import time
from sys import stderr
from rx import create, interval
from rx.core import Observer
from rx.disposable import Disposable
from rx.operators import *
from rx.scheduler.scheduler import Scheduler
from rx.scheduler import ThreadPoolScheduler
from rx.subject import ReplaySubject
flow = ReplaySubject(None)
pool = ThreadPoolScheduler(1)
def on_well(e):
if e == "Well":
flow.on_next("E!")
flow.pipe(subscribe_on(pool), retry(3), do_action(on_next=on_well)).subscribe(
on_next=lambda s: print(s), on_error=lambda e: print(e, file=stderr))
while True:
flow.on_next("Hi")
time.sleep(1)
flow.on_next("Well")
time.sleep(1)
class DefaultInstanceManager(InstanceManager):
def __init__(self, namespace: str, use_repeaters=True, networks=[]):
super().__init__(namespace)
self.__networks = networks
self.__reachable_peers: Set[InstanceReference] = set()
self.__resource_subjects: Dict[bytes, ReplaySubject] = {}
self.__peer_subjects: Dict[InstanceReference, ReplaySubject] = {}
self.__has_aip_group_peers = ReplaySubject()
if (len(networks) == 0):
port = 5156
while True:
try:
network = IPv4("0.0.0.0", port)
self.__networks.append(network)
break
except Exception as e:
if (port >= 9000):
raise e
port += 1
self.__muxer = MX2()
for network in self.__networks:
network.bring_up()
self.__muxer.register_network(network)
self.__discoverer = AIP(self.__muxer)
self.__instance = self.__muxer.create_instance(self.namespace)
self.__transport = STP(self.__muxer, self.__instance)
self.__path_finder = RPP(self.__muxer, self.__discoverer)
self.__path_finder.add_instance(self.__instance.reference)
self.__instance.incoming_greeting.subscribe(self.__received_greeting)
self.__transport.incoming_stream.subscribe(self.__new_stream)
for network in self.__networks:
self.__discoverer.add_network(network)
self.__info = ApplicationInformation.from_instance(self.__instance)
# Add the application to the discoverer
self.__discoverer.add_application(self.__info).subscribe(
self.__new_aip_app_peer)
def establish_stream(self,
peer: InstanceReference,
*,
in_reply_to=None) -> Subject:
# Settle on a reply
reply = in_reply_to or b"\x00" * 16
# Ask the transport to establish a stream
return self.__transport.initialise_stream(peer, in_reply_to=reply)
def find_resource_peers(self, resource: bytes) -> Subject:
# Do we already have a subject for this query?
if (resource not in self.__resource_subjects):
# Create one
self.__resource_subjects[resource] = ReplaySubject()
# Prepeare function to make the resource request
def find_peers(has_group_peers):
# Create a query for the resource
query = self.__discoverer.find_application_resource(
self.__info, resource)
# Subscribe to the queries answer
query.answer.subscribe(
lambda x: self.__found_resource_instance(x, resource))
# When we are in a position to ask group peers, do it
self.__has_aip_group_peers.pipe(take(1)).subscribe(find_peers)
# Return the resource subject
return self.__resource_subjects[resource]
@property
def resources(self) -> Set[bytes]:
return self.__info.resources
def __new_aip_app_peer(self, instance):
# Query for application instances
self.__discoverer.find_application_instance(self.__info).subscribe(
self.__found_instance)
# We now have an AIP group peer
self.__has_aip_group_peers.on_next(True)
def __found_instance(self, instance_info: InstanceInformation):
