# Released under the MIT License. See LICENSE for details.
#
"""Functionality for sending and responding to messages.
Supports static typing for message types and possible return types.
"""
from __future__ import annotations
from typing import TYPE_CHECKING
import traceback
import json
from efro.error import CleanError, CommunicationError
from efro.dataclassio import (
is_ioprepped_dataclass,
dataclass_to_dict,
dataclass_from_dict,
)
from efro.message._message import (
Message,
Response,
SysResponse,
ErrorSysResponse,
EmptySysResponse,
UnregisteredMessageIDError,
)
if TYPE_CHECKING:
from typing import Any, Literal
class MessageProtocol:
"""Wrangles a set of message types, formats, and response types.
Both endpoints must be using a compatible Protocol for communication
to succeed. To maintain Protocol compatibility between revisions,
all message types must retain the same id, message attr storage
names must not change, newly added attrs must have default values,
etc.
"""
def __init__(
self,
message_types: dict[int, type[Message]],
response_types: dict[int, type[Response]],
forward_communication_errors: bool = False,
forward_clean_errors: bool = False,
remote_errors_include_stack_traces: bool = False,
log_errors_on_receiver: bool = True,
) -> None:
"""Create a protocol with a given configuration.
If 'forward_communication_errors' is True,
efro.error.CommunicationErrors raised on the receiver end will
result in a matching error raised back on the sender. This can
be useful if the receiver will be in some way forwarding
messages along and the sender doesn't need to know where
communication breakdowns occurred; only that they did.
If 'forward_clean_errors' is True, efro.error.CleanError
exceptions raised on the receiver end will result in a matching
CleanError raised back on the sender.
When an exception is not covered by the optional forwarding
mechanisms above, it will come across as efro.error.RemoteError
and the exception will be logged on the receiver end - at least
by default (see details below).
If 'remote_errors_include_stack_traces' is True, stringified
stack traces will be returned with efro.error.RemoteError
exceptions. This is useful for debugging but should only be
enabled in cases where the sender is trusted to see internal
details of the receiver.
By default, when a message-handling exception will result in an
efro.error.RemoteError being returned to the sender, the
exception will be logged on the receiver. This is because the
goal is usually to avoid returning opaque RemoteErrors and to
instead return something meaningful as part of the expected
response type (even if that value itself represents a logical
error state). If 'log_errors_on_receiver' is False, however, such
exceptions will *not* be logged on the receiver. This can be
useful in combination with 'remote_errors_include_stack_traces'
and 'forward_clean_errors' in situations where all error
logging/management will be happening on the sender end. Be
aware, however, that in that case it may be possible for
communication errors to prevent such error messages from
ever being seen.
"""
# pylint: disable=too-many-locals
self.message_types_by_id: dict[int, type[Message]] = {}
self.message_ids_by_type: dict[type[Message], int] = {}
self.response_types_by_id: dict[
int, type[Response] | type[SysResponse]
] = {}
self.response_ids_by_type: dict[
type[Response] | type[SysResponse], int
] = {}
for m_id, m_type in message_types.items():
# Make sure only valid message types were passed and each
# id was assigned only once.
assert isinstance(m_id, int)
assert m_id >= 0
assert is_ioprepped_dataclass(m_type) and issubclass(
m_type, Message
)
assert self.message_types_by_id.get(m_id) is None
self.message_types_by_id[m_id] = m_type
self.message_ids_by_type[m_type] = m_id
for r_id, r_type in response_types.items():
assert isinstance(r_id, int)
assert r_id >= 0
assert is_ioprepped_dataclass(r_type) and issubclass(
r_type, Response
)
assert self.response_types_by_id.get(r_id) is None
self.response_types_by_id[r_id] = r_type
self.response_ids_by_type[r_type] = r_id
# Register our SysResponse types. These use negative
# IDs so as to never overlap with user Response types.
def _reg_sys(reg_tp: type[SysResponse], reg_id: int) -> None:
assert self.response_types_by_id.get(reg_id) is None
self.response_types_by_id[reg_id] = reg_tp
self.response_ids_by_type[reg_tp] = reg_id
_reg_sys(ErrorSysResponse, -1)
_reg_sys(EmptySysResponse, -2)
# Some extra-thorough validation in debug mode.
if __debug__:
# Make sure all Message types' return types are valid
# and have been assigned an ID as well.
all_response_types: set[type[Response] | None] = set()
for m_id, m_type in message_types.items():
m_rtypes = m_type.get_response_types()
assert isinstance(m_rtypes, list)
assert (
m_rtypes
), f'Message type {m_type} specifies no return types.'
