def test_cache_update(self):
c = Cache()
c["path"] = 2
c.apply_changes([[], {123: "test"}])
self.assertEqual("test", c[123])
with self.assertRaises(KeyError):
c["path"]
def __init__(self, name, sync_factory):
self.set_logger_name(name)
self.name = name
self.sync_factory = sync_factory
self.q = self.create_queue()
self._blocks = OrderedDict() # block_name -> Block
self._controllers = OrderedDict() # block_name -> Controller
self._block_state_cache = Cache()
self._recv_spawned = None
self._other_spawned = []
# lookup of all Subscribe requests, ordered to guarantee subscription
# notification ordering
# {Request.generate_key(): Subscribe}
self._subscriptions = OrderedDict()
self.comms = []
self._client_comms = OrderedDict() # client comms -> list of blocks
self._handle_functions = {
Post: self._forward_block_request,
Put: self._forward_block_request,
Get: self._handle_get,
Subscribe: self._handle_subscribe,
Unsubscribe: self._handle_unsubscribe,
BlockChanges: self._handle_block_changes,
BlockRespond: self._handle_block_respond,
BlockAdd: self._handle_block_add,
BlockList: self._handle_block_list,
AddSpawned: self._add_spawned,
}
self.create_process_block()
def __init__(self, process, _=None):
super(PvaServerComms, self).__init__(process)
self.name = "PvaServerComms"
self.set_logger_name(self.name)
self._lock = RLock()
self._current_id = 1
self._root_id = 0
self._blocklist = {}
self._cache = Cache()
self._server = None
self._endpoints = {}
self._cb = None
self._rpcs = {}
self._puts = {}
self._dead_rpcs = []
# Create the V4 PVA server object
self.create_pva_server()
# Add a thread for executing the V4 PVA server
self.add_spawn_function(self.start_pva_server)
# Set up the subscription for everything (root down)
request = Subscribe(None, self.q, [], True)
request.set_id(self._root_id)
self.process.q.put(request)
def test_cache_update(self):
c = Cache()
c["path"] = 2
c.apply_changes([[], {123:"test"}])
self.assertEqual("test", c[123])
with self.assertRaises(KeyError):
c["path"]
def __init__(self, name, sync_factory):
self.set_logger_name(name)
self.name = name
self.sync_factory = sync_factory
self.q = self.create_queue()
self._blocks = OrderedDict() # block_name -> Block
self._controllers = OrderedDict() # block_name -> Controller
self._block_state_cache = Cache()
self._recv_spawned = None
self._other_spawned = []
# lookup of all Subscribe requests, ordered to guarantee subscription
# notification ordering
# {Request.generate_key(): Subscribe}
self._subscriptions = OrderedDict()
self.comms = []
self._client_comms = OrderedDict() # client comms -> list of blocks
self._handle_functions = {
Post: self._forward_block_request,
Put: self._forward_block_request,
Get: self._handle_get,
Subscribe: self._handle_subscribe,
Unsubscribe: self._handle_unsubscribe,
BlockChanges: self._handle_block_changes,
BlockRespond: self._handle_block_respond,
BlockAdd: self._handle_block_add,
BlockList: self._handle_block_list,
AddSpawned: self._add_spawned,
}
self.create_process_block()
def __init__(self, name, sync_factory):
self.set_logger_name(name)
self.name = name
self.sync_factory = sync_factory
self.q = self.create_queue()
self._blocks = OrderedDict() # block name -> block
self._block_state_cache = Cache()
self._recv_spawned = None
self._other_spawned = []
self._subscriptions = []
self.comms = []
self._client_comms = OrderedDict() # client comms -> list of blocks
self._handle_functions = {
Post: self._forward_block_request,
Put: self._forward_block_request,
Get: self._handle_get,
Subscribe: self._handle_subscribe,
Unsubscribe: self._handle_unsubscribe,
BlockChanges: self._handle_block_changes,
BlockRespond: self._handle_block_respond,
BlockAdd: self._handle_block_add,
BlockList: self._handle_block_list,
}
self.create_process_block()
def __init__(self, name, sync_factory):
self.set_logger_name(name)
self.name = name
self.sync_factory = sync_factory
self.q = self.create_queue()
self._blocks = OrderedDict() # block name -> block
self._block_state_cache = Cache()
self._recv_spawned = None
self._other_spawned = []
self._subscriptions = OrderedDict() # block name -> list of subs
self._last_changes = OrderedDict() # block name -> list of changes
self._client_comms = OrderedDict() # client comms -> list of blocks
self._handle_functions = {
Post: self._forward_block_request,
Put: self._forward_block_request,
Get: self._handle_get,
Subscribe: self._handle_subscribe,
BlockNotify: self._handle_block_notify,
BlockChanged: self._handle_block_changed,
BlockRespond: self._handle_block_respond,
BlockAdd: self._handle_block_add,
BlockList: self._handle_block_list,
}
self.create_process_block()
def test_addition(self):
c = Cache()
c.apply_changes([["thing"], {1: 2}])
self.assertEqual(c["thing"][1], 2)
def test_deletion(self):
c = Cache()
c["path"] = 2
c.apply_changes([["path"]])
self.assertEqual(list(c), [])
class Process(Loggable):
"""Hosts a number of Blocks, distributing requests between them"""
def __init__(self, name, sync_factory):
self.set_logger_name(name)
self.name = name
self.sync_factory = sync_factory
self.q = self.create_queue()
self._blocks = OrderedDict() # block name -> block
self._block_state_cache = Cache()
self._recv_spawned = None
self._other_spawned = []
self._subscriptions = []
self.comms = []
self._client_comms = OrderedDict() # client comms -> list of blocks
self._handle_functions = {
Post: self._forward_block_request,
Put: self._forward_block_request,
Get: self._handle_get,
Subscribe: self._handle_subscribe,
Unsubscribe: self._handle_unsubscribe,
BlockChanges: self._handle_block_changes,
BlockRespond: self._handle_block_respond,
BlockAdd: self._handle_block_add,
BlockList: self._handle_block_list,
}
self.create_process_block()
def recv_loop(self):
"""Service self.q, distributing the requests to the right block"""
while True:
request = self.q.get()
self.log_debug("Received request %s", request)
