Add non_interactive_ioc() function

Resolves PR #156

CHANGELOG.rst

@@ -11,7 +11,9 @@ Unreleased_
 -----------
 
 Added:
+
 - `Enable setting alarm status of Out records <../../pull/157>`_
+- `Adding the non_interactive_ioc function <../../pull/156>`_
 
 Removed:
 

docs/reference/api.rst

@@ -120,6 +120,12 @@ Test Facilities`_ documentation for more details of each function.
 ..  autofunction:: generalTimeReport
 ..  autofunction:: eltc
 
+.. autofunction:: non_interactive_ioc
+
+When used with a service manager, use python's -u option or the environment
+variable PYTHONUNBUFFERED=TRUE. This ensures that python output, i.e. stdout
+and stderr streams, is sent directly to the terminal.
+
 ..  attribute:: exit
 
     Displaying this value will invoke ``epicsExit()`` causing the IOC to

softioc/asyncio_dispatcher.py

@@ -3,6 +3,7 @@
 import logging
 import threading
 import atexit
+import signal
 
 class AsyncioDispatcher:
     def __init__(self, loop=None, debug=False):
@@ -48,6 +49,17 @@ def close(self):
 
         self.__shutdown()
 
+    def wait_for_quit(self):
+        stop_event = threading.Event()
+
+        def signal_handler(signum, frame):
+            stop_event.set()
+
+        signal.signal(signal.SIGINT, signal_handler)
+        signal.signal(signal.SIGTERM, signal_handler)
+
+        stop_event.wait()
+
     async def __inloop(self, started):
         self.loop = asyncio.get_running_loop()
         self.__interrupt = asyncio.Event()

softioc/cothread_dispatcher.py

@@ -19,6 +19,8 @@ def __init__(self, dispatcher = None):
         else:
             self.__dispatcher = dispatcher
 
+        self.wait_for_quit = cothread.WaitForQuit
+
     def __call__(
             self,
             func,

softioc/softioc.py

@@ -352,3 +352,12 @@ def interactive_ioc(context = {}, call_exit = True):
 
     if call_exit:
         safeEpicsExit(0)
+
+
+def non_interactive_ioc():
+    '''Function to run the IOC in non-interactive mode. This mode is useful for
+    running the IOC as a background process without user interaction.
+    This function expects a stop signal. When it receives one, the IOC stops.
+    '''
+    device.dispatcher.wait_for_quit()
+    safeEpicsExit(0)