Wait for pid death

test_runner/fixtures/neon_fixtures.py

@@ -1488,17 +1488,25 @@ def start(self, overrides=()) -> 'NeonPageserver':
         self.running = True
         return self
 
+    def _wait_for_death(self):
+        """Wait for pageserver to die. Assumes kill signal is sent."""
+        pid_path = pathlib.Path(self.env.repo_dir) / "pageserver.pid"
+        pid = read_pid(pid_path)
+        retries_left = 20
+        while check_pid(pid):
+            time.sleep(0.1)
+            retries_left -= 1
+            if retries_left == 0:
+                raise AssertionError("Pageserver failed to die")
+
     def stop(self, immediate=False) -> 'NeonPageserver':
         """
         Stop the page server.
         Returns self.
         """
         if self.running:
             self.env.neon_cli.pageserver_stop(immediate)
-            # HACK This fixes https://github.com/neondatabase/neon/issues/2247
-            #      in most cases, but we should probably wait on some event rather
-            #      than wait 0.1 seconds.
-            time.sleep(0.1)
+            self._wait_for_death()
             self.running = False
         return self
 
@@ -2008,6 +2016,17 @@ def read_pid(path: Path) -> int:
     return int(path.read_text())
 
 
+def check_pid(pid):
+    """Check whether pid is running."""
+    try:
+        # If sig is 0, then no signal is sent, but error checking is still performed.
+        os.kill(pid, 0)
+    except OSError:
+        return False
+    else:
+        return True
+
+
 @dataclass
 class SafekeeperPort:
     pg: int