if request is PROCESS_STOP:
# Got the sentinel, stop immediately
break
try:
self._handle_functions[type(request)](request)
except Exception as e: # pylint:disable=broad-except
self.log_exception("Exception while handling %s", request)
request.respond_with_error(str(e))
def add_comms(self, comms):
assert not self._recv_spawned, \
"Can't add comms when process has been started"
self.comms.append(comms)
def start(self):
"""Start the process going"""
self._recv_spawned = self.sync_factory.spawn(self.recv_loop)
for comms in self.comms:
comms.start()
def stop(self, timeout=None):
"""Stop the process and wait for it to finish
Args:
timeout (float): Maximum amount of time to wait for each spawned
process. None means forever
"""
assert self._recv_spawned, "Process not started"
self.q.put(PROCESS_STOP)
for comms in self.comms:
comms.stop()
# Wait for recv_loop to complete first
self._recv_spawned.wait(timeout=timeout)
# Now wait for anything it spawned to complete
for s in self._other_spawned:
s.wait(timeout=timeout)
def _forward_block_request(self, request):
"""Lookup target Block and spawn block.handle_request(request)
Args:
request (Request): The message that should be passed to the Block
"""
block_name = request.endpoint[0]
block = self._blocks[block_name]
self._other_spawned.append(
self.sync_factory.spawn(block.handle_request, request))
def create_queue(self):
"""
Create a queue using sync_factory object
Returns:
Queue: New queue
"""
return self.sync_factory.create_queue()
def create_lock(self):
"""
Create a lock using sync_factory object
Returns:
Lock: New lock
"""
return self.sync_factory.create_lock()
def spawn(self, function, *args, **kwargs):
"""Calls SyncFactory.spawn()"""
spawned = self.sync_factory.spawn(function, *args, **kwargs)
self._other_spawned.append(spawned)
return spawned
def get_client_comms(self, block_name):
for client_comms, blocks in list(self._client_comms.items()):
if block_name in blocks:
return client_comms
def create_process_block(self):
self.process_block = Block()
# TODO: add a meta here
children = OrderedDict()
children["blocks"] = StringArrayMeta(
description="Blocks hosted by this Process"
).make_attribute([])
children["remoteBlocks"] = StringArrayMeta(
description="Blocks reachable via ClientComms"
).make_attribute([])
self.process_block.replace_endpoints(children)
self.process_block.set_parent(self, self.name)
self.add_block(self.process_block)
def update_block_list(self, client_comms, blocks):
self.q.put(BlockList(client_comms=client_comms, blocks=blocks))
def _handle_block_list(self, request):
self._client_comms[request.client_comms] = request.blocks
remotes = []
for blocks in self._client_comms.values():
remotes += [b for b in blocks if b not in remotes]
self.process_block["remoteBlocks"].set_value(remotes)
def _handle_block_changes(self, request):
"""Update subscribers with changes and applies stored changes to the
cached structure"""
# update cached dict
self._block_state_cache.apply_changes(*request.changes)
for subscription in self._subscriptions:
endpoint = subscription.endpoint
# find stuff that's changed that is relevant to this subscriber
changes = []
for change in request.changes:
change_path = change[0]
# look for a change_path where the beginning matches the
# endpoint path, then strip away the matching part and add
# to the change set
i = 0
for (cp_element, ep_element) in zip(change_path, endpoint):
if cp_element != ep_element:
break
i += 1
else:
# change has matching path, so keep it
# but strip off the end point path
filtered_change = [change_path[i:]] + change[1:]
changes.append(filtered_change)
if len(changes) > 0:
if subscription.delta:
# respond with the filtered changes
subscription.respond_with_delta(changes)
else:
# respond with the structure of everything
# below the endpoint
d = self._block_state_cache.walk_path(endpoint)
subscription.respond_with_update(d)
def report_changes(self, *changes):
self.q.put(BlockChanges(changes=list(changes)))
def block_respond(self, response, response_queue):
self.q.put(BlockRespond(response, response_queue))
def _handle_block_respond(self, request):
"""Push the response to the required queue"""
request.response_queue.put(request.response)
def add_block(self, block):
"""Add a block to be hosted by this process
Args:
block (Block): The block to be added
"""
path = block.path_relative_to(self)
assert len(path) == 1, \
"Expected block %r to have %r as parent, got path %r" % \
(block, self, path)
name = path[0]
assert name not in self._blocks, \
"There is already a block called %r" % name
request = BlockAdd(block=block, name=name)
if self._recv_spawned:
# Started, so call in Process thread
self.q.put(request)
else:
# Not started yet so we are safe to add in this thread
self._handle_block_add(request)
def _handle_block_add(self, request):
"""Add a block to be hosted by this process"""
block = request.block
assert request.name not in self._blocks, \
"There is already a block called %r" % request.name
self._blocks[request.name] = block
change_request = BlockChanges([[[request.name], block.to_dict()]])
self._handle_block_changes(change_request)
# Regenerate list of blocks
self.process_block["blocks"].set_value(list(self._blocks))
def get_block(self, block_name):
try:
return self._blocks[block_name]
except KeyError:
controller = ClientController(block_name, self)
return controller.block
def _handle_subscribe(self, request):
"""Add a new subscriber and respond with the current
sub-structure state"""
self._subscriptions.append(request)
d = self._block_state_cache.walk_path(request.endpoint)
self.log_debug("Initial subscription value %s", d)
if request.delta:
request.respond_with_delta([[[], d]])
else:
request.respond_with_update(d)
def _handle_unsubscribe(self, request):
"""Remove a subscriber and respond with success or error"""
subs = [s for s in self._subscriptions if s.id == request.id]