assert len(set(m_rtypes)) == len(m_rtypes) # check dups
for m_rtype in m_rtypes:
all_response_types.add(m_rtype)
for cls in all_response_types:
if cls is None:
continue
assert is_ioprepped_dataclass(cls)
assert issubclass(cls, Response)
if cls not in self.response_ids_by_type:
raise ValueError(
f'Possible response type {cls} needs to be included'
f' in response_types for this protocol.'
)
# Make sure all registered types have unique base names.
# We can take advantage of this to generate cleaner looking
# protocol modules. Can revisit if this is ever a problem.
mtypenames = set(tp.__name__ for tp in self.message_ids_by_type)
if len(mtypenames) != len(message_types):
raise ValueError(
'message_types contains duplicate __name__s;'
' all types are required to have unique names.'
)
self.forward_clean_errors = forward_clean_errors
self.forward_communication_errors = forward_communication_errors
self.remote_errors_include_stack_traces = (
remote_errors_include_stack_traces
)
self.log_errors_on_receiver = log_errors_on_receiver
[docs]
@staticmethod
def encode_dict(obj: dict) -> str:
"""Json-encode a provided dict."""
return json.dumps(obj, separators=(',', ':'))
[docs]
def message_to_dict(self, message: Message) -> dict:
"""Encode a message to a json ready dict."""
return self._to_dict(message, self.message_ids_by_type, 'message')
[docs]
def response_to_dict(self, response: Response | SysResponse) -> dict:
"""Encode a response to a json ready dict."""
return self._to_dict(response, self.response_ids_by_type, 'response')
[docs]
def error_to_response(self, exc: Exception) -> tuple[SysResponse, bool]:
"""Translate an Exception to a SysResponse.
Also returns whether the error should be logged if this happened
within handle_raw_message().
"""
# If anything goes wrong, return a ErrorSysResponse instead.
# (either CLEAN or generic REMOTE)
if self.forward_clean_errors and isinstance(exc, CleanError):
return (
ErrorSysResponse(
error_message=str(exc),
error_type=ErrorSysResponse.ErrorType.REMOTE_CLEAN,
),
False,
)
if self.forward_communication_errors and isinstance(
exc, CommunicationError
):
return (
ErrorSysResponse(
error_message=str(exc),
error_type=ErrorSysResponse.ErrorType.REMOTE_COMMUNICATION,
),
False,
)
return (
ErrorSysResponse(
error_message=(
traceback.format_exc()
if self.remote_errors_include_stack_traces
else 'An internal error has occurred.'
),
error_type=ErrorSysResponse.ErrorType.REMOTE,
),
self.log_errors_on_receiver,
)
def _to_dict(
self, message: Any, ids_by_type: dict[type, int], opname: str
) -> dict:
"""Encode a message to a json string for transport."""
m_id: int | None = ids_by_type.get(type(message))
if m_id is None:
raise TypeError(
f'{opname} type is not registered in protocol:'
f' {type(message)}'
)
out = {'t': m_id, 'm': dataclass_to_dict(message)}
return out
[docs]
@staticmethod
def decode_dict(data: str) -> dict:
"""Decode data to a dict."""
out = json.loads(data)
assert isinstance(out, dict)
return out
[docs]
def message_from_dict(self, data: dict) -> Message:
"""Decode a message from a json string."""
out = self._from_dict(data, self.message_types_by_id, 'message')
assert isinstance(out, Message)
return out
[docs]
def response_from_dict(self, data: dict) -> Response | SysResponse:
"""Decode a response from a json string."""
