//! Event management and forwarding //! //! This module provides components to perform event routing. The most important component for this //! task is the [EventManager]. It receives all events and then routes them to event subscribers //! where appropriate. #![cfg_attr(feature = "doc-images", cfg_attr(all(), doc = ::embed_doc_image::embed_image!("event_man_arch", "images/event_man_arch.png" )))] #![cfg_attr( not(feature = "doc-images"), doc = "**Doc images not enabled**. Compile with feature `doc-images` and Rust version >= 1.54 \ to enable." )] //! One common use case for satellite systems is to offer a light-weight publish-subscribe mechanism //! and IPC mechanism for software and hardware events which are also packaged as telemetry (TM) or //! can trigger a system response. //! //! The following graph shows how the event flow for such a setup could look like: //! //! ![Event flow][event_man_arch] //! //! The event manager has a listener table abstracted by the [ListenerTable], which maps //! listener groups identified by [ListenerKey]s to a [sender ID][ChannelId]. //! It also contains a sender table abstracted by the [SenderTable] which maps these sender IDs //! to a concrete [SendEventProvider]s. A simple approach would be to use one send event provider //! for each OBSW thread and then subscribe for all interesting events for a particular thread //! using the send event provider ID. //! //! This can be done with the [EventManager] like this: //! //! 1. Provide a concrete [EventReceiver] implementation. This abstraction allow to use different //! message queue backends. A straightforward implementation where dynamic memory allocation is //! not a big concern could use [std::sync::mpsc::channel] to do this and is provided in //! form of the [MpscEventReceiver]. //! 2. To set up event creators, create channel pairs using some message queue implementation. //! Each event creator gets a (cloned) sender component which allows it to send events to the //! manager. //! 3. The event manager receives the receiver component as part of a [EventReceiver] //! implementation so all events are routed to the manager. //! 4. Create the [send event providers][SendEventProvider]s which allow routing events to //! subscribers. You can now use their [sender IDs][SendEventProvider::id] to subscribe for //! event groups, for example by using the [EventManager::subscribe_single] method. //! 5. Add the send provider as well using the [EventManager::add_sender] call so the event //! manager can route listener groups to a the send provider. //! //! Some components like a PUS Event Service or PUS Event Action Service might require all //! events to package them as telemetry or start actions where applicable. //! Other components might only be interested in certain events. For example, a thermal system //! handler might only be interested in temperature events generated by a thermal sensor component. //! //! # Examples //! //! You can check [integration test](https://egit.irs.uni-stuttgart.de/rust/sat-rs/src/branch/main/satrs-core/tests/pus_events.rs) //! for a concrete example using multi-threading where events are routed to //! different threads. use crate::events::{EventU16, EventU32, GenericEvent, LargestEventRaw, LargestGroupIdRaw}; use crate::params::{Params, ParamsHeapless}; #[cfg(feature = "alloc")] use alloc::boxed::Box; #[cfg(feature = "alloc")] use alloc::vec; #[cfg(feature = "alloc")] use alloc::vec::Vec; use core::slice::Iter; #[cfg(feature = "alloc")] use hashbrown::HashMap; use crate::ChannelId; #[cfg(feature = "std")] pub use stdmod::*; #[derive(PartialEq, Eq, Hash, Copy, Clone, Debug)] pub enum ListenerKey { Single(LargestEventRaw), Group(LargestGroupIdRaw), All, } pub type EventWithHeaplessAuxData = (Event, Option); pub type EventU32WithHeaplessAuxData = EventWithHeaplessAuxData; pub type EventU16WithHeaplessAuxData = EventWithHeaplessAuxData; pub type EventWithAuxData = (Event, Option); pub type EventU32WithAuxData = EventWithAuxData; pub type EventU16WithAuxData = EventWithAuxData; pub trait SendEventProvider { type Error; fn id(&self) -> ChannelId; fn send_no_data(&self, event: Provider) -> Result<(), Self::Error> { self.send(event, None) } fn send(&self, event: Provider, aux_data: