chore: share HTTP server between tests (#6362)

test_util/src/lib.rs

@@ -12,8 +12,9 @@ use std::process::Child;
 use std::process::Command;
 use std::process::Output;
 use std::process::Stdio;
+use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering;
 use std::sync::Mutex;
-use std::sync::MutexGuard;
 use tempfile::TempDir;
 
 pub const PERMISSION_VARIANTS: [&str; 5] =
@@ -29,7 +30,8 @@ lazy_static! {
           r"[\x1b\x9b][\[()#;?]*(?:[0-9]{1,4}(?:;[0-9]{0,4})*)?[0-9A-PRZcf-nqry=><]"
   ).unwrap();
 
-  static ref GUARD: Mutex<()> = Mutex::new(());
+  static ref SERVER: Mutex<Option<Child>> = Mutex::new(None);
+  static ref SERVER_COUNT: AtomicUsize = AtomicUsize::new(0);
 }
 
 pub fn root_path() -> PathBuf {
@@ -56,55 +58,68 @@ pub fn deno_exe_path() -> PathBuf {
   p
 }
 
-pub struct HttpServerGuard<'a> {
-  #[allow(dead_code)]
-  g: MutexGuard<'a, ()>,
-  child: Child,
-}
+pub struct HttpServerGuard {}
 
-impl<'a> Drop for HttpServerGuard<'a> {
+impl Drop for HttpServerGuard {
   fn drop(&mut self) {
-    match self.child.try_wait() {
-      Ok(None) => {
-        self.child.kill().expect("failed to kill http_server.py");
-      }
-      Ok(Some(status)) => {
-        panic!("http_server.py exited unexpectedly {}", status)
-      }
-      Err(e) => panic!("http_server.py err {}", e),
+    let count = SERVER_COUNT.fetch_sub(1, Ordering::SeqCst);
+    // If no more tests hold guard we can kill the server
+
+    if count == 1 {
+      kill_http_server();
     }
   }
 }
 
-/// Starts tools/http_server.py when the returned guard is dropped, the server
-/// will be killed.
-pub fn http_server<'a>() -> HttpServerGuard<'a> {
-  // TODO(bartlomieju) Allow tests to use the http server in parallel.
-  let g = GUARD.lock().unwrap();
+fn kill_http_server() {
+  let mut server_guard = SERVER.lock().unwrap();
+  let mut child = server_guard
+    .take()
+    .expect("Trying to kill server but already killed");
+  match child.try_wait() {
+    Ok(None) => {
+      child.kill().expect("failed to kill http_server.py");
+    }
+    Ok(Some(status)) => panic!("http_server.py exited unexpectedly {}", status),
+    Err(e) => panic!("http_server.py error: {}", e),
+  }
+  drop(server_guard);
+}
 
-  println!("tools/http_server.py starting...");
-  let mut child = Command::new("python")
-    .current_dir(root_path())
-    .args(&["-u", "tools/http_server.py"])
-    .stdout(Stdio::piped())
-    .spawn()
-    .expect("failed to execute child");
+/// Starts tools/http_server.py when the returned guard is dropped and there are
+// no more guard being held, the server will be killed.
+pub fn http_server() -> HttpServerGuard {
+  SERVER_COUNT.fetch_add(1, Ordering::SeqCst);
 
-  let stdout = child.stdout.as_mut().unwrap();
-  use std::io::{BufRead, BufReader};
-  let lines = BufReader::new(stdout).lines();
-  // Wait for "ready" on stdout. See tools/http_server.py
-  for maybe_line in lines {
-    if let Ok(line) = maybe_line {
-      if line.starts_with("ready") {
-        break;
+  {
+    let mut server_guard = SERVER.lock().unwrap();
+    if server_guard.is_none() {
+      println!("tools/http_server.py starting...");
+      let mut child = Command::new("python")
+        .current_dir(root_path())
+        .args(&["-u", "tools/http_server.py"])
+        .stdout(Stdio::piped())
+        .spawn()
+        .expect("failed to execute child");
+
+      let stdout = child.stdout.as_mut().unwrap();
+      use std::io::{BufRead, BufReader};
+      let lines = BufReader::new(stdout).lines();
+      // Wait for "ready" on stdout. See tools/http_server.py
+      for maybe_line in lines {
+        if let Ok(line) = maybe_line {
+          if line.starts_with("ready") {
+            break;
+          }
+        } else {
+          panic!(maybe_line.unwrap_err());
+        }
       }
-    } else {
-      panic!(maybe_line.unwrap_err());
+      server_guard.replace(child);
     }
   }
 
-  HttpServerGuard { child, g }
+  HttpServerGuard {}
 }
 
 /// Helper function to strip ansi codes.