Gracefully handle SIGTERM as well as SIGINT, feature #5672

SIGTERM is caught by twisted, so we have to use addSystemEventTrigger()
to pass a custom handler to twisted reactor.

See https://leap.se/code/issues/5672 for more.

2 files changed, 20 insertions, 0 deletions

diff --git a/changes/feature-5672_gracefully-handle-SIGTERM b/changes/feature-5672_gracefully-handle-SIGTERM
new file mode 100644
index 00000000..a616430d
--- /dev/null
+++ b/changes/feature-5672_gracefully-handle-SIGTERM
@@ -0,0 +1 @@
+- Gracefully handle SIGTERM, with addSystemEventTrigger twisted reactor's method. Closes #5672.
diff --git a/src/leap/bitmask/app.py b/src/leap/bitmask/app.py
index 146743b5..e413ab4c 100644
--- a/src/leap/bitmask/app.py
+++ b/src/leap/bitmask/app.py
@@ -76,6 +76,16 @@ def sigint_handler(*args, **kwargs):
     mainwindow = args[0]
     mainwindow.quit()
 
+def sigterm_handler(*args, **kwargs):
+    """
+    Signal handler for SIGTERM.
+    This handler is actually passed to twisted reactor
+    """
+    logger = kwargs.get('logger', None)
+    if logger:
+        logger.debug("SIGTERM catched. shutting down...")
+    mainwindow = args[0]
+    mainwindow.quit()
 
 def add_logger_handlers(debug=False, logfile=None, replace_stdout=True):
     """
@@ -314,6 +324,9 @@ def main():
     sigint_window = partial(sigint_handler, window, logger=logger)
     signal.signal(signal.SIGINT, sigint_window)
 
+    # callable used in addSystemEventTrigger to handle SIGTERM
+    sigterm_window = partial(sigterm_handler, window, logger=logger)
+
     if IS_MAC:
         window.raise_()
 
@@ -324,6 +337,12 @@ def main():
 
     l = LoopingCall(QtCore.QCoreApplication.processEvents, 0, 10)
     l.start(0.01)
+
+    # SIGTERM can't be handled the same way SIGINT is, since it's
+    # caught by twisted. See _handleSignals method in
+    # twisted/internet/base.py#L1150. So, addSystemEventTrigger
+    # reactor's method is used.
+    reactor.addSystemEventTrigger('before', 'shutdown', sigterm_window)
     reactor.run()
 
 if __name__ == "__main__":