Option) -> Result<(), Self::Error>; } /// Generic abstraction for an event receiver. pub trait EventReceiver { /// This function has to be provided by any event receiver. A receive call may or may not return /// an event. /// /// To allow returning arbitrary additional auxiliary data, a mutable slice is passed to the /// [Self::receive] call as well. Receivers can write data to this slice, but care must be taken /// to avoid panics due to size missmatches or out of bound writes. fn receive(&self) -> Option<(Event, Option)>; } pub trait ListenerTable { fn get_listeners(&self) -> Vec; fn contains_listener(&self, key: &ListenerKey) -> bool; fn get_listener_ids(&self, key: &ListenerKey) -> Option>; fn add_listener(&mut self, key: ListenerKey, sender_id: ChannelId) -> bool; fn remove_duplicates(&mut self, key: &ListenerKey); } pub trait SenderTable { fn contains_send_event_provider(&self, id: &ChannelId) -> bool; fn get_send_event_provider( &mut self, id: &ChannelId, ) -> Option<&mut Box>>; fn add_send_event_provider( &mut self, send_provider: Box< dyn SendEventProvider, >, ) -> bool; } /// Generic event manager implementation. /// /// # Generics /// /// * `SendProviderError`: [SendEventProvider] error type /// * `Event`: Concrete event provider, currently either [EventU32] or [EventU16] /// * `AuxDataProvider`: Concrete auxiliary data provider, currently either [Params] or /// [ParamsHeapless] pub struct EventManager { listener_table: Box, sender_table: Box>, event_receiver: Box>, } /// Safety: It is safe to implement [Send] because all fields in the [EventManager] are [Send] /// as well #[cfg(feature = "std")] unsafe impl Send for EventManager { } #[cfg(feature = "std")] pub type EventManagerWithMpscQueue = EventManager< std::sync::mpsc::SendError<(Event, Option)>, Event, AuxDataProvider, >; #[derive(Debug)] pub enum EventRoutingResult { /// No event was received Empty, /// An event was received and routed. /// The first tuple entry will contain the number of recipients. Handled(u32, Event, Option), } #[derive(Debug)] pub enum EventRoutingError { SendError(E), NoSendersForKey(ListenerKey), NoSenderForId(ChannelId), } #[derive(Debug)] pub struct EventRoutingErrorsWithResult { pub result: EventRoutingResult, pub errors: [Option>; 3], } impl EventManager { pub fn remove_duplicates(&mut self, key: &ListenerKey) { self.listener_table.remove_duplicates(key) } /// Subscribe for a unique event. pub fn subscribe_single(&mut self, event: &Event, sender_id: ChannelId) { self.update_listeners(ListenerKey::Single(event.raw_as_largest_type()), sender_id); } /// Subscribe for an event group. pub fn subscribe_group(&mut self, group_id: LargestGroupIdRaw, sender_id: ChannelId) { self.update_listeners(ListenerKey::Group(group_id), sender_id); } /// Subscribe for all events received by the manager. /// /// For example, this can be useful for a handler component which sends every event as /// a telemetry packet. pub fn subscribe_all(&mut self, sender_id: ChannelId) { self.update_listeners(ListenerKey::All, sender_id); } } impl EventManager { /// Create an event manager where the sender table will be the [DefaultSenderTableProvider] /// and the listener table will be the [DefaultListenerTableProvider]. pub fn new(event_receiver: Box>) -> Self { let listener_table: Box = Box::default(); let sender_table: Box> = Box::default(); Self::new_custom_tables(listener_table, sender_table, event_receiver) } } impl EventManager { pub fn new_custom_tables( listener_table: Box, sender_table: Box>, event_receiver: Box>, ) -> Self { EventManager { listener_table, sender_table, event_receiver, } } pub fn add_sender( &mut self, send_provider: impl SendEventProvider + 'static, ) { if !self .sender_table .contains_send_event_provider(&send_provider.id()) { self.sender_table .add_send_event_provider(Box::new(send_provider)); } } fn update_listeners(&mut self, key: ListenerKey, sender_id: ChannelId) { self.listener_table.add_listener(key, sender_id); } /// This function will use the cached event receiver and try to receive one event. /// If an event was received, it will try to route that event to all subscribed event listeners. /// If this works without any issues, the [EventRoutingResult] will contain context information /// about the routed