out = self._from_dict(data, self.response_types_by_id, 'response')
assert isinstance(out, Response | SysResponse)
return out
# Weeeird; we get mypy errors returning dict[int, type] but
# dict[int, typing.Type] or dict[int, type[Any]] works..
def _from_dict(
self, data: dict, types_by_id: dict[int, type[Any]], opname: str
) -> Any:
"""Decode a message from a json string."""
msgdict: dict | None
m_id = data.get('t')
# Allow omitting 'm' dict if its empty.
msgdict = data.get('m', {})
assert isinstance(m_id, int)
assert isinstance(msgdict, dict)
# Decode this particular type.
msgtype = types_by_id.get(m_id)
if msgtype is None:
raise UnregisteredMessageIDError(
f'Got unregistered {opname} id of {m_id}.'
)
return dataclass_from_dict(msgtype, msgdict)
def _get_module_header(
self,
part: Literal['sender', 'receiver'],
extra_import_code: str | None,
enable_async_sends: bool,
) -> str:
"""Return common parts of generated modules."""
# pylint: disable=too-many-locals
# pylint: disable=too-many-branches
# pylint: disable=too-many-statements
import textwrap
tpimports: dict[str, list[str]] = {}
imports: dict[str, list[str]] = {}
single_message_type = len(self.message_ids_by_type) == 1
msgtypes = list(self.message_ids_by_type)
if part == 'sender':
msgtypes.append(Message)
for msgtype in msgtypes:
tpimports.setdefault(msgtype.__module__, []).append(
msgtype.__name__
)
rsptypes = list(self.response_ids_by_type)
if part == 'sender':
rsptypes.append(Response)
for rsp_tp in rsptypes:
# Skip these as they don't actually show up in code.
if rsp_tp is EmptySysResponse or rsp_tp is ErrorSysResponse:
continue
if (
single_message_type
and part == 'sender'
and rsp_tp is not Response
):
# We need to cast to the single supported response type
# in this case so need response types at runtime.
imports.setdefault(rsp_tp.__module__, []).append(
rsp_tp.__name__
)
else:
tpimports.setdefault(rsp_tp.__module__, []).append(
rsp_tp.__name__
)
import_lines = ''
tpimport_lines = ''
for module, names in sorted(imports.items()):
jnames = ', '.join(names)
line = f'from {module} import {jnames}'
if len(line) > 80:
# Recreate in a wrapping-friendly form.
line = f'from {module} import ({jnames})'
import_lines += f'{line}\n'
for module, names in sorted(tpimports.items()):
jnames = ', '.join(names)
line = f'from {module} import {jnames}'
if len(line) > 75: # Account for indent
# Recreate in a wrapping-friendly form.
line = f'from {module} import ({jnames})'
tpimport_lines += f'{line}\n'
if part == 'sender':
import_lines += (
'from efro.message import MessageSender, BoundMessageSender\n'
)
tpimport_typing_extras = ''
else:
if single_message_type:
import_lines += (
'from efro.message import (MessageReceiver,'
' BoundMessageReceiver, Message, Response)\n'
)
else:
import_lines += (
'from efro.message import MessageReceiver,'
' BoundMessageReceiver\n'
)
tpimport_typing_extras = ', Awaitable'
if extra_import_code is not None:
import_lines += extra_import_code
ovld = ', overload' if not single_message_type else ''
ovld2 = (
', cast, Awaitable'
if (single_message_type and part == 'sender' and enable_async_sends)
else ''
)
tpimport_lines = textwrap.indent(tpimport_lines, ' ')
baseimps = ['Any']
if part == 'receiver':
baseimps.append('Callable')
if part == 'sender' and enable_async_sends:
baseimps.append('Awaitable')
baseimps_s = ', '.join(baseimps)
out = (
'# Released under the MIT License. See LICENSE for details.\n'
f'#\n'
f'"""Auto-generated {part} module. Do not edit by hand."""\n'
f'\n'
f'from __future__ import annotations\n'
f'\n'
f'from typing import TYPE_CHECKING{ovld}{ovld2}\n'
f'\n'
f'{import_lines}'
f'\n'
f'if TYPE_CHECKING:\n'
f' from typing import {baseimps_s}'
f'{tpimport_typing_extras}\n'
f'{tpimport_lines}'
f'\n'
f'\n'
)
return out
[docs]
def do_create_sender_module(
self,
basename: str,
protocol_create_code: str,
enable_sync_sends: bool,
enable_async_sends: bool,
private: bool = False,
protocol_module_level_import_code: str | None = None,
) -> str:
"""Used by create_sender_module(); do not call directly."""
