@startuml

autonumber

participant ApplicationManager
participant RialtoServerManager

ApplicationManager             ->  RialtoServerManager:               create(state_observer, config)
note right: config allows app manager to specify number of preloaded servers, path to RialtoApplicationSessionServer binary, READY timer and heathcheck interval
loop For eachnum requestedof preloaded server
 ref over ApplicationManager, RialtoApplicationSessionServer : [[#RialtoApplicationSessionManagement-NotRunning→Inactive Not Running to Inactive]]RialtoServerManager            ->  RialtoServerManager:               Generate socketpair for Rialto Application Session Server to Server Manager communication
RialtoServerManager            ->  RialtoApplicationSessionServer **: Spawn(server_manager_socket)
note left
Spawn Application
Session Servers to speed up app launch time.
end note
RialtoServerManager            ->  RialtoServerManager:               Start [1] second READY timer
RialtoServerManager            --> ApplicationManager:                OK/ERROR
RialtoApplicationSessionServer ->  RialtoApplicationSessionServer:    Set current_state = Uninitialised

alt RialtoApplicationSessionServer started successfully

RialtoApplicationSessionServer -// RialtoServerManager:               stateChanged(AppState::Uninitialised)
RialtoServerManager            ->  RialtoServerManager:               Cancel READY timer
RialtoServerManager            -// ApplicationManager:                stateChanged(application_id, AppState::Uninitialised)
RialtoServerManager            ->  RialtoApplicationSessionServer:    SetConfiguration(session_management_socket_name, AppState::Inactive, resources, log_level)
note right
"resources" structure will specify the maximum decoder resources that the
application is permitted to use. For now it shall have a max_playback_sessions
property and a supports_web_audio flag. This may be enhanced for things like
HD/UHD, audio only etc in future.
end note
RialtoApplicationSessionServer --> RialtoServerManager:
RialtoApplicationSessionServer ->  RialtoApplicationSessionServer:    Create listening socket & bind to session_management_socket_name

alt State transition successful
RialtoApplicationSessionServer ->  RialtoApplicationSessionServer:    Set current_state = Inactive
RialtoApplicationSessionServer -// RialtoServerManager:               stateChanged(AppState::Inactive)
RialtoServerManager            -// ApplicationManager:                StateChanged(application_id, AppState::Inactive)
ApplicationManager             ->  RialtoServerManager:               getAppConnectionInfo()
RialtoServerManager            --> ApplicationManager:                session_management_socket_name
else State transition failed
RialtoApplicationSessionServer ->  RialtoApplicationSessionServer:    Unbind/free session management socket (if created)
RialtoApplicationSessionServer -// RialtoServerManager:               stateChanged(AppState::Error)
RialtoServerManager            -// ApplicationManager:                stateChanged(application_id, AppState::Error)
RialtoApplicationSessionServer ->  RialtoApplicationSessionServer !!: Exit process
end

else Session Server initialisation failed

RialtoApplicationSessionServer -// RialtoServerManager:               stateChanged(AppState::Error)
RialtoServerManager            ->  RialtoServerManager:               Cancel READY timer
RialtoApplicationSessionServer ->  RialtoApplicationSessionServer !!: Exit process
RialtoServerManager            -// ApplicationManager:                stateChanged(application_id, AppState::Error)

else READY timer expired

RialtoServerManager            ->  RialtoServerManager:               Kill spawned Rialto Application Session Server process
RialtoServerManager            -// ApplicationManager:                stateChanged(application_id, AppState::Error)

end
end

@enduml