ASM.Session.OwnerGuard (ASM v0.12.0)

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Binds a session subtree's lifetime to an owner process.

The provider form of ASM.query/3 starts a session, runs one prompt, and stops the session from the caller's after block. An untrappable Process.exit(caller, :kill) skips that block, and the supervised subtree keeps running with its provider process group still attached. This guard closes that window: it monitors the owner and terminates the subtree child through ASM.Session.Supervisor.stop_session/2 when the owner goes down.

Two placement facts matter:

  • stopping a session subtree is ASM.Session.Server stopping itself is not enough, because ASM.Session.Subtree would restart it; the subtree child itself has to be terminated
  • the guard therefore lives OUTSIDE the subtree it guards, under ASM.Session.GuardSupervisor. A guard supervised by the subtree it is terminating would be shut down while blocked in that very call

The guard also monitors the subtree, so an ordinary ASM.stop_session/1 retires the guard instead of leaving it waiting on an owner forever.

Summary

Types

state()

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

start_link(opts)

Types

state()

@type state() :: %{
  session_id: String.t(),
  supervisor: GenServer.server(),
  owner_ref: reference(),
  subtree_ref: reference()
}

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

start_link(opts)

@spec start_link(keyword()) :: GenServer.on_start()