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beaver-gateway/src/beaver_gateway/frontends/markdown/frontend.py
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2026-05-22 22:48:12 +02:00

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39 KiB
Python

"""``MarkdownFrontend`` — chat-via-markdown-files frontend.
Wires:
* ``POST /chat {filename, content?, agent?}`` — bearer-authenticated
trigger. The plugin in Obsidian fires this after the user edits a
``.md`` and the file gets synced (or with ``content`` to short-circuit
the sync delay). We parse the file, check the last turn — assistant
→ no-op, user → run the agent and append.
* ``GET /healthz`` — liveness.
Concurrency model: an in-memory ``set[Path]`` of files currently in
flight. Two concurrent requests for the same file → the second gets
409. The set is single-process (one gateway instance) — that's by
design; the markdown frontend is the only writer in its vault from
the gateway side.
Cross-frontend logging: when ``log_all_chats=True``, ``configure()``
registers a handler on ``runtime.turn_log_handlers`` so every other
frontend's completed turns also land in the vault. The handler logic
lives in :mod:`.crossfront` so this module stays focused on the HTTP
shape.
"""
from __future__ import annotations
import contextlib
import json
import logging
import os
import tempfile
import time
from pathlib import Path
from typing import TYPE_CHECKING, Any
import aiofile
from anthropic.types import RawContentBlockStopEvent
from fastapi import FastAPI, HTTPException, Request, status
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse, StreamingResponse
from beaver_gateway.backends.claude_code import ClaudeCodeBackendAdapter, TurnCapture
from beaver_gateway.core import audit
from beaver_gateway.core.conversation_store import (
diff_and_fork,
load_conversation,
load_messages,
mint_conversation,
rewrite_messages,
)
from beaver_gateway.core.turn_record import TurnRecord
from beaver_gateway.frontends._accumulate import StreamAccumulator
from beaver_gateway.frontends._auth import require_token
from beaver_gateway.frontends.base import Frontend
from beaver_gateway.frontends.markdown import parser, renderer
from beaver_gateway.frontends.markdown.crossfront import (
CrossFrontendLogger,
fingerprint_messages,
)
if TYPE_CHECKING:
from collections.abc import AsyncIterator, Callable
from anthropic.types import MessageParam
from beaver_gateway.frontends.base import GatewayRuntime
_log = logging.getLogger("beaver_gateway.frontends.markdown")
__all__ = ["MarkdownFrontend"]
# How often we re-render the assistant turn into the .md file while the
# backend stream is still open. Trades responsiveness (faster updates to
# Obsidian sync / Raycast tailers) against write amplification. Each
# ``RawContentBlockStopEvent`` also forces a flush regardless of the
# timer, so block boundaries always land in the file.
_STREAM_FLUSH_DEBOUNCE = 0.4
# Debounce for the SSE ``/chat/stream`` path. Network IO is cheaper than
# atomic file rewrites, so we send updates more frequently — the client
# wants the lowest possible latency and we control the renderer on the
# other end (the Obsidian plugin splices deltas into the editor, no
# disk round-trip).
_SSE_FLUSH_DEBOUNCE = 0.1
class MarkdownFrontend(Frontend):
"""FastAPI app behind ``POST /chat`` driven by Obsidian-vault files."""
def __init__(
self,
*,
vault_path: Path | str,
host: str = "0.0.0.0", # noqa: S104
port: int = 8003,
default_agent: str | None = None,
log_all_chats: bool = False,
logged_subdir: str = "_logs",
log_path: Callable[[TurnRecord, Path], Path] | None = None,
public_base_url: str | None = None,
) -> None:
self.vault_path = Path(vault_path).expanduser().resolve()
