spothole/server/webserver.py

import asyncio
import logging
import os

import tornado
from tornado.web import StaticFileHandler

from server.handlers.api.addspot import APISpotHandler
from server.handlers.api.alerts import APIAlertsHandler, APIAlertsStreamHandler
from server.handlers.api.lookups import APILookupCallHandler, APILookupSIGRefHandler, APILookupGridHandler
from server.handlers.api.options import APIOptionsHandler
from server.handlers.api.spots import APISpotsHandler, APISpotsStreamHandler
from server.handlers.api.status import APIStatusHandler
from server.handlers.metrics import PrometheusMetricsHandler
from server.handlers.pagetemplate import PageTemplateHandler


# Provides the public-facing web server.
class WebServer:
    # Constructor
    def __init__(self, spots, alerts, status_data, port):
        self.spots = spots
        self.alerts = alerts
        self.sse_spot_queues = []
        self.sse_alert_queues = []
        self.status_data = status_data
        self.port = port
        self.shutdown_event = asyncio.Event()
        self.web_server_metrics = {
            "last_page_access_time": None,
            "last_api_access_time": None,
            "page_access_counter": 0,
            "api_access_counter": 0,
            "status": "Starting"
        }

    # Start the web server
    def start(self):
        asyncio.run(self.start_inner())

    # Stop the web server
    def stop(self):
        self.shutdown_event.set()

    # Start method (async). Sets up the Tornado application.
    async def start_inner(self):
        app = tornado.web.Application([
            # Routes for API calls
            (r"/api/v1/spots", APISpotsHandler, {"spots": self.spots, "web_server_metrics": self.web_server_metrics}),
            (r"/api/v1/alerts", APIAlertsHandler, {"alerts": self.alerts, "web_server_metrics": self.web_server_metrics}),
            (r"/api/v1/spots/stream", APISpotsStreamHandler, {"sse_spot_queues": self.sse_spot_queues, "web_server_metrics": self.web_server_metrics}),
            (r"/api/v1/alerts/stream", APIAlertsStreamHandler, {"sse_alert_queues": self.sse_alert_queues, "web_server_metrics": self.web_server_metrics}),
            (r"/api/v1/options", APIOptionsHandler, {"status_data": self.status_data, "web_server_metrics": self.web_server_metrics}),
            (r"/api/v1/status", APIStatusHandler, {"status_data": self.status_data, "web_server_metrics": self.web_server_metrics}),
            (r"/api/v1/lookup/call", APILookupCallHandler, {"web_server_metrics": self.web_server_metrics}),
            (r"/api/v1/lookup/sigref", APILookupSIGRefHandler, {"web_server_metrics": self.web_server_metrics}),
            (r"/api/v1/lookup/grid", APILookupGridHandler, {"web_server_metrics": self.web_server_metrics}),
            (r"/api/v1/spot", APISpotHandler, {"spots": self.spots, "web_server_metrics": self.web_server_metrics}),
            # Routes for templated pages
            (r"/", PageTemplateHandler, {"template_name": "spots", "web_server_metrics": self.web_server_metrics}),
            (r"/map", PageTemplateHandler, {"template_name": "map", "web_server_metrics": self.web_server_metrics}),
            (r"/bands", PageTemplateHandler, {"template_name": "bands", "web_server_metrics": self.web_server_metrics}),
            (r"/alerts", PageTemplateHandler, {"template_name": "alerts", "web_server_metrics": self.web_server_metrics}),
            (r"/add-spot", PageTemplateHandler, {"template_name": "add_spot", "web_server_metrics": self.web_server_metrics}),
            (r"/status", PageTemplateHandler, {"template_name": "status", "web_server_metrics": self.web_server_metrics}),
            (r"/about", PageTemplateHandler, {"template_name": "about", "web_server_metrics": self.web_server_metrics}),
            (r"/apidocs", PageTemplateHandler, {"template_name": "apidocs", "web_server_metrics": self.web_server_metrics}),
            # Route for Prometheus metrics
            (r"/metrics", PrometheusMetricsHandler),
            # Default route to serve from "webassets"
            (r"/(.*)", StaticFileHandler, {"path": os.path.join(os.path.dirname(__file__), "../webassets")}),
        ],
            template_path=os.path.join(os.path.dirname(__file__), "../templates"),
            debug=False)
        app.listen(self.port)
        await self.shutdown_event.wait()

    # Internal method called when a new spot is added to the system. This is used to ping any SSE clients that are
    # awaiting a server-sent message with new spots.
    def notify_new_spot(self, spot):
        for queue in self.sse_spot_queues:
            try:
                queue.put(spot)
            except:
                # Cleanup thread was probably deleting the queue, that's fine
                pass
        pass

    # Internal method called when a new alert is added to the system. This is used to ping any SSE clients that are
    # awaiting a server-sent message with new spots.
    def notify_new_alert(self, alert):
        for queue in self.sse_alert_queues:
            try:
                queue.put(alert)
            except:
                # Cleanup thread was probably deleting the queue, that's fine
                pass
        pass

    # Clean up any SSE queues that are growing too large; probably their client disconnected and we didn't catch it
    # properly for some reason.
    def clean_up_sse_queues(self):
        for q in self.sse_spot_queues:
            try:
                if q.full():
                    logging.warn("A full SSE spot queue was found, presumably because the client disconnected strangely. It has been removed.")
                    self.sse_spot_queues.remove(q)
                    q.empty()
            except:
                # Probably got deleted already on another thread
                pass
        for q in self.sse_alert_queues:
            try:
                if q.full():
                    logging.warn("A full SSE alert queue was found, presumably because the client disconnected strangely. It has been removed.")
                    self.sse_alert_queues.remove(q)
                    q.empty()
            except:
                # Probably got deleted already on another thread
                pass
        pass