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7 Commits
clone-sess
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master
| Author | SHA1 | Date |
|---|---|---|
 Avril
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69b0d073ed
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4 years ago |
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Avril
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5fe9c4795c
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4 years ago |
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Avril
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5878be6216
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4 years ago |
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Avril
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578a9fd788
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4 years ago |
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Avril
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a17b2539d0
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4 years ago |
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Avril
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815feaa4a7
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4 years ago |
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Avril
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925770fbeb
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4 years ago |
@ -1,303 +0,0 @@
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//! Global state service
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use super::*;
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use tokio::{
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sync::{
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watch,
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mpsc,
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oneshot,
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broadcast,
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},
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task::JoinHandle,
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};
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use crate::service::{
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ExitStatus,
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};
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use std::{error, fmt};
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use std::sync::Weak;
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use std::any::Any;
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use std::collections::BTreeMap;
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id_type!(ServiceSubID; "Optional ID for filtering directed broadcast messages");
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/// Signal the shutdown method to the supervisor.
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#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy)]
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pub enum SupervisorShutdownStatus
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{
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/// Signal the subtask(s) to shut down, then wait for them and exit.
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Signal,
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/// Drop all handles and pipes to subtask(s) then immediately exit.
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Drop,
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/// Keep working
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Normal,
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/// Restart any and all subtask(s)
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Restart,
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}
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impl Default for SupervisorShutdownStatus
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{
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#[inline]
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fn default() -> Self
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{
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SupervisorShutdownStatus::Normal
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}
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}
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/// The kind of command to send to the the service
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#[derive(Debug)]
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pub enum ServiceCommandKind
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{
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}
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#[derive(Debug)]
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pub enum ServiceResponseKind
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{
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}
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#[derive(Debug)]
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pub struct ServiceResponse(Option<ServiceCommandKind>);
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#[derive(Debug)]
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pub struct ServiceCommand
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{
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kind: ServiceCommandKind,
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output: oneshot::Sender<ServiceResponse>,
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}
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/// Supervisor responsible for spawning the state handler service.
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#[derive(Debug)]
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pub(super) struct Supervisor
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{
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handle: JoinHandle<ExitStatus>,
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shutdown: watch::Sender<SupervisorShutdownStatus>,
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pipe: mpsc::Sender<ServiceCommand>,
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sub: BTreeMap<ServiceEventKind, ServiceEvent>
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}
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/// Object sent through the broadcast channel.
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///
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/// These objects can be cloned and downcasted, but can also be atomically refcounted if that is more desireable.
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///
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/// # Cloning
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/// The implementation of `Clone` for this instance clones the inner object, not the refcount. Use `clone_ref()` to *just* clone the refcount.
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/// To downcast and clone the inner object without an extra `Arc` allocation, use `downcast_clone()` or `downcast().map(Clone::clone)`.
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pub struct ServiceEventObject(Arc<dyn AnyCloneable + Send + Sync + 'static>);
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shim_debug!(ServiceEventObject);
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/// A weak reference to a `ServiceEventObject`.
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#[derive(Clone)]
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pub struct ServiceEventObjectRef(Weak<dyn AnyCloneable + Send + Sync + 'static>);
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shim_debug!(ServiceEventObjectRef);
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/// Wrapper used when broadcasting to prevent useless inner object clones.
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#[derive(Debug)]
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struct EventObjectRefCloneWrap(ServiceEventObject);
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impl Clone for EventObjectRefCloneWrap
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{
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fn clone(&self) -> Self {
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Self(self.0.clone_ref())
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}
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}
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impl Clone for ServiceEventObject
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{
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fn clone(&self) -> Self {
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Self(Arc::from(self.0.as_ref().clone_dyn()))
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}
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}
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impl ServiceEventObjectRef
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{
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/// Try to upgrade to a concrete reference, and then clone the inner object.
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pub fn try_clone(&self) -> Option<ServiceEventObject>
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{
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match self.0.upgrade()
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{
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Some(arc) => Some(ServiceEventObject(arc).clone()),
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None => None
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}
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}
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/// Try to upgrade to a concrete reference.
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pub fn upgrade(self) -> Result<ServiceEventObject, Self>
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{
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match self.0.upgrade()
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{
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Some(arc) => Ok(ServiceEventObject(arc)),
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None => Err(self),
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}
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}
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}
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impl ServiceEventObject
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{
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/// Get an owned reference counted handle to the object, without cloning the object itself.
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pub fn clone_ref(&self) -> Self
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{
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Self(Arc::clone(&self.0))
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}
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/// Get a weak reference counted handle to the object, without cloning the object itself.
