Reworks plugin loading and structure

Implements #4358

scripts/plugins/endpoints/discord_alert_endpoint/alert_endpoints/discord.lua

@@ -0,0 +1,181 @@
+--
+-- (C) 2020 - ntop.org
+--
+
+--
+-- This is the core plugin file where everything 
+-- has birth
+--
+
+require "lua_utils"
+local json = require "dkjson"
+local alert_utils = require "alert_utils"
+
+local endpoint_key = "discord_alert_endpoint"
+
+local discord = {
+   name = "Discord", -- A human readable name which will be shown in the UI
+
+   -- (1) Endpoint (see https://birdie0.github.io/discord-webhooks-guide/tools/curl.html)
+   conf_params = {
+      -- Define here the endpoint parameters used in the endpoint GUI
+      { param_name = "discord_url" },
+   },
+   
+   conf_template = {
+      plugin_key = endpoint_key, -- Unique string key
+
+      -- Filename of the GUI block for this endpoint
+      -- relative pathname to discord_alert_endpoint/templates/discord_endpoint.template
+      template_name = "discord_endpoint.template" 
+   },
+
+
+   -- (2) Recipient
+   recipient_params = {
+      -- Define here the endpoint parameters used in the recipient GUI
+      { param_name = "discord_username" }
+   },
+   recipient_template = {
+      plugin_key = endpoint_key, -- Unique string key
+
+      template_name = "discord_recipient.template"
+   },
+}
+
+-- ##############################################
+
+-- How often this script will be called (in seconds) for checking if there are messages to be processes
+discord.EXPORT_FREQUENCY = 5
+
+-- ##############################################
+
+-- Extract settings from recipients and place them on a simple datastructure
+local function readSettings(recipient)
+   local settings = {
+      -- Endpoint
+     url = recipient.endpoint_conf.discord_url, -- this information is coming from the endpoint configuration recipient.endpoint_conf. ...
+     -- Recipient
+     discord_username = recipient.recipient_params.discord_username, -- (**) this information is coming from the recipient configuration recipient.recipient_params. ...
+  }
+
+  return settings
+end
+
+-- ##############################################
+
+-- Function called whenever a message has to be sent out to discord
+function discord.sendMessage(message_body, settings)
+   local rc = false
+   local retry_attempts = 3
+   local username = settings.discord_username:gsub("%s+", "") -- Zap spaces
+
+   if isEmptyString(settings.url) then
+      return false
+   end
+
+   -- Discord usernames don't have spaces. This line of code will be removed when
+   -- (***) will be solved and the input will be clean
+
+   while retry_attempts > 0 do
+      local message = {
+	 username = username,
+	 content  = message_body,
+      }
+
+      local msg = json.encode(message)
+
+      if ntop.httpPost(settings.url, msg) then 
+	 rc = true
+	 break 
+      end
+      
+      retry_attempts = retry_attempts - 1
+   end
+
+   return rc
+end
+
+-- ##############################################
+
+local function formatDiscordMessage(alert)
+   local msg = alert_utils.formatAlertNotification(alert, {nohtml=true, add_cr=true, no_bracket_around_date=true})
+   
+   return(msg)
+end
+
+-- ##############################################
+
+-- Function called periodically to process queued alerts to be delivered via Discord
+function discord.dequeueRecipientAlerts(recipient, budget, high_priority)
+  local start_time = os.time()
+  local sent = 0
+  local more_available = true
+  local budget_used = 0
+  local settings = readSettings(recipient)
+  local max_alerts_per_request = 1 -- collapse up to X alerts per request
+
+  -- Dequeue alerts up to budget x max_alerts_per_request
+  -- Note: in this case budget is the number of email to send
+  while budget_used <= budget and more_available do
+    local diff = os.time() - start_time
+    if diff >= 5 then
+      break
+    end
+
+    -- Dequeue max_alerts_per_request notifications
+    local notifications = {}
+    for i=1, max_alerts_per_request 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
+      more_available = false
+      break
+    end
+
+    local alerts = {}
+
+    for _, json_message in ipairs(notifications) do
+       table.insert(alerts, formatDiscordMessage(json.decode(json_message)))       
+    end
+
+    if not discord.sendMessage(table.concat(alerts, "\n"), settings) then
+      return {success=false, error_message="Unable to send alerts to the discord"}
+    end
+
+    -- Remove the processed messages from the queue
+    budget_used = budget_used + #notifications
+    sent = sent + 1
+  end
+
+  return {success = true, more_available = more_available}
+end
+
+-- ##############################################
+
+-- This is a testing function invoked by the web GUI whenever a test message has to be sent out
+
+function discord.runTest(recipient)
+  local message_info
+
+  local settings = readSettings(recipient)
+
+  local success = discord.sendMessage("test", settings)
+
+  if not success then
+    message_info = i18n("discord_alert_endpoint.discord_send_error")
+  end
+
+  return success, message_info
+end
+
+-- ##############################################
+
+return discord
+

