deer-flow/backend/tests/test_stream_bridge.py
ly-wang19 f956682f31
perf(runtime): resolve SSE resume offset in O(1) via the event-id seq (#3700)
MemoryStreamBridge._resolve_start_offset scanned the retained event buffer
(up to queue_maxsize=256 entries) on every subscribe/reconnect carrying a
Last-Event-ID. Event ids are "{ts}-{seq}" where seq is a per-run monotonic
counter that equals the event's absolute offset, so the offset is computable
arithmetically. Parse seq, index into the buffer, and verify the id matches
exactly -- a stale/evicted/foreign/malformed id falls back to
replay-from-earliest, identical to the previous scan.

Co-authored-by: ly-wang19 <ly-wang19@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-23 10:25:18 +08:00

407 lines
13 KiB
Python

"""Tests for the in-memory StreamBridge implementation."""
import asyncio
import re
import anyio
import pytest
from deerflow.runtime import END_SENTINEL, HEARTBEAT_SENTINEL, MemoryStreamBridge, make_stream_bridge
# ---------------------------------------------------------------------------
# Unit tests for MemoryStreamBridge
# ---------------------------------------------------------------------------
@pytest.fixture
def bridge() -> MemoryStreamBridge:
return MemoryStreamBridge(queue_maxsize=256)
@pytest.mark.anyio
async def test_publish_subscribe(bridge: MemoryStreamBridge):
"""Three events followed by end should be received in order."""
run_id = "run-1"
await bridge.publish(run_id, "metadata", {"run_id": run_id})
await bridge.publish(run_id, "values", {"messages": []})
await bridge.publish(run_id, "updates", {"step": 1})
await bridge.publish_end(run_id)
received = []
async for entry in bridge.subscribe(run_id, heartbeat_interval=1.0):
received.append(entry)
if entry is END_SENTINEL:
break
assert len(received) == 4
assert received[0].event == "metadata"
assert received[1].event == "values"
assert received[2].event == "updates"
assert received[3] is END_SENTINEL
@pytest.mark.anyio
async def test_heartbeat(bridge: MemoryStreamBridge):
"""When no events arrive within the heartbeat interval, yield a heartbeat."""
run_id = "run-heartbeat"
bridge._get_or_create_stream(run_id) # ensure stream exists
received = []
async def consumer():
async for entry in bridge.subscribe(run_id, heartbeat_interval=0.1):
received.append(entry)
if entry is HEARTBEAT_SENTINEL:
break
await asyncio.wait_for(consumer(), timeout=2.0)
assert len(received) == 1
assert received[0] is HEARTBEAT_SENTINEL
@pytest.mark.anyio
async def test_cleanup(bridge: MemoryStreamBridge):
"""After cleanup, the run's stream/event log is removed."""
run_id = "run-cleanup"
await bridge.publish(run_id, "test", {})
assert run_id in bridge._streams
await bridge.cleanup(run_id)
assert run_id not in bridge._streams
assert run_id not in bridge._counters
@pytest.mark.anyio
async def test_history_is_bounded():
"""Retained history should be bounded by queue_maxsize."""
bridge = MemoryStreamBridge(queue_maxsize=1)
run_id = "run-bp"
await bridge.publish(run_id, "first", {})
await bridge.publish(run_id, "second", {})
await bridge.publish_end(run_id)
received = []
async for entry in bridge.subscribe(run_id, heartbeat_interval=1.0):
received.append(entry)
if entry is END_SENTINEL:
break
assert len(received) == 2
assert received[0].event == "second"
assert received[1] is END_SENTINEL
@pytest.mark.anyio
async def test_multiple_runs(bridge: MemoryStreamBridge):
"""Two different run_ids should not interfere with each other."""
await bridge.publish("run-a", "event-a", {"a": 1})
await bridge.publish("run-b", "event-b", {"b": 2})
await bridge.publish_end("run-a")
await bridge.publish_end("run-b")
events_a = []
async for entry in bridge.subscribe("run-a", heartbeat_interval=1.0):
events_a.append(entry)
if entry is END_SENTINEL:
break
events_b = []
async for entry in bridge.subscribe("run-b", heartbeat_interval=1.0):
events_b.append(entry)
if entry is END_SENTINEL:
break
assert len(events_a) == 2
assert events_a[0].event == "event-a"
assert events_a[0].data == {"a": 1}
assert len(events_b) == 2
assert events_b[0].event == "event-b"
assert events_b[0].data == {"b": 2}
@pytest.mark.anyio
async def test_event_id_format(bridge: MemoryStreamBridge):
"""Event IDs should use timestamp-sequence format."""
