Merge lp:~cjwatson/rabbitfixture/fix-stop into lp:rabbitfixture

[Colin Watson]

Handle SIGCHLD while stopping the RabbitServerRunner fixture.

The rabbitmq-server process we're trying to stop is our direct child process.

[Tom Wardill (twom)]

review: Approve

=== modified file 'NEWS.rst'
--- NEWS.rst	2021-02-01 10:26:51 +0000
+++ NEWS.rst	2021-02-01 10:41:20 +0000
@@ -6,6 +6,9 @@
 =====
 
 - Add tox testing support and drop buildout.
+- Handle ``SIGCHLD`` while stopping the ``RabbitServerRunner`` fixture,
+  since the ``rabbitmq-server`` process we're trying to stop is our direct
+  child process.
 
 0.4.2 (2019-08-23)
 ==================

=== modified file 'rabbitfixture/server.py'
--- rabbitfixture/server.py	2019-08-21 13:55:49 +0000
+++ rabbitfixture/server.py	2021-02-01 10:41:20 +0000
@@ -12,6 +12,8 @@
     "RabbitServerResources",
     ]
 
+import errno
+import logging
 import os
 import re
 import signal
@@ -384,32 +386,58 @@
 
     def _stop(self):
         """Stop the running server. Normally called by cleanups."""
+        def handle_sigchld(signum, frame):
+            while True:
+                try:
+                    pid, _ = os.waitpid(-1, os.WNOHANG)
+                    if not pid:
+                        break
+                except OSError as e:
+                    if e.errno == errno.ECHILD:
+                        break
+                    raise
+
+        original_sigchld = None
         try:
-            self._request_stop()
-            # Wait for the node to go down...
-            timeout = time.time() + self.environment.ctltimeout
+            # The rabbitmq-server process we're trying to stop is our direct
+            # child process, so we need to handle SIGCHLD in order for the
+            # process to go away gracefully.
+            original_sigchld = signal.signal(signal.SIGCHLD, handle_sigchld)
+            if original_sigchld is None:
+                logging.warning(
+                    "Previous SIGCHLD handler was installed by non-Python "
+                    "code; will restore to default action instead.")
+                original_sigchld = signal.SIG_DFL
+
+            try:
+                self._request_stop()
+                # Wait for the node to go down...
+                timeout = time.time() + self.environment.ctltimeout
+                while time.time() < timeout:
+                    if not self.environment.is_node_running():
+                        break
+                    time.sleep(0.3)
+                else:
+                    raise Exception(
+                        "Timeout waiting for RabbitMQ node to go down.")
+            except subprocess.TimeoutExpired:
+                # Go straight to killing the process directly.
+                timeout = time.time()
+
+            # Wait for the process to end...
+            timeout = max(timeout, time.time() + self.environment.ctltimeout)
             while time.time() < timeout:
-                if not self.environment.is_node_running():
+                if not self.is_running():
                     break
-                time.sleep(0.3)
+                self._signal(signal.SIGTERM)
+                time.sleep(0.1)
             else:
-                raise Exception(
-                    "Timeout waiting for RabbitMQ node to go down.")
-        except subprocess.TimeoutExpired:
-            # Go straight to killing the process directly.
-            timeout = time.time()
-
-        # Wait for the process to end...
-        timeout = max(timeout, time.time() + self.environment.ctltimeout)
-        while time.time() < timeout:
-            if not self.is_running():
-                break
-            self._signal(signal.SIGTERM)
-            time.sleep(0.1)
-        else:
-            # Die!!!
-            if self.is_running():
-                self.kill()
+                # Die!!!
+                if self.is_running():
+                    self.kill()
+        finally:
+            if original_sigchld is not None:
+                signal.signal(signal.SIGCHLD, original_sigchld)
 
     def _signal(self, code):
         """Send a signal to the server process and all its children."""