modularized the mini simulator

satrs-minisim/src/acs.rs

@@ -0,0 +1,148 @@
+use std::{f32::consts::PI, sync::mpsc, time::Duration};
+
+use asynchronix::{
+    model::{Model, Output},
+    time::Scheduler,
+};
+use satrs::power::SwitchState;
+use satrs_minisim::{
+    acs::{MgmSensorValues, MgtDipole, MGT_GEN_MAGNETIC_FIELD},
+    SimDevice, SimReply,
+};
+
+use crate::time::current_millis;
+
+// Earth magnetic field varies between -30 uT and 30 uT
+const AMPLITUDE_MGM: f32 = 0.03;
+// Lets start with a simple frequency here.
+const FREQUENCY_MGM: f32 = 1.0;
+const PHASE_X: f32 = 0.0;
+// Different phases to have different values on the other axes.
+const PHASE_Y: f32 = 0.1;
+const PHASE_Z: f32 = 0.2;
+
+/// Simple model for a magnetometer where the measure magnetic fields are modeled with sine waves.
+///
+/// Please note that that a more realistic MGM model wouold include the following components
+/// which are not included here to simplify the model:
+///
+/// 1. It would probably generate signed [i16] values which need to be converted to SI units
+///    because it is a digital sensor
+/// 2. It would sample the magnetic field at a high fixed rate. This might not be possible for
+///    a general purpose OS, but self self-sampling at a relatively high rate (20-40 ms) might
+///    stil lbe possible.
+pub struct MagnetometerModel {
+    pub switch_state: SwitchState,
+    pub periodicity: Duration,
+    pub external_mag_field: Option<MgmSensorValues>,
+    pub reply_sender: mpsc::Sender<SimReply>,
+}
+
+impl MagnetometerModel {
+    pub fn new(periodicity: Duration, reply_sender: mpsc::Sender<SimReply>) -> Self {
+        Self {
+            switch_state: SwitchState::Off,
+            periodicity,
+            external_mag_field: None,
+            reply_sender,
+        }
+    }
+
+    pub async fn switch_device(&mut self, switch_state: SwitchState) {
+        self.switch_state = switch_state;
+    }
+
+    pub async fn send_sensor_values(&mut self, _: (), scheduler: &Scheduler<Self>) {
+        let value = self.calculate_current_mgm_tuple(current_millis(scheduler.time()));
+        let reply = SimReply {
+            device: SimDevice::Mgm,
+            reply: serde_json::to_string(&value).unwrap(),
+        };
+        self.reply_sender
+            .send(reply)
+            .expect("sending MGM sensor values failed");
+    }
+
+    // Devices like magnetorquers generate a strong magnetic field which overrides the default
+    // model for the measured magnetic field.
+    pub async fn apply_external_magnetic_field(&mut self, field: MgmSensorValues) {
+        self.external_mag_field = Some(field);
+    }
+
+    fn calculate_current_mgm_tuple(&mut self, time_ms: u64) -> MgmSensorValues {
+        if let SwitchState::On = self.switch_state {
+            if let Some(ext_field) = self.external_mag_field {
+                return ext_field;
+            }
+            let base_sin_val = 2.0 * PI as f32 * FREQUENCY_MGM * (time_ms as f32 / 1000.0);
+            return MgmSensorValues {
+                x: AMPLITUDE_MGM * (base_sin_val + PHASE_X).sin(),
+                y: AMPLITUDE_MGM * (base_sin_val + PHASE_Y).sin(),
+                z: AMPLITUDE_MGM * (base_sin_val + PHASE_Z).sin(),
+            };
+        }
+        MgmSensorValues {
+            x: 0.0,
+            y: 0.0,
+            z: 0.0,
+        }
+    }
+}
+
+impl Model for MagnetometerModel {}
+
+pub struct MagnetorquerModel {
+    switch_state: SwitchState,
+    torquing: bool,
+    torque_dipole: Option<MgtDipole>,
+    gen_magnetic_field: Output<MgmSensorValues>,
+}
+
+impl MagnetorquerModel {
+    pub async fn apply_torque(
+        &mut self,
+        dipole: MgtDipole,
+        torque_duration: Duration,
+        scheduler: &Scheduler<Self>,
+    ) {
+        self.torque_dipole = Some(dipole);
+        self.torquing = true;
+        if scheduler
+            .schedule_event(torque_duration, Self::clear_torque, ())
+            .is_err()
+        {
+            log::warn!("torque clearing can only be set for a future time.");
+        }
+        self.generate_magnetic_field(()).await;
+    }
+
+    pub async fn clear_torque(&mut self, _: ()) {
+        self.torque_dipole = None;
+        self.torquing = false;
+        self.generate_magnetic_field(()).await;
+    }
+
+    pub async fn switch_device(&mut self, switch_state: SwitchState) {
+        self.switch_state = switch_state;
+        self.generate_magnetic_field(()).await;
+    }
+
+    fn calc_magnetic_field(&self, _: MgtDipole) -> MgmSensorValues {
+        // Simplified model: Just returns some fixed magnetic field for now.
+        // Later, we could make this more fancy by incorporating the commanded dipole.
+        MGT_GEN_MAGNETIC_FIELD
+    }
+
+    /// A torquing magnetorquer generates a magnetic field. This function can be used to apply
+    /// the magnetic field.
+    async fn generate_magnetic_field(&mut self, _: ()) {
+        if self.switch_state != SwitchState::On || !self.torquing {
+            return;
+        }
+        self.gen_magnetic_field
+            .send(self.calc_magnetic_field(self.torque_dipole.expect("expected valid dipole")))
+            .await;
+    }
+}
+
+impl Model for MagnetorquerModel {}

