stack/apps/coordinator/src/main.py

"""FastAPI application for mosaic-coordinator webhook receiver."""

import asyncio
import logging
import os
from collections.abc import AsyncIterator
from contextlib import asynccontextmanager
from pathlib import Path
from typing import Any

from fastapi import FastAPI, Request
from pydantic import BaseModel
from slowapi import Limiter, _rate_limit_exceeded_handler
from slowapi.errors import RateLimitExceeded
from slowapi.util import get_remote_address

from .config import settings
from .coordinator import Coordinator
from .queue import QueueManager
from .telemetry import TelemetryService, shutdown_telemetry
from .webhook import router as webhook_router


# Configure logging
def setup_logging() -> None:
    """Configure logging for the application."""
    log_level = getattr(logging, settings.log_level.upper(), logging.INFO)
    logging.basicConfig(
        level=log_level,
        format="%(asctime)s - %(name)s - %(levelname)s - %(message)s",
        datefmt="%Y-%m-%d %H:%M:%S",
    )


# Setup logging on module import
setup_logging()
logger = logging.getLogger(__name__)

# Global instances for application state
_coordinator: Coordinator | None = None
_coordinator_task: asyncio.Task[None] | None = None


def get_coordinator() -> Coordinator | None:
    """Get the global coordinator instance.

    Returns:
        The Coordinator instance if initialized, None otherwise
    """
    return _coordinator


@asynccontextmanager
async def lifespan(app: FastAPI) -> AsyncIterator[dict[str, Any]]:
    """Application lifespan manager.

    Handles startup and shutdown logic including coordinator lifecycle.

    Yields:
        State dict with shared resources
    """
    global _coordinator, _coordinator_task

    # Startup
    logger.info("Starting mosaic-coordinator webhook receiver")
    logger.info(f"Gitea URL: {settings.gitea_url}")
    logger.info(f"Log level: {settings.log_level}")
    logger.info(f"Server: {settings.host}:{settings.port}")

    # Initialize OpenTelemetry if enabled
    telemetry_enabled = os.getenv("OTEL_ENABLED", "true").lower() != "false"
    if telemetry_enabled:
        telemetry_service = TelemetryService()
        telemetry_service.initialize()
        logger.info("OpenTelemetry telemetry initialized")

    # Initialize queue manager
    queue_file = Path("queue.json")
    queue_manager = QueueManager(queue_file=queue_file)
    logger.info(f"Queue manager initialized (file: {queue_file})")

    # Initialize and start coordinator if enabled
    if settings.coordinator_enabled:
        _coordinator = Coordinator(
            queue_manager=queue_manager,
            poll_interval=settings.coordinator_poll_interval,
        )
        logger.info(
            f"Coordinator initialized (poll interval: {settings.coordinator_poll_interval}s, "
            f"max agents: {settings.coordinator_max_concurrent_agents})"
        )

        # Start coordinator in background
        _coordinator_task = asyncio.create_task(_coordinator.start())
        logger.info("Coordinator orchestration loop started")
    else:
        logger.info("Coordinator disabled via configuration")

    yield {"queue_manager": queue_manager, "coordinator": _coordinator}

    # Shutdown
    logger.info("Shutting down mosaic-coordinator")

    # Stop coordinator gracefully
    if _coordinator is not None:
        logger.info("Stopping coordinator...")
        await _coordinator.stop()
        if _coordinator_task is not None:
            _coordinator_task.cancel()
            try:
                await _coordinator_task
            except asyncio.CancelledError:
                pass
        logger.info("Coordinator stopped")

    # Shutdown OpenTelemetry
    if telemetry_enabled:
        shutdown_telemetry()
        logger.info("OpenTelemetry telemetry shut down")

    logger.info("Mosaic-coordinator shutdown complete")


# Initialize rate limiter
limiter = Limiter(key_func=get_remote_address)

# Create FastAPI application
app = FastAPI(
    title="Mosaic Coordinator",
    description="Webhook receiver for Gitea issue events",
    version="0.0.1",
    lifespan=lifespan,
)

# Instrument FastAPI with OpenTelemetry if enabled
if os.getenv("OTEL_ENABLED", "true").lower() != "false":
    from opentelemetry.instrumentation.fastapi import FastAPIInstrumentor

    FastAPIInstrumentor.instrument_app(app)
    logger.info("FastAPI instrumented with OpenTelemetry")

# Register rate limiter
app.state.limiter = limiter
app.add_exception_handler(RateLimitExceeded, _rate_limit_exceeded_handler)


class HealthResponse(BaseModel):
    """Health check response model."""

    status: str
    service: str
    coordinator_running: bool = False
    active_agents: int = 0


@app.get("/health", response_model=HealthResponse)
async def health_check() -> HealthResponse:
    """Health check endpoint.

    Returns:
        HealthResponse indicating service is healthy with coordinator status
    """
    coordinator_running = False
    active_agents = 0

    if _coordinator is not None:
        coordinator_running = _coordinator.is_running
        active_agents = _coordinator.get_active_agent_count()

    return HealthResponse(
        status="healthy",
        service="mosaic-coordinator",
        coordinator_running=coordinator_running,
        active_agents=active_agents,
    )


# Include webhook router
app.include_router(webhook_router)


if __name__ == "__main__":
    import uvicorn

    uvicorn.run(
        "src.main:app",
        host=settings.host,
        port=settings.port,
        reload=True,
        log_level=settings.log_level.lower(),
    )