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pub fn clone_weak(&self) -> ServiceEventObjectRef
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{
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ServiceEventObjectRef(Arc::downgrade(&self.0))
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}
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/// Try to downcast the inner object to a concrete type and then clone it.
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///
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/// This will fail if:
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/// * The downcasted type is invalid
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#[inline] pub fn downcast_clone<T: AnyCloneable + Send + Sync + 'static>(&self) -> Option<T>
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{
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self.downcast_ref::<T>().map(|x| *x.clone_dyn_any().downcast().unwrap())
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}
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/// Try to consume this instance into downcast.
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///
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/// This will fail if:
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/// * The downcasted type is invalid
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/// * There are other references to this object (created through `clone_ref()`.).
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pub fn try_into_downcast<T: AnyCloneable + Send + Sync + 'static>(self) -> Result<T, Self>
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{
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match Arc::downcast(self.0)
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{
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Ok(v) => v,
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Err(e) => Self(e),
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}
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}
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/// Check if there are any other references to this object
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#[inline] pub fn is_unique(&self) -> bool
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{
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Arc::strong_count(&self.0) == 1
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}
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/// Try to downcast the object into a concrete type
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#[inline] pub fn is<T: AnyCloneable + Send + Sync + 'static>(&self) -> Option<&T>
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{
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self.0.is()
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}
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/// Try to downcast the object into a concrete type
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#[inline] pub fn downcast_ref<T: AnyCloneable + Send + Sync + 'static>(&self) -> Option<&T>
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{
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self.0.downcast_ref()
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}
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}
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/// The kind of event outputted from a state service's broadcast stream
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#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Copy)]
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pub enum ServiceEventKind
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{
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/// Does nothing.
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///
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/// # Associated object
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/// None.
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KeepAlive,
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}
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/// An event outputted from a state service's broadcast stream
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#[derive(Debug, Clone)]
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pub struct ServiceEvent
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{
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kind: ServiceEventKind,
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directed: Option<MaybeVec<ServiceSubID>>,
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obj: Option<EventObjectRefCloneWrap>,
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}
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impl ServiceEvent
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{
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/// The kind of this event.
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pub fn kind(&self) -> ServiceEventKind
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{
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self.kind
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}
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/// Check if this event is for you
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pub fn is_directed_for(&self, whom: &ServiceSubID) -> bool
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{
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if let Some(yes) = self.directed.as_ref() {
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yes == whom
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} else {
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false
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}
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}
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/// Check if this event is directed to anyone
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pub fn is_directed(&self) -> bool
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{
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self.directed.is_some()
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}
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/// Check who this event is directed to.
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///
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/// If it is not directed, an empty slice will be returned.
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pub fn directed_to(&self) -> &[&ServiceSubID]
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{
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match self.directed.as_ref()
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{
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Some(yes) => &yes[..],
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None => &[],
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}
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}
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/// Get a reference to the object, if there is one.
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pub fn obj_ref(&self) -> Option<&ServiceEventObject>
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{
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self.obj.as_ref().map(|x| x.0)
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}
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/// Get a mutable reference to the object, if there is one.
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pub fn obj_mut(&mut self) -> Option<&mut ServiceEventObject>
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{
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self.obj.as_mut().map(|x| x.0)
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}
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/// Try to consume into the inner object. If there is no object, return self.
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pub fn try_into_object(self) -> Result<ServiceEventObject, Self>
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{
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match self.obj
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{
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Some(obj) => Ok(obj),
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None => Err(self),
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}
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}
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}
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impl From<ServiceEvent> for Option<ServiceEventObject>
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{
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#[inline] fn from(from: ServiceEvent) -> Self
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{
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from.obj
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}
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}
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impl TryFrom<ServiceEvent> for ServiceEventObject
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{
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type Error = NoObjectError;
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#[inline] fn try_from(from: ServiceEvent) -> Result<Self, Self::Error>
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{
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match from.obj
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{
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Some(obj) => Ok(obj.0),
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None => Err(NoObjectError),
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}
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}
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}
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#[derive(Debug)]
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/// Error returned from trying to extract an object from a `ServiceEvent` which has none.
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pub struct NoObjectError;
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impl error::Error for NoObjectError{}
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impl fmt::Display for NoObjectError
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{
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
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{
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write!(f, "there was no object broadcasted along with this ")
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}
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}
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@ -0,0 +1,141 @@
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//! Controls the broadcasting of events sent from the state service task
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use super::*;
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/// The kind of event outputted from a state service's broadcast stream
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#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Copy)]
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pub enum ServiceEventKind
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{
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/// Does nothing.
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///
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/// # Associated object
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/// `()`.
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Ping,
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/// Does nothing.
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///
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/// # Associated object
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/// None.
