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use super::*;
impl MeerkatMachine {
pub(super) async fn execute_meerkat_machine_drain_command(
self: &Arc<Self>,
command: MeerkatMachineCommand,
) -> Result<MeerkatMachineCommandResult, RuntimeDriverError> {
match command {
MeerkatMachineCommand::SetPeerIngressContext {
session_id,
keep_alive,
comms_runtime,
mob_id,
} => {
// Guard: session must exist.
if !self.sessions.read().await.contains_key(&session_id) {
return Err(RuntimeDriverError::NotReady {
state: RuntimeState::Destroyed,
});
}
// Guard: DrainBindingInvariant — no drain mutation on destroyed
// sessions.
if matches!(
self.existing_session_runtime_state(&session_id).await,
Some(RuntimeState::Destroyed)
) {
return Err(RuntimeDriverError::Destroyed);
}
let gate = self.session_mutation_gate(&session_id).await;
let _gate_guard = match gate {
Some(ref g) => Some(g.lock().await),
None => None,
};
self.stage_session_dsl_input(
&session_id,
crate::meerkat_machine::dsl::MeerkatMachineInput::SetPeerIngressContext {
keep_alive,
},
"SetPeerIngressContext",
)
.await
.map_err(|reason| RuntimeDriverError::ValidationFailed { reason })?;
// W2-G (issue #264): peer-ingress ownership is tracked by
// the DSL via `peer_ingress_owner_kind` +
// `peer_ingress_comms_runtime_id` + `peer_ingress_mob_id`.
// The `SetPeerIngressContext` transition above is a
// keep-alive-only self-loop that doesn't mutate those
// fields; the ownership-establishing transitions are
// `AttachSessionIngress` / `AttachMobIngress` at
// `meerkat-runtime/src/meerkat_machine/dsl.rs:6375-6407`.
//
// When a `comms_runtime` is provided:
// - If `mob_id` is present → fire `AttachMobIngress` to
// record `MobOwned { comms_runtime_id, mob_id }`.
// - Otherwise → fire `AttachSessionIngress` to record
// `SessionOwned { comms_runtime_id }`.
// The attach/detach transitions below encode exact
// idempotence in DSL guards. Any remaining rejection is an
// authoritative denial (for example a session attach trying
// to downgrade a mob-owned ingress) and must stop before the
// drain shell mutates task state.
//
// When `comms_runtime` is `None` the caller intends
// keep-alive-only; no ownership transition fires.
if let Some(ref runtime) = comms_runtime {
let comms_runtime_id =
crate::meerkat_machine::dsl::CommsRuntimeId::from_runtime(runtime);
let attach_input = if let Some(mob_id) = mob_id {
crate::meerkat_machine::dsl::MeerkatMachineInput::AttachMobIngress {
comms_runtime_id,
mob_id,
}
} else {
crate::meerkat_machine::dsl::MeerkatMachineInput::AttachSessionIngress {
comms_runtime_id,
}
};
self.stage_session_dsl_input(&session_id, attach_input, "AttachPeerIngress")
.await
.map_err(|reason| RuntimeDriverError::ValidationFailed { reason })?;
} else if !keep_alive {
// keep_alive=false + comms_runtime=None → caller is
// tearing down the drain. Fire `DetachIngress` to
// clear any active ownership. The DSL accepts exact
// no-op detach; other rejection stops the shell here.
self.stage_session_dsl_input(
&session_id,
crate::meerkat_machine::dsl::MeerkatMachineInput::DetachIngress,
"DetachIngress",
)
.await
.map_err(|reason| RuntimeDriverError::ValidationFailed { reason })?;
}
// Ownership transitions above have succeeded (or been
// idempotently rejected); dispatch the mechanical
// drain-task lifecycle side-effect. `update_peer_ingress_
// context_inner` stages `SpawnDrain` / `Abort` on the DSL
// and, on DSL accept, spawns / aborts the drain task.
// On DSL rejection it returns false without mutating
// shell slot state (preserving the bdd460951 invariant
// "no shell mutation after DSL rejection"). Its return
// value is the typed `Spawned(bool)` result the caller
// of `maybe_spawn_comms_drain` observes.
let spawned = self
.update_peer_ingress_context_inner(&session_id, keep_alive, comms_runtime)
.await;
Ok(MeerkatMachineCommandResult::Spawned(spawned))
}
MeerkatMachineCommand::NotifyDrainExited { session_id, reason } => {
// Guard: session must exist.
if !self.sessions.read().await.contains_key(&session_id) {
return Err(RuntimeDriverError::NotReady {
state: RuntimeState::Destroyed,
});
}
// Guard: DrainBindingInvariant — no drain mutation on destroyed
// sessions.
if matches!(
self.existing_session_runtime_state(&session_id).await,
Some(RuntimeState::Destroyed)
) {
return Err(RuntimeDriverError::Destroyed);
}
let gate = self.session_mutation_gate(&session_id).await;
let _gate_guard = match gate {
Some(ref g) => Some(g.lock().await),
None => None,
};
self.stage_session_dsl_input(
&session_id,
crate::meerkat_machine::dsl::MeerkatMachineInput::NotifyDrainExited {
reason: crate::meerkat_machine::dsl::DrainExitReason::from(reason),
},
"NotifyDrainExited",
)
.await
.map_err(|reason| RuntimeDriverError::ValidationFailed { reason })?;
self.notify_comms_drain_exited_inner(&session_id, reason)
.await;
Ok(MeerkatMachineCommandResult::Unit)
}
_ => unreachable!("non-drain command routed to drain handler"),
}
}
pub(super) async fn execute_meerkat_machine_drain_local_command(
&self,
command: MeerkatMachineCommand,
) -> Result<MeerkatMachineCommandResult, RuntimeDriverError> {
match command {
MeerkatMachineCommand::AbortAll => {
// Stage StopDrain for each session whose drain is Running.
