xml-pipeline/agentserver/message_bus.py

126 lines
No EOL
4.9 KiB
Python

import asyncio
import logging
from typing import Dict, Optional, Callable
from lxml import etree
from .xml_listener import XMLListener
from .utils.message import repair_and_canonicalize, XmlTamperError
# Constants for Internal Physics
ENV_NS = "https://xml-pipeline.org/ns/envelope/1"
ENV = f"{{{ENV_NS}}}"
LOG_TAG = "{https://xml-pipeline.org/ns/logger/1}log"
logger = logging.getLogger("agentserver.bus")
class MessageBus:
"""
The Pure Carrier: Routes XML trees between sovereign listeners.
- Core: High-speed tree-to-tree routing.
- Border: 'Air Lock' for ingesting raw bytes.
- Physics: Hardcoded hooks for the Audit Witness.
"""
def __init__(self, log_hook: Callable[[etree.Element], None]):
# root_tag -> {agent_name -> XMLListener}
self.listeners: Dict[str, Dict[str, XMLListener]] = {}
# Global lookup for directed <to/> routing
self.global_names: Dict[str, XMLListener] = {}
# The 'Physics' hook provided by the Host (AgentServer)
self._log_hook = log_hook
async def register_listener(self, listener: XMLListener) -> None:
"""Register an organ. Enforces global identity uniqueness."""
if listener.agent_name in self.global_names:
raise ValueError(f"Identity collision: {listener.agent_name}")
self.global_names[listener.agent_name] = listener
for tag in listener.listens_to:
tag_dict = self.listeners.setdefault(tag, {})
tag_dict[listener.agent_name] = listener
logger.info(f"Registered organ: {listener.agent_name}")
async def deliver_bytes(
self,
raw_xml: bytes,
client_id: Optional[str] = None
) -> Optional[str]:
"""
The Air Lock: Ingests raw bytes from unauthenticated or foreign sources.
Repairs and validates them before injecting the tree into the core.
"""
try:
# 1. Pressurize (Bytes -> Tree)
envelope_tree: etree._Element = repair_and_canonicalize(raw_xml)
# 2. Inject into core
return await self.dispatch(envelope_tree, client_id)
except XmlTamperError as e:
logger.warning(f"Air Lock Reject: {e}")
return None
async def dispatch(
self,
envelope_tree: etree._Element,
client_id: Optional[str] = None
) -> Optional[str]:
"""
The Pure Heart: Routes a tree. Returns a validated response string.
"""
# 1. WITNESS: Automatic logging of the truth
self._log_hook(envelope_tree)
# 2. Extract Metadata
meta = envelope_tree.find(f"{ENV}meta")
from_name = meta.findtext(f"{ENV}from")
to_name = meta.findtext(f"{ENV}to")
thread_id = meta.findtext(f"{ENV}thread")
payload_elem = next((c for c in envelope_tree.iterchildren() if c.tag != f"{ENV}meta"), None)
if payload_elem is None: return None
payload_tag = payload_elem.tag
# 3. AUTONOMIC REFLEX: The Logger Hook (Hardcoded Physics)
if payload_tag == LOG_TAG:
self._log_hook(envelope_tree)
return f"<message xmlns='{ENV_NS}'><meta><from>system</from><to>{from_name}</to><thread_id>{thread_id}</thread_id></meta><logged status='success'/></message>"
# 4. ROUTING
listeners_for_tag = self.listeners.get(payload_tag, {})
response_tree = None
responding_agent_name = "unknown"
if to_name:
# Directed Mode
target = listeners_for_tag.get(to_name) or self.global_names.get(to_name)
if target:
responding_agent_name = target.agent_name
response_tree = await target.handle(envelope_tree, thread_id, from_name or client_id)
else:
# Broadcast Mode
tasks = [l.handle(envelope_tree, thread_id, from_name or client_id) for l in listeners_for_tag.values()]
results = await asyncio.gather(*tasks, return_exceptions=True)
for i, resp in enumerate(results):
if isinstance(resp, etree._Element):
responding_agent_name = list(listeners_for_tag.values())[i].agent_name
response_tree = resp
break
# 5. EGRESS CUSTOMS: Final validation before bytes hit the wire
if response_tree is not None:
return self._inspect_and_serialize(response_tree, responding_agent_name)
return None
def _inspect_and_serialize(self, tree: etree._Element, expected_from: str) -> Optional[str]:
"""Ensures identity integrity and performs final string serialization."""
actual_from = tree.findtext(f"{ENV}meta/{ENV}from")
if actual_from != expected_from:
logger.critical(f"IDENTITY THEFT BLOCKED: {expected_from} spoofed {actual_from}")
return None
# noinspection PyTypeChecker
return etree.tostring(tree, encoding="unicode", pretty_print=True)