Machine state change with access control

src/api/machine.rs

@@ -4,6 +4,8 @@ use std::ops::Deref;
 use capnp::capability::Promise;
 use capnp::Error;
 
+use futures::FutureExt;
+
 use crate::schema::api_capnp::State;
 use crate::schema::api_capnp::machine::*;
 use crate::connection::Session;
@@ -85,13 +87,16 @@ impl write::Server for Write {
     {
         let uid = self.0.session.user.as_ref().map(|u| u.id.clone());
         let new_state = MachineState::used(uid.clone());
-        if let Ok(tok) = self.0.machine.request_state_change(self.0.session.user.as_ref(), new_state) {
-            info!(self.0.session.log, "yay");
-        } else {
-            info!(self.0.session.log, "nay");
-        }
+        let this = self.0.clone();
+        let f = this.machine.request_state_change(this.session.user.as_ref(), new_state)
+            .map(|res_token| match res_token {
+                Ok(tok) => {
+                    return Ok(());
+                },
+                Err(e) => Err(capnp::Error::failed("State change request returned an err".to_string())),
+        });
 
-        Promise::ok(())
+        Promise::from_future(f)
     }
 
     fn reserve(&mut self,

src/initiator.rs

@@ -34,6 +34,8 @@ pub struct Initiator {
     signal: MutableSignalCloned<Option<Machine>>,
     machine: Option<Machine>,
     future: Option<BoxFuture<'static, (Option<User>, MachineState)>>,
+    // TODO: Prepare the init for async state change requests.
+    state_change_fut: Option<BoxFuture<'static, Result<ReturnToken>>>,
     token: Option<ReturnToken>,
     sensor: BoxSensor,
 }
@@ -44,6 +46,7 @@ impl Initiator {
             signal: signal,
             machine: None,
             future: None,
+            state_change_fut: None,
             token: None,
             sensor: sensor,
         }
@@ -73,14 +76,43 @@ impl Future for Initiator {
 
         // Do as much work as we can:
         loop {
+            // Always poll the state change future first
+            if let Some(ref mut f) = this.state_change_fut {
+                print!("Polling state change fut ...");
+                match Future::poll(Pin::new(f), cx) {
+                    // If there is a state change future and it would block we return early
+                    Poll::Pending => {
+                        println!(" blocked");
+                        return Poll::Pending;
+                    },
+                    Poll::Ready(Ok(tok)) => {
+                        println!(" returned ok");
+                        // Explicity drop the future
+                        let _ = this.state_change_fut.take();
+
+                        // Store the given return token for future use
+                        this.token.replace(tok);
+                    }
+                    Poll::Ready(Err(e)) => {
+                        println!(" returned err: {:?}", e);
+                        // Explicity drop the future
+                        let _ = this.state_change_fut.take();
+                    }
+                }
+            }
+
             // If there is a future, poll it
             match this.future.as_mut().map(|future| Future::poll(Pin::new(future), cx)) {
                 None => {
                     this.future = Some(this.sensor.run_sensor());
                 },
                 Some(Poll::Ready((user, state))) => {
+                    println!("New sensor fut");
                     this.future.take();
-                    this.machine.as_mut().map(|machine| machine.request_state_change(user.as_ref(), state).unwrap());
+                    let f = this.machine.as_mut().map(|machine| {
+                        machine.request_state_change(user.as_ref(), state)
+                    });
+                    this.state_change_fut = f;
                 }
                 Some(Poll::Pending) => return Poll::Pending,
             }

src/machine.rs

@@ -12,6 +12,8 @@ use std::fs;
 
 use serde::{Serialize, Deserialize};
 
+use futures::future::BoxFuture;
+
 use futures_signals::signal::Signal;
 use futures_signals::signal::SignalExt;
 use futures_signals::signal::{Mutable, ReadOnlyMutable};
@@ -22,7 +24,7 @@ use crate::error::{Result, Error};
 
 use crate::db::access;
 use crate::db::machine::{MachineIdentifier, Status, MachineState};
-use crate::db::user::User;
+use crate::db::user::{User, UserData};
 
 use crate::network::MachineMap;
 
@@ -49,39 +51,68 @@ impl Index {
 
 #[derive(Debug, Clone)]
 pub struct Machine {
-    inner: Arc<Mutex<Inner>>
+    inner: Arc<Mutex<Inner>>,
+    access: Arc<access::AccessControl>,
 }
 
 impl Machine {
-    pub fn new(inner: Inner) -> Self {
-        Self { inner: Arc::new(Mutex::new(inner)) }
+    pub fn new(inner: Inner, access: Arc<access::AccessControl>) -> Self {
+        Self { inner: Arc::new(Mutex::new(inner)), access: access }
     }
 
     pub fn construct
         ( id: MachineIdentifier
         , desc: MachineDescription
         , state: MachineState
+        , access: Arc<access::AccessControl>
         ) -> Machine
     {
-        Self::new(Inner::new(id, desc, state))
+        Self::new(Inner::new(id, desc, state), access)
     }
 
-    pub fn from_file<P: AsRef<Path>>(path: P) -> Result<Vec<Machine>> {
+    pub fn from_file<P: AsRef<Path>>(path: P, access: Arc<access::AccessControl>) 
+        -> Result<Vec<Machine>> 
+    {
         let mut map: HashMap<MachineIdentifier, MachineDescription> = MachineDescription::load_file(path)?;
         Ok(map.drain().map(|(id, desc)| {
-            Self::construct(id, desc, MachineState::new())
+            Self::construct(id, desc, MachineState::new(), access.clone())
         }).collect())
     }
 
