Add signals_with_multiprocessing.py

1 files changed, 34 insertions, 0 deletions

diff --git a/signals_with_multiprocessing.py b/signals_with_multiprocessing.py
new file mode 100644
index 0000000..4cf0c01
--- /dev/null
+++ b/signals_with_multiprocessing.py
@@ -0,0 +1,34 @@
+import multiprocessing, time, sys, signal, os, inspect
+
+# Sending SIGTERM will terminate the main process
+# but the process running the 'a' function will remain dangling.
+
+def signal_handler(sig, fr):
+    print(inspect.stack()[0][3])
+    print('{}: Received {}'.format(os.getpid(), sig))
+    sys.exit(3)
+    # the statement below never executes, leaving the process dangling.
+    # p.terminate()
+
+signal.signal(signal.SIGTERM, signal_handler)
+
+def a(b):
+    def signal_handler(sig, fr):
+        print(inspect.stack()[0][3])
+        print('{}: 2Received {}'.format(os.getpid(), sig))
+        sys.exit(5)
+
+    # The process normally inherits parent signal handler
+    # but we overwrite it here.
+    signal.signal(signal.SIGTERM, signal_handler)
+
+    while True:
+        print('{}: {}'.format(os.getpid(), b))
+        time.sleep(1)
+
+p = multiprocessing.Process(target=a, args=('cool test',))
+p.start()
+
+print('PID: {}'.format(os.getpid()))
+
+sys.exit(4)