LedgerLine/services/notifier/app.py

from contextlib import asynccontextmanager

import asyncio

from fastapi import FastAPI, Request
from fastapi.responses import JSONResponse
from opentelemetry import trace
from opentelemetry.instrumentation.fastapi import FastAPIInstrumentor
from opentelemetry.instrumentation.sqlalchemy import SQLAlchemyInstrumentor
from opentelemetry.trace import StatusCode

from common.db import engine
from common.logging_config import configure_logging
from common.metrics import observe_db_pools, observe_stream_lag
from common.redis_client import redis_client
from common.telemetry import setup_telemetry

from . import consumer

SERVICE_NAME = "notifier"
logger = configure_logging(SERVICE_NAME)
setup_telemetry(service_name=SERVICE_NAME)


@asynccontextmanager
async def lifespan(app: FastAPI):
    task = asyncio.create_task(consumer.run())
    yield
    task.cancel()


app = FastAPI(title=SERVICE_NAME, lifespan=lifespan)

FastAPIInstrumentor.instrument_app(
    app,
    excluded_urls="/healthz",
    exclude_spans=["receive", "send"],
)
SQLAlchemyInstrumentor().instrument(engines=[engine.sync_engine])
observe_db_pools({"default": engine})
observe_stream_lag(consumer.GROUP)


@app.get("/")
async def root():
    return {"service": SERVICE_NAME, "version": "0.1.0"}


@app.get("/healthz")
async def healthz(request: Request):
    if request.headers.get("X-Ledgerline-Probe") == "chatty-health":
        logger.info("healthz_probe_received", probe="chatty-health")
    return {"status": "ok", "service": SERVICE_NAME}


@app.get("/readyz")
async def readyz():
    try:
        async with engine.connect() as conn:
            await conn.exec_driver_sql("SELECT 1")
        await redis_client.ping()
    except Exception as exc:
        span = trace.get_current_span()
        span.record_exception(exc)
        span.set_status(StatusCode.ERROR, str(exc))
        logger.exception("readyz_check_failed")
        return JSONResponse(status_code=503, content={"status": "unavailable"})
    return {"status": "ok"}