# pylint: disable=too-many-locals
# pylint: disable=too-many-branches
import textwrap
msgtypes = list(self.message_ids_by_type.keys())
ppre = '_' if private else ''
out = self._get_module_header(
'sender',
extra_import_code=protocol_module_level_import_code,
enable_async_sends=enable_async_sends,
)
ccind = textwrap.indent(protocol_create_code, ' ')
out += (
f'class {ppre}{basename}(MessageSender):\n'
f' """Protocol-specific sender."""\n'
f'\n'
f' def __init__(self) -> None:\n'
f'{ccind}\n'
f' super().__init__(protocol)\n'
f'\n'
f' def __get__(\n'
f' self, obj: Any, type_in: Any = None\n'
f' ) -> {ppre}Bound{basename}:\n'
f' return {ppre}Bound{basename}(obj, self)\n'
f'\n'
f'\n'
f'class {ppre}Bound{basename}(BoundMessageSender):\n'
f' """Protocol-specific bound sender."""\n'
)
def _filt_tp_name(rtype: type[Response] | None) -> str:
return 'None' if rtype is None else rtype.__name__
# Define handler() overloads for all registered message types.
if msgtypes:
for async_pass in False, True:
if async_pass and not enable_async_sends:
continue
if not async_pass and not enable_sync_sends:
continue
pfx = 'async ' if async_pass else ''
sfx = '_async' if async_pass else ''
# awt = 'await ' if async_pass else ''
awt = ''
how = 'asynchronously' if async_pass else 'synchronously'
if len(msgtypes) == 1:
# Special case: with a single message types we don't
# use overloads.
msgtype = msgtypes[0]
msgtypevar = msgtype.__name__
rtypes = msgtype.get_response_types()
if len(rtypes) > 1:
rtypevar = ' | '.join(_filt_tp_name(t) for t in rtypes)
else:
rtypevar = _filt_tp_name(rtypes[0])
if async_pass:
rtypevar = f'Awaitable[{rtypevar}]'
out += (
f'\n'
f' def send{sfx}(self,'
f' message: {msgtypevar})'
f' -> {rtypevar}:\n'
f' """Send a message {how}."""\n'
f' out = {awt}self._sender.'
f'send{sfx}(self._obj, message)\n'
)
if not async_pass:
out += (
f' assert isinstance(out, {rtypevar})\n'
' return out\n'
)
else:
out += f' return cast({rtypevar}, out)\n'
else:
for msgtype in msgtypes:
msgtypevar = msgtype.__name__
rtypes = msgtype.get_response_types()
if len(rtypes) > 1:
rtypevar = ' | '.join(
_filt_tp_name(t) for t in rtypes
)
else:
rtypevar = _filt_tp_name(rtypes[0])
out += (
f'\n'
f' @overload\n'
f' {pfx}def send{sfx}(self,'
f' message: {msgtypevar})'
f' -> {rtypevar}: ...\n'
)
rtypevar = 'Response | None'
if async_pass:
rtypevar = f'Awaitable[{rtypevar}]'
out += (
f'\n'
f' def send{sfx}(self, message: Message)'
f' -> {rtypevar}:\n'
f' """Send a message {how}."""\n'
f' return {awt}self._sender.'
f'send{sfx}(self._obj, message)\n'
)
return out
[docs]
def do_create_receiver_module(
self,
basename: str,
protocol_create_code: str,
is_async: bool,
private: bool = False,
protocol_module_level_import_code: str | None = None,
) -> str:
"""Used by create_receiver_module(); do not call directly."""
