class Controller(Loggable):
"""Implement the logic that takes a Block through its state machine"""
stateMachine = sm()
# Attributes for all controllers
state = None
status = None
busy = None
# BlockMeta for descriptions
meta = None
def __init__(self, process, parts, params):
"""
Args:
process (Process): The process this should run under
params (Map): The parameters specified in method_takes()
parts (list): [Part]
"""
self.process = process
self.params = params
self.mri = params.mri
controller_name = "%s(%s)" % (type(self).__name__, self.mri)
self.set_logger_name(controller_name)
self.block = Block()
self.log_debug("Creating block %r as %r", self.block, self.mri)
self.lock = process.create_lock()
# {part: task}
self.part_tasks = {}
# dictionary of dictionaries
# {state (str): {Meta/MethodMeta/Attribute: writeable (bool)}
self.children_writeable = {}
# dict {hook: name}
self.hook_names = self._find_hooks()
self.parts = self._setup_parts(parts, controller_name)
self._set_block_children()
self._do_transition(sm.DISABLED, "Disabled")
self.block.set_process_path(process, [self.mri])
process.add_block(self.block, self)
self.do_initial_reset()
def _find_hooks(self):
hook_names = {}
for n in dir(self):
attr = getattr(self, n)
if isinstance(attr, Hook):
assert attr not in hook_names, \
"Hook %s already in controller as %s" % (
n, hook_names[attr])
hook_names[attr] = n
return hook_names
def _setup_parts(self, parts, controller_name):
parts_dict = OrderedDict()
for part in parts:
part.set_logger_name("%s.%s" % (controller_name, part.name))
# Check part hooks into one of our hooks
for func_name, part_hook, _ in get_hook_decorated(part):
assert part_hook in self.hook_names, \
"Part %s func %s not hooked into %s" % (
part.name, func_name, self)
parts_dict[part.name] = part
return parts_dict
def do_initial_reset(self):
pass
def _set_block_children(self):
# reconfigure block with new children
child_list = [self.create_meta()]
child_list += list(self.create_attributes())
child_list += list(self.create_methods())
for part in self.parts.values():
child_list += list(part.create_attributes())
child_list += list(part.create_methods())
self.children_writeable = {}
writeable_functions = {}
children = OrderedDict()
for name, child, writeable_func in child_list:
if isinstance(child, Attribute):
states = child.meta.writeable_in
else:
states = child.writeable_in
children[name] = child
if states:
for state in states:
assert state in self.stateMachine.possible_states, \
"State %s is not one of the valid states %s" % \
(state, self.stateMachine.possible_states)
elif writeable_func is not None:
states = [
state for state in self.stateMachine.possible_states
if state not in (sm.DISABLING, sm.DISABLED)]
else:
continue
self.register_child_writeable(name, states)
if writeable_func:
writeable_functions[name] = functools.partial(
self.call_writeable_function, writeable_func)
self.block.replace_endpoints(children)
self.block.set_writeable_functions(writeable_functions)
def call_writeable_function(self, function, child, *args):
with self.lock:
if not child.writeable:
raise ValueError(
"Child %r is not writeable" % (child.process_path,))
result = function(*args)
return result
def create_meta(self):
self.meta = BlockMeta()
return "meta", self.meta, None
def create_attributes(self):
"""Method that should provide Attribute instances for Block
Yields:
tuple: (string name, Attribute, callable put_function).
"""
# Add the state, status and busy attributes
self.state = ChoiceMeta(
"State of Block", self.stateMachine.possible_states, label="State"
).make_attribute()
yield "state", self.state, None
self.status = StringMeta(
"Status of Block", label="Status"
).make_attribute()
yield "status", self.status, None
self.busy = BooleanMeta(
"Whether Block busy or not", label="Busy"
).make_attribute()
yield "busy", self.busy, None
def create_methods(self):
"""Method that should provide MethodMeta instances for Block
Yields:
tuple: (string name, MethodMeta, callable post_function).