# TODO: currently this will remove all subscriptions with a matching id
# there should only be one, we may want to warn if we see several
# Also, this should only filter by the queue/context, not sure
# which yet...
if len(subs) == 0:
request.respond_with_error(
"No subscription found for id %d" % request.id)
else:
self._subscriptions = \
[s for s in self._subscriptions if s.id != request.id]
request.respond_with_return()
def _handle_get(self, request):
d = self._block_state_cache.walk_path(request.endpoint)
request.respond_with_return(d)
def test_walk_path(self):
c = Cache()
c[1] = {2: {3: "end"}}
walked = c.walk_path([1, 2, 3])
self.assertEqual(walked, "end")
class Process(Loggable):
"""Hosts a number of Blocks, distributing requests between them"""
def __init__(self, name, sync_factory):
self.set_logger_name(name)
self.name = name
self.sync_factory = sync_factory
self.q = self.create_queue()
self._blocks = OrderedDict() # block_name -> Block
self._controllers = OrderedDict() # block_name -> Controller
self._block_state_cache = Cache()
self._recv_spawned = None
self._other_spawned = []
# lookup of all Subscribe requests, ordered to guarantee subscription
# notification ordering
# {Request.generate_key(): Subscribe}
self._subscriptions = OrderedDict()
self.comms = []
self._client_comms = OrderedDict() # client comms -> list of blocks
self._handle_functions = {
Post: self._forward_block_request,
Put: self._forward_block_request,
Get: self._handle_get,
Subscribe: self._handle_subscribe,
Unsubscribe: self._handle_unsubscribe,
BlockChanges: self._handle_block_changes,
BlockRespond: self._handle_block_respond,
BlockAdd: self._handle_block_add,
BlockList: self._handle_block_list,
AddSpawned: self._add_spawned,
}
self.create_process_block()
def recv_loop(self):
"""Service self.q, distributing the requests to the right block"""
while True:
request = self.q.get()
self.log_debug("Received request %s", request)
if request is PROCESS_STOP:
# Got the sentinel, stop immediately
break
try:
self._handle_functions[type(request)](request)
except Exception as e: # pylint:disable=broad-except
self.log_exception("Exception while handling %s", request)
try:
request.respond_with_error(str(e))
except Exception:
pass
def add_comms(self, comms):
assert not self._recv_spawned, \
"Can't add comms when process has been started"
self.comms.append(comms)
def start(self):
"""Start the process going"""
self._recv_spawned = self.sync_factory.spawn(self.recv_loop)
for comms in self.comms:
comms.start()
def stop(self, timeout=None):
"""Stop the process and wait for it to finish
Args:
timeout (float): Maximum amount of time to wait for each spawned
process. None means forever
"""
assert self._recv_spawned, "Process not started"
self.q.put(PROCESS_STOP)
for comms in self.comms:
comms.stop()
# Wait for recv_loop to complete first
self._recv_spawned.wait(timeout=timeout)
# Now wait for anything it spawned to complete
for s, _ in self._other_spawned:
s.wait(timeout=timeout)
# Garbage collect the syncfactory
del self.sync_factory
def _forward_block_request(self, request):
"""Lookup target Block and spawn block.handle_request(request)
Args:
request (Request): The message that should be passed to the Block
"""
block_name = request.endpoint[0]
block = self._blocks[block_name]
spawned = self.sync_factory.spawn(block.handle_request, request)
self._add_spawned(AddSpawned(spawned, block.handle_request))
def create_queue(self):
"""
Create a queue using sync_factory object
Returns:
Queue: New queue
"""
return self.sync_factory.create_queue()
def create_lock(self):
"""
Create a lock using sync_factory object
Returns:
New lock object
"""
return self.sync_factory.create_lock()
def spawn(self, function, *args, **kwargs):
"""Calls SyncFactory.spawn()"""
def catching_function():
try:
function(*args, **kwargs)
except Exception:
self.log_exception("Exception calling %s(*%s, **%s)", function,
args, kwargs)
raise
spawned = self.sync_factory.spawn(catching_function)
request = AddSpawned(spawned, function)
self.q.put(request)
return spawned
def _add_spawned(self, request):
spawned = self._other_spawned
self._other_spawned = []
spawned.append((request.spawned, request.function))
# Filter out the spawned that have completed to stop memory leaks
for sp, f in spawned:
if not sp.ready():
self._other_spawned.append((sp, f))
def get_client_comms(self, block_name):
for client_comms, blocks in list(self._client_comms.items()):
if block_name in blocks:
return client_comms
def create_process_block(self):
self.process_block = Block()
# TODO: add a meta here
children = OrderedDict()
children["blocks"] = StringArrayMeta(
description="Blocks hosted by this Process").make_attribute([])
children["remoteBlocks"] = StringArrayMeta(
description="Blocks reachable via ClientComms").make_attribute([])
self.process_block.replace_endpoints(children)
self.process_block.set_process_path(self, [self.name])
self.add_block(self.process_block, self)
def update_block_list(self, client_comms, blocks):
self.q.put(BlockList(client_comms=client_comms, blocks=blocks))
def _handle_block_list(self, request):
self._client_comms[request.client_comms] = request.blocks
remotes = []
for blocks in self._client_comms.values():
remotes += [b for b in blocks if b not in remotes]
self.process_block["remoteBlocks"].set_value(remotes)
def _handle_block_changes(self, request):
"""Update subscribers with changes and applies stored changes to the
cached structure"""
# update cached dict
subscription_changes = self._block_state_cache.apply_changes(
*request.changes)
# Send out the changes
for subscription, changes in subscription_changes.items():
if subscription.delta:
# respond with the filtered changes
subscription.respond_with_delta(changes)
else:
# respond with the structure of everything
# below the endpoint
d = self._block_state_cache.walk_path(subscription.endpoint)
subscription.respond_with_update(d)
def report_changes(self, *changes):
self.q.put(BlockChanges(changes=list(changes)))
def block_respond(self, response, response_queue):
self.q.put(BlockRespond(response, response_queue))
def _handle_block_respond(self, request):
"""Push the response to the required queue"""
request.response_queue.put(request.response)
def add_block(self, block, controller):
"""Add a block to be hosted by this process
Args:
block (Block): The block to be added
controller (Controller): Its controller
"""
path = block.process_path
assert len(path) == 1, \
"Expected block %r to have %r as parent, got path %r" % \
(block, self, path)
name = path[0]
