Newer
Older
import logging, threading
from typing import Any, Dict, Optional
from ._Driver import _Driver
from .DriverFactory import DriverFactory
from .Exceptions import DriverInstanceCacheTerminatedException
from .FilterFields import FilterFieldEnum
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
LOGGER = logging.getLogger(__name__)
class DriverInstanceCache:
def __init__(self, driver_factory : DriverFactory) -> None:
self._lock = threading.Lock()
self._terminate = threading.Event()
self._device_uuid__to__driver_instance : Dict[str, _Driver] = {}
self._driver_factory = driver_factory
def get(
self, device_uuid : str, filter_fields : Dict[FilterFieldEnum, Any] = {}, address : Optional[str] = None,
port : Optional[int] = None, settings : Dict[str, Any] = {}) -> _Driver:
if self._terminate.is_set():
raise DriverInstanceCacheTerminatedException()
filter_fields = {k.value:v for k,v in filter_fields.items()}
with self._lock:
driver_instance = self._device_uuid__to__driver_instance.get(device_uuid)
if driver_instance is not None: return driver_instance
if len(filter_fields) == 0: return None
MSG = 'Selecting driver for device({:s}) with filter_fields({:s})...'
LOGGER.info(MSG.format(str(device_uuid), str(filter_fields)))
driver_class = self._driver_factory.get_driver_class(**filter_fields)
MSG = 'Driver({:s}) selected for device({:s}) with filter_fields({:s})...'
LOGGER.info(MSG.format(str(driver_class.__name__), str(device_uuid), str(filter_fields)))
driver_instance : _Driver = driver_class(address, port, **settings)
self._device_uuid__to__driver_instance[device_uuid] = driver_instance
return driver_instance
def delete(self, device_uuid : str) -> None:
with self._lock:
device_driver = self._device_uuid__to__driver_instance.pop(device_uuid, None)
if device_driver is None: return
device_driver.Disconnect()
def terminate(self) -> None:
self._terminate.set()
with self._lock:
while len(self._device_uuid__to__driver_instance) > 0:
try:
device_uuid,device_driver = self._device_uuid__to__driver_instance.popitem()
device_driver.Disconnect()
except: # pylint: disable=bare-except
msg = 'Error disconnecting Driver({:s}) from device. Will retry later...'
LOGGER.exception(msg.format(device_uuid))
self._device_uuid__to__driver_instance[device_uuid] = device_driver