satrs-minisim/src/controller.rs

@@ -0,0 +1,70 @@
+use std::{sync::mpsc, time::Duration};
+
+use asynchronix::{
+    simulation::{Address, Simulation},
+    time::{Clock, MonotonicTime, SystemClock},
+};
+use satrs_minisim::{acs::MgmRequest, SimRequest};
+
+use crate::{
+    acs::MagnetometerModel,
+    eps::{PcduModel, PcduRequest},
+};
+
+// The simulation controller processes requests and drives the simulation.
+pub struct SimController {
+    pub sys_clock: SystemClock,
+    pub request_receiver: mpsc::Receiver<SimRequest>,
+    pub simulation: Simulation,
+    pub mgm_addr: Address<MagnetometerModel>,
+    pub pcdu_addr: Address<PcduModel>,
+}
+
+impl SimController {
+    pub fn run(&mut self, t0: MonotonicTime) {
+        let mut t = t0 + Duration::from_millis(10);
+        loop {
+            self.simulation
+                .step_until(t)
+                .expect("simulation step failed");
+            t += Duration::from_millis(10);
+            // TODO: Received and handle requests.
+
+            // TODO: Incorporate network latency.
+            self.sys_clock.synchronize(t);
+        }
+    }
+
+    fn handle_mgm_request(&mut self, request: &str) {
+        let mgm_request: serde_json::Result<MgmRequest> = serde_json::from_str(request);
+        if mgm_request.is_err() {
+            log::warn!("received invalid MGM request: {}", mgm_request.unwrap_err());
+            return;
+        }
+        let mgm_request = mgm_request.unwrap();
+        match mgm_request {
+            MgmRequest::RequestSensorData => {
+                self.simulation.send_event(
+                    MagnetometerModel::send_sensor_values,
+                    (),
+                    &self.mgm_addr,
+                );
+            }
+        }
+    }
+
+    fn handle_pcdu_request(&mut self, request: &str) {
+        let pcdu_request: serde_json::Result<PcduRequest> = serde_json::from_str(&request);
+        if pcdu_request.is_err() {
+            log::warn!(
+                "received invalid PCDU request: {}",
+                pcdu_request.unwrap_err()
+            );
+            return;
+        }
+        let pcdu_request = pcdu_request.unwrap();
+        match pcdu_request {
+            PcduRequest::RequestSwitchInfo => todo!(),
+        }
+    }
+}