event. /// /// This function will track up to 3 errors returned as part of the /// [EventRoutingErrorsWithResult] error struct. pub fn try_event_handling( &mut self, ) -> Result< EventRoutingResult, EventRoutingErrorsWithResult, > { let mut err_idx = 0; let mut err_slice = [None, None, None]; let mut num_recipients = 0; let mut add_error = |error: EventRoutingError| { if err_idx < 3 { err_slice[err_idx] = Some(error); err_idx += 1; } }; let mut send_handler = |key: &ListenerKey, event: Event, aux_data: &Option| { if self.listener_table.contains_listener(key) { if let Some(ids) = self.listener_table.get_listener_ids(key) { for id in ids { if let Some(sender) = self.sender_table.get_send_event_provider(id) { if let Err(e) = sender.send(event, aux_data.clone()) { add_error(EventRoutingError::SendError(e)); } else { num_recipients += 1; } } else { add_error(EventRoutingError::NoSenderForId(*id)); } } } else { add_error(EventRoutingError::NoSendersForKey(*key)); } } }; if let Some((event, aux_data)) = self.event_receiver.receive() { let single_key = ListenerKey::Single(event.raw_as_largest_type()); send_handler(&single_key, event, &aux_data); let group_key = ListenerKey::Group(event.group_id_as_largest_type()); send_handler(&group_key, event, &aux_data); send_handler(&ListenerKey::All, event, &aux_data); if err_idx > 0 { return Err(EventRoutingErrorsWithResult { result: EventRoutingResult::Handled(num_recipients, event, aux_data), errors: err_slice, }); } return Ok(EventRoutingResult::Handled(num_recipients, event, aux_data)); } Ok(EventRoutingResult::Empty) } } #[derive(Default)] pub struct DefaultListenerTableProvider { listeners: HashMap>, } pub struct DefaultSenderTableProvider< SendProviderError, Event: GenericEvent = EventU32, AuxDataProvider = Params, > { senders: HashMap< ChannelId, Box>, >, } impl Default for DefaultSenderTableProvider { fn default() -> Self { Self { senders: HashMap::new(), } } } impl ListenerTable for DefaultListenerTableProvider { fn get_listeners(&self) -> Vec { let mut key_list = Vec::new(); for key in self.listeners.keys() { key_list.push(*key); } key_list } fn contains_listener(&self, key: &ListenerKey) -> bool { self.listeners.contains_key(key) } fn get_listener_ids(&self, key: &ListenerKey) -> Option> { self.listeners.get(key).map(|vec| vec.iter()) } fn add_listener(&mut self, key: ListenerKey, sender_id: ChannelId) -> bool { if let Some(existing_list) = self.listeners.get_mut(&key) { existing_list.push(sender_id); } else { let new_list = vec![sender_id]; self.listeners.insert(key, new_list); } true } fn remove_duplicates(&mut self, key: &ListenerKey) { if let Some(list) = self.listeners.get_mut(key) { list.sort_unstable(); list.dedup(); } } } impl SenderTable for DefaultSenderTableProvider { fn contains_send_event_provider(&self, id: &ChannelId) -> bool { self.senders.contains_key(id) } fn get_send_event_provider( &mut self, id: &ChannelId, ) -> Option<&mut Box>> { self.senders.get_mut(id).filter(|sender| sender.id() == *id) } fn add_send_event_provider( &mut self, send_provider: Box< dyn SendEventProvider, >, ) -> bool { let id = send_provider.id(); if self.senders.contains_key(&id) { return false; } self.senders.insert(id, send_provider).is_none() } } #[cfg(feature = "std")] pub mod stdmod { use super::*; use crate::event_man::{EventReceiver, EventWithAuxData}; use crate::events::{EventU16, EventU32, GenericEvent}; use crate::params::Params; use std::sync::mpsc::{Receiver, SendError, Sender}; pub struct MpscEventReceiver { mpsc_receiver: Receiver<(Event, Option)>, } impl MpscEventReceiver { pub fn new(receiver: Receiver<(Event, Option)>) -> Self { Self { mpsc_receiver: receiver, } } } impl EventReceiver for MpscEventReceiver { fn receive(&self) -> Option> { if let Ok(event_and_data) = self.mpsc_receiver.try_recv() { return Some(event_and_data); } None } } pub type MpscEventU32Receiver = MpscEventReceiver; pub type MpscEventU16Receiver = MpscEventReceiver; #[derive(Clone)] pub struct MpscEventSendProvider { id: u32, sender: Sender<(Event, Option)>, } impl MpscEventSendProvider { pub fn new(id: u32, sender: Sender<(Event, Option)>) -> Self { Self { id, sender } } } impl SendEventProvider for MpscEventSendProvider { type Error = SendError<(Event, Option)>; fn