[buildstream] 09/25: job: no redundant signal code on win32

[gi...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

github-bot pushed a commit to branch aevri/win32_minimal
in repository https://gitbox.apache.org/repos/asf/buildstream.git

commit 4fe73d430e316a4c006f3df7e107fab731bc3332
Author: Angelos Evripiotis <je...@bloomberg.net>
AuthorDate: Fri Oct 4 18:11:02 2019 +0100

    job: no redundant signal code on win32
    
    There's no point blocking or handling signals that aren't supported on
    e.g. win32. Some of these signal ids aren't defined on unsupported
    platforms though, which would lead to an AttributeError at runtime.
    Avoid that by not invoking the redundant code.
---
 src/buildstream/_scheduler/jobs/job.py | 35 +++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/src/buildstream/_scheduler/jobs/job.py b/src/buildstream/_scheduler/jobs/job.py
index 7d901a3..46bb6bf 100644
--- a/src/buildstream/_scheduler/jobs/job.py
+++ b/src/buildstream/_scheduler/jobs/job.py
@@ -200,6 +200,7 @@ class Job():
         self._tries += 1
         self._parent_start_listening()
 
+        does_platform_support_signals = self._scheduler.context.platform.does_support_signals()
         child_job = self.create_child_job(  # pylint: disable=assignment-from-no-return
             action_name=self.action_name,
             messenger=self._scheduler.context.messenger,
@@ -209,6 +210,7 @@ class Job():
             tries=self._tries,
             message_element_name=self._message_element_name,
             message_element_key=self._message_element_key,
+            does_platform_support_signals=does_platform_support_signals,
         )
 
         if self._scheduler.context.platform.does_multiprocessing_start_require_pickling():
@@ -228,7 +230,10 @@ class Job():
         # the child process does not inherit the parent's state, but the main
         # process will be notified of any signal after we launch the child.
         #
-        with _signals.blocked([signal.SIGINT, signal.SIGTSTP, signal.SIGTERM], ignore=False):
+        if does_platform_support_signals:
+            with _signals.blocked([signal.SIGINT, signal.SIGTSTP, signal.SIGTERM], ignore=False):
+                self._process.start()
+        else:
             self._process.start()
 
         # Wait for the child task to complete.
@@ -631,7 +636,8 @@ class ChildJob():
 
     def __init__(
             self, action_name, messenger, logdir, logfile, max_retries, tries,
-            message_element_name, message_element_key):
+            message_element_name, message_element_key,
+            does_platform_support_signals):
 
         self.action_name = action_name
 
@@ -643,6 +649,8 @@ class ChildJob():
         self._message_element_name = message_element_name
         self._message_element_key = message_element_key
 
+        self._does_platform_support_signals = does_platform_support_signals
+
         self._queue = None
 
     # message():
@@ -732,17 +740,18 @@ class ChildJob():
     #
     def child_action(self, queue):
 
-        # This avoids some SIGTSTP signals from grandchildren
-        # getting propagated up to the master process
-        os.setsid()
-
-        # First set back to the default signal handlers for the signals
-        # we handle, and then clear their blocked state.
-        #
-        signal_list = [signal.SIGTSTP, signal.SIGTERM]
-        for sig in signal_list:
-            signal.signal(sig, signal.SIG_DFL)
-        signal.pthread_sigmask(signal.SIG_UNBLOCK, signal_list)
+        if (self._does_platform_support_signals):
+            # This avoids some SIGTSTP signals from grandchildren
+            # getting propagated up to the master process
+            os.setsid()
+
+            # First set back to the default signal handlers for the signals
+            # we handle, and then clear their blocked state.
+            #
+            signal_list = [signal.SIGTSTP, signal.SIGTERM]
+            for sig in signal_list:
+               signal.signal(sig, signal.SIG_DFL)
+            signal.pthread_sigmask(signal.SIG_UNBLOCK, signal_list)
 
         # Assign the queue we passed across the process boundaries
         #