"""
return get_method_decorated(self)
def transition(self, state, message):
"""
Change to a new state if the transition is allowed
Args:
state(str): State to transition to
message(str): Status message
"""
with self.lock:
if self.stateMachine.is_allowed(
initial_state=self.state.value, target_state=state):
self._do_transition(state, message)
else:
raise TypeError("Cannot transition from %s to %s" %
(self.state.value, state))
def _do_transition(self, state, message):
# transition is allowed, so set attributes
changes = []
changes.append([["state", "value"], state])
changes.append([["status", "value"], message])
changes.append([["busy", "value"],
state in self.stateMachine.busy_states])
# say which children are now writeable
for name in self.block:
try:
writeable = self.children_writeable[state][name]
except KeyError:
continue
child = self.block[name]
if isinstance(child, Attribute):
changes.append([[name, "meta", "writeable"], writeable])
elif isinstance(child, MethodMeta):
changes.append([[name, "writeable"], writeable])
for ename in child.takes.elements:
path = [name, "takes", "elements", ename, "writeable"]
changes.append([path, writeable])
self.log_debug("Transitioning to %s", state)
self.block.apply_changes(*changes)
def register_child_writeable(self, name, states):
"""
Set the states that the given method can be called in
Args:
name (str): Child name that will be set writeable or not
states (list[str]): states where method is writeable
"""
for state in self.stateMachine.possible_states:
writeable_dict = self.children_writeable.setdefault(state, {})
is_writeable = state in states
writeable_dict[name] = is_writeable
def create_part_tasks(self):
part_tasks = {}
for part_name, part in self.parts.items():
part_tasks[part] = Task("Task(%s)" % part_name, self.process)
return part_tasks
def run_hook(self, hook, part_tasks, *args, **params):
hook_queue, hook_runners = self.start_hook(
hook, part_tasks, *args, **params)
return_dict = self.wait_hook(hook_queue, hook_runners)
return return_dict
def start_hook(self, hook, part_tasks, *args, **params):
assert hook in self.hook_names, \
"Hook %s doesn't appear in controller hooks %s" % (
hook, self.hook_names)
# ask the hook to find the functions it should run
part_funcs = hook.find_hooked_functions(self.parts)
hook_runners = {}
self.log_debug("Run %s hook on %s",
self.hook_names[hook], [p.name for p in part_funcs])
# now start them off
hook_queue = self.process.create_queue()
for part, func_name in part_funcs.items():
task = weakref.proxy(part_tasks[part])
hook_runner = HookRunner(
hook_queue, part, func_name, task, *args, **params)
hook_runner.start()
hook_runners[part] = hook_runner
return hook_queue, hook_runners
def wait_hook(self, hook_queue, hook_runners):
# Wait for them all to finish
return_dict = {}
while hook_runners:
part, ret = hook_queue.get()
hook_runner = hook_runners.pop(part)
if isinstance(ret, AbortedError):
# If AbortedError, all tasks have already been stopped.
self.log_debug("Part %s Aborted", part.name)