satrs-minisim/src/eps.rs

@@ -0,0 +1,37 @@
+use asynchronix::model::{Model, Output};
+use satrs::power::{SwitchState, SwitchStateBinary};
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, PartialEq, Serialize)]
+pub struct PcduTuple {}
+
+pub enum PcduSwitches {
+    Mgm = 0,
+    Mgt = 1,
+}
+
+#[derive(Debug, Copy, Clone, Serialize, Deserialize)]
+pub enum PcduRequest {
+    RequestSwitchInfo,
+}
+
+pub struct PcduModel {
+    pub switcher_list: Output<Vec<SwitchStateBinary>>,
+    pub mgm_switch: Output<SwitchState>,
+    pub mgt_switch: Output<SwitchState>,
+}
+
+impl PcduModel {
+    pub async fn switch_device(&mut self, switch: PcduSwitches, switch_state: SwitchState) {
+        match switch {
+            PcduSwitches::Mgm => {
+                self.mgm_switch.send(switch_state).await;
+            }
+            PcduSwitches::Mgt => {
+                self.mgt_switch.send(switch_state).await;
+            }
+        }
+    }
+}
+
+impl Model for PcduModel {}

satrs-minisim/src/lib.rs

@@ -0,0 +1,53 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Copy, Clone, Serialize, Deserialize)]
+pub enum SimDevice {
+    Mgm,
+    Mgt,
+    Pcdu,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SimRequest {
+    pub device: SimDevice,
+    pub request: String,
+}
+
+#[derive(Serialize, Deserialize)]
+pub struct SimReply {
+    pub device: SimDevice,
+    pub reply: String,
+}
+
+pub mod acs {
+    use super::*;
+
+    #[derive(Debug, Copy, Clone, Serialize, Deserialize)]
+    pub enum MgmRequest {
+        RequestSensorData,
+    }
+
+    // Normally, small magnetometers generate their output as a signed 16 bit raw format or something
+    // similar which needs to be converted to a signed float value with physical units. We will
+    // simplify this now and generate the signed float values directly.
+    #[derive(Debug, Copy, Clone, PartialEq, Serialize, Deserialize)]
+    pub struct MgmSensorValues {
+        pub x: f32,
+        pub y: f32,
+        pub z: f32,
+    }
+
+    pub const MGT_GEN_MAGNETIC_FIELD: MgmSensorValues = MgmSensorValues {
+        x: 0.03,
+        y: -0.03,
+        z: 0.03,
+    };
+
+    // Simple model using i16 values.
+    #[derive(Debug, Copy, Clone, PartialEq, Serialize, Deserialize)]
+    pub struct MgtDipole {
+        pub x: i16,
+        pub y: i16,
+        pub z: i16,
+    }
+}

satrs-minisim/src/main.rs

@@ -1,387 +1,63 @@
-use asynchronix::model::{Model, Output};
+use acs::MagnetometerModel;
-use asynchronix::simulation::{EventSlot, Mailbox, SimInit, Simulation};
+use asynchronix::model::Model;
-use asynchronix::time::{MonotonicTime, Scheduler, SystemClock};
+use asynchronix::simulation::{Mailbox, SimInit};
-use log::{info, warn};
+use asynchronix::time::{MonotonicTime, SystemClock};
-use satrs::power::{SwitchState, SwitchStateBinary};
+use controller::SimController;
-use serde::{Deserialize, Serialize};
+use std::sync::mpsc;
-use std::f64::consts::PI;
+use std::thread;
-use std::future::Future;
+use std::time::{Duration, SystemTime};
-use std::net::{SocketAddr, UdpSocket};
+use udp::{SharedSocketAddr, UdpTcServer, UdpTmClient};
-use std::sync::{mpsc, Arc, Mutex};
-use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
-use std::{io, thread};
 
