Make FLightDB threadsafe, version 2.3.3

radar/__init__.py

@@ -1,7 +1,7 @@
 from pkg_resources import get_distribution, DistributionNotFound
 import os.path
 
-VERSION = "2.3"
+VERSION = "2.3.3"
 
 try:
  _dist = get_distribution('spots')

radar/radar.py

@@ -159,6 +159,9 @@ class FlightDB:
  """
 
  def __init__(self, loc):
+ self.logger = logging.getLogger('spots.FlightDB')
+ self.lock = threading.Lock()
+
  location = os.path.expanduser(loc)
  self.loc = loc
  self.loc_bck = self.loc + ".1"
@@ -172,34 +175,46 @@ def __init__(self, loc):
  self.db = simplejson.load(open(self.loc, 'rb'))
  except simplejson.JSONDecodeError:
  try:
+ self.logger.info("Init, DB file corrupt, using backup")
  # Current file is corrupt, try to fallback to backup file
  self.db = simplejson.load(open(self.loc_bck, 'rb'))
  except simplejson.JSONDecodeError:
+ self.logger.info("Init, DB file and backup corrupt, need to reinitialize")
  # No joy, give up and re-initialize
  self.db = init_db
  else:
  self.db = init_db
  self.dump()
 
  def add(self, flight):
+ self.lock.acquire()
  if flight in self.db['flights']:
  self.db['flights'][flight] += 1
  else:
  self.db['flights'][flight] = 1
  self.db['total_cnt'] += 1
+ self.lock.release()
 
  def get_head(self):
- return {k: v for k, v in self.db.iteritems() if k in ('version', 'start_date', 'total_cnt')}
+ self.lock.acquire()
+ res = {k: v for k, v in self.db.iteritems() if k in ('version', 'start_date', 'total_cnt')}
+ self.lock.release()
+ return res
 
  def get_flights(self):
  # Return a sorted dictionary of flights, descending order
  # See https://stackoverflow.com/questions/613183/how-do-i-sort-a-dictionary-by-value
- return {'flights': sorted(self.db['flights'].items(), key=operator.itemgetter(1), reverse=True)}
+ self.lock.acquire()
+ res = {'flights': sorted(self.db['flights'].items(), key=operator.itemgetter(1), reverse=True)}
+ self.lock.release()
+ return res
 
  def dump(self):
  shutil.copy2(self.loc, self.loc_bck) # Make a backup
+ self.lock.acquire()
  with open(self.loc, 'wt') as f:
  simplejson.dump(self.db, f, skipkeys=True, indent=4*' ')
+ self.lock.release()
 
 
 class Radar(basic.ADSB, threading.Thread):
@@ -387,7 +402,7 @@ def _die(self):
  self.logger.info("Radar dying")
 
  if basic.ADSB.cfg_use_flight_db:
- self.flight_db.dump()
+ self._dump_flight_db()
  self.flight_timer.cancel()
  self.finished.set()
  self.blip_timer.cancel()