def _fire_reply(self, message, reply_to):
"""
Tries to fire a reply to the given message
:param message: Message to send as a reply
:param reply_to: Message the first argument replies to
:return: The UID of the sent message
"""
# Use the message source peer
try:
transport = self._transports[reply_to.access]
except KeyError:
# Reception transport is not available anymore...
raise NoTransport(beans.Target(uid=reply_to.sender),
"No reply transport for access {0}"
.format(reply_to.access))
else:
# Try to get the Peer bean. If unknown, consider that the
# "extra" data will help the transport to reply
try:
peer = self._directory.get_peer(reply_to.sender)
except KeyError:
peer = None
try:
# Send the reply
transport.fire(peer, message, reply_to.extra)
except InvalidPeerAccess:
raise NoTransport(beans.Target(uid=reply_to.sender),
"Can't reply to {0} using {1} transport"
.format(peer, reply_to.access))
else:
# Reply sent. Stop here
return message.uid
def fire(self, target, message):
"""
Fires (and forget) the given message to the target
:param target: The UID of a Peer, or a Peer object
:param message: A Message bean
:return: The UID of the message sent
:raise KeyError: Unknown peer UID
:raise NoTransport: No transport found to send the message
"""
# Standard behavior
# Get the Peer object
if not isinstance(target, beans.Peer):
peer = self._directory.get_peer(target)
else:
peer = target
# Check if some transports are bound
if not self._transports:
raise NoTransport(beans.Target(uid=peer.uid),
"No transport bound yet.")
# Get accesses
accesses = peer.get_accesses()
for access in accesses:
try:
transport = self._transports[access]
except KeyError:
# No transport for this kind of access
pass
else:
try:
# Call it
transport.fire(peer, message)
except InvalidPeerAccess as ex:
# Transport can't read peer access data
_logger.debug("Error reading access for transport %s: %s",
access, ex)
except Exception as ex:
# Exception during transport
_logger.warning("Error using transport %s: %s", access, ex)
else:
# Success
break
else:
# No transport for those accesses
raise NoTransport(beans.Target(uid=peer.uid),
"No working transport found for peer {0}"
.format(peer))
return message.uid
def send(self, target, message, timeout=None):
"""
Sends a message, and waits for its reply
:param target: The UID of a Peer, or a Peer object
:param message: A Message bean
:param timeout: Maximum time to wait for an answer
:return: The reply message bean
:raise KeyError: Unknown peer UID
:raise NoTransport: No transport found to send the message
:raise NoListener: Message received, but nobody was registered to
listen to it
:raise HeraldTimeout: Timeout raised before getting an answer
"""
# Prepare an event, which will be set when the answer will be received
event = pelix.utilities.EventData()
self.__waiting_events[message.uid] = event
# Get the Peer object
if not isinstance(target, beans.Peer):
peer = self._directory.get_peer(target)
else:
peer = target
try:
# Fire the message
self.fire(peer, message)
# Message sent, wait for an answer
if event.wait(timeout):
if event.data is not None:
return event.data
else:
# Message cancelled due to invalidation
raise HeraldTimeout(beans.Target(uid=peer.uid),
"Herald stops listening to messages",
message)
else:
raise HeraldTimeout(beans.Target(uid=peer.uid),
"Timeout reached before receiving a reply",
message)
finally:
try:
# Clean up
del self.__waiting_events[message.uid]
except KeyError:
# Ignore errors at this point
pass
def fire(self, peer, message, extra=None):
"""
Fires a message to a peer
:param peer: A Peer bean
:param message: Message bean to send
:param extra: Extra information used in case of a reply
:raise InvalidPeerAccess: No information found to access the peer
:raise Exception: Error sending the request or on the server side
"""
# Get the request message UID, if any
parent_uid = None
if extra is not None:
parent_uid = extra.get('parent_uid')
# Try to read extra information
url = self.__get_access(peer, extra)
if not url:
# No HTTP access description
raise InvalidPeerAccess(beans.Target(uid=peer.uid),
"No '{0}' access found"
.format(self._access_id))
# Send the HTTP request (blocking) and raise an error if necessary
headers, content = self.__prepare_message(message, parent_uid)
response = self.__session.post(url, content, headers=headers)
response.raise_for_status()
def reply(self, message, content, subject=None):
"""
Replies to a message
:param message: Original message
:param content: Content of the response
:param subject: Reply message subject (same as request if None)
:raise NoTransport: No transport/access found to send the reply
"""
# Normalize subject. By default, add a 'reply' prefix,
# to avoid potential loops
if not subject:
subject = '/'.join(('reply', message.subject))
try:
# Try to reuse the same transport
self._fire_reply(beans.Message(subject, content), message)
except NoTransport:
