Start reimplementing worker

src/worker/coordinator.rs

@@ -1,104 +0,0 @@
-//! Coordinate performing runs across servers.
-
-use std::time::Duration;
-
-use time::OffsetDateTime;
-use tokio::sync::mpsc;
-
-struct Server {
-    name: String,
-    poke: mpsc::UnboundedSender<()>,
-}
-
-pub struct Coordinator {
-    servers: Vec<Server>,
-    active: usize,
-    active_since: OffsetDateTime,
-    busy: bool,
-}
-
-impl Coordinator {
-    pub fn new() -> Self {
-        Self {
-            servers: vec![],
-            active: 0,
-            active_since: OffsetDateTime::now_utc(),
-            busy: false,
-        }
-    }
-
-    pub fn register(&mut self, name: String, poke: mpsc::UnboundedSender<()>) {
-        // TODO Assert that no duplicate names exist?
-        self.servers.push(Server { name, poke });
-    }
-
-    pub fn active(&self, name: &str) -> ActiveInfo {
-        let active_server = self.servers.get(self.active);
-        let active = active_server.filter(|s| s.name == name).is_some();
-        ActiveInfo {
-            active,
-            active_since: self.active_since,
-            busy: self.busy,
-        }
-    }
-
-    pub fn look_busy(&mut self, name: &str) {
-        // Check just to prevent weird shenanigans
-        if !self.active(name).active {
-            return;
-        }
-
-        self.busy = true;
-    }
-
-    pub fn move_to_next_server(&mut self, name: &str) {
-        // Check just to prevent weird shenanigans
-        if !self.active(name).active {
-            return;
-        }
-
-        // At least one server (the current one) must be registered according to
-        // the previous check
-        assert!(!self.servers.is_empty());
-
-        self.active += 1;
-        self.active %= self.servers.len();
-        self.active_since = OffsetDateTime::now_utc();
-        self.busy = false;
-
-        // When the worker seeks work and a queue is idle, the next server
-        // should be queried immediately. Otherwise, we'd introduce lots of
-        // delay in the multi-server case were most queues are empty.
-        //
-        // However, if all server's queues were empty, this would generate a
-        // slippery cycle of requests that the worker sends as quickly as
-        // possible, only limited by the roundtrip time. Because we don't want
-        // this, we let the first task wait its full timeout. Effectively, this
-        // results in iterations starting at least the ping delay apart, which
-        // is pretty much what we want.
-        //
-        // The way this is implemented currently is sub-optimal however: If the
-        // chain takes even a fraction longer than the previous iteration, tasks
-        // will send two requests back-to-back: The first because their ping
-        // timeout ran out, and the second because they were poked. So far, I
-        // haven't been able to think of an elegant solution for this.
-        if self.active > 0 {
-            let _ = self.servers[self.active].poke.send(());
-        }
-    }
-}
-
-#[derive(Clone, Copy)]
-pub struct ActiveInfo {
-    pub active: bool,
-    pub active_since: OffsetDateTime,
-    pub busy: bool,
-}
-
-impl ActiveInfo {
-    pub fn in_batch(&self, batch_duration: Duration) -> bool {
-        let batch_end = self.active_since + batch_duration;
-        let now = OffsetDateTime::now_utc();
-        now <= batch_end
-    }
-}