self.host = host
self.port = port
self.default_agent = default_agent
self.log_all_chats = log_all_chats
self.logged_subdir = logged_subdir
self.log_path = log_path
# External URL prefix when behind a reverse proxy — same role as
# on the other bearer frontends. Trailing slash trimmed for
# idempotent concatenation; ``None`` means "no proxy / advertise
# raw host:port".
self.public_base_url = public_base_url.rstrip("/") if public_base_url else None
self._runtime: GatewayRuntime | None = None
self._app: FastAPI | None = None
# Files currently being processed by an in-flight ``POST /chat``.
# Checked-and-added atomically in the request handler (no
# ``await`` between the check and the insert) so a concurrent
# request reliably loses the race to 409.
self._busy: set[Path] = set()
self._crossfront: CrossFrontendLogger | None = None
def configure(self, runtime: GatewayRuntime) -> None:
self._runtime = runtime
self.vault_path.mkdir(parents=True, exist_ok=True)
if self.log_all_chats:
self._crossfront = CrossFrontendLogger(
vault_path=self.vault_path,
logged_subdir=self.logged_subdir,
log_path=self.log_path,
)
# Scan the existing logged files synchronously here so the
# fingerprint→path map is populated before the first
# cross-frontend turn arrives. Cheap: frontmatter-only read.
self._crossfront.warm_index()
runtime.turn_log_handlers.append(self._crossfront.handle)
self._app = self._build_app(runtime)
async def serve(self) -> None:
import uvicorn
if self._app is None:
msg = "configure() must be called before serve()"
raise RuntimeError(msg)
config = uvicorn.Config(
self._app, host=self.host, port=self.port, log_level="info"
)
server = uvicorn.Server(config)
await server.serve()
# ---- app builder ---------------------------------------------------
def _build_app(self, runtime: GatewayRuntime) -> FastAPI:
app = FastAPI(title="beaver-gateway / Markdown")
# ``/chat/stream`` is consumed via ``fetch`` from the Obsidian
# plugin (``requestUrl`` can't read a body incrementally), and
# ``fetch`` is subject to CORS. Auth is bearer-token so we don't
# need credentialed mode; allow any origin and the standard
# methods/headers. The other endpoints are happy to ride along.
app.add_middleware(
CORSMiddleware,
allow_origins=["*"],
allow_credentials=False,
allow_methods=["*"],
allow_headers=["*"],
)
@app.get("/healthz")
async def healthz() -> dict[str, str]:
return {"status": "ok"}
@app.get("/agents")
async def list_agents(request: Request) -> dict[str, Any]:
await require_token(request, runtime, scope="messages")
return {"agents": [{"name": a.name} for a in runtime.agents]}
@app.post("/chat")
async def chat(request: Request) -> Any:
token_name = await require_token(request, runtime, scope="messages")
try:
body = await request.json()
except json.JSONDecodeError as exc:
raise HTTPException(
status.HTTP_400_BAD_REQUEST, f"invalid JSON: {exc}"
) from exc
filename = body.get("filename")
if not isinstance(filename, str) or not filename.strip():
raise HTTPException(
status.HTTP_400_BAD_REQUEST, "missing or non-string `filename`"
)
content_override = body.get("content")
agent_override = body.get("agent")
if agent_override is not None and not isinstance(agent_override, str):
raise HTTPException(
status.HTTP_400_BAD_REQUEST, "`agent` must be a string"
)
file_path = self._resolve_path(filename)
# Atomic check-and-claim: both ops run between awaits, so a
# second request can't slip into the same file slot.
if file_path in self._busy:
return JSONResponse(
status_code=status.HTTP_409_CONFLICT,
content={"status": "in_progress", "filename": filename},
)
self._busy.add(file_path)
try:
return await self._handle_chat(
runtime=runtime,
token_name=token_name,
filename=filename,
file_path=file_path,
content_override=content_override,
agent_override=agent_override,
)
finally:
self._busy.discard(file_path)
@app.post("/chat/stream")
async def chat_stream(request: Request) -> Any:
# Same contract as ``/chat`` (bearer auth, identical body),
# but the response is ``text/event-stream`` and intermediate
# rendered states are pushed as ``delta`` events. The
# gateway-side disk write only happens once, at end of turn,
# so streaming consumers (Obsidian plugin) and Obsidian Sync
# don't fight over the same file mid-stream.
token_name = await require_token(request, runtime, scope="messages")
try:
body = await request.json()
except json.JSONDecodeError as exc:
raise HTTPException(
status.HTTP_400_BAD_REQUEST, f"invalid JSON: {exc}"
) from exc
filename = body.get("filename")
if not isinstance(filename, str) or not filename.strip():
raise HTTPException(
status.HTTP_400_BAD_REQUEST, "missing or non-string `filename`"
)
content_override = body.get("content")
agent_override = body.get("agent")
if agent_override is not None and not isinstance(agent_override, str):
raise HTTPException(
status.HTTP_400_BAD_REQUEST, "`agent` must be a string"
)
file_path = self._resolve_path(filename)
# 409 path stays JSON — the stream hasn't started yet, so
# the caller can read it the same way as on ``/chat``.
if file_path in self._busy:
return JSONResponse(
status_code=status.HTTP_409_CONFLICT,
content={"status": "in_progress", "filename": filename},
)
self._busy.add(file_path)
async def gen() -> AsyncIterator[bytes]:
try:
async for chunk in self._handle_chat_streaming(
runtime=runtime,
token_name=token_name,
filename=filename,
file_path=file_path,
content_override=content_override,
agent_override=agent_override,
):
yield chunk
finally:
self._busy.discard(file_path)
return StreamingResponse(
gen(),
media_type="text/event-stream",
headers={
"Cache-Control": "no-cache, no-transform",
"Connection": "keep-alive",
# nginx default-buffers SSE bodies; this header tells
# both nginx and uvicorn-behind-proxy to flush as we
# write. Harmless if the deployment has no reverse
# proxy in front.
"X-Accel-Buffering": "no",
},
)
return app
# ---- dispatch ------------------------------------------------------
async def _handle_chat(
self,
*,
runtime: GatewayRuntime,
token_name: str,
filename: str,
file_path: Path,
content_override: Any,
agent_override: str | None,
) -> Any:
if isinstance(content_override, str):
await _write_atomic(file_path, content_override)
file_text = content_override
elif content_override is None:
file_text = await _read_or_empty(file_path)
else:
raise HTTPException(
status.HTTP_400_BAD_REQUEST, "`content` must be a string when present"
)
parsed = parser.parse(file_text)
agent_name = parser.resolve_agent(
metadata=parsed.metadata,
request_override=agent_override,
default=self.default_agent,
)
if not agent_name:
raise HTTPException(
status.HTTP_400_BAD_REQUEST,
"no agent specified: pass `agent`, set frontmatter, "
"or configure `default_agent`",
)
# When the parser produced no messages (file empty / only
# frontmatter), there's nothing to dispatch.
if not parsed.messages:
return {
"status": "nothing_to_do",
"reason": "empty file",
"new_content": file_text,
}
if parser.last_role(parsed.messages) == "assistant":
return {
"status": "nothing_to_do",
"reason": "last turn is assistant",
"new_content": file_text,
}
agent = runtime.agents.get(agent_name)
if agent is None:
raise HTTPException(
status.HTTP_404_NOT_FOUND, f"unknown agent: {agent_name!r}"
)
backend = runtime.backends.get(agent.name)
if backend is None:
raise HTTPException(
status.HTTP_503_SERVICE_UNAVAILABLE,
f"no backend configured for agent {agent.name!r}",
)
_log.info(
"chat: actor=%s agent=%s file=%s msgs=%d",
token_name,
agent.name,
filename,
len(parsed.messages),
)
await audit.log(
runtime,
actor=f"token:{token_name}",
kind="markdown_chat",
agent_name=agent.name,
filename=filename,
msgs=len(parsed.messages),
)