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KeepAlive,
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}
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cfg_if!{
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if #[cfg(debug_assertions)] {
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/// Type used for directed array.
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/// Currently testing `smolset` over eagerly allocating.
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pub(super) type SESet<T> = smolset::SmolSet<[T; 1]>;
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} else {
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pub(super) type SESet<T> = std::collections::HashSet<T>;
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}
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}
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/// An event outputted from a state service's broadcast stream
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#[derive(Debug, Clone)]
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pub struct ServiceEvent
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{
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bc_id: BroadcastID,
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kind: ServiceEventKind,
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directed: Option<SESet<ServiceSubID>>,
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obj: Option<ServiceEventObject>,
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}
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impl ServiceEvent
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{
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/// Create a new event to be broadcast
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fn new<T>(kind: ServiceEventKind, directed: Option<impl IntoIterator<Item=ServiceSubID>>, obj: Option<T>) -> Self
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where T: Any + Send + Sync + 'static
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{
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Self {
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bc_id: BroadcastID::id_new(),
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kind,
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directed: directed.map(|x| x.into_iter().collect()).and_then(|n: SESet<_>| if n.len() < 1 {
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None
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} else {
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Some(n)
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}),
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obj: obj.map(|x| ServiceEventObject(Arc::new(x))),
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}
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}
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#[inline] pub fn id(&self) -> &BroadcastID
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{
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&self.bc_id
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}
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/// The kind of this event.
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#[inline] pub fn kind(&self) -> ServiceEventKind
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{
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self.kind
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}
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|
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/// Check if this event is for you
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pub fn is_directed_for(&self, whom: &ServiceSubID) -> bool
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{
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if let Some(yes) = self.directed.as_ref() {
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yes.contains(whom)
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} else {
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false
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}
|
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}
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/// Check if this event is directed to anyone
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pub fn is_directed(&self) -> bool
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{
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self.directed.is_some()
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}
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/// Check who this event is directed to.
|
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///
|
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/// If it is not directed, an empty slice will be returned.
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pub fn directed_to(&self) -> impl Iterator<Item = &'_ ServiceSubID> + '_
|
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{
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match self.directed.as_ref()
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{
|
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Some(yes) => MaybeIter::many(yes.iter()),
|
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None => MaybeIter::none(),
|
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}
|
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}
|
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|
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/// Get a reference to the object, if there is one.
|
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pub fn obj_ref(&self) -> Option<&ServiceEventObject>
|
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{
|
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self.obj.as_ref()
|
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}
|
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|
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/// Get a mutable reference to the object, if there is one.
|
||||
pub fn obj_mut(&mut self) -> Option<&mut ServiceEventObject>
|
||||
{
|
||||
self.obj.as_mut()
|
||||
}
|
||||
|
||||
/// Try to consume into the inner object. If there is no object, return self.
|
||||
pub fn try_into_object(self) -> Result<ServiceEventObject, Self>
|
||||
{
|
||||
match self.obj
|
||||
{
|
||||
Some(obj) => Ok(obj),
|
||||
None => Err(self),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
impl From<ServiceEvent> for Option<ServiceEventObject>
|
||||
{
|
||||
#[inline] fn from(from: ServiceEvent) -> Self
|
||||
{
|
||||
from.obj
|
||||
}
|
||||
}
|
||||
|
||||
impl TryFrom<ServiceEvent> for ServiceEventObject
|
||||
{
|
||||
type Error = NoObjectError;
|
||||
|
||||
#[inline] fn try_from(from: ServiceEvent) -> Result<Self, Self::Error>
|
||||
{
|
||||
match from.obj
|
||||
{
|
||||
Some(obj) => Ok(obj),
|
||||
None => Err(NoObjectError),
|
||||
}
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,28 @@
|
||||
//! Global state service
|
||||
use super::*;
|
||||
use tokio::{
|
||||
sync::{
|
||||
watch,
|
||||
mpsc,
|
||||
oneshot,
|
||||
broadcast,
|
||||
},
|
||||
task::JoinHandle,
|
||||
};
|
||||
use crate::service::{
|
||||
ExitStatus,
|
||||
};
|
||||
use std::{error, fmt};
|
||||
use std::sync::Weak;
|
||||
use std::any::Any;
|
||||
use std::collections::{BTreeMap};
|
||||
|
||||
|
||||
id_type!(ServiceSubID; "Optional ID for filtering directed broadcast messages");
|
||||
id_type!(BroadcastID; "Each broadcast message has a unique ID.");
|
||||
|
||||
mod supervisor; pub use supervisor::*;
|
||||
mod resreq; pub use resreq::*;
|
||||
mod obj; pub use obj::*;
|
||||
|
||||
mod events; pub use events::*;
|
||||
@ -0,0 +1,114 @@
|
||||
//! broadcast object definitions
|
||||
use super::*;
|
||||
|
||||
|
||||
/// Object sent through the broadcast channel.
