modes_kml: fix case where KML generation thread dies
SQLite does not deal well with concurrency. Avoid database locked errors by synchronizing database access using a threading.Lock().
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@ -93,14 +93,14 @@ class modes_kml(threading.Thread, modes_output_sql):
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#read the database and add KML
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q = "select distinct icao from positions where seen > datetime('now', '-5 minute')"
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c = self._db.cursor()
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c.execute(q)
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self.locked_execute(c, q)
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icaolist = c.fetchall()
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#now we have a list icaolist of all ICAOs seen in the last 5 minutes
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for icao in icaolist:
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#print "ICAO: %x" % icao
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q = "select * from positions where icao=%i and seen > datetime('now', '-2 hour') ORDER BY seen DESC" % icao
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c.execute(q)
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self.locked_execute(c, q)
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track = c.fetchall()
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#print "Track length: %i" % len(track)
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if len(track) != 0:
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@ -128,7 +128,7 @@ class modes_kml(threading.Thread, modes_output_sql):
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#now get metadata
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q = "select ident from ident where icao=%i" % icao
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c.execute(q)
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self.locked_execute(c, q)
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r = c.fetchall()
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if len(r) != 0:
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ident = r[0][0]
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@ -136,7 +136,7 @@ class modes_kml(threading.Thread, modes_output_sql):
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#if ident is None: ident = ""
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#get most recent speed/heading/vertical
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q = "select seen, speed, heading, vertical from vectors where icao=%i order by seen desc limit 1" % icao
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c.execute(q)
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self.locked_execute(c, q)
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r = c.fetchall()
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if len(r) != 0:
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seen = r[0][0]
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@ -19,7 +19,7 @@
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# Boston, MA 02110-1301, USA.
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#
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import time, os, sys
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import time, os, sys, threading
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from string import split, join
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import modes_parse
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import sqlite3
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@ -28,6 +28,8 @@ from modes_exceptions import *
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class modes_output_sql(modes_parse.modes_parse):
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def __init__(self, mypos, filename):
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modes_parse.modes_parse.__init__(self, mypos)
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self._lock = threading.Lock()
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#create the database
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self.db = sqlite3.connect(filename)
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#now execute a schema to create the tables you need
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@ -39,7 +41,7 @@ class modes_output_sql(modes_parse.modes_parse):
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"lat" REAL,
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"lon" REAL
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);"""
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c.execute(query)
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self.locked_execute(c, query)
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query = """CREATE TABLE IF NOT EXISTS "vectors" (
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"icao" INTEGER KEY NOT NULL,
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"seen" TEXT NOT NULL,
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@ -47,26 +49,31 @@ class modes_output_sql(modes_parse.modes_parse):
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"heading" REAL,
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"vertical" REAL
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);"""
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c.execute(query)
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self.locked_execute(c, query)
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query = """CREATE TABLE IF NOT EXISTS "ident" (
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"icao" INTEGER PRIMARY KEY NOT NULL,
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"ident" TEXT NOT NULL
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);"""
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c.execute(query)
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self.locked_execute(c, query)
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c.close()
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self.db.commit()
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def __del__(self):
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self.db.close()
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def locked_execute(self, c, query):
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with self._lock:
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c.execute(query)
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def output(self, message):
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try:
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query = self.make_insert_query(message)
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if query is not None:
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c = self.db.cursor()
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c.execute(query)
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c.close()
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self.db.commit()
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with self._lock:
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c = self.db.cursor()
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c.execute(query)
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c.close()
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self.db.commit()
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except ADSBError:
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pass
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