+    /// Requests to use a machine. Returns a return token if successful.
+    ///
+    /// This will update the internal state of the machine, notifying connected actors, if any.
+    /// The return token is a channel that considers the machine 'returned' if anything is sent
+    /// along it or if the sending end gets dropped. Anybody who holds this token needs to check if
+    /// the receiving end was canceled which indicates that the machine has been taken off their
+    /// hands.
     pub fn request_state_change(&self, who: Option<&User>, new_state: MachineState) 
-        -> Result<ReturnToken> 
+        -> BoxFuture<'static, Result<ReturnToken>>
     {
-        let mut guard = self.inner.try_lock().unwrap();
-        guard.request_state_change(who, new_state)
+        let this = self.clone();
+        let udata: Option<UserData> = who.map(|u| u.data.clone());
+
+        let f = async move {
+            if let Some(udata) = udata {
+                let mut guard = this.inner.try_lock().unwrap();
+                if this.access.check(&udata, &guard.desc.privs.write).await? {
+                    return guard.do_state_change(new_state);
+                }
+            } else {
+                if new_state == MachineState::free() {
+                    let mut guard = this.inner.try_lock().unwrap();
+                    return guard.do_state_change(new_state);
+                }
+            }
+
+            return Err(Error::Denied);
+        };
+
+        Box::pin(f)
     }
 
     pub fn signal(&self) -> impl Signal<Item=MachineState> {
-        let mut guard = self.inner.try_lock().unwrap();
+        let guard = self.inner.try_lock().unwrap();
         guard.signal()
     }
 }
@@ -117,7 +148,11 @@ pub struct Inner {
 }
 
 impl Inner {
-    pub fn new(id: MachineIdentifier, desc: MachineDescription, state: MachineState) -> Inner {
+    pub fn new ( id: MachineIdentifier
+               , desc: MachineDescription
+               , state: MachineState
+               ) -> Inner 
+    {
         Inner {
             id: id,
             desc: desc,
@@ -139,29 +174,7 @@ impl Inner {
         Box::pin(self.state.signal_cloned().dedupe_cloned())
     }
 
-    /// Requests to use a machine. Returns a return token if successful.
-    ///
-    /// This will update the internal state of the machine, notifying connected actors, if any.
-    /// The return token is a channel that considers the machine 'returned' if anything is sent
-    /// along it or if the sending end gets dropped. Anybody who holds this token needs to check if
-    /// the receiving end was canceled which indicates that the machine has been taken off their
-    /// hands.
-    pub fn request_state_change(&mut self, who: Option<&User>, new_state: MachineState) 
-        -> Result<ReturnToken>
-    {
-        if who.is_none() {
-            if new_state.state == Status::Free {
-                return self.do_state_change(new_state);
-            }
-        } else {
-            // TODO: Correctly check permissions here
-            return self.do_state_change(new_state);
-        }
-
-        return Err(Error::Denied);
-    }
-
-    fn do_state_change(&mut self, new_state: MachineState) -> Result<ReturnToken> {
+    pub fn do_state_change(&mut self, new_state: MachineState) -> Result<ReturnToken> {
             let (tx, rx) = futures::channel::oneshot::channel();
             let old_state = self.state.replace(new_state);
             self.reset.replace(old_state);
@@ -234,13 +247,15 @@ impl MachineDescription {
     }
 }
 
-pub fn load(config: &crate::config::Settings) -> Result<MachineMap> {
+pub fn load(config: &crate::config::Settings, access: Arc<access::AccessControl>) 
+    -> Result<MachineMap> 
+{
     let mut map = config.machines.clone();
 
     let it = map.drain()
         .map(|(k,v)| {
             // TODO: Read state from the state db
-            (v.name.clone(), Machine::construct(k, v, MachineState::new()))
+            (v.name.clone(), Machine::construct(k, v, MachineState::new(), access.clone()))
         });
     Ok(HashMap::from_iter(it))
 }

src/main.rs

@@ -153,13 +153,14 @@ fn maybe(matches: clap::ArgMatches, log: Arc<Logger>) -> Result<(), Error> {
         Ok(())
     } else {
         let ex = Executor::new();
+        let db = db::Databases::new(&log, &config)?;
 
         let mqtt = AsyncClient::new(config.mqtt_url.clone())?;
         let tok = mqtt.connect(paho_mqtt::ConnectOptions::new());
 
         smol::block_on(tok)?;
 
-        let machines = machine::load(&config)?;
+        let machines = machine::load(&config, db.access.clone())?;
         let (mut actor_map, actors) = actor::load(&log, &mqtt, &config)?;
         let (mut init_map, initiators) = initiator::load(&log, &mqtt, &config)?;
 
@@ -189,7 +190,6 @@ fn maybe(matches: clap::ArgMatches, log: Arc<Logger>) -> Result<(), Error> {
         let (_, r) = easy_parallel::Parallel::new()
             .each(0..4, |_| smol::block_on(ex.run(shutdown.recv())))
             .finish(|| {
-                let db = db::Databases::new(&log, &config)?;
                 // TODO: Spawn api connections on their own (non-main) thread, use the main thread to
                 // handle signals (a cli if stdin is not closed?) and make it stop and clean up all threads
                 // when bffh should exit