|
||||
///
|
||||
/// These objects can be cloned and downcasted, becaause they are atomically refcounted if that is more desireable.
|
||||
#[derive(Clone)]
|
||||
#[repr(transparent)]
|
||||
pub struct ServiceEventObject(pub(super) Arc<dyn Any + Send + Sync + 'static>);
|
||||
shim_debug!(ServiceEventObject);
|
||||
|
||||
/// A weak reference to a `ServiceEventObject`.
|
||||
#[derive(Clone)]
|
||||
#[repr(transparent)]
|
||||
pub struct ServiceEventObjectRef(pub(super) Weak<dyn Any + Send + Sync + 'static>);
|
||||
shim_debug!(ServiceEventObjectRef);
|
||||
|
||||
impl ServiceEventObjectRef
|
||||
{
|
||||
/// Try to upgrade to a concrete reference, and then clone the inner object.
|
||||
pub fn try_clone(&self) -> Option<ServiceEventObject>
|
||||
{
|
||||
match self.0.upgrade()
|
||||
{
|
||||
Some(arc) => Some(ServiceEventObject(arc).clone()),
|
||||
None => None
|
||||
}
|
||||
}
|
||||
/// Try to upgrade to a concrete reference.
|
||||
pub fn upgrade(self) -> Result<ServiceEventObject, Self>
|
||||
{
|
||||
match self.0.upgrade()
|
||||
{
|
||||
Some(arc) => Ok(ServiceEventObject(arc)),
|
||||
None => Err(self),
|
||||
}
|
||||
}
|
||||
|
||||
/// Check if the object has not been destroyed yet.
|
||||
pub fn is_alive(&self) -> bool
|
||||
{
|
||||
self.0.strong_count() > 0
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
impl ServiceEventObject
|
||||
{
|
||||
pub fn clone_inner(&self) -> Self
|
||||
{
|
||||
Self(Arc::from(self.0.clone_dyn_any_sync()))
|
||||
}
|
||||
/// Get a weak reference counted handle to the object, without cloning the object itself.
|
||||
pub fn clone_weak(&self) -> ServiceEventObjectRef
|
||||
{
|
||||
ServiceEventObjectRef(Arc::downgrade(&self.0))
|
||||
}
|
||||
|
||||
/// Try to downcast the inner object to a concrete type and then clone it.
|
||||
///
|
||||
/// This will fail if:
|
||||
/// * The downcasted type is invalid
|
||||
#[inline] pub fn downcast_clone<T: Any + Clone + Send + Sync + 'static>(&self) -> Option<T>
|
||||
{
|
||||
self.downcast_ref::<T>().map(|x| *x.clone_dyn_any().downcast().unwrap())
|
||||
}
|
||||
/// Try to consume this instance into downcast.
|
||||
///
|
||||
/// This will fail if:
|
||||
/// * The downcasted type is invalid
|
||||
/// * There are other references to this object (created through `clone_ref()`.).
|
||||
pub fn try_into_downcast<T: Any + Send + Sync + 'static>(self) -> Result<T, Self>
|
||||
{
|
||||
match Arc::downcast(self.0)
|
||||
{
|
||||
Ok(v) => match Arc::try_unwrap(v) {
|
||||
Ok(v) => Ok(v),
|
||||
Err(s) => Err(Self(s)),
|
||||
},
|
||||
Err(e) => Err(Self(e)),
|
||||
}
|
||||
}
|
||||
|
||||
/// Check if there are any other references to this object
|
||||
#[inline] pub fn is_unique(&self) -> bool
|
||||
{
|
||||
Arc::strong_count(&self.0) == 1
|
||||
}
|
||||
|
||||
/// Try to downcast the object into a concrete type
|
||||
#[inline] pub fn is<T: Any + Send + Sync + 'static>(&self) -> bool
|
||||
{
|
||||
self.0.as_ref().is::<T>()
|
||||
}
|
||||
/// Try to downcast the object into a concrete type
|
||||
#[inline] pub fn downcast_ref<T: Any + Send + Sync + 'static>(&self) -> Option<&T>
|
||||
{
|
||||
self.0.as_ref().downcast_ref::<T>()
|
||||
}
|
||||
}
|
||||
|
||||
#[derive(Debug)]
|
||||
/// Error returned from trying to extract an object from a `ServiceEvent` which has none.
