forked from borgmatic-collective/borgmatic
92 lines
2.6 KiB
Python
92 lines
2.6 KiB
Python
import logging
|
|
|
|
PAYLOAD_TRUNCATION_INDICATOR = '...\n'
|
|
|
|
|
|
class Forgetful_buffering_handler(logging.Handler):
|
|
'''
|
|
A buffering log handler that stores log messages in memory, and throws away messages (oldest
|
|
first) once a particular capacity in bytes is reached. But if the given byte capacity is zero,
|
|
don't throw away any messages.
|
|
|
|
The given identifier is used to distinguish the instance of this handler used for one monitoring
|
|
hook from those instances used for other monitoring hooks.
|
|
'''
|
|
|
|
def __init__(self, identifier, byte_capacity, log_level):
|
|
super().__init__()
|
|
|
|
self.identifier = identifier
|
|
self.byte_capacity = byte_capacity
|
|
self.byte_count = 0
|
|
self.buffer = []
|
|
self.forgot = False
|
|
self.setLevel(log_level)
|
|
|
|
def emit(self, record):
|
|
message = record.getMessage() + '\n'
|
|
self.byte_count += len(message)
|
|
self.buffer.append(message)
|
|
|
|
if not self.byte_capacity:
|
|
return
|
|
|
|
while self.byte_count > self.byte_capacity and self.buffer:
|
|
self.byte_count -= len(self.buffer[0])
|
|
self.buffer.pop(0)
|
|
self.forgot = True
|
|
|
|
|
|
def add_handler(handler): # pragma: no cover
|
|
'''
|
|
Add the given handler to the global logger.
|
|
'''
|
|
logging.getLogger().addHandler(handler)
|
|
|
|
|
|
def get_handler(identifier):
|
|
'''
|
|
Given the identifier for an existing Forgetful_buffering_handler instance, return the handler.
|
|
|
|
Raise ValueError if the handler isn't found.
|
|
'''
|
|
try:
|
|
return next(
|
|
handler
|
|
for handler in logging.getLogger().handlers
|
|
if isinstance(handler, Forgetful_buffering_handler) and handler.identifier == identifier
|
|
)
|
|
except StopIteration:
|
|
raise ValueError(f'A buffering handler for {identifier} was not found')
|
|
|
|
|
|
def format_buffered_logs_for_payload(identifier):
|
|
'''
|
|
Get the handler previously added to the root logger, and slurp buffered logs out of it to
|
|
send to Healthchecks.
|
|
'''
|
|
try:
|
|
buffering_handler = get_handler(identifier)
|
|
except ValueError:
|
|
# No handler means no payload.
|
|
return ''
|
|
|
|
payload = ''.join(message for message in buffering_handler.buffer)
|
|
|
|
if buffering_handler.forgot:
|
|
return PAYLOAD_TRUNCATION_INDICATOR + payload
|
|
|
|
return payload
|
|
|
|
|
|
def remove_handler(identifier):
|
|
'''
|
|
Given the identifier for an existing Forgetful_buffering_handler instance, remove it.
|
|
'''
|
|
logger = logging.getLogger()
|
|
|
|
try:
|
|
logger.removeHandler(get_handler(identifier))
|
|
except ValueError:
|
|
pass
|