82b5fcdd78
Major refactor of the message pump architecture: - Replace bus.py with stream_pump.py using aiostream for composable stream processing with natural fan-out via flatmap - Add to_id field to MessageState for explicit routing - Fix routing to use to_id.class format (e.g., "greeter.greeting") - Generate XSD schemas from xmlified payload classes - Fix xmlable imports (absolute -> relative) and parse_element ctx New features: - handlers/hello.py: Sample Greeting/GreetingResponse handler - config/organism.yaml: Sample organism configuration - 41 tests (31 unit + 10 integration) all passing Schema changes: - envelope.xsd: Allow any namespace payloads (##other -> ##any) Dependencies added to pyproject.toml: - aiostream>=0.5 (core dependency) - pyhumps, termcolor (for xmlable) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
101 lines
No EOL
3.5 KiB
Python
101 lines
No EOL
3.5 KiB
Python
"""
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payload_extraction.py — Extract the inner payload from the validated <message> envelope.
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After envelope_validation_step confirms a correct outer <message> envelope,
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this step extracts metadata from <meta> and isolates the single payload element.
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The payload is expected to be exactly one root element (the capability-specific XML).
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If zero or multiple payload roots are found, we set a clear error — this protects
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against malformed or ambiguous messages.
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Part of AgentServer v2.1 message pump.
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"""
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from lxml import etree
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from agentserver.message_bus.message_state import MessageState
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# Envelope namespace for easy reference
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_ENVELOPE_NS = "https://xml-pipeline.org/ns/envelope/v1"
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_MESSAGE_TAG = f"{{{_ENVELOPE_NS}}}message"
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_META_TAG = f"{{{_ENVELOPE_NS}}}meta"
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_FROM_TAG = f"{{{_ENVELOPE_NS}}}from"
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_TO_TAG = f"{{{_ENVELOPE_NS}}}to"
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_THREAD_TAG = f"{{{_ENVELOPE_NS}}}thread"
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async def payload_extraction_step(state: MessageState) -> MessageState:
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"""
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Extract the single payload element from the validated envelope.
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Expected structure (per envelope.xsd):
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<message xmlns="https://xml-pipeline.org/ns/envelope/v1">
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<meta>
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<from>sender</from>
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<to>receiver</to> <!-- optional -->
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<thread>uuid</thread>
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</meta>
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<payload_root xmlns="..."> ← this is what we extract
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...
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</payload_root>
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</message>
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On success: state.payload_tree is set to the payload Element.
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On failure: state.error is set with a clear diagnostic.
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"""
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if state.envelope_tree is None:
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state.error = "payload_extraction_step: no envelope_tree (previous step failed)"
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return state
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# Basic sanity — root must be <message> in correct namespace
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if state.envelope_tree.tag != _MESSAGE_TAG:
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state.error = "payload_extraction_step: root tag is not <message> in envelope namespace"
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return state
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# Find <meta> block and extract provenance
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meta_elem = state.envelope_tree.find(_META_TAG)
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if meta_elem is None:
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state.error = "payload_extraction_step: missing <meta> block in envelope"
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return state
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# Extract from_id (required)
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from_elem = meta_elem.find(_FROM_TAG)
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if from_elem is not None and from_elem.text:
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state.from_id = from_elem.text.strip()
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else:
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state.error = "payload_extraction_step: missing <from> in <meta>"
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return state
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# Extract thread_id (required)
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thread_elem = meta_elem.find(_THREAD_TAG)
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if thread_elem is not None and thread_elem.text:
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state.thread_id = thread_elem.text.strip()
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else:
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state.error = "payload_extraction_step: missing <thread> in <meta>"
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return state
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# Optional: extract <to> for direct routing
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to_elem = meta_elem.find(_TO_TAG)
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if to_elem is not None and to_elem.text:
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state.to_id = to_elem.text.strip()
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# Find all direct children that are NOT <meta> — those are payload candidates
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payload_candidates = [
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child for child in state.envelope_tree
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if child.tag != _META_TAG
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]
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if len(payload_candidates) == 0:
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state.error = "payload_extraction_step: no payload element found inside <message>"
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return state
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if len(payload_candidates) > 1:
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state.error = (
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"payload_extraction_step: multiple payload roots found — "
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"exactly one capability payload element is allowed"
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)
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return state
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# Success — exactly one payload element
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state.payload_tree = payload_candidates[0]
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return state |