|
||||
pub struct NoObjectError;
|
||||
|
||||
impl error::Error for NoObjectError{}
|
||||
impl fmt::Display for NoObjectError
|
||||
{
|
||||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
|
||||
{
|
||||
write!(f, "there was no object broadcasted along with this ")
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,65 @@
|
||||
//! Responses and requests for the state service(s).
|
||||
//!
|
||||
//! These are sent to `Supervisor` which then dispatches them accordingly.
|
||||
use super::*;
|
||||
|
||||
|
||||
/// The kind of request to send to the the service
|
||||
#[derive(Debug)]
|
||||
#[non_exhaustive]
|
||||
pub enum ServiceRequestKind
|
||||
{
|
||||
/// A no-op request.
|
||||
None,
|
||||
|
||||
/// Test request.
|
||||
#[cfg(debug_assertions)] EchoRequest(String),
|
||||
}
|
||||
|
||||
/// The kind of response to expect from a service query, if any.
|
||||
#[derive(Debug)]
|
||||
#[non_exhaustive]
|
||||
pub enum ServiceResponseKind
|
||||
{
|
||||
/// Test response.
|
||||
#[cfg(debug_assertions)] EchoResponse(String),
|
||||
|
||||
/// Empty response
|
||||
None,
|
||||
}
|
||||
|
||||
/// A response from a service to a specific query.
|
||||
///
|
||||
/// It is sent theough the `output` onehot channel in the `ServiceCommand` struct.
|
||||
#[derive(Debug)]
|
||||
pub struct ServiceResponse(ServiceRequestKind);
|
||||
|
||||
impl ServiceResponse
|
||||
{
|
||||
/// An empty (default) response
|
||||
#[inline] pub const fn none() -> Self
|
||||
{
|
||||
Self(ServiceRequestKind::None)
|
||||
}
|
||||
}
|
||||
|
||||
/// A formed service request.
|
||||
#[derive(Debug)]
|
||||
pub struct ServiceRequest
|
||||
{
|
||||
kind: ServiceRequestKind,
|
||||
output: oneshot::Sender<ServiceResponse>, // If there is no response, this sender will just be dropped and the future impl can return `None` instead of `Some(response)`.
|
||||
}
|
||||
|
||||
impl ServiceRequest
|
||||
{
|
||||
/// Create a new request
|
||||
pub(in super) fn new(kind: ServiceRequestKind) -> (Self, oneshot::Receiver<ServiceResponse>)
|
||||
{
|
||||
let (tx, rx) = oneshot::channel();
|
||||
(Self {
|
||||
kind,
|
||||
output: tx
|
||||
}, rx)
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,92 @@
|
||||
//! Dispatching to state service task(s) through a supervisor
|
||||
use super::*;
|
||||
use tokio::time;
|
||||
use std::{fmt, error};
|
||||
use futures::prelude::*;
|
||||
|
||||
impl Supervisor
|
||||
{
|
||||
/// Dispatch a request to the supervisor to be passed through to a subtask.
|
||||
///
|
||||
/// # Returns
|
||||
/// Returns a `Future` that can be awaited on to produce the value sent back by the task (if there is one).
|
||||
///
|
||||
/// # Errors
|
||||
/// * The first failure will be caused if sending to the supervisor fails.
|
||||
/// * The 2nd failure will be caused if either the supervisor, or its delegated task panics before being able to respond, or if the task simply does not respond.
|
||||
pub async fn dispatch_req(&mut self, kind: ServiceRequestKind) -> Result<impl Future<Output=Result<ServiceResponse, SupervisorDispatchError>> + 'static, SupervisorDispatchError>
|
||||
{
|
||||
let (req, rx) = ServiceRequest::new(kind);
|
||||
self.pipe.send(req).await.map_err(|_| SupervisorDispatchError::Send)?;
|
||||
Ok(rx.map_err(|_| SupervisorDispatchError::Recv))
|
||||
}
|
||||
|
||||
/// Dispatch a request to the supervisor to be passed through to a subtask and then wait for a response from it.
|
||||
///
|
||||
/// # Returns
|
||||
/// Returns the value sent back by the task, if there is one
|
||||
pub async fn dispatch_and_wait(&mut self, kind: ServiceRequestKind) -> Result<ServiceResponse, SupervisorDispatchError>
|
||||
{
|
||||
Ok(self.dispatch_req(kind)
|
||||
.await?
|
||||
.await?)
|
||||
}
|
||||
|
||||
/// Dispatch a request to the supervisor to be passed through to a subtask and then wait for a response from it.
|
||||
/// If the timeout expires before a response from the server is received, then the operation will cancel and the error returned will be `SupervisorDispatchError::Timeout`.