assert name not in self._blocks, \
"There is already a block called %r" % name
request = BlockAdd(block=block, controller=controller, name=name)
if self._recv_spawned:
# Started, so call in Process thread
self.q.put(request)
else:
# Not started yet so we are safe to add in this thread
self._handle_block_add(request)
def _handle_block_add(self, request):
"""Add a block to be hosted by this process"""
assert request.name not in self._blocks, \
"There is already a block called %r" % request.name
self._blocks[request.name] = request.block
self._controllers[request.name] = request.controller
serialized = request.block.to_dict()
change_request = BlockChanges([[[request.name], serialized]])
self._handle_block_changes(change_request)
# Regenerate list of blocks
self.process_block["blocks"].set_value(list(self._blocks))
def get_block(self, block_name):
try:
return self._blocks[block_name]
except KeyError:
if block_name in self.process_block.remoteBlocks:
return self.make_client_block(block_name)
else:
raise
def make_client_block(self, block_name):
params = ClientController.MethodMeta.prepare_input_map(mri=block_name)
controller = ClientController(self, {}, params)
return controller.block
def get_controller(self, block_name):
return self._controllers[block_name]
def _handle_subscribe(self, request):
"""Add a new subscriber and respond with the current
sub-structure state"""
key = request.generate_key()
assert key not in self._subscriptions, \
"Subscription on %s already exists" % (key,)
self._subscriptions[key] = request
self._block_state_cache.add_subscriber(request, request.endpoint)
d = self._block_state_cache.walk_path(request.endpoint)
self.log_debug("Initial subscription value %s", d)
if request.delta:
request.respond_with_delta([[[], d]])
else:
request.respond_with_update(d)
def _handle_unsubscribe(self, request):
"""Remove a subscriber and respond with success or error"""
key = request.generate_key()
try:
subscription = self._subscriptions.pop(key)
except KeyError:
request.respond_with_error("No subscription found for %s" %
(key, ))
else:
self._block_state_cache.remove_subscriber(subscription,
subscription.endpoint)
request.respond_with_return()
def _handle_get(self, request):
d = self._block_state_cache.walk_path(request.endpoint)
request.respond_with_return(d)
class Process(Loggable):
"""Hosts a number of Blocks, distributing requests between them"""
def __init__(self, name, sync_factory):
self.set_logger_name(name)
self.name = name
self.sync_factory = sync_factory
self.q = self.create_queue()
self._blocks = OrderedDict() # block_name -> Block
self._controllers = OrderedDict() # block_name -> Controller
self._block_state_cache = Cache()
self._recv_spawned = None
self._other_spawned = []
# lookup of all Subscribe requests, ordered to guarantee subscription
# notification ordering
# {Request.generate_key(): Subscribe}
self._subscriptions = OrderedDict()
self.comms = []
self._client_comms = OrderedDict() # client comms -> list of blocks
self._handle_functions = {
Post: self._forward_block_request,
Put: self._forward_block_request,
Get: self._handle_get,
Subscribe: self._handle_subscribe,
Unsubscribe: self._handle_unsubscribe,
BlockChanges: self._handle_block_changes,
BlockRespond: self._handle_block_respond,
BlockAdd: self._handle_block_add,
BlockList: self._handle_block_list,
AddSpawned: self._add_spawned,
}
self.create_process_block()
def recv_loop(self):
"""Service self.q, distributing the requests to the right block"""
while True:
request = self.q.get()
self.log_debug("Received request %s", request)
if request is PROCESS_STOP:
# Got the sentinel, stop immediately
break
try:
self._handle_functions[type(request)](request)
except Exception as e: # pylint:disable=broad-except
self.log_exception("Exception while handling %s", request)
try:
request.respond_with_error(str(e))
except Exception:
pass
def add_comms(self, comms):
assert not self._recv_spawned, \
"Can't add comms when process has been started"
self.comms.append(comms)
def start(self):
"""Start the process going"""
self._recv_spawned = self.sync_factory.spawn(self.recv_loop)
for comms in self.comms:
comms.start()
def stop(self, timeout=None):
"""Stop the process and wait for it to finish
Args:
timeout (float): Maximum amount of time to wait for each spawned
process. None means forever
"""
assert self._recv_spawned, "Process not started"
self.q.put(PROCESS_STOP)
for comms in self.comms:
comms.stop()
# Wait for recv_loop to complete first
self._recv_spawned.wait(timeout=timeout)
# Now wait for anything it spawned to complete
for s, _ in self._other_spawned:
s.wait(timeout=timeout)
# Garbage collect the syncfactory
del self.sync_factory
def _forward_block_request(self, request):
"""Lookup target Block and spawn block.handle_request(request)
Args:
request (Request): The message that should be passed to the Block
"""
block_name = request.endpoint[0]
block = self._blocks[block_name]
spawned = self.sync_factory.spawn(block.handle_request, request)
self._add_spawned(AddSpawned(spawned, block.handle_request))
def create_queue(self):
"""
Create a queue using sync_factory object
Returns:
Queue: New queue
"""
return self.sync_factory.create_queue()
def create_lock(self):
"""
Create a lock using sync_factory object
Returns:
New lock object
"""
return self.sync_factory.create_lock()
def spawn(self, function, *args, **kwargs):
"""Calls SyncFactory.spawn()"""
def catching_function():
try:
function(*args, **kwargs)
except Exception:
self.log_exception(
"Exception calling %s(*%s, **%s)", function, args, kwargs)
raise
spawned = self.sync_factory.spawn(catching_function)
request = AddSpawned(spawned, function)
self.q.put(request)
return spawned
def _add_spawned(self, request):
spawned = self._other_spawned
self._other_spawned = []
spawned.append((request.spawned, request.function))
# Filter out the spawned that have completed to stop memory leaks
for sp, f in spawned:
if not sp.ready():
self._other_spawned.append((sp, f))
def get_client_comms(self, block_name):
for client_comms, blocks in list(self._client_comms.items()):
if block_name in blocks:
return client_comms
def create_process_block(self):
self.process_block = Block()
# TODO: add a meta here
children = OrderedDict()
children["blocks"] = StringArrayMeta(
description="Blocks hosted by this Process"
).make_attribute([])
children["remoteBlocks"] = StringArrayMeta(
description="Blocks reachable via ClientComms"
).make_attribute([])
self.process_block.replace_endpoints(children)
self.process_block.set_process_path(self, [self.name])