# Resolve / mint the conversation row, align incoming against
# stored history, and feed the aligned messages to the backend
# — see ``core/conversation_store.py`` for the full rationale.
# If the backend isn't claude-code (no ``TurnCapture`` support)
# we fall through to the legacy parser-only path.
conv, conv_external_id, stored_msgs = await self._resolve_conversation(
runtime=runtime, metadata=parsed.metadata, agent_name=agent.name
)
outcome = diff_and_fork(stored=stored_msgs, incoming=parsed.turns)
capture: TurnCapture | None = (
TurnCapture() if isinstance(backend, ClaudeCodeBackendAdapter) else None
)
kwargs: dict[str, Any] = {}
if capture is not None:
kwargs["capture"] = capture
events = backend.complete(
agent=agent, messages=outcome.messages, system=None, **kwargs
)
try:
message = await self._stream_to_file(
events=events,
file_path=file_path,
parsed=parsed,
model=agent.model or agent.name,
filename=filename,
)
except HTTPException:
raise
except Exception as exc:
raise HTTPException(
status.HTTP_500_INTERNAL_SERVER_ERROR, f"backend error: {exc}"
) from exc
new_content = await self._write_assistant_reply(
file_path=file_path,
parsed=parsed,
message=message,
agent_name=agent.name,
conv_external_id=conv_external_id,
)
await self._persist_canonical_history(
runtime=runtime,
conversation_id=conv.id,
persist_messages=outcome.persist_messages,
new_user_text=parsed.turns[-1].text,
capture=capture,
message=message,
)
# Broadcast our own turn so other handlers (none today, but the
# symmetry is worth keeping) see what happened. ``source`` marks
# the origin so ``CrossFrontendLogger`` can skip its own files.
record = TurnRecord(
agent_name=agent.name,
input_messages=list(parsed.messages),
output_message=message,
system=None,
source="markdown",
)
for handler in runtime.turn_log_handlers:
try:
await handler(record)
except Exception: # noqa: BLE001
_log.exception("turn_log_handler raised; continuing")
return {
"status": "ok",
"turns_appended": 1,
"agent": agent.name,
"new_content": new_content,
}
# ---- streaming dispatch (SSE) --------------------------------------
async def _handle_chat_streaming( # noqa: PLR0915 — mirrors _handle_chat, splitting only doubles read cost
self,
*,
runtime: GatewayRuntime,
token_name: str,
filename: str,
file_path: Path,
content_override: Any,
agent_override: str | None,
) -> AsyncIterator[bytes]:
"""SSE counterpart of :meth:`_handle_chat`.
Mirrors the same pipeline (resolve file → parse → resolve agent →
run backend → persist), but emits ``event: delta`` frames as the
rendered turn grows and a single terminal ``event: done`` /
``event: error``. Errors that ``_handle_chat`` would surface as
``HTTPException`` go out as ``error`` frames here (the HTTP
envelope is already 200 by the time the stream starts).
Intermediate disk writes are deliberately skipped — only the
post-stream :meth:`_write_assistant_reply` lands on disk, so the
gateway-side vault and the plugin-side editor are the only
writers in their respective halves of Obsidian Sync. Final
content is identical on both sides, so Sync no-ops.
"""