-// Normally, small magnetometers generate their output as a signed 16 bit raw format or something
+mod acs;
-// similar which needs to be converted to a signed float value with physical units. We will
+mod controller;
-// simplify this now and generate the signed float values directly.
+mod eps;
-#[derive(Debug, Copy, Clone, PartialEq, Serialize)]
+mod time;
-pub struct MgmTuple {
+mod udp;
-    x: f32,
-    y: f32,
-    z: f32,
-}
-
-// Earth magnetic field varies between -30 uT and 30 uT
-const AMPLITUDE_MGM: f32 = 0.03;
-// Lets start with a simple frequency here.
-const FREQUENCY_MGM: f32 = 1.0;
-const PHASE_X: f32 = 0.0;
-// Different phases to have different values on the other axes.
-const PHASE_Y: f32 = 0.1;
-const PHASE_Z: f32 = 0.2;
-
-const MGT_GEN_MAGNETIC_FIELD: MgmTuple = MgmTuple {
-    x: 0.03,
-    y: -0.03,
-    z: 0.03,
-};
-
-pub struct MagnetometerModel {
-    pub switch_state: SwitchState,
-    pub periodicity: Duration,
-    pub external_mag_field: Option<MgmTuple>,
-    pub sensor_values: Output<MgmTuple>,
-}
-
-impl MagnetometerModel {
-    fn new(periodicity: Duration) -> Self {
-        Self {
-            switch_state: SwitchState::Off,
-            periodicity,
-            external_mag_field: None,
-            sensor_values: Default::default(),
-        }
-    }
-
-    pub async fn start(&mut self, _: (), scheduler: &Scheduler<Self>) {
-        self.generate_output_self_scheduling((), scheduler).await;
-    }
-
-    pub async fn switch_device(&mut self, switch_state: SwitchState, scheduler: &Scheduler<Self>) {
-        self.switch_state = switch_state;
-        self.generate_output((), scheduler).await;
-    }
-
-    // Devices like magnetorquers generate a strong magnetic field which overrides the default
-    // model for the measured magnetic field.
-    pub async fn apply_external_magnetic_field(
-        &mut self,
-        field: MgmTuple,
-        scheduler: &Scheduler<Self>,
-    ) {
-        self.external_mag_field = Some(field);
-        self.generate_output((), scheduler).await;
-    }
-
-    // Simple unit input to request MGM tuple for current time.
-    //
-    // Need the partially desugared function signature, see [asynchronix::time::Scheduler] docs.
-    #[allow(clippy::manual_async_fn)]
-    pub fn generate_output_self_scheduling<'a>(
-        &'a mut self,
-        _: (),
-        scheduler: &'a Scheduler<Self>,
-    ) -> impl Future<Output = ()> + Send + 'a {
-        async move {
-            if scheduler
-                .schedule_event(self.periodicity, Self::generate_output_self_scheduling, ())
-                .is_err()
-            {
-                warn!("output generation can only be set for a future time.");
-            }
-            self.generate_output((), scheduler).await;
-        }
-    }
-
-    pub async fn generate_output(&mut self, _: (), scheduler: &Scheduler<Self>) {
-        let value = self.calculate_current_mgm_tuple(current_millis(scheduler.time()));
-        self.sensor_values.send(value).await;
-    }
-
-    fn calculate_current_mgm_tuple(&mut self, time_ms: u64) -> MgmTuple {
-        if let SwitchState::On = self.switch_state {
-            if let Some(ext_field) = self.external_mag_field {
-                return ext_field;
-            }
-            let base_sin_val = 2.0 * PI as f32 * FREQUENCY_MGM * (time_ms as f32 / 1000.0);
-            return MgmTuple {
-                x: AMPLITUDE_MGM * (base_sin_val + PHASE_X).sin(),
-                y: AMPLITUDE_MGM * (base_sin_val + PHASE_Y).sin(),
-                z: AMPLITUDE_MGM * (base_sin_val + PHASE_Z).sin(),