self.add_block(self.process_block, self)
def update_block_list(self, client_comms, blocks):
self.q.put(BlockList(client_comms=client_comms, blocks=blocks))
def _handle_block_list(self, request):
self._client_comms[request.client_comms] = request.blocks
remotes = []
for blocks in self._client_comms.values():
remotes += [b for b in blocks if b not in remotes]
self.process_block["remoteBlocks"].set_value(remotes)
def _handle_block_changes(self, request):
"""Update subscribers with changes and applies stored changes to the
cached structure"""
# update cached dict
subscription_changes = self._block_state_cache.apply_changes(
*request.changes)
# Send out the changes
for subscription, changes in subscription_changes.items():
if subscription.delta:
# respond with the filtered changes
subscription.respond_with_delta(changes)
else:
# respond with the structure of everything
# below the endpoint
d = self._block_state_cache.walk_path(subscription.endpoint)
subscription.respond_with_update(d)
def report_changes(self, *changes):
self.q.put(BlockChanges(changes=list(changes)))
def block_respond(self, response, response_queue):
self.q.put(BlockRespond(response, response_queue))
def _handle_block_respond(self, request):
"""Push the response to the required queue"""
request.response_queue.put(request.response)
def add_block(self, block, controller):
"""Add a block to be hosted by this process
Args:
block (Block): The block to be added
controller (Controller): Its controller
"""
path = block.process_path
assert len(path) == 1, \
"Expected block %r to have %r as parent, got path %r" % \
(block, self, path)
name = path[0]
assert name not in self._blocks, \
"There is already a block called %r" % name
request = BlockAdd(block=block, controller=controller, name=name)
if self._recv_spawned:
# Started, so call in Process thread
self.q.put(request)
else:
# Not started yet so we are safe to add in this thread
self._handle_block_add(request)
def _handle_block_add(self, request):
"""Add a block to be hosted by this process"""
assert request.name not in self._blocks, \
"There is already a block called %r" % request.name
self._blocks[request.name] = request.block
self._controllers[request.name] = request.controller
serialized = request.block.to_dict()
change_request = BlockChanges([[[request.name], serialized]])
self._handle_block_changes(change_request)
# Regenerate list of blocks
self.process_block["blocks"].set_value(list(self._blocks))
def get_block(self, block_name):
try:
return self._blocks[block_name]
except KeyError:
if block_name in self.process_block.remoteBlocks:
return self.make_client_block(block_name)
else:
raise
def make_client_block(self, block_name):
params = ClientController.MethodMeta.prepare_input_map(
mri=block_name)
controller = ClientController(self, {}, params)
return controller.block
def get_controller(self, block_name):
return self._controllers[block_name]
def _handle_subscribe(self, request):
"""Add a new subscriber and respond with the current
sub-structure state"""
key = request.generate_key()
assert key not in self._subscriptions, \
"Subscription on %s already exists" % (key,)
self._subscriptions[key] = request
self._block_state_cache.add_subscriber(request, request.endpoint)
d = self._block_state_cache.walk_path(request.endpoint)
self.log_debug("Initial subscription value %s", d)
if request.delta:
request.respond_with_delta([[[], d]])
else:
request.respond_with_update(d)
def _handle_unsubscribe(self, request):
"""Remove a subscriber and respond with success or error"""
key = request.generate_key()
try:
subscription = self._subscriptions.pop(key)
except KeyError:
request.respond_with_error(
"No subscription found for %s" % (key,))
else:
self._block_state_cache.remove_subscriber(
subscription, subscription.endpoint)
request.respond_with_return()
def _handle_get(self, request):
d = self._block_state_cache.walk_path(request.endpoint)
request.respond_with_return(d)
class Process(Loggable):
"""Hosts a number of Blocks, distributing requests between them"""
def __init__(self, name, sync_factory):
self.set_logger_name(name)
self.name = name
self.sync_factory = sync_factory
self.q = self.create_queue()
self._blocks = OrderedDict() # block name -> block
self._block_state_cache = Cache()
self._recv_spawned = None
self._other_spawned = []
self._subscriptions = OrderedDict() # block name -> list of subs
self._last_changes = OrderedDict() # block name -> list of changes
self._client_comms = OrderedDict() # client comms -> list of blocks
self._handle_functions = {
Post: self._forward_block_request,
Put: self._forward_block_request,
Get: self._handle_get,
Subscribe: self._handle_subscribe,
BlockNotify: self._handle_block_notify,
BlockChanged: self._handle_block_changed,
BlockRespond: self._handle_block_respond,
BlockAdd: self._handle_block_add,
BlockList: self._handle_block_list,
}
self.create_process_block()
def recv_loop(self):
"""Service self.q, distributing the requests to the right block"""
while True:
request = self.q.get()
self.log_debug("Received request %s", request)
if request is PROCESS_STOP:
# Got the sentinel, stop immediately
break
try:
self._handle_functions[type(request)](request)
except Exception:
self.log_exception("Exception while handling %s", request)
def start(self):
"""Start the process going"""
self._recv_spawned = self.sync_factory.spawn(self.recv_loop)
def stop(self, timeout=None):
"""Stop the process and wait for it to finish
Args:
timeout (float): Maximum amount of time to wait for each spawned
process. None means forever
"""
assert self._recv_spawned, "Process not started"
self.q.put(PROCESS_STOP)
# Wait for recv_loop to complete first
self._recv_spawned.wait(timeout=timeout)
# Now wait for anything it spawned to complete
for s in self._other_spawned:
s.wait(timeout=timeout)
def _forward_block_request(self, request):
"""Lookup target Block and spawn block.handle_request(request)
Args:
request (Request): The message that should be passed to the Block
"""
block_name = request.endpoint[0]
block = self._blocks[block_name]
self._other_spawned.append(
self.sync_factory.spawn(block.handle_request, request))
def create_queue(self):
"""
Create a queue using sync_factory object
Returns:
Queue: New queue
"""
return self.sync_factory.create_queue()
def create_lock(self):
"""
Create a lock using sync_factory object
Returns:
Lock: New lock
"""
return self.sync_factory.create_lock()
def spawn(self, function, *args, **kwargs):
"""Calls SyncFactory.spawn()"""
spawned = self.sync_factory.spawn(function, *args, **kwargs)