# Do not wait on them otherwise we might get a deadlock...
raise ret
# Wait for the process to terminate
hook_runner.wait()
return_dict[part.name] = ret
self.log_debug("Part %s returned %r. Still waiting for %s",
part.name, ret, [p.name for p in hook_runners])
if isinstance(ret, Exception):
# Got an error, so stop and wait all hook runners
for h in hook_runners.values():
h.stop()
# Wait for them to finish
for h in hook_runners.values():
h.wait()
raise ret
return return_dict
class Controller(Loggable):
"""Implement the logic that takes a Block through its state machine"""
# Attributes for all controllers
state = None
status = None
busy = None
# BlockMeta for descriptions
meta = None
def __init__(self, block_name, process, parts=None, params=None):
"""
Args:
process (Process): The process this should run under
"""
controller_name = "%s(%s)" % (type(self).__name__, block_name)
self.set_logger_name(controller_name)
self.block = Block()
self.log_debug("Creating block %r as %r" % (self.block, block_name))
self.block_name = block_name
self.params = params
self.process = process
self.lock = process.create_lock()
# {part: task}
self.part_tasks = {}
# dictionary of dictionaries
# {state (str): {MethodMeta: writeable (bool)}
self.methods_writeable = {}
# dict {hook: name}
self.hook_names = self._find_hooks()
self.parts = self._setup_parts(parts, controller_name)
self._set_block_children()
self._do_transition(sm.DISABLED, "Disabled")
self.block.set_parent(process, block_name)
process.add_block(self.block)
self.do_initial_reset()
def _find_hooks(self):
hook_names = {}
for n in dir(self):
attr = getattr(self, n)
if isinstance(attr, Hook):
assert attr not in hook_names, \
"Hook %s already in controller as %s" % (
n, hook_names[attr])
hook_names[attr] = n
return hook_names
def _setup_parts(self, parts, controller_name):
if parts is None:
parts = {}
for part_name, part in parts.items():
part.set_logger_name("%s.%s" % (controller_name, part_name))
# Check part hooks into one of our hooks
for func_name, part_hook, _ in get_hook_decorated(part):
assert part_hook in self.hook_names, \
"Part %s func %s not hooked into %s" % (
part, func_name, self)
return parts
def do_initial_reset(self):
request = Post(None, self.process.create_queue(),
[self.block_name, "reset"])
self.process.q.put(request)
def add_change(self, changes, item, attr, value):
path = item.path_relative_to(self.block) + [attr]
changes.append([path, value])
def _set_block_children(self):
# reconfigure block with new children
child_list = [self.create_meta()]
child_list += list(self._create_default_attributes())
child_list += list(self.create_attributes())
child_list += list(self.create_methods())
for part in self.parts.values():
child_list += list(part.create_attributes())
child_list += list(part.create_methods())
self.methods_writeable = {}
writeable_functions = {}
children = OrderedDict()
for name, child, writeable_func in child_list:
if isinstance(child, MethodMeta):
# Set if the method is writeable
if child.only_in is None:
states = [
state for state in self.stateMachine.possible_states
if state not in (sm.DISABLING, sm.DISABLED)
]
else:
states = child.only_in
for state in states:
assert state in self.stateMachine.possible_states, \
"State %s is not one of the valid states %s" % \
(state, self.stateMachine.possible_states)
# Make a copy otherwise all instances will own the same one
child = MethodMeta.from_dict(child.to_dict())
self.register_method_writeable(child, states)
elif isinstance(child, Attribute):
child.meta.set_writeable(writeable_func is not None)
children[name] = child
if writeable_func:
writeable_functions[name] = functools.partial(
self.call_writeable_function, writeable_func)
self.block.replace_endpoints(children)
self.block.set_writeable_functions(writeable_functions)
def call_writeable_function(self, function, child, *args):
with self.lock:
if not child.writeable:
child.log_error("I'm not writeable")
raise ValueError("Child %r is not writeable" % (child, ))
result = function(*args)
return result
def _create_default_attributes(self):
# Add the state, status and busy attributes
self.state = ChoiceMeta("State of Block",
self.stateMachine.possible_states,
label="State").make_attribute()
yield "state", self.state, None
self.status = StringMeta("Status of Block",
label="Status").make_attribute()
yield "status", self.status, None
self.busy = BooleanMeta("Whether Block busy or not",
label="Busy").make_attribute()
yield "busy", self.busy, None
def create_meta(self):
self.meta = BlockMeta()
return "meta", self.meta, None
def create_attributes(self):
"""Method that should provide Attribute instances for Block
Yields:
tuple: (string name, Attribute, callable put_function).
"""
return iter(())
def create_methods(self):
"""Method that should provide MethodMeta instances for Block
Yields:
tuple: (string name, MethodMeta, callable post_function).
