From 8a571a10a5543c059575189737fed444dfa6005f Mon Sep 17 00:00:00 2001
From: j <j@mailb.org>
Date: Thu, 11 Feb 2016 19:56:12 +0530
Subject: [PATCH] implement priority queue

---
 oml/tasks.py | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/oml/tasks.py b/oml/tasks.py
index 15577c9..8e662b5 100644
--- a/oml/tasks.py
+++ b/oml/tasks.py
@@ -2,7 +2,7 @@
 # vi:si:et:sw=4:sts=4:ts=4
 import os
 import json
-from queue import Queue
+from queue import PriorityQueue
 from threading import Thread
 
 from websocket import trigger_event
@@ -17,23 +17,23 @@ class Tasks(Thread):
 
     def __init__(self):
         self._taskspath = os.path.join(settings.data_path, 'tasks.json')
-        self.q = Queue()
+        self.q = PriorityQueue()
         Thread.__init__(self)
         self.daemon = True
         self.start()
-        self.queue('scan')
-        self.load_tasks()
 
     def run(self):
+        self.load_tasks()
+        self.queue('scan')
         import item.scan
         from item.models import sync_metadata, get_preview, get_cover
         from user.models import export_list, update_user_peering
         shutdown = False
         while not shutdown:
-            m = self.q.get()
+            p, m = self.q.get()
             if m:
                 if state.shutdown:
-                    self._tasks.append(m)
+                    self._tasks.append((p, m))
                 else:
                     try:
                         action, data = m
@@ -86,12 +86,20 @@ class Tasks(Thread):
                 json.dump(self._tasks, f)
 
     def join(self):
-        self.q.put(None)
+        self.q.put((1000, None))
         r = Thread.join(self)
         self.save_tasks()
         return r
 
-    def queue(self, action, data=None):
+    def queue(self, action, data=None, priority=None):
+        if priority is None:
+            priority = 100
+            if action in ('getcover', 'getpreview'):
+                priority += 1
+            if action in ('import', 'export'):
+                priority -= 1
+            if action in ('peering', 'changelibrarypath'):
+                priority -= 2
         if not state.shutdown:
-            logger.debug('%s queued', action)
-            self.q.put((action, data))
+            #logger.debug('queue: %s (%s)', action, data)
+            self.q.put((priority, (action, data)))