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Handle device closing a bit more sensibly

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This commit is contained in:
Joel Collins 2019-07-16 14:39:08 +01:00
parent 769a260e0b
commit 2a7362b5e6
1 changed files with 28 additions and 19 deletions
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47
openflexure_microscope/stage/sangaboard/extensible_serial_instrument.py
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@ -26,8 +26,8 @@ from serial import PARITY_NONE, PARITY_EVEN, PARITY_ODD, PARITY_MARK, PARITY_SPA
from serial import STOPBITS_ONE, STOPBITS_ONE_POINT_FIVE, STOPBITS_TWO from serial import STOPBITS_ONE, STOPBITS_ONE_POINT_FIVE, STOPBITS_TWO
import io import io
import time import time
import warnings
import logging import logging
import warnings
class ExtensibleSerialInstrument(object): class ExtensibleSerialInstrument(object):
""" """
@ -83,29 +83,39 @@ class ExtensibleSerialInstrument(object):
#be set to 1 byte for maximum responsiveness. #be set to 1 byte for maximum responsiveness.
assert self.test_communications(), "The instrument doesn't seem to be responding. Did you specify the right port?" assert self.test_communications(), "The instrument doesn't seem to be responding. Did you specify the right port?"
def close(self): def close_serial_communications(self):
"""Release the serial port""" """
logging.debug("Closing serial connection") Close communication to the serial device. No exception handling.
"""
with self.communications_lock: with self.communications_lock:
try: self._ser.close()
self._ser.close()
except Exception as e: def close(self):
logging.warning("The serial port didn't close cleanly:", e) """Cleanly close the device. Includes proper logging statements."""
logging.debug("Closing serial connection")
try:
self.close_serial_communications()
except Exception as e:
logging.warning("The serial port didn't close cleanly: {}".format(e))
logging.debug("Connection closed") logging.debug("Connection closed")
def __del__(self): def __del__(self):
"""Close the port when the object is deleted """Emergency close the device. Try to avoid having to use this."""
if hasattr(self, '_ser') and self._ser.isOpen():
NB if the object is created in a with statement, this will cause print(
the port to be closed at the end of the with block.""" "Closing an open serial communication has been triggered by garbage collection!\n"\
self.close() "Please close this device more sensibly in future.")
try:
self.close_serial_communications()
except Exception as e:
print("The serial port didn't close cleanly: {}".format(e))
def __enter__(self): def __enter__(self):
return self return self
def __exit__(self, type, value, traceback): def __exit__(self, type, value, traceback):
"""Close down the instrument. This happens in __del__ though.""" """Cleanly close down the instrument at end of a with block."""
pass self.close()
def write(self,query_string): def write(self,query_string):
"""Write a string to the serial port""" """Write a string to the serial port"""
@ -234,7 +244,7 @@ class ExtensibleSerialInstrument(object):
reply = self.readline().strip() reply = self.readline().strip()
res=re.search(response_regex, reply, flags=re_flags) res=re.search(response_regex, reply, flags=re_flags)
if res is not None: if res is not None:
warnings.warn("Query suceeded after initially receieving unmatched response ('%s') to '%s'. Match pattern /%s/ (generated regex /%s/)"%(original_reply, query_string, response_string, response_regex),RuntimeWarning) warnings.warn("Query suceeded after initially receieving unmatched response ('%s') to '%s'. Match pattern /%s/ (generated regex /%s/)"%(original_reply, query_string, response_string, response_regex), RuntimeWarning)
else: else:
raise ValueError("Stage response to '%s' ('%s') wasn't matched by /%s/ (generated regex /%s/)" % (query_string, original_reply, response_string, response_regex)) raise ValueError("Stage response to '%s' ('%s') wasn't matched by /%s/ (generated regex /%s/)" % (query_string, original_reply, response_string, response_regex))
try: try:
@ -244,9 +254,8 @@ class ExtensibleSerialInstrument(object):
else: else:
return parsed_result return parsed_result
except ValueError: except ValueError:
logging.error("Parsing Error") logging.info("Matched Groups: {}".format(res.groups()))
logging.info("Matched Groups:", res.groups()) logging.info("Parsing Functions {}:".format(parse_function))
logging.info("Parsing Functions:", parse_function)
raise ValueError("Stage response to %s ('%s') couldn't be parsed by the supplied function" % (query_string, reply)) raise ValueError("Stage response to %s ('%s') couldn't be parsed by the supplied function" % (query_string, reply))
def int_query(self, query_string, **kwargs): def int_query(self, query_string, **kwargs):
"""Perform a query and return the result(s) as integer(s) (see parsedQuery)""" """Perform a query and return the result(s) as integer(s) (see parsedQuery)"""