# Is this peer already reachable?
if (instance_info.instance_reference in self.__reachable_peers):
# Don't harras it
return
# Inquire about the peer
subject = self.__muxer.inquire(self.__instance,
instance_info.instance_reference,
instance_info.connection_methods)
# Handle timeouts
subject.subscribe(on_error=lambda x: self.__greeting_timeout(
instance_info.instance_reference))
def __found_resource_instance(self, instance_info: InstanceInformation,
resource: bytes):
# Get the resource subject
resource_subject = self.__resource_subjects[resource]
# Get the instance subject
instance_subject = self.__get_instance_subject(
instance_info.instance_reference)
# Notify resource subject when instance subject is reachable
instance_subject.subscribe(resource_subject.on_next)
# Handle new instance
self.__found_instance(instance_info)
def __received_greeting(self, instance: InstanceReference):
# Have we already marked this instance as reachable
if (instance in self.__reachable_peers):
# Don't notify app again
return
# Add to reachable peers
self.__reachable_peers.add(instance)
# Notify instance subject
self.__get_instance_subject(instance).on_next(instance)
# Notify the app
self.new_peer.on_next(instance)
def __new_stream(self, stream):
# Notify app of new stream
self.new_stream.on_next(stream)
def __get_instance_subject(self, ref: InstanceReference) -> Subject:
# Do we have it?
if (ref in self.__peer_subjects):
# Yes
return self.__peer_subjects[ref]
# No, create it
subject = ReplaySubject()
self.__peer_subjects[ref] = subject
return subject
def __greeting_timeout(self, target: InstanceReference):
# Have we already found this peer?
if (target in self.__instance.reachable_peers
or not self.use_repeaters):
return
# Did not receive greeting from instance, ask for paths via repeaters
query = self.__path_finder.find_path(target)
def handle_route(paths):
# Have we already found this peer?
if (target in self.__instance.reachable_peers):
return
# We have a path, inquire
self.__muxer.inquire_via_paths(self.__instance, target, paths)
# Subscribe to answers
query.subscribe(handle_route)
class WorkQueue(object):
def __init__(self, concurrency_per_group, description=None):
self.scheduler = ThreadPoolScheduler(concurrency_per_group)
self._requests = Subject()
self._output = ReplaySubject()
self._description = description
self._subscription = self._requests.pipe(
group_by(lambda r: r['concurrency_group']),
flat_map(lambda concurrency_group: concurrency_group.pipe(
map(lambda r: r['request']),
merge(max_concurrent=concurrency_per_group)))).subscribe(
on_next=lambda request: self._output.on_next(request),
on_error=lambda error: logging.exception(
'Error in {} request stream'.format(self)),
on_completed=lambda: logging.error(
'{} request stream unexpectedly completed'.format(self
)),
scheduler=self.scheduler)
def enqueue(self,
observable: Observable,
group: str = None,
retries: int = 0,
description: str = None):
# Provide a function returning a callable?
description = description or str(Observable)
key = '{}({})'.format(description, random.random())
def log_status(status):
logging.debug(
str({
'WorkQueue': str(self),
'group': group,
'key': key,
status: description
}))
log_status('ENQUEUED')
error: Optional[Exception] = None
def handle_error(e):
log_status('FAILED')
nonlocal error
error = e
return of({'key': key, 'error': e})
def throw_if_error(request):
if error:
return throw(error)
else:
return of(request)
def extract_value(value):
if type(value) == Observable:
return value
else:
return of(value)
request = of(True).pipe(
do_action(lambda _: log_status('STARTED')),
flat_map(lambda _: observable.pipe(
flat_map(extract_value),
map(lambda value: {
'key': key,
'value': value
}),
retry_with_backoff(
retries=retries,
description='{}.enqueue(group={}, description={})'.format(
self, group, description)),
catch(handler=lambda e, o: handle_error(e)),
)),
concat(
of({
'key': key,
'complete': True
}).pipe(do_action(lambda _: log_status('COMPLETED')))))
result_stream = self._output.pipe(
filter(lambda request: request['key'] == key),
flat_map(lambda request: throw_if_error(request)),
take_while(lambda request: not request.get('complete')),
flat_map(lambda request: of(request.get('value'))))
self._requests.on_next({
'request': request,
'concurrency_group': group
})
return result_stream
def dispose(self):
if self._subscription:
self._subscription.dispose()
def __str__(self):
return 'WorkQueue({})'.format(
self._description) if self._description else super().__str__()
