NewsBlur-viq/utils/feedcache/threading_model.py
Samuel Clay 48ba40e29b Initial
2009-06-16 03:08:55 +00:00

102 lines
No EOL
2.6 KiB
Python

# Import system modules
import Queue
import sys
import shelve
import threading
# Import local modules
import cache
from cachestoragelock import CacheStorageLock
from django.core.cache import cache as dj_cache
MAX_THREADS=1
OUTPUT_DIR = '.temp'
def fetch_feeds(force_update, feeds=None):
if not feeds:
print 'Specify the URLs to a few RSS or Atom feeds on the command line.'
return
# Decide how many threads to start
num_threads = min(len(feeds), MAX_THREADS)
# Add the URLs to a queue
url_queue = Queue.Queue()
for f in feeds:
url_queue.put(f)
# Add poison pills to the url queue to cause
# the worker threads to break out of their loops
for i in range(num_threads):
url_queue.put(None)
# Track the entries in the feeds being fetched
entry_queue = Queue.Queue()
storage = dj_cache
# Start a few worker threads
worker_threads = []
for i in range(num_threads):
t = threading.Thread(target=fetch_urls,
args=(storage, url_queue, entry_queue,))
worker_threads.append(t)
t.setDaemon(True)
t.start()
# Start a thread to print the results
printer_thread = threading.Thread(target=print_entries, args=(force_update, entry_queue,))
printer_thread.setDaemon(True)
printer_thread.start()
# Wait for all of the URLs to be processed
url_queue.join()
# Wait for the worker threads to finish
for t in worker_threads:
t.join()
# Poison the print thread and wait for it to exit
entry_queue.put((None,None,))
entry_queue.join()
printer_thread.join()
# finally:
# storage.close()
return
def fetch_urls(storage, input_queue, output_queue):
"""Thread target for fetching feed data.
"""
c = cache.Cache(storage)
while True:
feed = input_queue.get()
if feed is None: # None causes thread to exit
print "--- Thread completed"
input_queue.task_done()
break
feed_data = c.fetch(feed.feed_address)
output_queue.put( (feed, feed_data) )
input_queue.task_done()
return
def print_entries(force_update, input_queue):
"""Thread target for printing the contents of the feeds.
"""
while True:
feed, feed_data = input_queue.get()
if feed_data is None: # None causes thread to exist
input_queue.task_done()
break
print 'Fetched: %s' % (feed.feed_title)
feed.update(force_update, feed_data)
input_queue.task_done()
return