|
||||
///
|
||||
/// # Returns
|
||||
/// Returns the value sent back by the task, if there is one
|
||||
pub async fn dispatch_and_wait_timeout(&mut self, kind: ServiceRequestKind, timeout: time::Duration) -> Result<ServiceResponse, SupervisorDispatchError>
|
||||
{
|
||||
let resp_wait = self.dispatch_req(kind)
|
||||
.await?;
|
||||
tokio::select! {
|
||||
val = resp_wait => {
|
||||
return Ok(val?);
|
||||
}
|
||||
_ = time::delay_for(timeout) => {
|
||||
return Err(SupervisorDispatchError::Timeout("receiving response", Some(timeout)))
|
||||
}
|
||||
}
|
||||
}
|
||||
/// Dispatch a request to the supervisor to be passed through to a subtask and then wait for a response from it.
|
||||
/// If the future `until` completes before a response from the server is received, then the operation will cancel and the error returned will be `SupervisorDispatchError::Timeout`.
|
||||
///
|
||||
/// # Returns
|
||||
/// Returns the value sent back by the task, if there is one
|
||||
pub async fn dispatch_and_wait_until(&mut self, kind: ServiceRequestKind, until: impl Future) -> Result<ServiceResponse, SupervisorDispatchError>
|
||||
{
|
||||
let resp_wait = self.dispatch_req(kind)
|
||||
.await?;
|
||||
tokio::select! {
|
||||
val = resp_wait => {
|
||||
return Ok(val?);
|
||||
}
|
||||
_ = until => {
|
||||
return Err(SupervisorDispatchError::Timeout("receiving response", None))
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Error when dispatching a request to the supervisor
|
||||
#[derive(Debug)]
|
||||
pub enum SupervisorDispatchError
|
||||
{
|
||||
Send, Recv, Timeout(&'static str, Option<tokio::time::Duration>),
|
||||
}
|
||||
|
||||
impl error::Error for SupervisorDispatchError{}
|
||||
impl fmt::Display for SupervisorDispatchError
|
||||
{
|
||||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
|
||||
{
|
||||
match self {
|
||||
Self::Send => write!(f, "dispatching the request failed"),
|
||||
Self::Recv => write!(f, "receiving the response failed"),
|
||||
Self::Timeout(msg, Some(duration)) => write!(f, "timeout on {} was reached ({:?})", msg, duration),
|
||||
Self::Timeout(msg, _) => write!(f, "timeout on {} was reached", msg),
|
||||
}
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,309 @@
|
||||
//! Handles spawning and restarting service task(s)
|
||||
use super::*;
|
||||
use tokio::sync::RwLock;
|
||||
use std::mem::MaybeUninit;
|
||||
use std::ops;
|
||||
use futures::prelude::*;
|
||||
use tokio::time;
|
||||
use std::{fmt, error};
|
||||
|
||||
const SUPERVISOR_BACKLOG: usize = 32;
|
||||
|
||||
mod dispatch; pub use dispatch::*;
|
||||
|
||||
TODO: This all needs redoing when i'm actually lucid. This part seems okay but the rest of `service` needs to go and be replaced by something like this
|
||||
|
||||
/// Signal the shutdown method to the supervisor.
|
||||
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy)]
|
||||
pub enum SupervisorControl
|
||||
{
|
||||
/// Normal working
|
||||
Initialise,
|
||||
/// Signal the subtask(s) to shut down, then wait for them and exit, with an optional timeout.
|
||||
///
|
||||
/// # Notes
|
||||
/// If the timeout expires while waiting, then the mode is switched to `Drop`.
|
||||
Signal(Option<time::Duration>),
|
||||
/// Drop all handles and pipes to subtask(s) then immediately exit.
|
||||
Drop,
|
||||
/// Restart any and all subtask(s)
|
||||
Restart,
|
||||
|
||||
/// Set the max task limit. Default is 0.
|
||||
TaskLimit(usize),
|
||||
}
|
||||
|
||||
impl Default for SupervisorControl
|
||||
{
|
||||
#[inline]
|
||||
fn default() -> Self
|
||||
{
|
||||
Self::Initialise
|
||||
}
|
||||
}
|
||||
|
||||
/// Supervisor responsible for spawning the state handler service.
|
||||
#[derive(Debug)]
|
||||
pub(super) struct Supervisor
|
||||
{
|
||||
/// Handle for the supervisor task itself
|
||||
handle: JoinHandle<ExitStatus>,
|
||||
|
||||
/// Watch sender for signalling shutdowns the supervisor task itself
|
||||
shutdown: watch::Sender<SupervisorControl>,
|
||||
|
||||
/// The pipe to send requests to the supervisor's subtasks
|
||||
pipe: mpsc::Sender<ServiceRequest>,
|
||||
|
||||
/// The initial receiver created from `broadcast_root`.
