Enable new recipient based notification for the syslog endpoint

scripts/plugins/syslog_alert_endpoint/alert_endpoints/syslog.lua

@@ -16,7 +16,6 @@ local syslog = {
       template_name = "syslog_endpoint.template"
    },
    recipient_params = {
-      -- TODO: add channel
    },
    recipient_template = {
       plugin_key = "syslog_alert_endpoint",
@@ -36,9 +35,7 @@ end
 
 -- ##############################################
 
-function syslog.dequeueAlerts(queue, budget)
-
-   -- TODO handle budget (pay attention to severity/priority)
+function syslog.dequeueAlerts(queue)
 
    local notifications = ntop.lrangeCache(queue, 0, -1)
 
@@ -100,6 +97,69 @@ end
 
 -- ##############################################
 
+-- Dequeue alerts from a recipient queue for sending notifications
+function syslog.dequeueRecipientAlerts(recipient, budget)
+
+   local notifications = ntop.lrangeCache(recipient.export_queue, 0, budget-1)
+
+   if not notifications or #notifications == 0 then
+      return {success = true}
+   end
+
+   local syslog_format = recipient.endpoint_conf.endpoint_conf.syslog_alert_format
+   if isEmptyString(syslog_format) then
+      syslog_format = "plaintext"
+   end
+
+   -- Separate by severity and channel
+   local alerts_by_types = {}
+
+   for _, json_message in ipairs(notifications) do
+      local notif = json.decode(json_message)
+      if notif.alert_entity then
+         alerts_by_types[notif.alert_entity] = alerts_by_types[notif.alert_entity] or {}
+         alerts_by_types[notif.alert_entity][notif.alert_severity] = alerts_by_types[notif.alert_entity][notif.alert_severity] or {}
+         table.insert(alerts_by_types[notif.alert_entity][notif.alert_severity], notif)
+      end
+   end
+
+   for _, by_severity in pairs(alerts_by_types) do
+      for severity, sev_notifications in pairs(by_severity) do
+        severity = alert_consts.alertSeverityRaw(severity)
+
+	 -- Most recent notifications first
+	 for _, notif in pairsByValues(sev_notifications, alert_utils.notification_timestamp_rev) do
+	    local syslog_severity = alert_consts.alertLevelToSyslogLevel(severity)
+
+	    local msg
+
+	    if syslog_format == "plaintext" then
+	       -- prepare a plaintext message
+	       msg = alert_utils.formatAlertNotification(notif, {nohtml = true,
+						     show_severity = true,
+						     show_entity = true})
+	    else -- syslog_format == "json" then
+	       -- send out the json message but prepare a nice
+	       -- message
+	       notif.message  = alert_utils.formatAlertNotification(notif, {nohtml = true,
+								show_severity = false,
+								show_entity = false})
+	       msg = json.encode(notif)
+	    end
+
+	    ntop.syslog(msg, syslog_severity)
+	 end
+      end
+   end
+
+   -- Remove the processed messages from the queue
+   ntop.ltrimCache(recipient.export_queue, #notifications, -1)
+
+   return {success = true}
+end
+
+-- ##############################################
+
 function syslog.printPrefs(alert_endpoints, subpage_active, showElements)
    print('<thead class="thead-light"><tr><th colspan="2" class="info">'..i18n("prefs.syslog_notification")..'</th></tr></thead>')