First attempt at SSE backend #3

spothole.py

@@ -3,11 +3,13 @@ import importlib
 import logging
 import signal
 import sys
+from time import sleep
 
 from diskcache import Cache
+from gevent import monkey; monkey.patch_all()
 
 from core.cleanup import CleanupTimer
-from core.config import config, WEB_SERVER_PORT, SERVER_OWNER_CALLSIGN
+from core.config import config, WEB_SERVER_PORT, SERVER_OWNER_CALLSIGN, MAX_SPOT_AGE
 from core.constants import SOFTWARE_NAME, SOFTWARE_VERSION
 from core.lookup_helper import lookup_helper
 from core.status_reporter import StatusReporter
@@ -16,14 +18,17 @@ from server.webserver import WebServer
 # Globals
 spots = Cache('cache/spots_cache')
 alerts = Cache('cache/alerts_cache')
+web_server = None
 status_data = {}
 spot_providers = []
 alert_providers = []
 cleanup_timer = None
+run = True
 
 
 # Shutdown function
 def shutdown(sig, frame):
+    global spot_providers, alert_providers, cleanup_timer, spots, alerts, run
     logging.info("Stopping program, this may take a few seconds...")
     for p in spot_providers:
         if p.enabled:
@@ -35,6 +40,7 @@ def shutdown(sig, frame):
     lookup_helper.stop()
     spots.close()
     alerts.close()
+    run = False
 
 
 # Utility method to get a spot provider based on the class specified in its config entry.
@@ -50,6 +56,24 @@ def get_alert_provider_from_config(config_providers_entry):
     provider_class = getattr(module, config_providers_entry["class"])
     return provider_class(config_providers_entry)
 
+# Utility method to add a spot, notifying the web server in case any Server-Sent Event connections need to have data
+# sent immediately. If the spot has already expired due to loading old data, it will be ignored.
+def add_spot(spot):
+    global web_server
+    if not spot.expired():
+        spots.add(spot.id, spot, expire=MAX_SPOT_AGE)
+        if web_server:
+            web_server.notify_new_spot(spot)
+
+# Utility method to add an alert, notifying the web server in case any Server-Sent Event connections need to have data
+# sent immediately. If the alert has already expired due to loading old data, it will be ignored.
+def add_alert(alert):
+    global web_server
+    if not alert.expired():
+        alerts.add(alert.id, alert, expire=MAX_SPOT_AGE)
+        if web_server:
+            web_server.notify_new_alert(alert)
+
 
 # Main function
 if __name__ == '__main__':
@@ -72,6 +96,10 @@ if __name__ == '__main__':
     # Set up lookup helper
     lookup_helper.start()
 
+    # Set up web server
+    web_server = WebServer(spots=spots, alerts=alerts, status_data=status_data, port=WEB_SERVER_PORT)
+    web_server.start()
+
     # Fetch, set up and start spot providers
     for entry in config["spot-providers"]:
         spot_providers.append(get_spot_provider_from_config(entry))
@@ -89,13 +117,9 @@ if __name__ == '__main__':
             p.start()
 
     # Set up timer to clear spot list of old data
-    cleanup_timer = CleanupTimer(spots=spots, alerts=alerts, cleanup_interval=60)
+    cleanup_timer = CleanupTimer(spots=spots, alerts=alerts, web_server=web_server, cleanup_interval=60)
     cleanup_timer.start()
 
-    # Set up web server
-    web_server = WebServer(spots=spots, alerts=alerts, status_data=status_data, port=WEB_SERVER_PORT)
-    web_server.start()
-
     # Set up status reporter
     status_reporter = StatusReporter(status_data=status_data, spots=spots, alerts=alerts, web_server=web_server,
                                      cleanup_timer=cleanup_timer, spot_providers=spot_providers,
@@ -103,3 +127,6 @@ if __name__ == '__main__':
     status_reporter.start()
 
     logging.info("Startup complete.")
+
+    while (run):
+        sleep(1)