# File-text resolution + early bailouts. ``content_override`` is
# still written to disk on the gateway side because that's the
# state the rest of the request consumes; it just doesn't keep
# ticking after that single write.
if isinstance(content_override, str):
await _write_atomic(file_path, content_override)
file_text = content_override
elif content_override is None:
file_text = await _read_or_empty(file_path)
else:
yield _sse_pack(
"error",
{
"status_code": status.HTTP_400_BAD_REQUEST,
"detail": "`content` must be a string when present",
},
)
return
parsed = parser.parse(file_text)
agent_name = parser.resolve_agent(
metadata=parsed.metadata,
request_override=agent_override,
default=self.default_agent,
)
if not agent_name:
yield _sse_pack(
"error",
{
"status_code": status.HTTP_400_BAD_REQUEST,
"detail": (
"no agent specified: pass `agent`, set frontmatter, "
"or configure `default_agent`"
),
},
)
return
if not parsed.messages:
yield _sse_pack(
"done",
{
"status": "nothing_to_do",
"reason": "empty file",
"new_content": file_text,
},
)
return
if parser.last_role(parsed.messages) == "assistant":
yield _sse_pack(
"done",
{
"status": "nothing_to_do",
"reason": "last turn is assistant",
"new_content": file_text,
},
)
return
agent = runtime.agents.get(agent_name)
if agent is None:
yield _sse_pack(
"error",
{
"status_code": status.HTTP_404_NOT_FOUND,
"detail": f"unknown agent: {agent_name!r}",
},
)
return
backend = runtime.backends.get(agent.name)
if backend is None:
yield _sse_pack(
"error",
{
"status_code": status.HTTP_503_SERVICE_UNAVAILABLE,
"detail": f"no backend configured for agent {agent.name!r}",
},
)
return
_log.info(
"chat/stream: actor=%s agent=%s file=%s msgs=%d",
token_name,
agent.name,
filename,
len(parsed.messages),
)
await audit.log(
runtime,
actor=f"token:{token_name}",
kind="markdown_chat_stream",
agent_name=agent.name,
filename=filename,
msgs=len(parsed.messages),
)
conv, conv_external_id, stored_msgs = await self._resolve_conversation(
runtime=runtime, metadata=parsed.metadata, agent_name=agent.name
)
_log.info(
"chat/stream: file=%s conv_external_id=%s conv_id=%d "
"stored_msgs=%d incoming_turns=%d",
filename,
conv_external_id,
conv.id or -1,
len(stored_msgs),
len(parsed.turns),
)
outcome = diff_and_fork(stored=stored_msgs, incoming=parsed.turns)
_log.info(
"chat/stream: file=%s diff_and_fork divergence=%s "
"backend_msgs=%d persist_msgs=%d",
filename,
outcome.divergence_index,
len(outcome.messages),
len(outcome.persist_messages),
)
capture: TurnCapture | None = (
TurnCapture() if isinstance(backend, ClaudeCodeBackendAdapter) else None
)
kwargs: dict[str, Any] = {}
if capture is not None:
kwargs["capture"] = capture
_log.info(
"chat/stream: file=%s calling backend.complete agent=%s capture=%s",
filename,
agent.name,
capture is not None,
)
events = backend.complete(
agent=agent, messages=outcome.messages, system=None, **kwargs
)
acc = StreamAccumulator()
model = agent.model or agent.name
last_flush = time.monotonic()
last_payload: str | None = None
def snapshot() -> str | None:
partial = acc.finalize(model=model)
if not partial.content:
return None
rendered = renderer.render_assistant_message(partial)
new_body = renderer.append_to_body(parsed.body, rendered)
return _reattach_frontmatter(parsed.metadata, new_body)
try:
async for ev in events:
acc.feed(ev)
now = time.monotonic()
if (
isinstance(ev, RawContentBlockStopEvent)
or (now - last_flush) >= _SSE_FLUSH_DEBOUNCE
):
payload = snapshot()
# Skip duplicate snapshots — e.g. tool_use blocks
# render to the same prefix as before they closed
# (we don't surface the tool-call args in markdown).
if payload is not None and payload != last_payload:
yield _sse_pack("delta", {"new_content": payload})
last_payload = payload
last_flush = now
except Exception as exc: # noqa: BLE001 — wire any backend failure as an SSE error frame
_log.exception("backend failed for %s", filename)
