refactor management. now reloads all bureaus on HUP, restarts crashed ones.

screenless/mgmt.py

@@ -9,51 +9,85 @@ import configparser
 import importlib
 import multiprocessing
 import os
+import signal
 import time
 
-def mgmt():
+
+class Management:
     """
-    Primary management function.  Main loop that starts and runs all bureaus.
-    Some day this will do nice supervisory things like restart crashed buros.
+    Management is the executive of the Screenless Office.  It can start, stop
+    and reconfigure the subordinate bureaus of the office.
     """
+    def __init__(self):
         basepath = os.path.expanduser("~/.screenless")
         if not os.path.exists(basepath):
             os.mkdir(basepath)
         os.chdir(basepath)
 
-    config = configparser.ConfigParser()
-    procs = {}
-
+        self.procs = {}
+        self.org_chart = []
+        self._load_config()
 
+    def _load_config(self): 
+        config = configparser.ConfigParser()
         try:
             config.read("mgmt.ini")
-        org_chart = config["mgmt"]["bureaus"].split()
+            self.org_chart = config["mgmt"]["bureaus"].split()
         except KeyError:
             config["mgmt"] = {"bureaus":
                               "ihr typing publicrelations photography jokes"}
             with open("mgmt.ini", "w") as configfile:
                 config.write(configfile)
-        print("created new mgmt.ini config file.  please modify this to suit.")
-        org_chart = config["mgmt"]["bureaus"].split()
-
-    print("org chart:", org_chart)
+            print("Created new mgmt.ini config file.  Please modify to suit.")
+            self.org_chart = config["mgmt"]["bureaus"].split()
 
-    for buro in org_chart:
+    def _start_bureaus(self):
+        """
+        Initialized and start all child bureaus
+        """
+        for buro in self.org_chart:
+            # TODO: this may need some sanity checking for crash/reload
             lib = importlib.import_module("bureau." + buro)
             proc = multiprocessing.Process(target=lib.main)
-        procs[buro] = proc
+            self.procs[buro] = proc
             proc.start()
 
+    def _stop_bureaus(self):
+        """
+        Terminates all running bureau children
+        """
+        for buro in self.org_chart:
+            proc = self.procs[buro]
+            proc.terminate()
+
+    def reload(self, signum=None, frame=None):
+        """
+        stop all bureaus, reload config, restart all bureaus.
+        Note, this may cause a loss of state in some cases.
+        """
+        self._stop_bureaus()
+        self._load_config()
+        self._start_bureaus()
+
+    def run(self):
+        """
+        main loop for Management, will restart crashed bureaus
+        and reload everything when sent a SIGHUP
+        """
+        signal.signal(signal.SIGHUP, self.reload)
+
+        self._start_bureaus()
         while True:
-        for buro in org_chart:
-            proc = procs[buro]
+            for buro in self.org_chart:
+                proc = self.procs[buro]
                 if not proc.is_alive():
                     print("bureau", buro, "has crashed!  Call the consultants!")
-                #TODO this should probably restart in some sensible way
+                    print("restarting...")
+                    #TODO this should probably only retry a few times
+                    proc.start()
             time.sleep(1)
 
 
-
-
 if __name__ == "__main__":
-    mgmt()
+    mgmt = Management()
+    mgmt.run()