-            };
-        }
-        MgmTuple {
-            x: 0.0,
-            y: 0.0,
-            z: 0.0,
-        }
-    }
-}
-
-impl Model for MagnetometerModel {}
-
-#[derive(Debug, Clone, PartialEq, Serialize)]
-pub struct PcduTuple {}
-
-pub enum PcduSwitches {
-    Mgm = 0,
-    Mgt = 1,
-}
-
-#[derive(Debug, Copy, Clone, Serialize, Deserialize)]
-pub enum PcduRequest {
-    RequestSwitchInfo,
-}
-
-pub struct PcduModel {
-    pub switcher_list: Output<Vec<SwitchStateBinary>>,
-    pub mgm_switch: Output<SwitchState>,
-    pub mgt_switch: Output<SwitchState>,
-}
-
-impl PcduModel {
-    pub async fn switch_device(&mut self, switch: PcduSwitches, switch_state: SwitchState) {
-        match switch {
-            PcduSwitches::Mgm => {
-                self.mgm_switch.send(switch_state).await;
-            }
-            PcduSwitches::Mgt => {
-                self.mgt_switch.send(switch_state).await;
-            }
-        }
-    }
-}
-
-impl Model for PcduModel {}
-
-// Simple model using i16 values.
-#[derive(Debug, Copy, Clone, PartialEq, Serialize)]
-pub struct Dipole {
-    pub x: i16,
-    pub y: i16,
-    pub z: i16,
-}
-
-pub struct MagnetorquerModel {
-    switch_state: SwitchState,
-    torquing: bool,
-    //torque_duration: Duration,
-    torque_dipole: Option<Dipole>,
-    gen_magnetic_field: Output<MgmTuple>,
-}
-
-impl MagnetorquerModel {
-    pub async fn apply_torque(
-        &mut self,
-        dipole: Dipole,
-        torque_duration: Duration,
-        scheduler: &Scheduler<Self>,
-    ) {
-        self.torque_dipole = Some(dipole);
-        self.torquing = true;
-        if scheduler
-            .schedule_event(torque_duration, Self::clear_torque, ())
-            .is_err()
-        {
-            warn!("torque clearing can only be set for a future time.");
-        }
-        self.generate_magnetic_field(()).await;
-    }
-
-    pub async fn clear_torque(&mut self, _: ()) {
-        self.torque_dipole = None;
-        self.torquing = false;
-        self.generate_magnetic_field(()).await;
-    }
-
-    pub async fn switch_device(&mut self, switch_state: SwitchState) {
-        self.switch_state = switch_state;
-        self.generate_magnetic_field(()).await;
-    }
-
-    fn calc_magnetic_field(&self, _: Dipole) -> MgmTuple {
-        // Simplified model: Just returns some fixed magnetic field for now.
-        // Later, we could make this more fancy by incorporating the commanded dipole.
-        MGT_GEN_MAGNETIC_FIELD
-    }
-
-    /// A torquing magnetorquer generates a magnetic field. This function can be used to apply
-    /// the magnetic field.
-    async fn generate_magnetic_field(&mut self, _: ()) {
-        if self.switch_state != SwitchState::On || !self.torquing {
-            return;
-        }
-        self.gen_magnetic_field
-            .send(self.calc_magnetic_field(self.torque_dipole.expect("expected valid dipole")))
-            .await;
-    }
-}
-
-impl Model for MagnetorquerModel {}
-
-// A helper object which sends back all replies to the UDP client.
-//
-// This helper is scheduled separately to minimize the delay between the requests and replies.
-pub struct UdpTmSender {
-    reply_receiver: mpsc::Receiver<SimReply>,
-    last_sender: Arc<Mutex<Option<SocketAddr>>>,
-}
-
-#[derive(Debug, Copy, Clone, Serialize, Deserialize)]
-pub enum SimDevice {
-    Mgm,
-    Mgt,
-    Pcdu,
-}
-
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct SimRequest {
-    device: SimDevice,
-    request: String,
-}
-
-#[derive(Serialize, Deserialize)]
-pub struct SimReply {
-    device: SimDevice,
