Reworks plugin loading and structure

Implements #4358

scripts/plugins/endpoints/syslog_alert_endpoint/alert_endpoints/syslog.lua

@@ -0,0 +1,127 @@
+--
+-- (C) 2018 - ntop.org
+--
+
+require "lua_utils"
+local json = require "dkjson"
+local alert_utils = require "alert_utils"
+local alert_consts = require "alert_consts"
+
+local syslog = {
+   name = "Syslog",
+   conf_max_num = 1, -- At most 1 endpoint
+   conf_params = {
+      { param_name = "syslog_alert_format" },
+   },
+   conf_template = {
+      plugin_key = "syslog_alert_endpoint",
+      template_name = "syslog_endpoint.template"
+   },
+   recipient_params = {
+   },
+   recipient_template = {
+      plugin_key = "syslog_alert_endpoint",
+      template_name = "syslog_recipient.template" -- TODO: add template
+   },
+}
+
+-- syslog.DEFAULT_SEVERITY = "info"
+syslog.EXPORT_FREQUENCY = 1 -- 1 second, i.e., as soon as possible
+syslog.prio = 300
+
+-- ##############################################
+
+function syslog.isAvailable()
+   return(ntop.syslog ~= nil)
+end
+
+-- ##############################################
+
+function syslog.sendMessage(notif, severity, syslog_format)
+   local syslog_severity = alert_consts.alertLevelToSyslogLevel(severity)
+   local msg
+
+   if syslog_format and 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)
+   else -- syslog_format == "plaintext"
+      -- prepare a plaintext message
+      msg = alert_utils.formatAlertNotification(notif, {
+         nohtml = true,
+	 show_severity = true,
+	 show_entity = true})
+   end
+
+   ntop.syslog(msg, syslog_severity)
+
+   return true
+end
+
+-- ##############################################
+
+-- Dequeue alerts from a recipient queue for sending notifications
+function syslog.dequeueRecipientAlerts(recipient, budget, high_priority)   
+    local notifications = {}
+    for i = 1, budget do
+       local notification = ntop.recipient_dequeue(recipient.recipient_id, high_priority)
+       if notification then 
+	  notifications[#notifications + 1] = notification
+       else
+	  break
+       end
+    end
+
+   if not notifications or #notifications == 0 then
+      return {success = true, more_available = false}
+   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
+            syslog.sendMessage(notif, severity, recipient.endpoint_conf.syslog_alert_format)
+	 end
+      end
+   end
+
+   return {success = true,  more_available = true}
+end
+
+-- ##############################################
+
+function syslog.runTest(recipient)
+  local now = os.time()
+  local notif = {
+    alert_tstamp = now,
+    alert_entity = alert_consts.alert_entities.test.entity_id,
+  }
+
+  local success = syslog.sendMessage(notif, "info", recipient.endpoint_conf.syslog_alert_format)
+
+  local message_info = i18n("prefs.syslog_sent_successfully")
+  return success, message_info
+end
+
+
+-- ##############################################
+
+return syslog