# Mirror the legacy path: write the last partial + an error
# callout to disk so other consumers (logs, file watchers)
# see what arrived. The client gets a clean SSE ``error``.
partial = acc.finalize(model=model)
new_body = parsed.body
if partial.content:
new_body = renderer.append_to_body(
new_body, renderer.render_assistant_message(partial)
)
new_body = renderer.append_to_body(new_body, _render_error_block(exc))
await _write_atomic(
file_path, _reattach_frontmatter(parsed.metadata, new_body)
)
yield _sse_pack(
"error",
{
"status_code": status.HTTP_500_INTERNAL_SERVER_ERROR,
"detail": f"backend error: {exc}",
},
)
return
message = acc.finalize(model=model)
new_content = await self._write_assistant_reply(
file_path=file_path,
parsed=parsed,
message=message,
agent_name=agent.name,
conv_external_id=conv_external_id,
)
await self._persist_canonical_history(
runtime=runtime,
conversation_id=conv.id,
persist_messages=outcome.persist_messages,
new_user_text=parsed.turns[-1].text,
capture=capture,
message=message,
)
record = TurnRecord(
agent_name=agent.name,
input_messages=list(parsed.messages),
output_message=message,
system=None,
source="markdown",
)
for handler in runtime.turn_log_handlers:
try:
await handler(record)
except Exception: # noqa: BLE001
_log.exception("turn_log_handler raised; continuing")
yield _sse_pack(
"done",
{
"status": "ok",
"turns_appended": 1,
"agent": agent.name,
"new_content": new_content,
},
)
# ---- helpers -------------------------------------------------------
async def _stream_to_file(
self,
*,
events: Any,
file_path: Path,
parsed: parser.ParsedFile,
model: str,
filename: str,
) -> Any:
"""Drain ``events`` into a ``Message``, flushing partials to disk.
Flushes happen on each ``RawContentBlockStopEvent`` (natural
block boundary, content is markdown-consistent) and on the
``_STREAM_FLUSH_DEBOUNCE`` timer between events. The partial
write keeps the as-parsed frontmatter; the post-stream final
write in ``_write_assistant_reply`` is what stamps the refreshed
fingerprint / agent / conversation_id.
On backend exception we still flush the last partial and append
an error callout, so the human sees both what arrived and why it
stopped. The exception propagates so ``_handle_chat`` can map it
to a 500.
"""
acc = StreamAccumulator()
async def flush_partial() -> None:
partial = acc.finalize(model=model)
if not partial.content:
return
rendered = renderer.render_assistant_message(partial)
new_body = renderer.append_to_body(parsed.body, rendered)
await _write_atomic(
file_path, _reattach_frontmatter(parsed.metadata, new_body)
)
try:
last_flush = time.monotonic()
async for ev in events:
acc.feed(ev)
now = time.monotonic()
if (
isinstance(ev, RawContentBlockStopEvent)
or (now - last_flush) >= _STREAM_FLUSH_DEBOUNCE
):
await flush_partial()
last_flush = now
except Exception as exc:
_log.exception("backend failed for %s", filename)
partial = acc.finalize(model=model)
new_body = parsed.body
if partial.content:
new_body = renderer.append_to_body(
new_body, renderer.render_assistant_message(partial)
)
new_body = renderer.append_to_body(new_body, _render_error_block(exc))
await _write_atomic(
file_path, _reattach_frontmatter(parsed.metadata, new_body)
)
raise
return acc.finalize(model=model)
async def _write_assistant_reply(
self,
*,
file_path: Path,
parsed: parser.ParsedFile,
message: Any,
agent_name: str,
conv_external_id: str,
) -> str:
"""Render the assistant turn, append to the file, refresh frontmatter."""
rendered = renderer.render_assistant_message(message)
new_body = renderer.append_to_body(parsed.body, rendered)
new_body = renderer.append_to_body(new_body, renderer.USER_SCAFFOLD)
# Recompute fingerprint so a future cross-frontend hit on this
# same conversation can find it. Stored as hex string in
# frontmatter — only the markdown frontend reads it.
assistant_param: MessageParam = {
"role": "assistant",
"content": _flatten_assistant_text(message),
}
updated_messages: list[MessageParam] = [*parsed.messages, assistant_param]
updated_metadata = dict(parsed.metadata)
updated_metadata["agent"] = agent_name
updated_metadata["conversation_id"] = conv_external_id
updated_metadata["fingerprint"] = fingerprint_messages(updated_messages)
new_content = _reattach_frontmatter(updated_metadata, new_body)
await _write_atomic(file_path, new_content)
return new_content
async def _resolve_conversation(
self, *, runtime: GatewayRuntime, metadata: dict[str, Any], agent_name: str
) -> tuple[Any, str, list[dict[str, Any]]]:
"""Resolve the conversation row + stored messages for this request.