id(&self) -> u32 { self.id } fn send(&self, event: Event, aux_data: Option) -> Result<(), Self::Error> { self.sender.send((event, aux_data)) } } pub type MpscEventU32SendProvider = MpscEventSendProvider; pub type MpscEventU16SendProvider = MpscEventSendProvider; } #[cfg(test)] mod tests { use super::*; use crate::event_man::EventManager; use crate::events::{EventU32, GenericEvent, Severity}; use crate::params::ParamsRaw; use alloc::boxed::Box; use std::format; use std::sync::mpsc::{channel, Receiver, SendError, Sender}; #[derive(Clone)] struct MpscEventSenderQueue { id: u32, mpsc_sender: Sender, } impl MpscEventSenderQueue { fn new(id: u32, mpsc_sender: Sender) -> Self { Self { id, mpsc_sender } } } impl SendEventProvider for MpscEventSenderQueue { type Error = SendError; fn id(&self) -> u32 { self.id } fn send(&self, event: EventU32, aux_data: Option) -> Result<(), Self::Error> { self.mpsc_sender.send((event, aux_data)) } } fn check_next_event( expected: EventU32, receiver: &Receiver, ) -> Option { if let Ok(event) = receiver.try_recv() { assert_eq!(event.0, expected); return event.1; } None } fn check_handled_event( res: EventRoutingResult, expected: EventU32, expected_num_sent: u32, ) { assert!(matches!(res, EventRoutingResult::Handled { .. })); if let EventRoutingResult::Handled(num_recipients, event, _aux_data) = res { assert_eq!(event, expected); assert_eq!(num_recipients, expected_num_sent); } } fn generic_event_man() -> ( Sender, EventManager>, ) { let (event_sender, manager_queue) = channel(); let event_man_receiver = MpscEventReceiver::new(manager_queue); ( event_sender, EventManager::new(Box::new(event_man_receiver)), ) } #[test] fn test_basic() { let (event_sender, mut event_man) = generic_event_man(); let event_grp_0 = EventU32::new(Severity::INFO, 0, 0).unwrap(); let event_grp_1_0 = EventU32::new(Severity::HIGH, 1, 0).unwrap(); let (single_event_sender, single_event_receiver) = channel(); let single_event_listener = MpscEventSenderQueue::new(0, single_event_sender); event_man.subscribe_single(&event_grp_0, single_event_listener.id()); event_man.add_sender(single_event_listener); let (group_event_sender_0, group_event_receiver_0) = channel(); let group_event_listener = MpscEventSenderQueue { id: 1, mpsc_sender: group_event_sender_0, }; event_man.subscribe_group(event_grp_1_0.group_id(), group_event_listener.id()); event_man.add_sender(group_event_listener); // Test event with one listener event_sender .send((event_grp_0, None)) .expect("Sending single error failed"); let res = event_man.try_event_handling(); assert!(res.is_ok()); check_handled_event(res.unwrap(), event_grp_0, 1); check_next_event(event_grp_0, &single_event_receiver); // Test event which is sent to all group listeners event_sender .send((event_grp_1_0, None)) .expect("Sending group error failed"); let res = event_man.try_event_handling(); assert!(res.is_ok()); check_handled_event(res.unwrap(), event_grp_1_0, 1); check_next_event(event_grp_1_0, &group_event_receiver_0); } #[test] fn test_with_basic_aux_data() { let (event_sender, mut event_man) = generic_event_man(); let event_grp_0 = EventU32::new(Severity::INFO, 0, 0).unwrap(); let (single_event_sender, single_event_receiver) = channel(); let single_event_listener = MpscEventSenderQueue::new(0, single_event_sender); event_man.subscribe_single(&event_grp_0, single_event_listener.id()); event_man.add_sender(single_event_listener); event_sender .send((event_grp_0, Some(Params::Heapless((2_u32, 3_u32).into())))) .expect("Sending group error failed"); let res = event_man.try_event_handling(); assert!(res.is_ok()); check_handled_event(res.unwrap(), event_grp_0, 1); let aux = check_next_event(event_grp_0, &single_event_receiver); assert!(aux.is_some()); let aux = aux.unwrap(); if let Params::Heapless(ParamsHeapless::Raw(ParamsRaw::U32Pair(pair))) = aux { assert_eq!(pair.0, 2); assert_eq!(pair.1, 3); } else { panic!("{}", format!("Unexpected auxiliary value type {:?}", aux)); } } /// Test listening for multiple groups #[test] fn test_multi_group() { let (event_sender, mut event_man) = generic_event_man(); let res = event_man.try_event_handling(); assert!(res.is_ok()); let hres = res.unwrap(); assert!(matches!