From ca5f85c815616aa3b9d72513b6be2267c9f6e33d Mon Sep 17 00:00:00 2001
From: pyranota <pyra@duck.com>
Date: Mon, 30 Dec 2024 17:42:30 +0300
Subject: [PATCH] fix(python): Fix uv install job not exiting on fail
 Specifically with nmslib installation was hanging without any output, even
 tho library build was failed.

It can be monitored with strace or catp.
---
 .../windmill-worker/src/python_executor.rs    | 24 +++++++++----------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/backend/windmill-worker/src/python_executor.rs b/backend/windmill-worker/src/python_executor.rs
index 44b40a4c5a..34f313e653 100644
--- a/backend/windmill-worker/src/python_executor.rs
+++ b/backend/windmill-worker/src/python_executor.rs
@@ -1245,7 +1245,6 @@ async fn spawn_uv_install(
                 "--target",
                 venv_p,
                 "--no-cache",
-                "-q",
             ]
         };
 
@@ -1768,10 +1767,12 @@ pub async fn handle_python_reqs(
                 }
             };
 
-            let mut stderr = uv_install_proccess
+            let mut stderr_buf = String::new();
+            let mut stderr_pipe = uv_install_proccess
                 .stderr
                 .take()
                 .ok_or(anyhow!("Cannot take stderr from uv_install_proccess"))?;
+            let stderr_future = stderr_pipe.read_to_string(&mut stderr_buf);
 
             if let Some(pid) = pids.lock().await.get_mut(i) {
                 *pid = uv_install_proccess.id();
@@ -1788,9 +1789,12 @@ pub async fn handle_python_reqs(
                     uv_install_proccess.kill().await?;
                     pids.lock().await.get_mut(i).and_then(|e| e.take());
                     return Err(anyhow::anyhow!("uv pip install was canceled"));
-                }
-                // Finished
-                exitstatus = uv_install_proccess.wait() => match exitstatus {
+                },                
+                (_, exitstatus) = async {
+                    // See tokio::process::Child::wait_with_output() for more context
+                    // Sometimes uv_install_proccess.wait() is not exiting if stderr is not awaited before it :/
+                    (stderr_future.await, uv_install_proccess.wait().await)
+                 } => match exitstatus {
                     Ok(status) => if !status.success() {
                         tracing::warn!(
                             workspace_id = %w_id,
@@ -1799,24 +1803,18 @@ pub async fn handle_python_reqs(
                             status.code()
                         );
 
-                        let mut buf = String::new();
-                        stderr.read_to_string(&mut buf).await.unwrap_or_else(|_|{
-                            buf = "Cannot read stderr to string".to_owned();
-                            0
-                        });
-
                         append_logs(
                             &job_id,
                             w_id,
                             format!(
-                                "\nError while installing {}:\n{buf}",
+                                "\nError while installing {}:\n{stderr_buf}",
                                 &req
                             ),
                             db,
                         )
                         .await;
                         pids.lock().await.get_mut(i).and_then(|e| e.take());
-                        return Err(anyhow!(buf));
+                        return Err(anyhow!(stderr_buf));
                     },
                     Err(e) => {
                         tracing::error!(