# Continue...
pass
else:
# No error
return
# If not possible: fire a standard reply
try:
# Fire the reply
self.fire(message.sender, beans.Message(subject, content))
except KeyError:
# Convert KeyError to NoTransport
raise NoTransport(beans.Target(uid=message.sender),
"No access to reply to {0}"
.format(message.sender))
def _handle_error(self, message, kind):
"""
Handles an error message
:param message: MessageReceived bean, received from another peer
:param kind: Kind of error
"""
if kind == 'no-listener':
# No listener found for a given message
# ... release send() calls
try:
# Get the original message UID and Subject
uid = message.content['uid']
exception = NoListener(beans.Target(message.sender), uid,
message.content['subject'])
except KeyError:
# Invalid error content...
return
try:
# Unlock the poster with an exception
self.__waiting_events.pop(uid).raise_exception(exception)
except KeyError:
# Nobody was waiting for the event
pass
# ... notify post() callers
try:
self.__waiting_posts[uid].errback(self, exception)
except KeyError:
# No error callback for this message
pass
def fire(self, peer, message, extra=None):
"""
Fires a message to a peer
:param peer: A Peer bean
:param message: Message bean to send
:param extra: Extra information used in case of a reply
:raise InvalidPeerAccess: No information found to access the peer
:raise Exception: Error sending the request or on the server side
"""
# Get the request message UID, if any
parent_uid = None
if extra is not None:
parent_uid = extra.get('parent_uid')
# Try to read extra information
url = self.__get_access(peer, extra)
if not url:
# No HTTP access description
raise InvalidPeerAccess(
beans.Target(peer=peer),
"No '{0}' access found".format(self._access_id))
# Send the HTTP request (blocking) and raise an error if necessary
headers, content = self.__prepare_message(message,
parent_uid,
target_peer=peer)
# Log before sending
self._probe.store(
herald.PROBE_CHANNEL_MSG_SEND, {
"uid": message.uid,
"timestamp": time.time(),
"transport": ACCESS_ID,
"subject": message.subject,
"target": peer.uid if peer else "<unknown>",
"transportTarget": url,
"repliesTo": parent_uid or ""
})
self._probe.store(herald.PROBE_CHANNEL_MSG_CONTENT, {
"uid": message.uid,
"content": content
})
response = self.__post_message(url, content, headers)
if response is None:
# The error has been logged in post_message
raise IOError("Error sending message {0}".format(message.uid))
else:
# Raise an error if the status isn't 2XX
response.raise_for_status()
def fire(self, peer, message, extra=None):
"""
Fires a message to a peer
:param peer: A Peer bean
:param message: Message to send
:param extra: Extra information used in case of a reply
"""
# Get the request message UID, if any
parent_uid = None
if extra is not None:
parent_uid = extra.get('parent_uid')
# Try to read extra information
jid = self.__get_jid(peer, extra)
if jid:
# Log before sending
self._probe.store(
herald.PROBE_CHANNEL_MSG_SEND, {
"uid": message.uid,
"timestamp": time.time(),
"transport": ACCESS_ID,
"subject": message.subject,
"target": peer.uid if peer else "<unknown>",
"transportTarget": str(jid),
"repliesTo": parent_uid or ""
})
# Send the XMPP message
self.__send_message("chat",
jid,
message,
parent_uid,
target_peer=peer)
else:
# No XMPP access description
raise InvalidPeerAccess(
beans.Target(uid=peer.uid),
"No '{0}' access found".format(self._access_id))
def fire(self, peer, message, extra=None):
"""
Fires a message to a peer
:param peer: A Peer bean
:param message: Message to send
:param extra: Extra information used in case of a reply
"""
# Get the request message UID, if any
parent_uid = None
if extra is not None:
parent_uid = extra.get('parent_uid')
# Try to read extra information
jid = self.__get_jid(peer, extra)
if jid:
# Send the XMPP message
self.__send_message("chat", jid, message, parent_uid)
else:
# No XMPP access description
raise InvalidPeerAccess(
beans.Target(uid=peer.uid),
"No '{0}' access found".format(self._access_id))
def post_group(self, group, message, callback, errback,
timeout=180):
"""
Posts a message to a group of peers. The given methods will be called
back as soon as a result is given, or in case of error.