(hres, EventRoutingResult::Empty)); let event_grp_0 = EventU32::new(Severity::INFO, 0, 0).unwrap(); let event_grp_1_0 = EventU32::new(Severity::HIGH, 1, 0).unwrap(); let (event_grp_0_sender, event_grp_0_receiver) = channel(); let event_grp_0_and_1_listener = MpscEventSenderQueue { id: 0, mpsc_sender: event_grp_0_sender, }; event_man.subscribe_group(event_grp_0.group_id(), event_grp_0_and_1_listener.id()); event_man.subscribe_group(event_grp_1_0.group_id(), event_grp_0_and_1_listener.id()); event_man.add_sender(event_grp_0_and_1_listener); event_sender .send((event_grp_0, None)) .expect("Sending Event Group 0 failed"); event_sender .send((event_grp_1_0, None)) .expect("Sendign Event Group 1 failed"); let res = event_man.try_event_handling(); assert!(res.is_ok()); check_handled_event(res.unwrap(), event_grp_0, 1); let res = event_man.try_event_handling(); assert!(res.is_ok()); check_handled_event(res.unwrap(), event_grp_1_0, 1); check_next_event(event_grp_0, &event_grp_0_receiver); check_next_event(event_grp_1_0, &event_grp_0_receiver); } /// Test listening to the same event from multiple listeners. Also test listening /// to both group and single events from one listener #[test] fn test_listening_to_same_event_and_multi_type() { let (event_sender, mut event_man) = generic_event_man(); let event_0 = EventU32::new(Severity::INFO, 0, 5).unwrap(); let event_1 = EventU32::new(Severity::HIGH, 1, 0).unwrap(); let (event_0_tx_0, event_0_rx_0) = channel(); let (event_0_tx_1, event_0_rx_1) = channel(); let event_listener_0 = MpscEventSenderQueue { id: 0, mpsc_sender: event_0_tx_0, }; let event_listener_1 = MpscEventSenderQueue { id: 1, mpsc_sender: event_0_tx_1, }; let event_listener_0_sender_id = event_listener_0.id(); event_man.subscribe_single(&event_0, event_listener_0_sender_id); event_man.add_sender(event_listener_0); let event_listener_1_sender_id = event_listener_1.id(); event_man.subscribe_single(&event_0, event_listener_1_sender_id); event_man.add_sender(event_listener_1); event_sender .send((event_0, None)) .expect("Triggering Event 0 failed"); let res = event_man.try_event_handling(); assert!(res.is_ok()); check_handled_event(res.unwrap(), event_0, 2); check_next_event(event_0, &event_0_rx_0); check_next_event(event_0, &event_0_rx_1); event_man.subscribe_group(event_1.group_id(), event_listener_0_sender_id); event_sender .send((event_0, None)) .expect("Triggering Event 0 failed"); event_sender .send((event_1, None)) .expect("Triggering Event 1 failed"); // 3 Events messages will be sent now let res = event_man.try_event_handling(); assert!(res.is_ok()); check_handled_event(res.unwrap(), event_0, 2); let res = event_man.try_event_handling(); assert!(res.is_ok()); check_handled_event(res.unwrap(), event_1, 1); // Both the single event and the group event should arrive now check_next_event(event_0, &event_0_rx_0); check_next_event(event_1, &event_0_rx_0); // Do double insertion and then remove duplicates event_man.subscribe_group(event_1.group_id(), event_listener_0_sender_id); event_man.remove_duplicates(&ListenerKey::Group(event_1.group_id())); event_sender .send((event_1, None)) .expect("Triggering Event 1 failed"); let res = event_man.try_event_handling(); assert!(res.is_ok()); check_handled_event(res.unwrap(), event_1, 1); } #[test] fn test_all_events_listener() { let (event_sender, manager_queue) = channel(); let event_man_receiver = MpscEventReceiver::new(manager_queue); let mut event_man: EventManager> = EventManager::new(Box::new(event_man_receiver)); let event_0 = EventU32::new(Severity::INFO, 0, 5).unwrap(); let event_1 = EventU32::new(Severity::HIGH, 1, 0).unwrap(); let (event_0_tx_0, all_events_rx) = channel(); let all_events_listener = MpscEventSenderQueue { id: 0, mpsc_sender: event_0_tx_0, }; event_man.subscribe_all(all_events_listener.id()); event_man.add_sender(all_events_listener); event_sender .send((event_0, None)) .expect("Triggering event 0 failed"); event_sender .send((event_1, None)) .expect("Triggering event 1 failed"); let res = event_man.try_event_handling(); assert!(res.is_ok()); check_handled_event(res.unwrap(), event_0, 1); let res = event_man.try_event_handling(); assert!(res.is_ok()); check_handled_event(res.unwrap(), event_1, 1); check_next_event(event_0, &all_events_rx); check_next_event(event_1, &all_events_rx); } }