self._other_spawned.append(spawned)
return spawned
def get_client_comms(self, block_name):
for client_comms, blocks in list(self._client_comms.items()):
if block_name in blocks:
return client_comms
def create_process_block(self):
self.process_block = Block()
a = Attribute(
StringArrayMeta(description="Blocks hosted by this Process"))
self.process_block.add_attribute("blocks", a)
a = Attribute(
StringArrayMeta(description="Blocks reachable via ClientComms"))
self.process_block.add_attribute("remoteBlocks", a)
self.add_block(self.name, self.process_block)
def update_block_list(self, client_comms, blocks):
self.q.put(BlockList(client_comms=client_comms, blocks=blocks))
def _handle_block_list(self, request):
self._client_comms[request.client_comms] = request.blocks
remotes = []
for blocks in self._client_comms.values():
remotes += [b for b in blocks if b not in remotes]
self.process_block.remoteBlocks.set_value(remotes)
def notify_subscribers(self, block_name):
self.q.put(BlockNotify(name=block_name))
def _handle_block_notify(self, request):
"""Update subscribers with changes and applies stored changes to the
cached structure"""
# update cached dict
for delta in self._last_changes.setdefault(request.name, []):
self._block_state_cache.delta_update(delta)
for subscription in self._subscriptions.setdefault(request.name, []):
endpoint = subscription.endpoint
# find stuff that's changed that is relevant to this subscriber
changes = []
for change in self._last_changes[request.name]:
change_path = change[0]
# look for a change_path where the beginning matches the
# endpoint path, then strip away the matching part and add
# to the change set
i = 0
for (cp_element, ep_element) in zip(change_path, endpoint):
if cp_element != ep_element:
break
i += 1
else:
# change has matching path, so keep it
# but strip off the end point path
filtered_change = [change_path[i:]] + change[1:]
changes.append(filtered_change)
if len(changes) > 0:
if subscription.delta:
# respond with the filtered changes
response = Delta(subscription.id_, subscription.context,
changes)
else:
# respond with the structure of everything
# below the endpoint
d = self._block_state_cache.walk_path(endpoint)
response = Update(subscription.id_, subscription.context,
d)
self.log_debug("Responding to subscription %s", response)
subscription.response_queue.put(response)
self._last_changes[request.name] = []
def on_changed(self, change, notify=True):
self.q.put(BlockChanged(change=change))
if notify:
block_name = change[0][0]
self.notify_subscribers(block_name)
def _handle_block_changed(self, request):
"""Record changes to made to a block"""
# update changes
path = request.change[0]
block_changes = self._last_changes.setdefault(path[0], [])
block_changes.append(request.change)
def block_respond(self, response, response_queue):
self.q.put(BlockRespond(response, response_queue))
def _handle_block_respond(self, request):
"""Push the response to the required queue"""
request.response_queue.put(request.response)
def add_block(self, name, block):
"""Add a block to be hosted by this process
Args:
block (Block): The block to be added
"""
assert name not in self._blocks, \
"There is already a block called %s" % name
block.set_parent(self, name)
self.q.put(BlockAdd(block=block))
def _handle_block_add(self, request):
"""Add a block to be hosted by this process"""
block = request.block
assert block.name not in self._blocks, \
"There is already a block called %s" % block.name
self._blocks[block.name] = block
self._block_state_cache[block.name] = block.to_dict()
block.lock = self.create_lock()
# Regenerate list of blocks
self.process_block.blocks.set_value(list(self._blocks))
def _handle_subscribe(self, request):
"""Add a new subscriber and respond with the current
sub-structure state"""
subs = self._subscriptions.setdefault(request.endpoint[0], [])
subs.append(request)
d = self._block_state_cache.walk_path(request.endpoint)
self.log_debug("Initial subscription value %s", d)
if request.delta:
request.respond_with_delta([[[], d]])
else:
request.respond_with_update(d)
def _handle_get(self, request):
d = self._block_state_cache.walk_path(request.endpoint)
response = Return(request.id_, request.context, d)
request.response_queue.put(response)
def test_deletion(self):
c = Cache()
c[1] = 2
c.delta_update([[1]])
self.assertEqual(list(c), [])
def test_change(self):
c = Cache()
c[1] = 3
c.apply_changes([["path"], 4])
self.assertEqual(c["path"], 4)
def test_update_root_errors(self):
c = Cache()
self.assertRaises(AssertionError, c.delta_update, [[], 3])
class Process(Loggable):
"""Hosts a number of Blocks, distributing requests between them"""
def __init__(self, name, sync_factory):
self.set_logger_name(name)
self.name = name
self.sync_factory = sync_factory
self.q = self.create_queue()
self._blocks = OrderedDict() # block name -> block
self._block_state_cache = Cache()
self._recv_spawned = None
self._other_spawned = []
self._subscriptions = OrderedDict() # block name -> list of subs
self._last_changes = OrderedDict() # block name -> list of changes
self._client_comms = OrderedDict() # client comms -> list of blocks
self._handle_functions = {
Post: self._forward_block_request,
Put: self._forward_block_request,
Get: self._handle_get,
Subscribe: self._handle_subscribe,
BlockNotify: self._handle_block_notify,
BlockChanged: self._handle_block_changed,
BlockRespond: self._handle_block_respond,
BlockAdd: self._handle_block_add,
BlockList: self._handle_block_list,
}
self.create_process_block()
def recv_loop(self):
"""Service self.q, distributing the requests to the right block"""
while True:
request = self.q.get()
self.log_debug("Received request %s", request)
if request is PROCESS_STOP:
# Got the sentinel, stop immediately
break
try:
self._handle_functions[type(request)](request)
except Exception:
self.log_exception("Exception while handling %s", request)
def start(self):
"""Start the process going"""
self._recv_spawned = self.sync_factory.spawn(self.recv_loop)
def stop(self, timeout=None):
"""Stop the process and wait for it to finish
Args:
timeout (float): Maximum amount of time to wait for each spawned
process. None means forever
"""
assert self._recv_spawned, "Process not started"
self.q.put(PROCESS_STOP)
# Wait for recv_loop to complete first
self._recv_spawned.wait(timeout=timeout)
# Now wait for anything it spawned to complete
for s in self._other_spawned:
s.wait(timeout=timeout)
def _forward_block_request(self, request):
"""Lookup target Block and spawn block.handle_request(request)
