issue #159: tidy up service.py docstrings again.

pull/193/head
David Wilson 6 years ago
parent e2eac65347
commit c12ae16369

@ -78,16 +78,23 @@ class ContextService(mitogen.service.Service):
def __init__(self, *args, **kwargs):
super(ContextService, self).__init__(*args, **kwargs)
#: JoinPoint for context responses.
self._lock = threading.Lock()
#: Records the :meth:`get` result dict for successful calls, returned
#: for identical subsequent calls. Keyed by :meth:`key_from_kwargs`.
self._response_by_key = {}
#: List of :class:`mitogen.core.Message` waiting for the result dict
#: for a particular connection config. Keyed as sbove.
self._waiters_by_key = {}
#: Active context count.
#: Mapping of :class:`mitogen.core.Context` -> reference count. Each
#: call to :meth:`get` increases this by one. Calls to :meth:`put`
#: decrease it by one.
self._refs_by_context = {}
#: List of contexts in creation order by via= parameter.
self._lru_by_via = {}
#: (method_name, kwargs) pairs by Conetxt
self._cfg_by_context = {}
#: List of contexts in creation order by via= parameter. When
#: :attr:`max_interpreters` is reached, the most recently used context
#: is destroyed to make room for any additional context.
self._update_lru_by_via = {}
#: :meth:`key_from_kwargs` result by Context.
self._key_by_context = {}
@mitogen.service.expose(mitogen.service.AllowParents())
@mitogen.service.arg_spec({
@ -111,6 +118,17 @@ class ContextService(mitogen.service.Service):
return pprint.pformat(kwargs)
def _produce_response(self, key, response):
"""
Reply to every waiting request matching a configuration key with a
response dictionary, deleting the list of waiters when done.
:param str key:
Result of :meth:`key_from_kwargs`
:param dict response:
Response dictionary
:returns:
Number of waiters that were replied to.
"""
self._lock.acquire()
try:
waiters = self._waiters_by_key.pop(key)
@ -121,13 +139,18 @@ class ContextService(mitogen.service.Service):
self._lock.release()
return count
def _lru(self, new_context, **kwargs):
def _update_lru(self, new_context, **kwargs):
"""
Update the LRU ("MRU"?) list associated with the connection described
by `kwargs`, destroying the most recently created context if the list
is full. Finally add `new_context` to the list.
"""
via = kwargs.get('via')
if via is None:
# We don't have a limit on the number of directly connections.
return
lru = self._lru_by_via.setdefault(via, [])
lru = self._update_lru_by_via.setdefault(via, [])
if len(lru) < self.max_interpreters:
lru.append(new_context)
return
@ -143,20 +166,44 @@ class ContextService(mitogen.service.Service):
LOG.info('%r._discard_one(): shutting down %r', self, context)
context.shutdown()
method_name, kwargs = self._cfg_by_context[context]
key = self.key_from_kwargs(method_name=method_name, **kwargs)
key = self._key_by_context[context]
self._lock.acquire()
try:
del self._response_by_key[key]
del self._refs_by_context[context]
del self._cfg_by_context[context]
del self._key_by_context[context]
lru.remove(context)
lru.append(new_context)
finally:
self._lock.release()
def _connect(self, method_name, **kwargs):
def _connect(self, key, method_name, **kwargs):
"""
Actual connect implementation. Arranges for the Mitogen connection to
be created and enqueues an asynchronous call to start the forked task
parent in the remote context.
:param key:
Deduplication key representing the connection configuration.
:param method_name:
:class:`mitogen.parent.Router` method implementing the connection
type.
:param kwargs:
Keyword arguments passed to the router method.
:returns:
Dict like::
{
'context': mitogen.core.Context or None,
'home_dir': str or None,
'msg': str or None
}
Where either `msg` is an error message and the remaining fields are
:data:`None`, or `msg` is :data:`None` and the remaining fields are
set.
"""
method = getattr(self.router, method_name, None)
if method is None:
raise Error('no such Router method: %s' % (method_name,))
@ -171,13 +218,13 @@ class ContextService(mitogen.service.Service):
}
if kwargs.get('via'):
self._lru(context, method_name=method_name, **kwargs)
self._update_lru(context, method_name=method_name, **kwargs)
home_dir = context.call(os.path.expanduser, '~')
# We don't need to wait for the result of this. Ideally we'd check its
# return value somewhere, but logs will catch a failure anyway.
context.call_async(ansible_mitogen.target.start_fork_parent)
self._cfg_by_context[context] = (method_name, kwargs)
self._key_by_context[context] = key
self._refs_by_context[context] = 0
return {
'context': context,
@ -222,13 +269,14 @@ class ContextService(mitogen.service.Service):
finally:
self._lock.release()
# I'm the first thread to wait on a result, so I will create the
# connection.
# I'm the first thread to wait, so I will create the connection.
try:
response = self._connect(**kwargs)
response = self._connect(key, **kwargs)
count = self._produce_response(key, response)
if response['msg'] is None:
# Only record the response for non-error results.
self._response_by_key[key] = response
# Set the reference count to the number of waiters.
self._refs_by_context[response['context']] += count
except mitogen.core.CallError:
e = sys.exc_info()[1]

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