-    reply: String,
-}
-
-pub type SharedSocketAddr = Arc<Mutex<Option<SocketAddr>>>;
-
-// A UDP server which handles all TC received by a client application.
-pub struct UdpTcServer {
-    socket: UdpSocket,
-    request_sender: mpsc::Sender<SimRequest>,
-    last_sender: SharedSocketAddr,
-}
-
-impl UdpTcServer {
-    pub fn new(
-        request_sender: mpsc::Sender<SimRequest>,
-        last_sender: SharedSocketAddr,
-    ) -> io::Result<Self> {
-        let socket = UdpSocket::bind("0.0.0.0:7303")?;
-        Ok(Self {
-            socket,
-            request_sender,
-            last_sender,
-        })
-    }
-
-    pub fn run(&mut self) {
-        loop {
-            // Buffer to store incoming data.
-            let mut buffer = [0u8; 4096];
-            // Block until data is received. `recv_from` returns the number of bytes read and the
-            // sender's address.
-            let (bytes_read, src) = self
-                .socket
-                .recv_from(&mut buffer)
-                .expect("could not read from socket");
-
-            // Convert the buffer into a string slice and print the message.
-            let req_string = std::str::from_utf8(&buffer[..bytes_read])
-                .expect("Could not write buffer as string");
-            println!("Received from {}: {}", src, req_string);
-            let sim_req: serde_json::Result<SimRequest> = serde_json::from_str(req_string);
-            if sim_req.is_err() {
-                warn!(
-                    "received UDP request with invalid format: {}",
-                    sim_req.unwrap_err()
-                );
-                continue;
-            }
-            self.request_sender.send(sim_req.unwrap()).unwrap();
-            self.last_sender.lock().unwrap().replace(src);
-            /*
-            let sim_req = sim_req.unwrap();
-            match sim_req.device {
-                SimDevice::Mgm => {
-                    self.handle_mgm_request(&src, &sim_req);
-                }
-                SimDevice::Mgt => {}
-                SimDevice::Pcdu => {
-                    self.handle_pcdu_request(&src, &sim_req);
-                }
-            }
-            */
-        }
-    }
-
-    fn handle_mgm_request(&mut self, sender: &SocketAddr, sim_req: &SimRequest) {
-        /*
-        let tuple = self.mgm_out.take().expect("expected output");
-        let reply = ValueReply {
-            device: sim_req.device,
-            reply: serde_json::to_string(&tuple).unwrap(),
-        };
-        let reply_string = serde_json::to_string(&reply).expect("generating reply string failed");
-        self.socket
-            .send_to(reply_string.as_bytes(), sender)
-            .expect("could not send data");
-        */
-    }
-
-    fn handle_pcdu_request(&mut self, sender: &SocketAddr, sim_req: &SimRequest) {
-        let pcdu_request: serde_json::Result<PcduRequest> = serde_json::from_str(&sim_req.request);
-        if pcdu_request.is_err() {
-            warn!(
-                "received invalid PCDU request: {}",
-                pcdu_request.unwrap_err()
-            );
-            return;
-        }
-    }
-}
-
-// The simulation controller processes requests and drives the simulation.
-// TODO: How do we process requests and drive the simulation at the same time?
-pub struct SimController {
-    pub request_receiver: mpsc::Receiver<SimRequest>,
-    pub simulation: Simulation,
-}
-
-impl SimController {}
-
-pub fn current_millis(time: MonotonicTime) -> u64 {
-    (time.as_secs() as u64 * 1000) + (time.subsec_nanos() as u64 / 1_000_000)
-}
 