Args:
request (Request): The message that should be passed to the Block
"""
block_name = request.endpoint[0]
block = self._blocks[block_name]
self._other_spawned.append(
self.sync_factory.spawn(block.handle_request, request))
def create_queue(self):
"""
Create a queue using sync_factory object
Returns:
Queue: New queue
"""
return self.sync_factory.create_queue()
def create_lock(self):
"""
Create a lock using sync_factory object
Returns:
Lock: New lock
"""
return self.sync_factory.create_lock()
def spawn(self, function, *args, **kwargs):
"""Calls SyncFactory.spawn()"""
spawned = self.sync_factory.spawn(function, *args, **kwargs)
self._other_spawned.append(spawned)
return spawned
def get_client_comms(self, block_name):
for client_comms, blocks in list(self._client_comms.items()):
if block_name in blocks:
return client_comms
def create_process_block(self):
self.process_block = Block()
a = Attribute(StringArrayMeta(
description="Blocks hosted by this Process"))
self.process_block.add_attribute("blocks", a)
a = Attribute(StringArrayMeta(
description="Blocks reachable via ClientComms"))
self.process_block.add_attribute("remoteBlocks", a)
self.add_block(self.name, self.process_block)
def update_block_list(self, client_comms, blocks):
self.q.put(BlockList(client_comms=client_comms, blocks=blocks))
def _handle_block_list(self, request):
self._client_comms[request.client_comms] = request.blocks
remotes = []
for blocks in self._client_comms.values():
remotes += [b for b in blocks if b not in remotes]
self.process_block.remoteBlocks.set_value(remotes)
def notify_subscribers(self, block_name):
self.q.put(BlockNotify(name=block_name))
def _handle_block_notify(self, request):
"""Update subscribers with changes and applies stored changes to the
cached structure"""
# update cached dict
for delta in self._last_changes.setdefault(request.name, []):
self._block_state_cache.delta_update(delta)
for subscription in self._subscriptions.setdefault(request.name, []):
endpoint = subscription.endpoint
# find stuff that's changed that is relevant to this subscriber
changes = []
for change in self._last_changes[request.name]:
change_path = change[0]
# look for a change_path where the beginning matches the
# endpoint path, then strip away the matching part and add
# to the change set
i = 0
for (cp_element, ep_element) in zip(change_path, endpoint):
if cp_element != ep_element:
break
i += 1
else:
# change has matching path, so keep it
# but strip off the end point path
filtered_change = [change_path[i:]] + change[1:]
changes.append(filtered_change)
if len(changes) > 0:
if subscription.delta:
# respond with the filtered changes
response = Delta(
subscription.id_, subscription.context, changes)
else:
# respond with the structure of everything
# below the endpoint
d = self._block_state_cache.walk_path(endpoint)
response = Update(
subscription.id_, subscription.context, d)
self.log_debug("Responding to subscription %s", response)
subscription.response_queue.put(response)
self._last_changes[request.name] = []
def on_changed(self, change, notify=True):
self.q.put(BlockChanged(change=change))
if notify:
block_name = change[0][0]
self.notify_subscribers(block_name)
def _handle_block_changed(self, request):
"""Record changes to made to a block"""
# update changes
path = request.change[0]
block_changes = self._last_changes.setdefault(path[0], [])
block_changes.append(request.change)
def block_respond(self, response, response_queue):
self.q.put(BlockRespond(response, response_queue))
def _handle_block_respond(self, request):
"""Push the response to the required queue"""
request.response_queue.put(request.response)
def add_block(self, name, block):
"""Add a block to be hosted by this process
Args:
block (Block): The block to be added
"""
assert name not in self._blocks, \
"There is already a block called %s" % name
block.set_parent(self, name)
self.q.put(BlockAdd(block=block))
def _handle_block_add(self, request):
"""Add a block to be hosted by this process"""
block = request.block
assert block.name not in self._blocks, \
"There is already a block called %s" % block.name
self._blocks[block.name] = block
self._block_state_cache[block.name] = block.to_dict()
block.lock = self.create_lock()
# Regenerate list of blocks
self.process_block.blocks.set_value(list(self._blocks))
def _handle_subscribe(self, request):
"""Add a new subscriber and respond with the current
sub-structure state"""
subs = self._subscriptions.setdefault(request.endpoint[0], [])
subs.append(request)
d = self._block_state_cache.walk_path(request.endpoint)
self.log_debug("Initial subscription value %s", d)
if request.delta:
request.respond_with_delta([[[], d]])
else:
request.respond_with_update(d)
def _handle_get(self, request):
d = self._block_state_cache.walk_path(request.endpoint)
response = Return(request.id_, request.context, d)
request.response_queue.put(response)
def test_change(self):
c = Cache()
c[1] = 3
c.delta_update([[1], 4])
self.assertEqual(c[1], 4)
def test_deletion(self):
c = Cache()
c[1] = 2
c.delta_update([[1]])
self.assertEqual(list(c), [])
def test_addition(self):
c = Cache()
c.delta_update([["thing"], {1: 2}])
self.assertEqual(c["thing"][1], 2)
class PvaServerComms(ServerComms, PvaUtil):
"""A class for communication between pva client and server"""
CACHE_UPDATE = 0
def __init__(self, process, _=None):
super(PvaServerComms, self).__init__(process)
self.name = "PvaServerComms"
self.set_logger_name(self.name)
self._lock = RLock()
self._current_id = 1
self._root_id = 0
self._blocklist = {}
self._cache = Cache()
self._server = None
self._endpoints = {}
self._cb = None
self._rpcs = {}
self._puts = {}
self._dead_rpcs = []
# Create the V4 PVA server object
self.create_pva_server()
# Add a thread for executing the V4 PVA server
self.add_spawn_function(self.start_pva_server)
# Set up the subscription for everything (root down)
request = Subscribe(None, self.q, [], True)
request.set_id(self._root_id)
self.process.q.put(request)
def _get_unique_id(self):
with self._lock:
self._current_id += 1
return self._current_id
def _update_block_list(self):
with self._lock:
old_blocks = self._blocklist.copy()
for name in self._cache:
if name in self._blocklist:
old_blocks.pop(name)
else:
# New block, so create the new Pva endpoint
self.log_debug("Adding malcolm block to PVA list: %s", name)
self._blocklist[name] = self._get_unique_id()
self._add_new_pva_channel(name)
# Now loop over any remaining old blocks and remove their subscriptions
for name in old_blocks:
