navi/backend/services/navi_offroute/app.py

"""navi-offroute Flask application factory + gunicorn entry.

Gunicorn entry:
    gunicorn 'services.navi_offroute.app:create_app()' --bind 127.0.0.1:8428 --workers 2
"""
import logging
import time

from flask import Flask

from shared.git_sha import git_short_sha

from . import offroute_route, admin
from .mvum import MVUMSpatialIndex
from .mvum_transitions import load_trailheads
from .mvum_parking import load_parking_index

# Emit INFO+ so PR #34 per-stage Auto timing logs (single-mode probing took...,
# hybrid candidate gathering..., hybrid probing took...) reach stderr/journal;
# navi-offroute had no logging config, so the last-resort handler dropped INFO.
logging.basicConfig(level=logging.INFO)

# Process-wide singleton: build the MVUM spatial index once per process (per gunicorn
# worker in prod; once across create_app() calls in tests), not once per app instance.
_MVUM_INDEX = None


def _get_mvum_index():
    global _MVUM_INDEX
    if _MVUM_INDEX is None:
        _MVUM_INDEX = MVUMSpatialIndex()
    return _MVUM_INDEX



def create_app():
    app = Flask(__name__)

    app.config['VERSION'] = git_short_sha()
    app.config['METRICS'] = {
        'start_time': time.time(),
        'request_count': 0,
        'last_error_at': None,
    }

    @app.before_request
    def _count_request():
        app.config['METRICS']['request_count'] += 1

    @app.after_request
    def _track_errors(response):
        if response.status_code >= 500:
            app.config['METRICS']['last_error_at'] = time.strftime(
                '%Y-%m-%dT%H:%M:%SZ', time.gmtime()
            )
        return response

    # Load the MVUM spatial index once at service init (logs its own load line).
    try:
        app.config['MVUM_SPATIAL_INDEX'] = _get_mvum_index()
    except Exception as e:
        app.logger.warning("MVUM spatial index failed to load: %s", e)
        app.config['MVUM_SPATIAL_INDEX'] = None

    # Layer 3a: trailhead transition index (process-wide singleton, logs its own line).
    try:
        app.config['MVUM_TRAILHEAD_INDEX'] = load_trailheads()
    except Exception as e:
        app.logger.warning("MVUM trailhead index failed to load: %s", e)
        app.config['MVUM_TRAILHEAD_INDEX'] = None

    # Layer 3b: OSM parking index (process-wide singleton, logs its own line).
    try:
        app.config['OSM_PARKING_INDEX'] = load_parking_index()
    except Exception as e:
        app.logger.warning("OSM parking index failed to load: %s", e)
        app.config['OSM_PARKING_INDEX'] = None

    app.register_blueprint(offroute_route.bp)
    app.register_blueprint(admin.bp)
    return app