling a reload()
  39   void handle_notify(RGWRealmNotify type, bufferlist::iterator& p) override;
  40
  41  private:
  42   /// pause frontends and replace the RGWRados instance
  43   void reload();
  44
  45   class C_Reload; //< Context that calls reload()
  46
  47   /// main()'s RGWRados pointer as a reference, modified by reload()
  48   RGWRados*& store;
  49   Pauser *const frontends;
  50
  51   /// reload() takes a significant amount of time, so we don't want to run
  52   /// it in the handle_notify() thread. we choose a timer thread instead of a
  53   /// Finisher because it allows us to cancel events that were scheduled while
  54   /// reload() is still running
  55   SafeTimer timer;
  56   Mutex mutex; //< protects access to timer and reload_scheduled
  57   Cond cond; //< to signal reload() after an invalid realm config
  58   C_Reload* reload_scheduled; //< reload() context if scheduled
  59 };
  60
  61 #endif // RGW_REALM_RELOADER_H