|
||||
broadcast_receiver: broadcast::Receiver<ServiceEvent>,
|
||||
|
||||
/// Data shared between the supervisor's task and its controller instance here.
|
||||
shared: Arc<SupervisorShared>,
|
||||
}
|
||||
|
||||
/// Object shared btweeen the Supervisor control instance and its supervisor task.
|
||||
#[derive(Debug)]
|
||||
struct SupervisorShared
|
||||
{
|
||||
/// this is for filtering specific messages to specific subscribers
|
||||
sub: RwLock<BTreeMap<ServiceEventKind, SESet<ServiceSubID>>>,
|
||||
|
||||
broadcast_root: broadcast::Sender<ServiceEvent>,
|
||||
state: state::State,
|
||||
}
|
||||
|
||||
/// A subscriber to supervisor task(s) event pump
|
||||
#[derive(Debug)]
|
||||
pub struct Subscriber
|
||||
{
|
||||
id: ServiceSubID,
|
||||
|
||||
/// For directed messages
|
||||
spec: mpsc::Receiver<ServiceEvent>,
|
||||
/// For broadcast messages
|
||||
broad: broadcast::Receiver<ServiceEvent>,
|
||||
}
|
||||
|
||||
|
||||
impl Supervisor
|
||||
{
|
||||
/// Attempt to send a control signal to the supervisor itself
|
||||
pub fn signal_control(&self, sig: SupervisorControl) -> Result<(), watch::error::SendError<SupervisorControl>>
|
||||
{
|
||||
self.shutdown.broadcast(sig)?;
|
||||
Ok(())
|
||||
}
|
||||
|
||||
/// Drop all communications with background worker and wait for it to complete
|
||||
pub async fn join_now(self) -> eyre::Result<()>
|
||||
{
|
||||
let handle = {
|
||||
let Self { handle, ..} = self; // drop everything else
|
||||
handle
|
||||
};
|
||||
handle.await?;
|
||||
|
||||
Ok(())
|
||||
}
|
||||
|
||||
/// Check if the background worker has not been dropped.
|
||||
///
|
||||
/// If this returns false it usually indicates a fatal error.
|
||||
pub fn is_alive(&self) -> bool
|
||||
{
|
||||
Arc::strong_count(&self.shared) > 1
|
||||
}
|
||||
|
||||
/// Create a new supervisor for this state.
|
||||
pub fn new(state: state::State) -> Self
|
||||
{
|
||||
let shutdown = watch::channel(Default::default());
|
||||
let pipe = mpsc::channel(SUPERVISOR_BACKLOG);
|
||||
let (broadcast_root, broadcast_receiver) = broadcast::channel(SUPERVISOR_BACKLOG);
|
||||
|
||||
let shared = Arc::new(SupervisorShared{
|
||||
broadcast_root,
|
||||
state,
|
||||
});
|
||||
|
||||
let (shutdown_0, shutdown_1) = shutdown;
|
||||
let (pipe_0, pipe_1) = pipe;
|
||||
|
||||
Self {
|
||||
shutdown: shutdown_0,
|
||||
pipe: pipe_0,
|
||||
broadcast_receiver,
|
||||
shared: Arc::clone(&shared),
|
||||
|
||||
handle: tokio::spawn(async move {
|
||||
let shared = shared;
|
||||
ExitStatus::from(service_fn(SupervisorTaskState {
|
||||
shared,
|
||||
recv: pipe_1,
|
||||
shutdown: shutdown_1,
|
||||
}).await.or_else(|err| err.into_own_result()))
|
||||
}),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// The state held by the running superviser service
|
||||
#[derive(Debug)]
|
||||
struct SupervisorTaskState
|
||||
{
|
||||
shutdown: watch::Receiver<SupervisorControl>,
|
||||
recv: mpsc::Receiver<ServiceRequest>,
|
||||
shared: Arc<SupervisorShared>,
|
||||
}
|
||||
|
||||
/// Detached supervisor server
|
||||
async fn service_fn(SupervisorTaskState {shared, mut recv, mut shutdown}: SupervisorTaskState) -> Result<(), ServiceTerminationError>
|
||||
{
|
||||
impl Default for TerminationKind
|
||||
{
|
||||
#[inline]
|
||||
fn default() -> Self
|
||||
{
|
||||
Self::Graceful
|
||||
}
|
||||
}
|
||||
|
||||
// The command stream to dispatch to the worker tasks
|
||||
let command_dispatch = async {
|
||||
while let Some(req) = recv.recv().await {
|
||||
todo!("Dispatch to child(s)");
|
||||
}
|
||||
TerminationKind::Graceful
|
||||
};
|
||||
tokio::pin!(command_dispatch);
|
||||
|
||||
// The signal stream to be handled here
|
||||
let signal_stream = async {
|
||||
while let Some(value) = shutdown.recv().await
|
||||
{
|
||||
use SupervisorControl::*;
|
||||
match value {
|
||||
Initialise => info!("Initialised"),
|
||||
Signal(None) => return TerminationKind::SignalHup,
|
||||
Signal(Some(to)) => return TerminationKind::SignalTimeout(to),
|
||||
Drop => return TerminationKind::Immediate,
|
||||
Restart => todo!("not implemented"),
|
||||
TaskLimit(_limit) => todo!("not implemented"),
|
||||
}
|
||||
}
|
||||
TerminationKind::Graceful
|
||||
};
|
||||
tokio::pin!(signal_stream);
|
||||
|
||||
//loop {
|
||||
tokio::select! {
|
||||
sd_kind = &mut signal_stream => {
|
||||
// We received a signal
|
||||
|
||||
Err(ServiceTerminationError::Signal(sd_kind))
|
||||
}
|
||||
disp_end = &mut command_dispatch => {
|
||||
// The command dispatch exited first, the logical error is `Graceful`. But it's not really an error, so...