Looks up by frontmatter ``conversation_id``, mints a new row if
missing, and returns ``(conv, external_id, stored_messages)``.
``conv.id`` is guaranteed non-None because both
``load_conversation`` (after refresh on a committed row) and
``mint_conversation`` (post-commit refresh) populate it. We
coerce with a runtime check so the rest of the handler can
treat it as ``int``.
"""
raw = metadata.get("conversation_id")
lookup_id = raw if isinstance(raw, str) and raw else None
async with runtime.db.session() as session:
conv = None
if lookup_id is not None:
conv = await load_conversation(
session, frontend="markdown", external_id=lookup_id
)
if conv is None:
_log.info(
"_resolve_conversation: frontmatter conv_id=%s "
"not found in DB, will mint new",
lookup_id,
)
else:
_log.info(
"_resolve_conversation: LOADED existing conv "
"id=%d external_id=%s",
conv.id or -1,
conv.external_id,
)
if conv is None:
conv = await mint_conversation(
session, frontend="markdown", agent_name=agent_name
)
_log.info(
"_resolve_conversation: MINTED new conv "
"id=%d external_id=%s agent=%s",
conv.id or -1,
conv.external_id,
agent_name,
)
if conv.id is None:
msg = "conversation row missing primary key after commit"
raise RuntimeError(msg)
stored = await load_messages(session, conversation_id=conv.id)
return conv, conv.external_id, stored
async def _persist_canonical_history(
self,
*,
runtime: GatewayRuntime,
conversation_id: int,
persist_messages: list[dict[str, Any]],
new_user_text: str,
capture: TurnCapture | None,
message: Any,
) -> None:
"""Stamp the DB with the post-turn canonical Anthropic-shape history.
Combines the matched/spliced prior state, the new user prompt,
and the synthesized assistant↔tool cycle from the backend (or
a text-only fallback for backends without ``TurnCapture``).
"""
new_user_msg = {"role": "user", "content": new_user_text}
synthesized = (
capture.synthesized_messages
if capture is not None
else _fallback_synthesized(message)
)
canonical = [*persist_messages, new_user_msg, *synthesized]
_log.info(
"_persist_canonical_history: conv_id=%d writing %d msgs "
"(prior=%d + new_user + synth=%d)",
conversation_id,
len(canonical),
len(persist_messages),
len(synthesized),
)
async with runtime.db.session() as session:
await rewrite_messages(
session, conversation_id=conversation_id, messages=canonical
)
_log.info(
"_persist_canonical_history: conv_id=%d DB committed", conversation_id
)
def _resolve_path(self, filename: str) -> Path:
"""Resolve ``filename`` under the vault; reject escapes."""
# ``filename`` may be relative or absolute; we always anchor
# under ``vault_path`` so absolute paths from outside the vault
# don't sneak through. ``Path("/foo/bar")`` combined with a
# vault path keeps the absolute side; we strip leading slashes
# to coerce the rooted form into a relative path before joining.
rel = filename.lstrip("/")
if not rel.endswith(".md"):
rel = rel + ".md"
candidate = (self.vault_path / rel).resolve()
try:
candidate.relative_to(self.vault_path)
except ValueError as exc:
raise HTTPException(
status.HTTP_400_BAD_REQUEST, f"filename escapes vault: {filename!r}"
) from exc
return candidate
# ---- module-level utilities ----------------------------------------------
def _sse_pack(event: str, data: dict[str, Any]) -> bytes:
r"""Format one Server-Sent Event frame.
Uses named events (``event: <name>``) so the plugin can dispatch on
type without parsing JSON discriminators. ``ensure_ascii=False`` so
multibyte content rides through verbatim instead of becoming
``\uXXXX`` blobs that bloat the wire.
"""
body = json.dumps(data, ensure_ascii=False)
return f"event: {event}\ndata: {body}\n\n".encode()
async def _read_or_empty(path: Path) -> str:
"""Return file contents, or empty string if the file doesn't exist."""