self.log_debug("Removing stale malcolm block: %s", name)
def _update_cache(self, response):
if response.changes:
self.log_debug("Update received: %s", response.changes)
self._cache.apply_changes(*response.changes)
# Update the block list to create new PVA channels if required
self._update_block_list()
def send_to_client(self, response):
"""Abstract method to dispatch response to a client
Args:
response (Response): The message to pass to the client
"""
if isinstance(response, Return):
# Notify RPC of return value
self.log_debug("Response: %s", response)
if response["id"] in self._rpcs:
self._rpcs[response["id"]].notify_reply(response)
elif response["id"] in self._puts:
self._puts[response["id"]].notify_reply(response)
elif isinstance(response, Error):
# Notify RPC of error value
self.log_debug("Response: %s", response)
if response["id"] in self._rpcs:
self._rpcs[response["id"]].notify_reply(response)
elif response["id"] in self._puts:
self._puts[response["id"]].notify_reply(response)
else:
# Update the cache
self._update_cache(response)
def _add_new_pva_channel(self, block):
"""Create a new PVA endpoint for the block name
Args:
name (str): The name of the block to create the PVA endpoint for
"""
self.log_debug("Creating PVA endpoint for %s", block)
self._endpoints[block] = PvaEndpoint(self.name, block, self._server, self)
def create_pva_server(self):
#self.log_debug("Creating PVA server object")
self._server = pvaccess.PvaServer()
def start_pva_server(self):
self.log_debug("Starting PVA server")
#self._server.listen()
self._server.startListener()
def stop_pva_server(self):
self.log_debug("Executing stop PVA server")
self._server.stop()
def register_rpc(self, id, rpc):
with self._lock:
self.log_debug("Registering RPC object with ID %d", id)
self._rpcs[id] = rpc
def register_put(self, id, put):
with self._lock:
self.log_debug("Registering Put object with ID %d", id)
self._puts[id] = put
def remove_put(self, id):
with self._lock:
self.log_debug("Removing Put object with ID %d", id)
if id in self._puts:
if self._puts[id].check_lock():
self._puts.pop(id, None)
def register_dead_rpc(self, id):
with self._lock:
self.log_debug("Notifying server that RPC [%d] can be tested for purging", id)
self._dead_rpcs.append(id)
def purge_rpcs(self):
with self._lock:
rpc_list = list(self._dead_rpcs)
for id in rpc_list:
self.log_debug("Testing for purge RPC [%d]", id)
if id in self._rpcs:
if self._rpcs[id].check_lock():
# We've gained the lock, so we are OK to purge this RPC
self.log_debug("Purging dead RPC [%d]", id)
self._rpcs.pop(id, None)
self._dead_rpcs.remove(id)
else:
self.log_debug("RPC [%d] was not present (already purged?)", id)
if id in self._dead_rpcs:
self._dead_rpcs.remove(id)
def cache_to_pvobject(self, name, paths=None):
self.log_debug("Cache[%s]: %s", name, self._cache[name])
# Test parsing the cache to create the PV structure
try:
block = self._cache[name]
if not paths:
# No paths provided, so just return the whole block
pv_object = self.dict_to_pv_object(block)
else:
#self.log_debug("Path route: %s", paths)
# List of path lists provided
# Create empty dict to store the structure
path_dict = OrderedDict()
# Create empty dict to store the values
val_dict = OrderedDict()
# Loop over each path list
for path in paths:
# Insert the block name as the first endpoint (needed for walking cache)
path.insert(0, name)
# set pointer to structure dict
d = path_dict
# set pointer to value dict
v = val_dict
# set pointer to cache
t = self._cache
# Loop over each node in the path (except for the last)
for node in path[:-1]:
#self.log_debug("Node: %s", node)
# Update the cache pointer
t = t[node]
# Check if the structure for this node has already been created
if node not in d:
# No structure, so create it
d[node] = OrderedDict()
# Collect and assign the correct type for this structure
d[node]["typeid"] = t["typeid"]
# Update the structure pointer
d = d[node]
# Check if the value structure for this node has already been created
if node not in v:
# No value structure so create it
v[node] = OrderedDict()
# Update the value pointer
v = v[node]
# Walk the cache path and update the structure with the final element
d[path[-1]] = self._cache.walk_path(path)
# Walk the cache path and update the value with the final element
v[path[-1]] = self._cache.walk_path(path)
#self.log_debug("Walk path: %s", path)
#self.log_debug("Path dict: %s", path_dict)
# Create our PV object from the structure dict
pv_object = self.dict_to_pv_object_structure(path_dict[name])
# Set the value of the PV object from the value dict
pv_object.set(self.strip_type_id(val_dict[name]))
except:
raise
return pv_object
def get_request(self, block, request):
self.log_debug("Get request made with: %s", request)
try:
# We need to convert the request object into a set of paths
if "field" not in request:
pv_object = self.cache_to_pvobject(block)
else:
field_dict = request["field"]
if not field_dict:
# The whole block has been requested
self.log_debug("Complete block %s requested for pvget", block)
# Retrieve the entire block structure
pv_object = self.cache_to_pvobject(block)
else:
paths = self.dict_to_path(field_dict)
self.log_debug("Paths: %s", paths)
pv_object = self.cache_to_pvobject(block, paths)
except:
# There has been a failure, return an error object
err = Error(id_=1, message="Failed to retrieve endpoints")
response_dict = err.to_dict()
response_dict.pop("id")
pv_object = self.dict_to_pv_object(response_dict)
return pv_object
def dict_to_path(self, dict_in):
items = []
for item in dict_in:
if not dict_in[item]:
items.append([item])
else:
temp_list = self.dict_to_path(dict_in[item])
for temp_item in temp_list:
if isinstance(temp_item, list):
temp_item.insert(0, item)
items.append(temp_item)
else:
items.append([item, temp_item])
return items
def test_change(self):
c = Cache()
c[1] = 3
c.apply_changes([["path"], 4])
self.assertEqual(c["path"], 4)
def test_change(self):
c = Cache()
c[1] = 3
c.delta_update([[1], 4])
self.assertEqual(c[1], 4)
def test_non_string_path_errors(self):
c = Cache()
self.assertRaises(AssertionError, c.apply_changes, [[1], 3])
def test_addition(self):
c = Cache()
c.apply_changes([["thing"], {1: 2}])
self.assertEqual(c["thing"][1], 2)
def test_walk_path(self):
c = Cache()
c[1] = {2: {3: "end"}}
walked = c.walk_path([1, 2, 3])
self.assertEqual(walked, "end")
def test_deletion(self):
c = Cache()
c["path"] = 2
c.apply_changes([["path"]])
self.assertEqual(list(c), [])
def test_addition(self):
c = Cache()
c.delta_update([["thing"], {1: 2}])
self.assertEqual(c["thing"][1], 2)