|
||||
disp_end.into()
|
||||
}
|
||||
}
|
||||
// }
|
||||
|
||||
}
|
||||
/// The mannor in which the supervisor exited.
|
||||
#[derive(Debug)]
|
||||
pub enum TerminationKind
|
||||
{
|
||||
/// The child task(s) were signalled to stop and they were waited on.
|
||||
SignalHup,
|
||||
/// If there was a timeout specified, and that timeout expired, the message will be `SignalTimeout` instead of `SignalHup`.
|
||||
SignalTimeout(time::Duration),
|
||||
/// Immediately drop everything and exit
|
||||
Immediate,
|
||||
/// A non-signalled shutdown. There were no more watchers for the shutdown channel.
|
||||
Graceful,
|
||||
}
|
||||
|
||||
impl TerminationKind
|
||||
{
|
||||
/// Convert `TerminationKind::Graceful` into a non-error
|
||||
fn strip_grace(self) -> Result<(), Self>
|
||||
{
|
||||
match self {
|
||||
Self::Graceful => Ok(()),
|
||||
e => Err(e),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl error::Error for TerminationKind{}
|
||||
impl fmt::Display for TerminationKind
|
||||
{
|
||||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
|
||||
{
|
||||
match self {
|
||||
Self::SignalHup => write!(f, "children were signalled to shut down and compiled"),
|
||||
Self::SignalTimeout(to) => write!(f, "children were signalled to shut but did not do so within the {:?} timeout", to),
|
||||
Self::Immediate => write!(f, "children were dropped and an immediate exit was made"),
|
||||
Self::Graceful => write!(f, "a graceful shutdown order was issued and compiled with"),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
/// The error returned on a failed service termination.
|
||||
#[derive(Debug)]
|
||||
#[non_exhaustive]
|
||||
pub enum ServiceTerminationError
|
||||
{
|
||||
/// Was terminated by a signal.
|
||||
Signal(TerminationKind),
|
||||
/// Was terminated by a panic.
|
||||
Panic,
|
||||
/// There were no more commands being sent through, and the worker gracefully shut down.
|
||||
Interest,
|
||||
}
|
||||
|
||||
impl From<TerminationKind> for Result<(), ServiceTerminationError>
|
||||
{
|
||||
fn from(from: TerminationKind) -> Self
|
||||
{
|
||||
ServiceTerminationError::Signal(from).into_own_result()
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
impl ServiceTerminationError
|
||||
{
|
||||
fn into_own_result(self) -> Result<(), Self>
|
||||
{
|
||||
match self {
|
||||
Self::Signal(term) => term.strip_grace().map_err(Self::Signal),
|
||||
x => Err(x),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl error::Error for ServiceTerminationError
|
||||
{
|
||||
fn source(&self) -> Option<&(dyn error::Error + 'static)>
|
||||
{
|
||||
Some(match &self {
|
||||
Self::Signal(ts) => ts,
|
||||
_ => return None,
|
||||
})
|
||||
}
|
||||
}
|
||||
impl fmt::Display for ServiceTerminationError
|
||||
{
|
||||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
|
||||
{
|
||||
match self {
|
||||
Self::Signal(_) => write!(f, "shut down by signal"),
|
||||
Self::Panic => write!(f, "shut down by panic. this is usually fatal"),
|
||||
Self::Interest => write!(f, "all communications with this service stopped"),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Loading…
Reference in new issue