# ``path.exists()`` here is a metadata stat — microseconds — and
# gating an async read on whether the file is there is exactly the
# check we want. Switching to anyio.Path / aiofiles.os just to
# silence the async-pathlib lint would cost a dep edge for no
# practical win.
if not path.exists(): # noqa: ASYNC240
return ""
async with aiofile.async_open(path, "r", encoding="utf-8") as f:
return await f.read()
async def _write_atomic(path: Path, content: str) -> None:
"""Write ``content`` to ``path`` via tmp + ``os.replace`` (atomic)."""
path.parent.mkdir(parents=True, exist_ok=True)
# ``NamedTemporaryFile`` keeps the file open which complicates
# ``os.replace`` on some platforms. Build the tmp name manually,
# write+fsync, then rename. Same-directory so the rename is atomic.
tmp_name = tempfile.mkstemp(
prefix=f".{path.name}.", suffix=".tmp", dir=str(path.parent)
)
fd, tmp_path = tmp_name
try:
async with aiofile.async_open(tmp_path, "w", encoding="utf-8") as f:
await f.write(content)
os.close(fd)
# ``os.replace`` is the atomic primitive — ``Path.replace`` is a
# thin wrapper around the same syscall; either works, ``os.`` is
# the one Linux/POSIX docs reach for.
os.replace(tmp_path, path) # noqa: PTH105
except BaseException:
# Cleanup on failure: close fd, remove tmp.
with contextlib.suppress(OSError):
os.close(fd)
with contextlib.suppress(OSError):
os.unlink(tmp_path) # noqa: PTH108
raise
def _reattach_frontmatter(metadata: dict[str, Any], body: str) -> str:
r"""Re-emit a ``.md`` file with YAML frontmatter at the top.
Empty metadata → no frontmatter block (avoid littering every file
with a hollow ``---\n---``).
"""
if not metadata:
return body if body.endswith("\n") else body + "\n"
import frontmatter as _fm
post = _fm.Post(content=body, **metadata)
return _fm.dumps(post) + "\n"
def _fallback_synthesized(message: Any) -> list[dict[str, Any]]:
"""Build a single-assistant ``synthesized_messages`` list from a raw ``Message``.
For backends that don't populate a :class:`TurnCapture` (anthropic
HTTP, raycast, …) we don't have access to per-tool-cycle
granularity, so the assistant reply lands in the DB as one
canonical-block message. Tool memory across cache misses would
degrade in that case, but those backends don't have the cache-miss
re-seed problem to begin with — they manage history client-side.
"""
content: list[dict[str, Any]] = []
for block in getattr(message, "content", ()):
btype = getattr(block, "type", None)
if btype == "text":
content.append({"type": "text", "text": getattr(block, "text", "") or ""})
elif btype == "tool_use":
content.append(
{
"type": "tool_use",
"id": getattr(block, "id", ""),
"name": getattr(block, "name", ""),
"input": getattr(block, "input", {}),
}
)
elif btype == "thinking":
content.append(
{
"type": "thinking",
"thinking": getattr(block, "thinking", "") or "",
"signature": getattr(block, "signature", "") or "",
}
)
if not content:
return []
return [{"role": "assistant", "content": content}]
def _flatten_assistant_text(message: Any) -> str:
"""Pull all text blocks from an assistant ``Message`` and join them.
Used when we need the assistant content as a plain string for
fingerprinting / equality with a parser-shaped history (parser
already drops thinking + tool_use from assistant turns).
"""
chunks = [
getattr(block, "text", "") or ""
for block in getattr(message, "content", ())
if getattr(block, "type", None) == "text"
]
return "\n\n".join(c for c in chunks if c)
def _render_error_block(exc: BaseException) -> str:
"""Render a backend failure as an Assistant turn with a ``[!error]-`` callout."""
msg = str(exc) or exc.__class__.__name__
safe = msg.replace("\n", " ").strip()
return f"### Assistant:\n\n> [!error]-\n> {safe}\n"