run_id = "run-id-format"
await bridge.publish(run_id, "test", {"key": "value"})
await bridge.publish_end(run_id)
received = []
async for entry in bridge.subscribe(run_id, heartbeat_interval=1.0):
received.append(entry)
if entry is END_SENTINEL:
break
event = received[0]
assert re.match(r"^\d+-\d+$", event.id), f"Expected timestamp-seq format, got {event.id}"
@pytest.mark.anyio
async def test_subscribe_replays_after_last_event_id(bridge: MemoryStreamBridge):
"""Reconnect should replay buffered events after the provided Last-Event-ID."""
run_id = "run-replay"
await bridge.publish(run_id, "metadata", {"run_id": run_id})
await bridge.publish(run_id, "values", {"step": 1})
await bridge.publish(run_id, "updates", {"step": 2})
await bridge.publish_end(run_id)
first_pass = []
async for entry in bridge.subscribe(run_id, heartbeat_interval=1.0):
first_pass.append(entry)
if entry is END_SENTINEL:
break
received = []
async for entry in bridge.subscribe(
run_id,
last_event_id=first_pass[0].id,
heartbeat_interval=1.0,
):
received.append(entry)
if entry is END_SENTINEL:
break
assert [entry.event for entry in received[:-1]] == ["values", "updates"]
assert received[-1] is END_SENTINEL
@pytest.mark.anyio
async def test_slow_subscriber_does_not_skip_after_buffer_trim():
"""A slow subscriber should continue from the correct absolute offset."""
bridge = MemoryStreamBridge(queue_maxsize=2)
run_id = "run-slow-subscriber"
await bridge.publish(run_id, "e1", {"step": 1})
await bridge.publish(run_id, "e2", {"step": 2})
stream = bridge._streams[run_id]
e1_id = stream.events[0].id
assert stream.start_offset == 0
await bridge.publish(run_id, "e3", {"step": 3}) # trims e1
assert stream.start_offset == 1
assert [entry.event for entry in stream.events] == ["e2", "e3"]
resumed_after_e1 = []
async for entry in bridge.subscribe(
run_id,
last_event_id=e1_id,
heartbeat_interval=1.0,
):
resumed_after_e1.append(entry)
if len(resumed_after_e1) == 2:
break
assert [entry.event for entry in resumed_after_e1] == ["e2", "e3"]
e2_id = resumed_after_e1[0].id
await bridge.publish_end(run_id)
received = []
async for entry in bridge.subscribe(
run_id,
last_event_id=e2_id,
heartbeat_interval=1.0,
):
received.append(entry)
if entry is END_SENTINEL:
break
assert [entry.event for entry in received[:-1]] == ["e3"]
assert received[-1] is END_SENTINEL
# ---------------------------------------------------------------------------
# Stream termination tests
# ---------------------------------------------------------------------------
@pytest.mark.anyio
async def test_publish_end_terminates_even_when_history_is_full():
"""publish_end() should terminate subscribers without mutating retained history."""
bridge = MemoryStreamBridge(queue_maxsize=2)
run_id = "run-end-history-full"
await bridge.publish(run_id, "event-1", {"n": 1})
await bridge.publish(run_id, "event-2", {"n": 2})
stream = bridge._streams[run_id]
assert [entry.event for entry in stream.events] == ["event-1", "event-2"]
await bridge.publish_end(run_id)
assert [entry.event for entry in stream.events] == ["event-1", "event-2"]
events = []
async for entry in bridge.subscribe(run_id, heartbeat_interval=0.1):
events.append(entry)
if entry is END_SENTINEL:
break
assert [entry.event for entry in events[:-1]] == ["event-1", "event-2"]
assert events[-1] is END_SENTINEL
@pytest.mark.anyio
async def test_publish_end_without_history_yields_end_immediately():
"""Subscribers should still receive END when a run completes without events."""
bridge = MemoryStreamBridge(queue_maxsize=2)
run_id = "run-end-empty"
await bridge.publish_end(run_id)
events = []
async for entry in bridge.subscribe(run_id, heartbeat_interval=0.1):
events.append(entry)
if entry is END_SENTINEL:
break
assert len(events) == 1
assert events[0] is END_SENTINEL
@pytest.mark.anyio
async def test_publish_end_preserves_history_when_space_available():
"""When history has spare capacity, publish_end should preserve prior events."""
bridge = MemoryStreamBridge(queue_maxsize=10)
run_id = "run-no-evict"
await bridge.publish(run_id, "event-1", {"n": 1})
await bridge.publish(run_id, "event-2", {"n": 2})
await bridge.publish_end(run_id)
events = []
async for entry in bridge.subscribe(run_id, heartbeat_interval=0.1):
events.append(entry)
if entry is END_SENTINEL:
break
# All events plus END should be present
assert len(events) == 3
assert events[0].event == "event-1"
assert events[1].event == "event-2"
assert events[2] is END_SENTINEL
@pytest.mark.anyio
async def test_concurrent_tasks_end_sentinel():
"""Multiple concurrent producer/consumer pairs should all terminate properly.
