Starting to implement alerts #17

alertproviders/alert_provider.py

@@ -0,0 +1,43 @@
+from datetime import datetime
+
+import pytz
+
+from core.config import SERVER_OWNER_CALLSIGN, MAX_ALERT_AGE
+from core.constants import SOFTWARE_NAME, SOFTWARE_VERSION
+
+
+# Generic alert provider class. Subclasses of this query the individual APIs for alerts.
+class AlertProvider:
+
+    # HTTP headers used for spot providers that use HTTP
+    HTTP_HEADERS = { "User-Agent": SOFTWARE_NAME + " " + SOFTWARE_VERSION + " (operated by " + SERVER_OWNER_CALLSIGN + ")" }
+
+    # Constructor
+    def __init__(self, provider_config):
+        self.name = provider_config["name"]
+        self.enabled = provider_config["enabled"]
+        self.last_update_time = datetime.min.replace(tzinfo=pytz.UTC)
+        self.status = "Not Started" if self.enabled else "Disabled"
+        self.alerts = None
+
+    # Set up the provider, e.g. giving it the alert list to work from
+    def setup(self, alerts):
+        self.alerts = alerts
+
+    # Start the provider. This should return immediately after spawning threads to access the remote resources
+    def start(self):
+        raise NotImplementedError("Subclasses must implement this method")
+
+    # Submit a batch of alerts retrieved from the provider. There is no timestamp checking like there is for spots,
+    # because alerts could be created at any point for any time in the future. Rely on hashcode-based id matching
+    # to deal with duplicates.
+    def submit_batch(self, alerts):
+        for alert in alerts:
+            # Fill in any blanks
+            alert.infer_missing()
+            # Add to the list
+            self.alerts.add(alert.id, alert, expire=MAX_ALERT_AGE)
+
+    # Stop any threads and prepare for application shutdown
+    def stop(self):
+        raise NotImplementedError("Subclasses must implement this method")