"""The Dispatcher.
The dispatcher is responsible for coordinating data flow between handlers, providing
lifecycle hook callbacks storing state for message threads, etc.
"""
import asyncio
import logging
import os
from typing import Callable, Coroutine, Optional, Tuple, Union
import warnings
import weakref
from aiohttp.web import HTTPException
from ..connections.base_manager import BaseConnectionManager
from ..connections.models.conn_record import ConnRecord
from ..core.profile import Profile
from ..messaging.agent_message import AgentMessage
from ..messaging.base_message import BaseMessage
from ..messaging.error import MessageParseError
from ..messaging.models.base import BaseModelError
from ..messaging.request_context import RequestContext
from ..messaging.responder import BaseResponder, SKIP_ACTIVE_CONN_CHECK_MSG_TYPES
from ..messaging.util import datetime_now
from ..protocols.problem_report.v1_0.message import ProblemReport
from ..transport.inbound.message import InboundMessage
from ..transport.outbound.message import OutboundMessage
from ..transport.outbound.status import OutboundSendStatus
from ..utils.stats import Collector
from ..utils.task_queue import CompletedTask, PendingTask, TaskQueue
from ..utils.tracing import get_timer, trace_event
from .error import ProtocolMinorVersionNotSupported
from .protocol_registry import ProtocolRegistry
from .util import get_version_from_message_type, validate_get_response_version
[docs]class ProblemReportParseError(MessageParseError):
"""Error to raise on failure to parse problem-report message."""
[docs]class Dispatcher:
"""Dispatcher class.
Class responsible for dispatching messages to message handlers and responding
to other agents.
"""
def __init__(self, profile: Profile):
"""Initialize an instance of Dispatcher."""
self.collector: Collector = None
self.profile = profile
self.task_queue: TaskQueue = None
self.logger: logging.Logger = logging.getLogger(__name__)
[docs] async def setup(self):
"""Perform async instance setup."""
self.collector = self.profile.inject_or(Collector)
max_active = int(os.getenv("DISPATCHER_MAX_ACTIVE", 50))
self.task_queue = TaskQueue(
max_active=max_active, timed=bool(self.collector), trace_fn=self.log_task
)
[docs] def put_task(
self, coro: Coroutine, complete: Callable = None, ident: str = None
) -> PendingTask:
"""Run a task in the task queue, potentially blocking other handlers."""
return self.task_queue.put(coro, complete, ident)
[docs] def run_task(
self, coro: Coroutine, complete: Callable = None, ident: str = None
) -> asyncio.Task:
"""Run a task in the task queue, potentially blocking other handlers."""
return self.task_queue.run(coro, complete, ident)
[docs] def log_task(self, task: CompletedTask):
"""Log a completed task using the stats collector."""
if task.exc_info and not issubclass(task.exc_info[0], HTTPException):
# skip errors intentionally returned to HTTP clients
self.logger.exception(
"Handler error: %s", task.ident or "", exc_info=task.exc_info
)
if self.collector:
timing = task.timing
if "queued" in timing:
self.collector.log(
"Dispatcher:queued", timing["unqueued"] - timing["queued"]
)
if task.ident:
self.collector.log(task.ident, timing["ended"] - timing["started"])
[docs] def queue_message(
self,
profile: Profile,
inbound_message: InboundMessage,
send_outbound: Coroutine,
complete: Callable = None,
) -> PendingTask:
"""Add a message to the processing queue for handling.
Args:
profile: The profile associated with the inbound message
inbound_message: The inbound message instance
send_outbound: Async function to send outbound messages
complete: Function to call when the handler has completed
Returns:
A pending task instance resolving to the handler task
"""
return self.put_task(
self.handle_message(profile, inbound_message, send_outbound),
complete,
)
[docs] async def handle_message(
self,
profile: Profile,
inbound_message: InboundMessage,
send_outbound: Coroutine,
):
"""Configure responder and message context and invoke the message handler.
