Files
LedgerLine/services/notifier/consumer.py
T
Movses AslanyanandClaude Opus 5.5 d1c158c835 Carry trace context across the Redis Stream by hand
Redis Streams have no headers, so the gateway injects traceparent into
the message fields inside a PRODUCER span. The notifier and audit
consumers extract it and open one CONSUMER span per message, so their
DB and XACK spans join the transaction's trace. The idle XREADGROUP poll
runs under suppress_instrumentation (it was a ~2s root trace every loop),
and audit strips the trace fields so its stored payload is unchanged.

The gateway also stops tracing its frontend's /api/health/ polling.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-13 17:46:51 +03:30

98 lines
3.3 KiB
Python

import asyncio
import logging
import random
import uuid
import sqlalchemy as sa
from opentelemetry import propagate, trace
from opentelemetry.instrumentation.utils import suppress_instrumentation
from opentelemetry.trace import SpanKind
from common.db import Session
from common.redis_client import redis_client
from common.settings import settings
from . import chaos
logger = logging.getLogger("notifier")
tracer = trace.get_tracer(__name__)
GROUP = "notifier"
CONSUMER = "notifier-1"
async def ensure_group():
try:
await redis_client.xgroup_create(settings.stream_name, GROUP, id="$", mkstream=True)
except Exception as exc:
if "BUSYGROUP" not in str(exc):
raise
async def _handle(fields: dict):
if await chaos.slow_consumer_enabled():
await asyncio.sleep(chaos.SLEEP_SECONDS)
async with Session() as session:
await session.execute(
sa.text(
"INSERT INTO notifications (id, transaction_id, channel, status, attempts, sent_at) "
"VALUES (:id, :tx_id, :channel, 'sent', 1, now())"
),
{
"id": str(uuid.uuid4()),
"tx_id": fields.get("transaction_id"),
"channel": random.choice(["email", "push", "sms"]),
},
)
await session.commit()
async def run():
"""Background consumer loop for the `notifier` consumer group -- a second,
independent group (`audit`) reads the same stream in services/audit/worker.py.
Redis Streams carry no automatic context propagation, deliberately."""
await ensure_group()
logger.info("notifier consumer started")
while True:
try:
# The blocking poll would otherwise be a ~2s root trace every loop.
with suppress_instrumentation():
resp = await redis_client.xreadgroup(
groupname=GROUP,
consumername=CONSUMER,
streams={settings.stream_name: ">"},
count=10,
block=2000,
)
except asyncio.CancelledError:
raise
except Exception:
logger.exception("notifier consumer read failed")
await asyncio.sleep(1)
continue
if not resp:
continue
for _, messages in resp:
for msg_id, fields in messages:
# Parent is the gateway's PRODUCER span, carried in the message.
with tracer.start_as_current_span(
f"process {settings.stream_name}",
context=propagate.extract(fields),
kind=SpanKind.CONSUMER,
attributes={
"messaging.system": "redis",
"messaging.destination.name": settings.stream_name,
"messaging.operation.type": "process",
"messaging.consumer.group.name": GROUP,
"messaging.message.id": msg_id,
},
):
try:
await _handle(fields)
except Exception:
logger.exception(f"notifier failed to process message {msg_id}")
await redis_client.xack(settings.stream_name, GROUP, msg_id)