"""
return get_method_decorated(self)
def transition(self, state, message, create_tasks=False):
"""
Change to a new state if the transition is allowed
Args:
state(str): State to transition to
message(str): Status message
create_tasks(bool): If true then make self.part_tasks
"""
with self.lock:
if self.stateMachine.is_allowed(initial_state=self.state.value,
target_state=state):
self._do_transition(state, message)
if create_tasks:
self.part_tasks = self.create_part_tasks()
else:
raise TypeError("Cannot transition from %s to %s" %
(self.state.value, state))
def _do_transition(self, state, message):
# transition is allowed, so set attributes
changes = []
self.add_change(changes, self.state, "value", state)
self.add_change(changes, self.status, "value", message)
self.add_change(changes, self.busy, "value", state
in self.stateMachine.busy_states)
# say which methods can now be called
for name in self.block:
child = self.block[name]
if isinstance(child, MethodMeta):
method = child
writeable = self.methods_writeable[state][method]
self.add_change(changes, method, "writeable", writeable)
for ename in method.takes.elements:
meta = method.takes.elements[ename]
self.add_change(changes, meta, "writeable", writeable)
self.log_debug("Transitioning to %s", state)
self.block.apply_changes(*changes)
def register_method_writeable(self, method, states):
"""
Set the states that the given method can be called in
Args:
method(MethodMeta): Method that will be set writeable or not
states(list[str]): List of states where method is writeable
"""
for state in self.stateMachine.possible_states:
writeable_dict = self.methods_writeable.setdefault(state, {})
is_writeable = state in states
writeable_dict[method] = is_writeable
def create_part_tasks(self):
part_tasks = {}
for part_name, part in self.parts.items():
part_tasks[part] = Task("Task(%s)" % part_name, self.process)
return part_tasks
def run_hook(self, hook, part_tasks, **kwargs):
hook_queue, func_tasks, task_part_names = self.start_hook(
hook, part_tasks, **kwargs)
return_table = hook.make_return_table(part_tasks)
return_dict = self.wait_hook(hook_queue, func_tasks, task_part_names)
for part_name in self.parts:
return_map = return_dict.get(part_name, None)
if return_map:
self.fill_in_table(part_name, return_table, return_map)
return return_table
def fill_in_table(self, part_name, table, return_map):
# Find all the array columns
arrays = {}
for column_name in table.meta.elements:
meta = table.meta.elements[column_name]
if "hook:return_array" in meta.tags:
arrays[column_name] = return_map[column_name]
# If there are any arrays, make sure they are the right length
lengths = set(len(arr) for arr in arrays.values())
if len(lengths) == 0:
# no arrays
iterations = 1
else:
assert len(lengths) == 1, \
"Varying array length %s for rows %s" % (lengths, arrays)
iterations = lengths.pop()
for i in range(iterations):
row = []
for k in table.endpoints:
if k == "name":
row.append(part_name)
elif k in arrays:
row.append(arrays[k][i])
else:
row.append(return_map[k])
table.append(row)
def make_task_return_value_function(self, hook_queue, **kwargs):
def task_return(func, task):
try:
result = func.MethodMeta.call_post_function(func, kwargs, task)
except StopIteration as e:
self.log_debug("%s has been aborted", func)
result = e
except Exception as e: # pylint:disable=broad-except
self.log_exception("%s %s raised exception", func, kwargs)
result = e
self.log_debug("Putting %r on queue", result)
hook_queue.put((func, result))
return task_return
def start_hook(self, hook, part_tasks, **kwargs):
assert hook in self.hook_names, \
"Hook %s doesn't appear in controller hooks %s" % (
hook, self.hook_names)
self.log_debug("Running %s hook", self.hook_names[hook])
# ask the hook to find the functions it should run
func_tasks = hook.find_func_tasks(part_tasks)
# now start them off
hook_queue = self.process.create_queue()
task_return = self.make_task_return_value_function(
hook_queue, **kwargs)
for func, task in func_tasks.items():
task.define_spawn_function(task_return, func, task)
self.log_debug("Starting task %r", task)
task.start()
# Create the reverse dictionary so we know where to store the results
task_part_names = {}
for part_name, part in self.parts.items():
if part in part_tasks:
task_part_names[part_tasks[part]] = part_name
return hook_queue, func_tasks, task_part_names
def wait_hook(self, hook_queue, func_tasks, task_part_names):
# Wait for them all to finish
return_dict = {}
while func_tasks:
func, ret = hook_queue.get()
task = func_tasks.pop(func)
part_name = task_part_names[task]
return_dict[part_name] = ret
if isinstance(ret, Exception):
# Stop all other tasks
for task in func_tasks.values():
task.stop()
for task in func_tasks.values():
task.wait()
# If we got a StopIteration, someone asked us to stop, so
# don't wait, otherwise make sure we finished
if not isinstance(ret, StopIteration):
task.wait()
if isinstance(ret, Exception):
raise ret
return return_dict
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 = []
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)
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 Controller(Loggable):
"""Implement the logic that takes a Block through its state machine"""
stateMachine = sm()
# Attributes for all controllers
state = None
status = None
busy = None
# BlockMeta for descriptions
meta = None
def __init__(self, process, parts, params):
"""
Args:
process (Process): The process this should run under
params (Map): The parameters specified in method_takes()
parts (list): [Part]
"""
self.process = process
self.params = params
self.mri = params.mri
controller_name = "%s(%s)" % (type(self).__name__, self.mri)
self.set_logger_name(controller_name)
self.block = Block()
self.log_debug("Creating block %r as %r", self.block, self.mri)
self.lock = process.create_lock()
# {part: task}
self.part_tasks = {}
# dictionary of dictionaries
# {state (str): {Meta/MethodMeta/Attribute: writeable (bool)}
self.children_writeable = {}
# dict {hook: name}
self.hook_names = self._find_hooks()
self.parts = self._setup_parts(parts, controller_name)
self._set_block_children()
self._do_transition(sm.DISABLED, "Disabled")
self.block.set_process_path(process, [self.mri])
process.add_block(self.block, self)
self.do_initial_reset()
def _find_hooks(self):
hook_names = {}
for n in dir(self):
attr = getattr(self, n)
if isinstance(attr, Hook):
assert attr not in hook_names, \
"Hook %s already in controller as %s" % (
n, hook_names[attr])
hook_names[attr] = n
return hook_names
def _setup_parts(self, parts, controller_name):
parts_dict = OrderedDict()
for part in parts:
part.set_logger_name("%s.%s" % (controller_name, part.name))
# Check part hooks into one of our hooks
for func_name, part_hook, _ in get_hook_decorated(part):
assert part_hook in self.hook_names, \
"Part %s func %s not hooked into %s" % (
part.name, func_name, self)
parts_dict[part.name] = part
return parts_dict
def do_initial_reset(self):
pass
def _set_block_children(self):
# reconfigure block with new children
child_list = [self.create_meta()]
child_list += list(self.create_attributes())
child_list += list(self.create_methods())
for part in self.parts.values():
child_list += list(part.create_attributes())
child_list += list(part.create_methods())
self.children_writeable = {}
writeable_functions = {}
children = OrderedDict()
for name, child, writeable_func in child_list:
if isinstance(child, Attribute):
states = child.meta.writeable_in
else:
states = child.writeable_in
children[name] = child
if states:
for state in states:
assert state in self.stateMachine.possible_states, \
"State %s is not one of the valid states %s" % \
(state, self.stateMachine.possible_states)
elif writeable_func is not None:
states = [
state for state in self.stateMachine.possible_states
if state not in (sm.DISABLING, sm.DISABLED)
]
else:
continue
self.register_child_writeable(name, states)
if writeable_func:
writeable_functions[name] = functools.partial(
self.call_writeable_function, writeable_func)
self.block.replace_endpoints(children)
self.block.set_writeable_functions(writeable_functions)
def call_writeable_function(self, function, child, *args):
with self.lock:
if not child.writeable:
raise ValueError("Child %r is not writeable" %
(child.process_path, ))
result = function(*args)
return result
def create_meta(self):
self.meta = BlockMeta()
return "meta", self.meta, None
def create_attributes(self):
"""Method that should provide Attribute instances for Block
Yields:
tuple: (string name, Attribute, callable put_function).