Args:
profile: The profile associated with the inbound message
inbound_message: The inbound message instance
send_outbound: Async function to send outbound messages
# Raises:
# MessageParseError: If the message type version is not supported
Returns:
The response from the handler
"""
r_time = get_timer()
error_result = None
version_warning = None
message = None
try:
(message, warning) = await self.make_message(
profile, inbound_message.payload
)
except ProblemReportParseError:
pass # avoid problem report recursion
except MessageParseError as e:
self.logger.error(
f"Message parsing failed: {str(e)}, sending problem report"
)
error_result = ProblemReport(
description={
"en": str(e),
"code": "message-parse-failure",
}
)
if inbound_message.receipt.thread_id:
error_result.assign_thread_id(inbound_message.receipt.thread_id)
# if warning:
# warning_message_type = inbound_message.payload.get("@type")
# if warning == WARNING_DEGRADED_FEATURES:
# self.logger.error(
# f"Sending {WARNING_DEGRADED_FEATURES} problem report, "
# "message type received with a minor version at or higher"
# " than protocol minimum supported and current minor version "
# f"for message_type {warning_message_type}"
# )
# version_warning = ProblemReport(
# description={
# "en": (
# "message type received with a minor version at or "
# "higher than protocol minimum supported and current"
# f" minor version for message_type {warning_message_type}"
# ),
# "code": WARNING_DEGRADED_FEATURES,
# }
# )
# elif warning == WARNING_VERSION_MISMATCH:
# self.logger.error(
# f"Sending {WARNING_VERSION_MISMATCH} problem report, message "
# "type received with a minor version higher than current minor "
# f"version for message_type {warning_message_type}"
# )
# version_warning = ProblemReport(
# description={
# "en": (
# "message type received with a minor version higher"
# " than current minor version for message_type"
# f" {warning_message_type}"
# ),
# "code": WARNING_VERSION_MISMATCH,
# }
# )
# elif warning == WARNING_VERSION_NOT_SUPPORTED:
# raise MessageParseError(
# f"Message type version not supported for {warning_message_type}"
# )
# if version_warning and inbound_message.receipt.thread_id:
# version_warning.assign_thread_id(inbound_message.receipt.thread_id)
trace_event(
self.profile.settings,
message,
outcome="Dispatcher.handle_message.START",
)
context = RequestContext(profile)
context.message = message
context.message_receipt = inbound_message.receipt
responder = DispatcherResponder(
context,
inbound_message,
send_outbound,
reply_session_id=inbound_message.session_id,
reply_to_verkey=inbound_message.receipt.sender_verkey,
)
context.injector.bind_instance(BaseResponder, responder)
# When processing oob attach message we supply the connection id
# associated with the inbound message
if inbound_message.connection_id:
async with self.profile.session() as session:
connection = await ConnRecord.retrieve_by_id(
session, inbound_message.connection_id
)
else:
connection_mgr = BaseConnectionManager(profile)
connection = await connection_mgr.find_inbound_connection(
inbound_message.receipt
)
del connection_mgr
if connection:
inbound_message.connection_id = connection.connection_id
context.connection_ready = connection and connection.is_ready
context.connection_record = connection
responder.connection_id = connection and connection.connection_id
if error_result:
await responder.send_reply(error_result)
elif version_warning:
await responder.send_reply(version_warning)
elif context.message:
context.injector.bind_instance(BaseResponder, responder)
handler_cls = context.message.Handler
handler = handler_cls().handle
if self.collector:
handler = self.collector.wrap_coro(handler, [handler.__qualname__])
await handler(context, responder)
trace_event(
self.profile.settings,
context.message,
outcome="Dispatcher.handle_message.END",
perf_counter=r_time,
)
[docs] async def make_message(
self, profile: Profile, parsed_msg: dict
) -> Tuple[BaseMessage, Optional[str]]:
"""Deserialize a message dict into the appropriate message instance.
Given a dict describing a message, this method
returns an instance of the related message class.
