The get_entities_changed function was changed to return all changed
entities since the given stream position, rather than only those changed
from a given list of entities. This resulted in the function incorrectly
returning large numbers of entities that, for example, caused large
increases in database usage.
parse_integer and parse_string can take a request and raise errors
in case we have wrong or missing params.
This PR tries to use them more to deduplicate some code and make it
better readable
The stream cache keeps track of all entities that have changed since
a particular stream position, so get_entities_changed does not need to
return unknown entites when given a larger stream position.
This makes it consistent with the behaviour of has_entity_changed.
This line shows up as about 5% of cpu time on a synchrotron:
not_known_entities = set(entities) - set(self._entity_to_key)
Presumably the problem here is that _entity_to_key can be largeish, and
building a set for its keys every time this function is called is slow.
Here we rewrite the logic to avoid building so many sets.
We need to do a bit more validation when we get a server name, but don't want
to be re-doing it all over the shop, so factor out a separate
parse_and_validate_server_name, and do the extra validation.
Also, use it to verify the server name in the config file.
Make sure that server_names used in auth headers are sane, and reject them with
a sensible error code, before they disappear off into the depths of the system.
otherwise we explode with:
```
Traceback (most recent call last):
File /usr/lib/python2.7/logging/handlers.py, line 78, in emit
logging.FileHandler.emit(self, record)
File /usr/lib/python2.7/logging/__init__.py, line 950, in emit
StreamHandler.emit(self, record)
File /usr/lib/python2.7/logging/__init__.py, line 887, in emit
self.handleError(record)
File /usr/lib/python2.7/logging/__init__.py, line 810, in handleError
None, sys.stderr)
File /usr/lib/python2.7/traceback.py, line 124, in print_exception
_print(file, 'Traceback (most recent call last):')
File /usr/lib/python2.7/traceback.py, line 13, in _print
file.write(str+terminator)
File /home/matrix/.synapse/local/lib/python2.7/site-packages/twisted/logger/_io.py, line 170, in write
self.log.emit(self.level, format=u{log_io}, log_io=line)
File /home/matrix/.synapse/local/lib/python2.7/site-packages/twisted/logger/_logger.py, line 144, in emit
self.observer(event)
File /home/matrix/.synapse/local/lib/python2.7/site-packages/twisted/logger/_observer.py, line 136, in __call__
errorLogger = self._errorLoggerForObserver(brokenObserver)
File /home/matrix/.synapse/local/lib/python2.7/site-packages/twisted/logger/_observer.py, line 156, in _errorLoggerForObserver
if obs is not observer
File /home/matrix/.synapse/local/lib/python2.7/site-packages/twisted/logger/_observer.py, line 81, in __init__
self.log = Logger(observer=self)
File /home/matrix/.synapse/local/lib/python2.7/site-packages/twisted/logger/_logger.py, line 64, in __init__
namespace = self._namespaceFromCallingContext()
File /home/matrix/.synapse/local/lib/python2.7/site-packages/twisted/logger/_logger.py, line 42, in _namespaceFromCallingContext
return currentframe(2).f_globals[__name__]
File /home/matrix/.synapse/local/lib/python2.7/site-packages/twisted/python/compat.py, line 93, in currentframe
for x in range(n + 1):
RuntimeError: maximum recursion depth exceeded while calling a Python object
Logged from file site.py, line 129
File /usr/lib/python2.7/logging/__init__.py, line 859, in emit
msg = self.format(record)
File /usr/lib/python2.7/logging/__init__.py, line 732, in format
return fmt.format(record)
File /usr/lib/python2.7/logging/__init__.py, line 471, in format
record.message = record.getMessage()
File /usr/lib/python2.7/logging/__init__.py, line 335, in getMessage
msg = msg % self.args
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 4: ordinal not in range(128)
Logged from file site.py, line 129
```
...where the logger apparently recurses whilst trying to log the error, hitting the
maximum recursion depth and killing everything badly.