let session_ids: Vec<meerkat_core::types::SessionId> = {
let sessions = self.sessions.read().await;
sessions
.iter()
.filter(|(_, entry)| {
entry.drain_slot.phase
== crate::meerkat_machine::CommsDrainPhase::Running
})
.map(|(sid, _)| sid.clone())
.collect()
};
let mut accepted_session_ids = Vec::new();
for sid in &session_ids {
if self.stage_drain_stop_dsl(sid).await {
accepted_session_ids.push(sid.clone());
}
}
let mut sessions = self.sessions.write().await;
for sid in accepted_session_ids {
if let Some(entry) = sessions.get_mut(&sid) {
abort_slot(&mut entry.drain_slot);
}
}
Ok(MeerkatMachineCommandResult::Unit)
}
MeerkatMachineCommand::Abort { session_id } => {
// Guard: session must be registered.
if !self.sessions.read().await.contains_key(&session_id) {
return Err(RuntimeDriverError::NotReady {
state: RuntimeState::Destroyed,
});
}
// Stage StopDrain if drain is Running.
let drain_is_running = {
let sessions = self.sessions.read().await;
sessions
.get(&session_id)
.map(|entry| {
entry.drain_slot.phase
== crate::meerkat_machine::CommsDrainPhase::Running
})
.unwrap_or(false)
};
if drain_is_running && !self.stage_drain_stop_dsl(&session_id).await {
return Ok(MeerkatMachineCommandResult::Unit);
}
let mut sessions = self.sessions.write().await;
if let Some(entry) = sessions.get_mut(&session_id) {
abort_slot(&mut entry.drain_slot);
}
Ok(MeerkatMachineCommandResult::Unit)
}
MeerkatMachineCommand::Wait { session_id } => {
// Guard: session must be registered.
if !self.sessions.read().await.contains_key(&session_id) {
return Err(RuntimeDriverError::NotReady {
state: RuntimeState::Destroyed,
});
}
let handle = {
let mut sessions = self.sessions.write().await;
sessions
.get_mut(&session_id)
.and_then(|entry| entry.drain_slot.handle.take())
};
if let Some(handle) = handle {
let _ = handle.await;
}
// Re-read post-await to safety-net a panicked task that
// never notified the authority. Record the stage-if-running
// decision under the same lock acquisition so authority
// and slot updates stay ordered: DSL input first, then
// mark the slot exited. Dropping and re-acquiring the
// write guard between DSL and slot mutation preserves the
// pre-collapse pattern where the sibling map was touched
// after the `sessions` lock was released.
let is_respawnable = {
let sessions = self.sessions.read().await;
sessions.get(&session_id).and_then(|entry| {
(entry.drain_slot.phase == crate::meerkat_machine::CommsDrainPhase::Running)
.then_some(
entry.drain_slot.mode
== Some(crate::meerkat_machine::CommsDrainMode::PersistentHost),
)
})
};
if let Some(is_respawnable) = is_respawnable {
let dsl_input = if is_respawnable {
crate::meerkat_machine::dsl::MeerkatMachineInput::DrainExitedRespawnable
} else {
crate::meerkat_machine::dsl::MeerkatMachineInput::DrainExitedClean
};
let context = if is_respawnable {
"DrainExitedRespawnable(safety)"
} else {
"DrainExitedClean(safety)"
};
let dsl_accepted = {
let mut sessions = self.sessions.write().await;
if let Some(entry) = sessions.get_mut(&session_id) {
let mut authority = entry
.dsl_authority
.lock()
.unwrap_or_else(std::sync::PoisonError::into_inner);
if let Err(err) =
crate::meerkat_machine::dsl::MeerkatMachineMutator::apply(
&mut *authority,
dsl_input,
)
{
tracing::warn!(
error = %crate::meerkat_machine::dsl_authority::map_error(err, context),
"DSL rejected drain exit safety net"
);
false
} else {
true
}
} else {
false
}
};
tracing::warn!(
"comms_drain: task exited without notifying authority (likely panicked), \
submitting Failed safety net"
);
if dsl_accepted {
let mut sessions = self.sessions.write().await;
if let Some(entry) = sessions.get_mut(&session_id) {
entry.drain_slot.mark_task_exit_if_running_for_safety(
crate::meerkat_machine::DrainExitReason::Failed,
);
}
}
}
Ok(MeerkatMachineCommandResult::Unit)
}
_ => unreachable!("non-drain-local command routed to drain-local handler"),
}
}
/// Fire the typed `StopDrain` DSL input for `session_id` if the session
/// still has a live DSL authority. Returns whether the machine accepted
/// the transition; callers use that gate before applying shell-side abort
/// projection.
async fn stage_drain_stop_dsl(&self, session_id: &meerkat_core::types::SessionId) -> bool {
let mut sessions = self.sessions.write().await;
let Some(entry) = sessions.get_mut(session_id) else {
return false;
};
let mut authority = entry
.dsl_authority
.lock()
.unwrap_or_else(std::sync::PoisonError::into_inner);
if let Err(err) = crate::meerkat_machine::dsl::MeerkatMachineMutator::apply(
&mut *authority,
crate::meerkat_machine::dsl::MeerkatMachineInput::StopDrain,
) {
tracing::warn!(
%session_id,
error = %crate::meerkat_machine::dsl_authority::map_error(err, "StopDrain"),
"DSL rejected StopDrain; skipping drain abort"
);
false
} else {
true
}
}
}