Args:
parsed_msg: The parsed message
profile: Profile
Returns:
An instance of the corresponding message class for this message
Raises:
MessageParseError: If the message doesn't specify @type
MessageParseError: If there is no message class registered to handle
the given type
"""
if not isinstance(parsed_msg, dict):
raise MessageParseError("Expected a JSON object")
message_type = parsed_msg.get("@type")
if not message_type:
raise MessageParseError("Message does not contain '@type' parameter")
message_type_rec_version = get_version_from_message_type(message_type)
registry: ProtocolRegistry = self.profile.inject(ProtocolRegistry)
try:
message_cls = registry.resolve_message_class(message_type)
except ProtocolMinorVersionNotSupported as e:
raise MessageParseError(f"Problem parsing message type. {e}")
if not message_cls:
raise MessageParseError(f"Unrecognized message type {message_type}")
try:
instance = message_cls.deserialize(parsed_msg)
except BaseModelError as e:
if "/problem-report" in message_type:
raise ProblemReportParseError("Error parsing problem report message")
raise MessageParseError(f"Error deserializing message: {e}") from e
_, warning = await validate_get_response_version(
profile, message_type_rec_version, message_cls
)
return (instance, warning)
[docs] async def complete(self, timeout: float = 0.1):
"""Wait for pending tasks to complete."""
await self.task_queue.complete(timeout=timeout)
[docs]class DispatcherResponder(BaseResponder):
"""Handle outgoing messages from message handlers."""
def __init__(
self,
context: RequestContext,
inbound_message: InboundMessage,
send_outbound: Coroutine,
**kwargs,
):
"""Initialize an instance of `DispatcherResponder`.
Args:
context: The request context of the incoming message
inbound_message: The inbound message triggering this handler
send_outbound: Async function to send outbound message
"""
super().__init__(**kwargs)
# Weakly hold the context so it can be properly garbage collected.
# Binding this DispatcherResponder into the context creates a circular
# reference.
self._context = weakref.ref(context)
self._inbound_message = inbound_message
self._send = send_outbound
[docs] async def create_outbound(
self, message: Union[AgentMessage, BaseMessage, str, bytes], **kwargs
) -> OutboundMessage:
"""Create an OutboundMessage from a message body.
Args:
message: The message payload
"""
context = self._context()
if not context:
raise RuntimeError("weakref to context has expired")
if isinstance(message, AgentMessage) and context.settings.get("timing.enabled"):
# Inject the timing decorator
in_time = context.message_receipt and context.message_receipt.in_time
if not message._decorators.get("timing"):
message._decorators["timing"] = {
"in_time": in_time,
"out_time": datetime_now(),
}
return await super().create_outbound(message, **kwargs)
[docs] async def send_outbound(
self, message: OutboundMessage, **kwargs
) -> OutboundSendStatus:
"""Send outbound message.
Args:
message: The `OutboundMessage` to be sent
"""
context = self._context()
if not context:
raise RuntimeError("weakref to context has expired")
msg_type = kwargs.get("message_type")
msg_id = kwargs.get("message_id")
if (
message.connection_id
and msg_type
and msg_type not in SKIP_ACTIVE_CONN_CHECK_MSG_TYPES
and not await super().conn_rec_active_state_check(
profile=context.profile,
connection_id=message.connection_id,
)
):
raise RuntimeError(
f"Connection {message.connection_id} is not ready"
" which is required for sending outbound"
f" message {msg_id} of type {msg_type}."
)
return await self._send(context.profile, message, self._inbound_message)
[docs] async def send_webhook(self, topic: str, payload: dict):
"""Dispatch a webhook. DEPRECATED: use the event bus instead.
Args:
topic: the webhook topic identifier
payload: the webhook payload value
"""
warnings.warn(
"responder.send_webhook is deprecated; please use the event bus instead.",
DeprecationWarning,
)
context = self._context()
if not context:
raise RuntimeError("weakref to context has expired")
await context.profile.notify("acapy::webhook::" + topic, payload)