# pylint: disable=too-many-locals
import textwrap
desc = 'asynchronous' if is_async else 'synchronous'
ppre = '_' if private else ''
msgtypes = list(self.message_ids_by_type.keys())
out = self._get_module_header(
'receiver',
extra_import_code=protocol_module_level_import_code,
enable_async_sends=False,
)
ccind = textwrap.indent(protocol_create_code, ' ')
out += (
f'class {ppre}{basename}(MessageReceiver):\n'
f' """Protocol-specific {desc} receiver."""\n'
f'\n'
f' is_async = {is_async}\n'
f'\n'
f' def __init__(self) -> None:\n'
f'{ccind}\n'
f' super().__init__(protocol)\n'
f'\n'
f' def __get__(\n'
f' self,\n'
f' obj: Any,\n'
f' type_in: Any = None,\n'
f' ) -> {ppre}Bound{basename}:\n'
f' return {ppre}Bound{basename}('
f'obj, self)\n'
)
# Define handler() overloads for all registered message types.
def _filt_tp_name(rtype: type[Response] | None) -> str:
return 'None' if rtype is None else rtype.__name__
if msgtypes:
cbgn = 'Awaitable[' if is_async else ''
cend = ']' if is_async else ''
if len(msgtypes) == 1:
# Special case: when we have a single message type we don't
# use overloads.
msgtype = msgtypes[0]
msgtypevar = msgtype.__name__
rtypes = msgtype.get_response_types()
if len(rtypes) > 1:
rtypevar = ' | '.join(_filt_tp_name(t) for t in rtypes)
else:
rtypevar = _filt_tp_name(rtypes[0])
rtypevar = f'{cbgn}{rtypevar}{cend}'
out += (
f'\n'
f' def handler(\n'
f' self,\n'
f' call: Callable[[Any, {msgtypevar}], '
f'{rtypevar}],\n'
f' )'
f' -> Callable[[Any, {msgtypevar}], {rtypevar}]:\n'
f' """Decorator to register message handlers."""\n'
f' from typing import cast, Callable, Any\n'
f'\n'
f' self.register_handler(cast(Callable'
f'[[Any, Message], Response], call))\n'
f' return call\n'
)
else:
for msgtype in msgtypes:
msgtypevar = msgtype.__name__
rtypes = msgtype.get_response_types()
if len(rtypes) > 1:
rtypevar = ' | '.join(_filt_tp_name(t) for t in rtypes)
else:
rtypevar = _filt_tp_name(rtypes[0])
rtypevar = f'{cbgn}{rtypevar}{cend}'
out += (
f'\n'
f' @overload\n'
f' def handler(\n'
f' self,\n'
f' call: Callable[[Any, {msgtypevar}], '
f'{rtypevar}],\n'
f' )'
f' -> Callable[[Any, {msgtypevar}], {rtypevar}]: ...\n'
)
out += (
'\n'
' def handler(self, call: Callable) -> Callable:\n'
' """Decorator to register message handlers."""\n'
' self.register_handler(call)\n'
' return call\n'
)
out += (
f'\n'
f'\n'
f'class {ppre}Bound{basename}(BoundMessageReceiver):\n'
f' """Protocol-specific bound receiver."""\n'
)
if is_async:
out += (
'\n'
' def handle_raw_message(\n'
' self, message: str, raise_unregistered: bool = False\n'
' ) -> Awaitable[str]:\n'
' """Asynchronously handle a raw incoming message."""\n'
' return self._receiver.'
'handle_raw_message_async(\n'
' self._obj, message, raise_unregistered\n'
' )\n'
)
else:
out += (
'\n'
' def handle_raw_message(\n'
' self, message: str, raise_unregistered: bool = False\n'
' ) -> str:\n'
' """Synchronously handle a raw incoming message."""\n'
' return self._receiver.handle_raw_message(\n'
' self._obj, message, raise_unregistered\n'
' )\n'
)
return out