From 453ff83e6cda30100e9c7d8079854f651f1e3787 Mon Sep 17 00:00:00 2001
From: Ilion Beyst <ilion.beyst@gmail.com>
Date: Sat, 3 Dec 2022 15:57:59 +0100
Subject: hotfix: enable reading lines split over multiple stdout buffers

---
 planetwars-matchrunner/Cargo.toml                |  1 +
 planetwars-matchrunner/src/docker_runner.rs      | 14 +++++++++++---
 planetwars-matchrunner/tests/test_matchrunner.rs | 17 +++++++++++++++++
 3 files changed, 29 insertions(+), 3 deletions(-)

(limited to 'planetwars-matchrunner')

diff --git a/planetwars-matchrunner/Cargo.toml b/planetwars-matchrunner/Cargo.toml
index 10d1c99..4a0e05e 100644
--- a/planetwars-matchrunner/Cargo.toml
+++ b/planetwars-matchrunner/Cargo.toml
@@ -18,6 +18,7 @@ chrono = { version = "0.4", features = ["serde"] }
 bollard = { git = "https://github.com/fussybeaver/bollard", rev = "c5d87a4934c70a04f9c649fedb241dbd4943c927" }
 bytes = "1.1"
 async-trait = "0.1"
+memchr = "2.5.0"
 
 [dev-dependencies]
 tempfile = "3"
\ No newline at end of file
diff --git a/planetwars-matchrunner/src/docker_runner.rs b/planetwars-matchrunner/src/docker_runner.rs
index a4415ca..04d7ecb 100644
--- a/planetwars-matchrunner/src/docker_runner.rs
+++ b/planetwars-matchrunner/src/docker_runner.rs
@@ -5,7 +5,7 @@ use std::sync::{Arc, Mutex};
 use async_trait::async_trait;
 use bollard::container::{self, AttachContainerOptions, AttachContainerResults, LogOutput};
 use bollard::Docker;
-use bytes::Bytes;
+use bytes::{Bytes, BytesMut};
 use futures::{Stream, StreamExt};
 use tokio::io::{AsyncWrite, AsyncWriteExt};
 use tokio::sync::mpsc;
@@ -168,6 +168,8 @@ fn run_docker_bot(
         event_bus,
         match_logger,
         rx,
+
+        stdout_buf: BytesMut::new(),
     };
 
     let join_handle = tokio::spawn(bot_runner.run());
@@ -198,6 +200,9 @@ pub struct DockerBotRunner {
     rx: mpsc::UnboundedReceiver<RequestMessage>,
     match_logger: MatchLogger,
     player_id: u32,
+
+    stdout_buf: BytesMut,
+    // stderr_buf: BytesMut,
 }
 
 impl DockerBotRunner {
@@ -243,8 +248,11 @@ impl DockerBotRunner {
             let log_output = item.expect("failed to get log output");
             match log_output {
                 LogOutput::StdOut { message } => {
-                    // TODO: this is not correct (buffering and such)
-                    return Ok(message);
+                    self.stdout_buf.extend_from_slice(&message);
+                    if let Some(split_idx) = memchr::memchr(b'\n', &self.stdout_buf) {
+                        let line = self.stdout_buf.split_to(split_idx+1);
+                        return Ok(line.freeze())
+                    }
                 }
                 LogOutput::StdErr { mut message } => {
                     // TODO
diff --git a/planetwars-matchrunner/tests/test_matchrunner.rs b/planetwars-matchrunner/tests/test_matchrunner.rs
index 43afd85..c2b324c 100644
--- a/planetwars-matchrunner/tests/test_matchrunner.rs
+++ b/planetwars-matchrunner/tests/test_matchrunner.rs
@@ -148,3 +148,20 @@ async fn docker_runner_crash() {
     })
     .await;
 }
+
+#[tokio::test]
+async fn test_long_line() {
+    let bot_spec = simple_python_docker_bot_spec("./bots", "echo_bot.py");
+    let len = 10 * 2_usize.pow(20); // 10 megabytes - hopefully large enough to cause buffering
+    let buf = std::iter::repeat(b'a').take(len).collect::<Vec<u8>>();
+    with_bot_match_ctx(bot_spec, |ctx| {
+        async move {
+            let resp = ctx.request(1, buf, Duration::from_millis(200)).await;
+
+            let resp_bytes = resp.expect("unexpected error");
+            assert_eq!(resp_bytes.len(), len + 1);
+        }
+        .boxed()
+    })
+    .await;
+}
-- 
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