If no timeout is given, the message UID must be forgotten manually.
:param group: The name of a group of peers
:param message: A Message bean
:param callback: Method to call back when a reply is received
:param errback: Method to call back if an error occurs
:param timeout: Time after which the message will be forgotten
:return: The message UID
:raise KeyError: Unknown group
:raise NoTransport: No transport found to send the message
"""
# Get all peers known in the group
all_peers = self._directory.get_peers_for_group(group)
# Check if some transports are bound
if not self._transports:
raise NoTransport(
beans.Target(group=group,
uids=[peer.uid for peer in all_peers]),
"No transport bound yet.")
with self.__gc_lock:
# Prepare an entry in the waiting posts
self.__waiting_posts[message.uid] = \
_WaitingPost(callback, errback, timeout, False)
# Find the common accesses
accesses = {}
for peer in all_peers:
for access in peer.get_accesses():
accesses.setdefault(access, set()).add(peer)
for access, access_peers in accesses.items():
if not access_peers:
# Nothing to do
continue
try:
transport = self._transports[access]
except KeyError:
# No transport for this kind of access
pass
else:
try:
# Call it
transport.fire_group(group, access_peers, message)
except InvalidPeerAccess:
# Transport can't find group access data
pass
else:
# Success: clean up waiting peers
all_done = True
for remaining_peers in accesses.values():
remaining_peers.difference_update(access_peers)
if remaining_peers:
# Still some peers to notify
all_done = False
if all_done:
break
return message.uid
def fire_group(self, group, message):
"""
Fires (and forget) the given message to the given group of peers
:param group: The name of a group of peers
:param message: A Message bean
:return: A tuple: the UID of the message sent and the list of peers
:raise KeyError: Unknown group
:raise NoTransport: No transport found to send the message
"""
# Get all peers known in the group
all_peers = self._directory.get_peers_for_group(group)
if not all_peers:
_logger.warning("No peer in group %s", group)
return message.uid, set()
# Check if some transports are bound
if not self._transports:
raise NoTransport(
beans.Target(group=group,
uids=[peer.uid for peer in all_peers]),
"No transport bound yet.")
# Find the common accesses
accesses = {}
for peer in all_peers:
for access in peer.get_accesses():
accesses.setdefault(access, set()).add(peer)
missing = []
for access, access_peers in accesses.items():
if not access_peers:
# Nothing to do
continue
try:
transport = self._transports[access]
except KeyError:
# No transport for this kind of access
_logger.debug("No transport for %s", access)
else:
try:
# Call it
reached_peers = transport.fire_group(group, access_peers,
message)
if reached_peers is None:
reached_peers = access_peers
except InvalidPeerAccess as ex:
# Transport can't find group access data
_logger.debug("Missing access info: %s", ex)
else:
# Success: clean up waiting peers
all_done = True
for remaining_peers in accesses.values():
remaining_peers.difference_update(reached_peers)
if remaining_peers:
# Still some peers to notify
all_done = False
if all_done:
break
else:
missing = set(itertools.chain(*accesses.values()))
if missing:
_logger.warning("Some peers haven't been notified: %s",
', '.join(str(peer) for peer in missing))
else:
_logger.debug("No peer to send the message to.")
return message.uid, missing
