Re: [jboss-as7-dev] Graceful Shutdown (Revision 2)

Are you sure explicity granting "permits" through a "Shutdown Manager" the way to go? Having to interact with a central service that grants permits per-request is very worrisome. The subsystem may already have a better way to do graceful shutdown, or just cannot follow a permit pattern. Is it not simpler and gives more flexibility to a subsystem to drive this via events rather than explicit callbacks to a Shutdown Manager? i.e. class Suspending extends ShutdownEvent { void iFinishedSuspending(); // the callback to the Shutdown Manager } GIves the subsystem flexibility on how best to implement a graceful shutdown. On 6/26/12 11:00 AM, Jason T. Greene wrote: > *EDITED* > > We've worked out the rough outline of how graceful shutdown will work in > AS7. > > The process of graceful shutdown actually is reflected by a number of > states: > > 1. Running - all services acting normally > 2. Suspending - services refuse new "permits" (see below), existing > permits are allowed to be retained (and threads running under such a > permit may still acquire new permits) > 3. Suspended - no permits are present and none may be issued > 4. Shutting Down - our existing server stop process / reload admin mode > > The following transitions are allowed: > > 1. Running → Suspending: Transition occurs at user request (to suspend > or gracefully shut down). > 2. Suspending → Suspended: Transition occurs when all permits are cleared. > 3. Suspending → Running: Transition occurs at user request (to exit > suspend mode or cancel graceful shutdown before it completes). > 4. Suspended → Running: Transition occurs at user request (to exit > suspend mode). > 5. Suspended → Shutting Down: Transition occurs automatically (if a > graceful shutdown was requested) or at user request (if a shut down > request of any kind is entered in the Suspended state). > 6. Running → Shutting Down: Transition occurs at user request (to shut > down the server "un-gracefully"). > 7. Suspending → Shutting Down (User aborts a graceful shutdown) > > These "permits" are issued by the "Shutdown Manager", whose job is to > manage these states. They are issued corresponding to the following events: > > 1. The invocation of an EJB method > 2. The creation of a web session > 3. A creation of a transaction > 4. MessageEndpoint and WorkManager aquire permit allowing for release() > from a thirdparty to indicate connection close. > > When a permit cannot be issued due to the server shutting down, a > standard exception message should be produced so that the user can see a > familiar error message regardless of what mechanism is used to access > the server. >