# -*- coding: utf-8 -*-
import os
from ._compat import exists
from ._globals import GLOBAL_LOCKER, THREAD_LOCAL
from .helpers.classes import UseDatabaseStoredFile
[docs]class ConnectionPool(object):
POOLS = {}
check_active_connection = True
@staticmethod
[docs] def set_folder(folder):
THREAD_LOCAL.folder = folder
[docs] def close(self, action='commit', really=True):
#: if we have an action (commit, rollback), try to execute it
succeeded = True
if action:
try:
if callable(action):
action(self)
else:
getattr(self, action)()
except:
#: connection had some problems, we want to drop it
succeeded = False
#: if we have pools, we should recycle the connection (but only when
# we succeded in `action`, if any and `len(pool)` is good)
if self.pool_size and succeeded:
GLOBAL_LOCKER.acquire()
pool = ConnectionPool.POOLS[self.uri]
if len(pool) < self.pool_size:
pool.append(self.connection)
really = False
GLOBAL_LOCKER.release()
#: closing the connection when we `really` want to, in particular:
# - when we had an exception running `action`
# - when we don't have pools
# - when we have pools but they're full
if really:
try:
self.close_connection()
except:
pass
#: always unset `connection` attribute
self.connection = None
@staticmethod
[docs] def close_all_instances(action):
""" to close cleanly databases in a multithreaded environment """
dbs = getattr(THREAD_LOCAL, 'db_instances', {}).items()
for db_uid, db_group in dbs:
for db in db_group:
if hasattr(db, '_adapter'):
db._adapter.close(action)
getattr(THREAD_LOCAL, 'db_instances', {}).clear()
getattr(THREAD_LOCAL, 'db_instances_zombie', {}).clear()
if callable(action):
action(None)
return
[docs] def find_or_make_work_folder(self):
#this actually does not make the folder. it has to be there
self.folder = getattr(THREAD_LOCAL, 'folder', '')
if os.path.isabs(self.folder) and \
isinstance(self, UseDatabaseStoredFile) and \
self.folder.startswith(os.getcwd()):
self.folder = os.path.relpath(self.folder, os.getcwd())
# Creating the folder if it does not exist
if False and self.folder and not exists(self.folder):
os.mkdir(self.folder)
[docs] def after_connection_hook(self):
"""Hook for the after_connection parameter"""
if callable(self._after_connection):
self._after_connection(self)
self.after_connection()
[docs] def after_connection(self):
#this it is supposed to be overloaded by adapters
pass
[docs] def reconnect(self, f=None, cursor=True):
"""
Defines: `self.connection` and `self.cursor`
(if cursor is True)
if `self.pool_size>0` it will try pull the connection from the pool
if the connection is not active (closed by db server) it will loop
if not `self.pool_size` or no active connections in pool makes a new one
"""
if getattr(self, 'connection', None) is not None:
return
if f is None:
f = self.connector
# if not hasattr(self, "driver") or self.driver is None:
# LOGGER.debug("Skipping connection since there's no driver")
# return
if not self.pool_size:
self.connection = f()
self.cursor = cursor and self.connection.cursor()
else:
uri = self.uri
POOLS = ConnectionPool.POOLS
while True:
GLOBAL_LOCKER.acquire()
if uri not in POOLS:
POOLS[uri] = []
if POOLS[uri]:
self.connection = POOLS[uri].pop()
GLOBAL_LOCKER.release()
self.cursor = cursor and self.connection.cursor()
try:
if self.cursor and self.check_active_connection:
self.execute(self.test_query)
break
except:
pass
else:
GLOBAL_LOCKER.release()
self.connection = f()
self.cursor = cursor and self.connection.cursor()
break
self.after_connection_hook()