Simulates the production scenario where multiple runs share a single
bridge instance — each must receive its own END sentinel.
"""
bridge = MemoryStreamBridge(queue_maxsize=4)
num_runs = 4
async def producer(run_id: str):
for i in range(10): # More events than queue capacity
await bridge.publish(run_id, f"event-{i}", {"i": i})
await bridge.publish_end(run_id)
async def consumer(run_id: str) -> list:
events = []
async for entry in bridge.subscribe(run_id, heartbeat_interval=0.1):
events.append(entry)
if entry is END_SENTINEL:
return events
return events # pragma: no cover
run_ids = [f"concurrent-{i}" for i in range(num_runs)]
results: dict[str, list] = {}
async def consume_into(run_id: str) -> None:
results[run_id] = await consumer(run_id)
with anyio.fail_after(10):
async with anyio.create_task_group() as task_group:
for run_id in run_ids:
task_group.start_soon(consume_into, run_id)
await anyio.sleep(0)
for run_id in run_ids:
task_group.start_soon(producer, run_id)
for run_id in run_ids:
events = results[run_id]
assert events[-1] is END_SENTINEL, f"Run {run_id} did not receive END sentinel"
# ---------------------------------------------------------------------------
# Factory tests
# ---------------------------------------------------------------------------
@pytest.mark.anyio
async def test_make_stream_bridge_defaults():
"""make_stream_bridge() with no config yields a MemoryStreamBridge."""
async with make_stream_bridge() as bridge:
assert isinstance(bridge, MemoryStreamBridge)
# ---------------------------------------------------------------------------
# _resolve_start_offset: O(1) seq-indexed resolution (parity with linear scan)
# ---------------------------------------------------------------------------
def _linear_resolve(stream, last_event_id):
"""The original linear-scan resolver, kept as a parity reference."""
if last_event_id is None:
return stream.start_offset
for index, entry in enumerate(stream.events):
if entry.id == last_event_id:
return stream.start_offset + index + 1
return stream.start_offset
@pytest.mark.parametrize(
"event_id,expected",
[
("1718000000000-0", 0),
("1718000000000-42", 42),
("garbage", None), # no separator
("1718000000000-x", None), # non-integer seq
("", None),
],
)
def test_parse_event_seq(event_id, expected):
assert MemoryStreamBridge._parse_event_seq(event_id) == expected
@pytest.mark.anyio
async def test_resolve_start_offset_matches_linear_scan():
"""The seq-indexed resolver must return exactly what the linear scan returned,
across retained, evicted, foreign (same seq / wrong ts), malformed, and None ids."""
bridge = MemoryStreamBridge(queue_maxsize=4)
run_id = "run-parity"
ids = []
for i in range(10):
await bridge.publish(run_id, f"e{i}", {"i": i})
ids.append(bridge._streams[run_id].events[-1].id) # includes ids that later evict
stream = bridge._streams[run_id]
assert stream.start_offset == 6 # 10 published, buffer of 4 retains seq 6..9
# A foreign id: a retained event's seq but a different timestamp -> must NOT match.
ts, _, seq_text = stream.events[0].id.rpartition("-")
foreign_id = f"{int(ts) + 1}-{seq_text}"
candidates = [None, "garbage", "1718000000000-x", "999999-999999", foreign_id, *ids]
for eid in candidates:
assert bridge._resolve_start_offset(stream, eid) == _linear_resolve(stream, eid), eid
@pytest.mark.anyio
async def test_subscribe_with_unknown_last_event_id_replays_from_earliest():
"""A foreign/garbage Last-Event-ID falls back to replaying retained events."""
bridge = MemoryStreamBridge(queue_maxsize=10)
run_id = "run-unknown-id"
await bridge.publish(run_id, "first", {})
await bridge.publish(run_id, "second", {})
await bridge.publish_end(run_id)
received = []
async for entry in bridge.subscribe(run_id, last_event_id="not-a-real-id", heartbeat_interval=1.0):
received.append(entry)
if entry is END_SENTINEL:
break
assert [entry.event for entry in received[:-1]] == ["first", "second"]
assert received[-1] is END_SENTINEL