 fn main() {
     let shared_socket_addr = SharedSocketAddr::default();
-    let (req_sender, req_receiver) = mpsc::channel();
+    let (request_sender, request_receiver) = mpsc::channel();
+    let (reply_sender, reply_receiver) = mpsc::channel();
 
     // Instantiate models and their mailboxes.
-    let mut mgm_sim = MagnetometerModel::new(Duration::from_millis(50));
+    let mgm_sim = MagnetometerModel::new(Duration::from_millis(50), reply_sender.clone());
 
     let mgm_mailbox = Mailbox::new();
-    let mgm_input_addr = mgm_mailbox.address();
+    let mgm_addr = mgm_mailbox.address();
+    let pcdu_mailbox = Mailbox::new();
+    let pcdu_addr = pcdu_mailbox.address();
 
-    // Keep handles to the main input and output.
-    // let output_slot = mgm_sim.sensor_values.connect_slot().0;
-    // let output_slot_2 = mgm_sim.sensor_values.connect_slot().0;
-    let t0 = MonotonicTime::EPOCH;
-    let clock = SystemClock::from_system_time(t0, SystemTime::now());
     // Instantiate the simulator
-    let mut simu = SimInit::new()
+    let t0 = MonotonicTime::EPOCH;
-        .add_model(mgm_sim, mgm_mailbox)
+    let sys_clock = SystemClock::from_system_time(t0, SystemTime::now());
-        .init_with_clock(t0, clock);
+    let simulation = SimInit::new().add_model(mgm_sim, mgm_mailbox).init(t0);
+
+    let mut sim_controller = SimController {
+        sys_clock,
+        request_receiver,
+        simulation,
+        mgm_addr,
+        pcdu_addr,
+    };
 
     // This thread schedules the simulator.
     let sim_thread = thread::spawn(move || {
-        // The magnetometer will schedule itself at fixed intervals.
+        sim_controller.run(t0);
-        simu.send_event(MagnetometerModel::start, (), &mgm_input_addr);
-        loop {
-            simu.step();
-        }
     });
 
-    // This thread manages the simulator UDP server.
+    let mut server = UdpTcServer::new(request_sender, shared_socket_addr.clone()).unwrap();
-    let udp_thread = thread::spawn(move || {
+    // This thread manages the simulator UDP TC server.
-        let mut server = UdpTcServer::new(req_sender, shared_socket_addr).unwrap();
+    let udp_tc_thread = thread::spawn(move || {
         server.run();
     });
 
+    let mut client = UdpTmClient::new(reply_receiver, 200, shared_socket_addr);
+    // This thread manages the simulator UDP TM client.
+    let udp_tm_thread = thread::spawn(move || {
+        client.run();
+    });
+
     sim_thread.join().expect("joining simulation thread failed");
-    udp_thread.join().expect("joining UDP thread failed");
+    udp_tc_thread.join().expect("joining UDP TC thread failed");
+    udp_tm_thread.join().expect("joining UDP TM thread failed");
 }

satrs-minisim/src/time.rs

@@ -0,0 +1,5 @@
+use asynchronix::time::MonotonicTime;
+
+pub fn current_millis(time: MonotonicTime) -> u64 {
+    (time.as_secs() as u64 * 1000) + (time.subsec_nanos() as u64 / 1_000_000)
+}

