Add acknowledged alert history and HTML email digests

store.go

@@ -97,6 +97,13 @@ func openStore(path string) (*Store, error) {
 			zfs_usage REAL NOT NULL, guests_cpu REAL NOT NULL, guests_memory REAL NOT NULL
 		)`,
 		`CREATE INDEX IF NOT EXISTS history_ts_idx ON history(ts)`,
+		`CREATE TABLE IF NOT EXISTS alert_events (
+			id INTEGER PRIMARY KEY AUTOINCREMENT, alert_key TEXT NOT NULL, severity TEXT NOT NULL,
+			source TEXT NOT NULL, title TEXT NOT NULL, message TEXT NOT NULL,
+			first_seen INTEGER NOT NULL, last_seen INTEGER NOT NULL, resolved_at INTEGER,
+			acknowledged_at INTEGER, email_sent_at INTEGER
+		)`,
+		`CREATE INDEX IF NOT EXISTS alert_events_active_idx ON alert_events(alert_key,resolved_at)`,
 	}
 	for _, statement := range statements {
 		if _, err := db.Exec(statement); err != nil {