"""
# Add the state, status and busy attributes
self.state = ChoiceMeta("State of Block",
self.stateMachine.possible_states,
label="State").make_attribute()
yield "state", self.state, None
self.status = StringMeta("Status of Block",
label="Status").make_attribute()
yield "status", self.status, None
self.busy = BooleanMeta("Whether Block busy or not",
label="Busy").make_attribute()
yield "busy", self.busy, None
def create_methods(self):
"""Method that should provide MethodMeta instances for Block
Yields:
tuple: (string name, MethodMeta, callable post_function).
"""
return get_method_decorated(self)
def transition(self, state, message):
"""
Change to a new state if the transition is allowed
Args:
state(str): State to transition to
message(str): Status message
"""
with self.lock:
if self.stateMachine.is_allowed(initial_state=self.state.value,
target_state=state):
self._do_transition(state, message)
else:
raise TypeError("Cannot transition from %s to %s" %
(self.state.value, state))
def _do_transition(self, state, message):
# transition is allowed, so set attributes
changes = []
changes.append([["state", "value"], state])
changes.append([["status", "value"], message])
changes.append([["busy", "value"], state
in self.stateMachine.busy_states])
# say which children are now writeable
for name in self.block:
try:
writeable = self.children_writeable[state][name]
except KeyError:
continue
child = self.block[name]
if isinstance(child, Attribute):
changes.append([[name, "meta", "writeable"], writeable])
elif isinstance(child, MethodMeta):
changes.append([[name, "writeable"], writeable])
for ename in child.takes.elements:
path = [name, "takes", "elements", ename, "writeable"]
changes.append([path, writeable])
self.log_debug("Transitioning to %s", state)
self.block.apply_changes(*changes)
def register_child_writeable(self, name, states):
"""
Set the states that the given method can be called in
Args:
name (str): Child name that will be set writeable or not
states (list[str]): states where method is writeable
"""
for state in self.stateMachine.possible_states:
writeable_dict = self.children_writeable.setdefault(state, {})
is_writeable = state in states
writeable_dict[name] = is_writeable
def create_part_tasks(self):
part_tasks = {}
for part_name, part in self.parts.items():
part_tasks[part] = Task("Task(%s)" % part_name, self.process)
return part_tasks
def run_hook(self, hook, part_tasks, *args, **params):
hook_queue, hook_runners = self.start_hook(hook, part_tasks, *args,
**params)
return_dict = self.wait_hook(hook_queue, hook_runners)
return return_dict
def start_hook(self, hook, part_tasks, *args, **params):
assert hook in self.hook_names, \
"Hook %s doesn't appear in controller hooks %s" % (
hook, self.hook_names)
# ask the hook to find the functions it should run
part_funcs = hook.find_hooked_functions(self.parts)
hook_runners = {}
self.log_debug("Run %s hook on %s", self.hook_names[hook],
[p.name for p in part_funcs])
# now start them off
hook_queue = self.process.create_queue()
for part, func_name in part_funcs.items():
task = weakref.proxy(part_tasks[part])
hook_runner = HookRunner(hook_queue, part, func_name, task, *args,
**params)
hook_runner.start()
hook_runners[part] = hook_runner
return hook_queue, hook_runners
def wait_hook(self, hook_queue, hook_runners):
# Wait for them all to finish
return_dict = {}
while hook_runners:
part, ret = hook_queue.get()
hook_runner = hook_runners.pop(part)
if isinstance(ret, AbortedError):
# If AbortedError, all tasks have already been stopped.
self.log_debug("Part %s Aborted", part.name)
# Do not wait on them otherwise we might get a deadlock...
raise ret
# Wait for the process to terminate
hook_runner.wait()
return_dict[part.name] = ret
self.log_debug("Part %s returned %r. Still waiting for %s",
part.name, ret, [p.name for p in hook_runners])
if isinstance(ret, Exception):
# Got an error, so stop and wait all hook runners
for h in hook_runners.values():
h.stop()
# Wait for them to finish
for h in hook_runners.values():
h.wait()
raise ret
return return_dict