satrs-minisim/src/udp.rs

@@ -0,0 +1,152 @@
+use std::{
+    collections::VecDeque,
+    net::{SocketAddr, UdpSocket},
+    sync::{mpsc, Arc, Mutex},
+    time::Duration,
+};
+
+use satrs_minisim::{SimReply, SimRequest};
+
+pub type SharedSocketAddr = Arc<Mutex<Option<SocketAddr>>>;
+
+// A UDP server which handles all TC received by a client application.
+pub struct UdpTcServer {
+    socket: UdpSocket,
+    request_sender: mpsc::Sender<SimRequest>,
+    shared_last_sender: SharedSocketAddr,
+}
+
+impl UdpTcServer {
+    pub fn new(
+        request_sender: mpsc::Sender<SimRequest>,
+        shared_last_sender: SharedSocketAddr,
+    ) -> std::io::Result<Self> {
+        let socket = UdpSocket::bind("0.0.0.0:7303")?;
+        Ok(Self {
+            socket,
+            request_sender,
+            shared_last_sender,
+        })
+    }
+
+    pub fn run(&mut self) {
+        let mut last_socket_addr = None;
+        loop {
+            // Buffer to store incoming data.
+            let mut buffer = [0u8; 4096];
+            // Block until data is received. `recv_from` returns the number of bytes read and the
+            // sender's address.
+            let (bytes_read, src) = self
+                .socket
+                .recv_from(&mut buffer)
+                .expect("could not read from socket");
+
+            // Convert the buffer into a string slice and print the message.
+            let req_string = std::str::from_utf8(&buffer[..bytes_read])
+                .expect("Could not write buffer as string");
+            println!("Received from {}: {}", src, req_string);
+            let sim_req: serde_json::Result<SimRequest> = serde_json::from_str(req_string);
+            if sim_req.is_err() {
+                log::warn!(
+                    "received UDP request with invalid format: {}",
+                    sim_req.unwrap_err()
+                );
+                continue;
+            }
+            self.request_sender.send(sim_req.unwrap()).unwrap();
+            // Only set last sender if it has changed.
+            if last_socket_addr.is_some() && src != last_socket_addr.unwrap() {
+                self.shared_last_sender.lock().unwrap().replace(src);
+            }
+            last_socket_addr = Some(src);
+        }
+    }
+}
+
+// A helper object which sends back all replies to the UDP client.
+//
+// This helper is scheduled separately to minimize the delay between the requests and replies.
+pub struct UdpTmClient {
+    reply_receiver: mpsc::Receiver<SimReply>,
+    reply_queue: VecDeque<SimReply>,
+    max_num_replies: usize,
+    socket: UdpSocket,
+    last_sender: SharedSocketAddr,
+}
+
+impl UdpTmClient {
+    pub fn new(
+        reply_receiver: mpsc::Receiver<SimReply>,
+        max_num_replies: usize,
+        last_sender: SharedSocketAddr,
+    ) -> Self {
+        let socket =
+            UdpSocket::bind("127.0.0.1:0").expect("creating UDP client for TM sender failed");
+        Self {
+            reply_receiver,
+            reply_queue: VecDeque::new(),
+            max_num_replies,
+            socket,
+            last_sender,
+        }
+    }
+
+    pub fn run(&mut self) {
+        loop {
+            let processed_replies = self.process_replies();
+            let last_sender_lock = self
+                .last_sender
+                .lock()
+                .expect("locking last UDP sender failed");
+            let last_sender = *last_sender_lock;
+            drop(last_sender_lock);
+            let mut sent_replies = false;
+            if let Some(last_sender) = last_sender {
+                sent_replies = self.send_replies(last_sender);
+            }
+            if !processed_replies && !sent_replies {
+                std::thread::sleep(Duration::from_millis(20));
+            }
+        }
+    }
+
+    fn process_replies(&mut self) -> bool {
+        let mut processed_replies = false;
+        loop {
+            match self.reply_receiver.try_recv() {
+                Ok(reply) => {
+                    if self.reply_queue.len() >= self.max_num_replies {
+                        self.reply_queue.pop_front();
+                    }
+                    self.reply_queue.push_back(reply);
+                    processed_replies = true;
+                }
+                Err(e) => match e {
+                    mpsc::TryRecvError::Empty => return processed_replies,
+                    mpsc::TryRecvError::Disconnected => {
+                        log::error!("all UDP reply senders disconnected")
+                    }
+                },
+            }
+        }
+    }
+
+    fn send_replies(&mut self, last_sender: SocketAddr) -> bool {
+        let mut sent_replies = false;
+        self.socket
+            .connect(last_sender)
+            .expect("connecting to last sender failed");
+        while !self.reply_queue.is_empty() {
+            let next_reply_to_send = self.reply_queue.pop_front().unwrap();
+            self.socket
+                .send(
+                    serde_json::to_string(&next_reply_to_send)
+                        .unwrap()
+                        .as_bytes(),
+                )
+                .expect("sending reply failed");
+            sent_replies = true;
+        }
+        sent_replies
+    }
+}