ensure bots cleanly stop before a match completes

planetwars-matchrunner/src/bot_runner.rs

@@ -6,14 +6,18 @@ use std::sync::Mutex;
 use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader, Lines};
 use tokio::process;
 use tokio::sync::mpsc;
+use tokio::task::JoinHandle;
 use tokio::time::timeout;
 
 use super::match_context::EventBus;
 use super::match_context::PlayerHandle;
 use super::match_context::RequestError;
 use super::match_context::RequestMessage;
+// TODO: this is exactly the same as the docker bot handle.
+// should this abstraction be removed?
 pub struct LocalBotHandle {
     tx: mpsc::UnboundedSender<RequestMessage>,
+    join_handle: JoinHandle<()>,
 }
 
 impl PlayerHandle for LocalBotHandle {
@@ -22,6 +26,10 @@ impl PlayerHandle for LocalBotHandle {
             .send(r)
             .expect("failed to send message to local bot");
     }
+
+    fn into_join_handle(self: Box<Self>) -> JoinHandle<()> {
+        self.join_handle
+    }
 }
 
 pub fn run_local_bot(player_id: u32, event_bus: Arc<Mutex<EventBus>>, bot: Bot) -> LocalBotHandle {
@@ -33,9 +41,9 @@ pub fn run_local_bot(player_id: u32, event_bus: Arc<Mutex<EventBus>>, bot: Bot)
         player_id,
         bot,
     };
-    tokio::spawn(runner.run());
+    let join_handle = tokio::spawn(runner.run());
 
-    LocalBotHandle { tx }
+    LocalBotHandle { tx, join_handle }
 }
 
 pub struct LocalBotRunner {

planetwars-matchrunner/src/docker_runner.rs

@@ -9,6 +9,7 @@ use bytes::Bytes;
 use futures::{Stream, StreamExt};
 use tokio::io::{AsyncWrite, AsyncWriteExt};
 use tokio::sync::mpsc;
+use tokio::task::JoinHandle;
 use tokio::time::timeout;
 
 use crate::match_context::{EventBus, PlayerHandle, RequestError, RequestMessage};
@@ -42,8 +43,7 @@ impl BotSpec for DockerBotSpec {
         match_logger: MatchLogger,
     ) -> Box<dyn PlayerHandle> {
         let process = spawn_docker_process(self).await.unwrap();
-        let (handle, runner) = create_docker_bot(process, player_id, event_bus, match_logger);
-        tokio::spawn(runner.run());
+        let handle = run_docker_bot(process, player_id, event_bus, match_logger);
         return Box::new(handle);
     }
 }
@@ -155,14 +155,13 @@ impl ContainerProcess {
     }
 }
 
-fn create_docker_bot(
+fn run_docker_bot(
     process: ContainerProcess,
     player_id: u32,
     event_bus: Arc<Mutex<EventBus>>,
     match_logger: MatchLogger,
-) -> (DockerBotHandle, DockerBotRunner) {
+) -> DockerBotHandle {
     let (tx, rx) = mpsc::unbounded_channel();
-    let bot_handle = DockerBotHandle { tx };
     let bot_runner = DockerBotRunner {
         process,
         player_id,
@@ -170,11 +169,15 @@ fn create_docker_bot(
         match_logger,
         rx,
     };
-    (bot_handle, bot_runner)
+
+    let join_handle = tokio::spawn(bot_runner.run());
+
+    DockerBotHandle { tx, join_handle }
 }
 
 pub struct DockerBotHandle {
     tx: mpsc::UnboundedSender<RequestMessage>,
+    join_handle: JoinHandle<()>,
 }
 
 impl PlayerHandle for DockerBotHandle {
@@ -183,6 +186,10 @@ impl PlayerHandle for DockerBotHandle {
             .send(r)
             .expect("failed to send message to local bot");
     }
+
+    fn into_join_handle(self: Box<Self>) -> JoinHandle<()> {
+        self.join_handle
+    }
 }
 
 pub struct DockerBotRunner {

planetwars-matchrunner/src/lib.rs

@@ -106,11 +106,9 @@ pub async fn run_match(config: MatchConfig) -> MatchOutcome {
     // )
     // .unwrap();
 
-    let mut match_state = pw_match::PwMatch::create(match_ctx, pw_config);
-    match_state.run().await;
+    let final_state = pw_match::PwMatch::create(match_ctx, pw_config).run().await;
 
-    let final_state = match_state.match_state.state();
-    let survivors = final_state.living_players();
+    let survivors = final_state.state().living_players();
     let winner = if survivors.len() == 1 {
         Some(survivors[0])
     } else {

planetwars-matchrunner/src/match_context.rs

@@ -7,6 +7,7 @@ use std::{
     collections::HashMap,
     sync::{Arc, Mutex},
 };
+use tokio::task::JoinHandle;
 
 use crate::match_log::{MatchLogMessage, MatchLogger};
 
@@ -71,10 +72,19 @@ impl MatchCtx {
     pub fn log(&mut self, message: MatchLogMessage) {
         self.match_logger.send(message).expect("write failed");
     }
+
+    pub async fn shutdown(self) {
+        let join_handles = self
+            .players
+            .into_iter()
+            .map(|(_player_id, player_data)| player_data.handle.into_join_handle());
+        futures::future::join_all(join_handles).await;
+    }
 }
 
 pub trait PlayerHandle: Send {
     fn send_request(&mut self, r: RequestMessage);
+    fn into_join_handle(self: Box<Self>) -> JoinHandle<()>;
 }
 
 struct PlayerData {

planetwars-matchrunner/src/pw_match.rs

@@ -39,7 +39,7 @@ impl PwMatch {
         }
     }
 
-    pub async fn run(&mut self) {
+    pub async fn run(mut self) -> PlanetWars {
         // log initial state
         self.log_game_state();
 
@@ -53,6 +53,9 @@ impl PwMatch {
             self.match_state.step();
             self.log_game_state();
         }
+
+        self.match_ctx.shutdown().await;
+        self.match_state
     }
 
     async fn prompt_players(&mut self) -> Vec<(usize, RequestResult<Vec<u8>>)> {

planetwars-matchrunner/tests/test_matchrunner.rs

@@ -70,5 +70,6 @@ async fn docker_runner_timeout() {
         .request(1, b"sup".to_vec(), Duration::from_millis(1000))
         .await;
 
-    assert_eq!(resp, Err(RequestError::Timeout))
+    assert_eq!(resp, Err(RequestError::Timeout));
+    ctx.shutdown().await;
 }