Handle sigchld, so we can run governor and postgres inside docker safely

governor.py

@@ -16,6 +16,17 @@ def sigterm_handler(signo, stack_frame):
     sys.exit()
 
 
+# handle SIGCHILD, since we are the equivalent of the INIT process
+def sigchld_handler(signo, stack_frame):
+    try:
+        while True:
+            ret = os.waitpid(-1, os.WNOHANG)
+            if ret == (0, 0):
+                break
+    except OSError:
+        pass
+
+
 class Governor:
 
     def __init__(self, config):
@@ -78,4 +89,5 @@ def main():
 if __name__ == '__main__':
     logging.basicConfig(format='%(asctime)s %(levelname)s: %(message)s', level=logging.INFO)
     signal.signal(signal.SIGTERM, sigterm_handler)
+    signal.signal(signal.SIGCHLD, sigchld_handler)
     main()