scripts/plugins/endpoints/discord_alert_endpoint/http_lint.lua

@@ -0,0 +1,28 @@
+--
+-- (C) 2019-20 - ntop.org
+--
+--
+
+-- Place here the checks for parameters used by this plugins
+-- In essence it extends (and references) checks present in
+-- scripts/lua/modules/http_lint.lua
+--
+
+local script = {}
+
+-- ##############################################
+
+-- @brief Called by the main http_lint module to load additional parameters.
+-- @params http_lint a reference to the scripts/lua/modules/http_lint.lua module
+-- @return a (possibly empty) table with parameter_name -> validator mappings
+function script.getAdditionalParameters(http_lint)
+   return {
+      ["discord_url"]       = { http_lint.webhookCleanup, http_lint.validateUnquoted },
+      ["discord_sender"]    = http_lint.validateUnquoted,
+      ["discord_username"]  = http_lint.validateEmptyOr(http_lint.validateSingleWord),
+  }
+end
+
+-- ##############################################
+
+return(script)

scripts/plugins/endpoints/discord_alert_endpoint/locales/en.lua

@@ -0,0 +1,18 @@
+--
+-- (C) 2020 - ntop.org
+--
+
+return {
+   url = "WebHook URL",
+   username = "Username",
+   validation = {
+      empty_url = "Discord Webook URL cannot be empty.",
+      invalid_url = "Invalid Discord Webhook URL. See https://support.discord.com/hc/en-us/articles/228383668-Intro-to-Webhooks.",
+      invalid_username = "Invalid Discord username.",
+   },
+   discord_send_error = "Error sending message to Discord.",
+   message_sender = "Nickname of the discord message sender (optional). ",
+
+   webhook_description = "Instructions:<ul><li>Open the Discord channel you want to receive ntopng notifications from.<li>From the channel menu, select Edit channel (or click on the wheel icon). <li>Click on Webhooks menu item.<li>Click the Create Webhook button and fill in the name of the bot that will post the messages (note that you can set it on the ntopng recipients page)<li>Note the URL from the WebHook URL field to be copied in the field above. <li>Click the Save button.</ul>"
+      
+}

scripts/plugins/endpoints/discord_alert_endpoint/manifest.lua

@@ -0,0 +1,16 @@
+--
+-- (C) 2019-20 - ntop.org
+--
+
+-- This file contains the plugin metadata information.
+
+-- NOTE: Plugins are loaded at startup, any change to this plugin
+-- can be applied by restarting ntopng or by manually reloading the
+-- plugins from http://127.0.0.1:3000/lua/plugins_overview.lua .
+
+return {
+  title = "Discords Alert Endpoint",
+  description = "Provides alerts notifications to discord",
+  author = "ntop",
+  dependencies = {},
+}

scripts/plugins/endpoints/discord_alert_endpoint/templates/discord_endpoint.template

@@ -0,0 +1,12 @@
+<div class="form-group row">
+    <label class="col-form-label col-sm-3">
+	<b>{{ i18n("discord_alert_endpoint.url") }}</b>
+    </label>
+    <div class="col-sm-5">
+	<input
+	data-validation-message="{{ i18n('discord_alert_endpoint.validation.invalid_url') }}"
+	data-validation-empty-message="{{ i18n('discord_alert_endpoint.validation.empty_url') }}"
+	data-pattern="https" name="discord_url" type="text" class="form-control" required />
+    </div>
+</div>
+<small>{* i18n('discord_alert_endpoint.webhook_description') *}</small>

scripts/plugins/endpoints/discord_alert_endpoint/templates/discord_recipient.template

@@ -0,0 +1,11 @@
+<div class="form-group row">
+    <label class="col-form-label col-sm-3">
+        {{ i18n("discord_alert_endpoint.username") }}
+    </label>
+    <div class="col-sm-5">
+        <input
+	data-validation-message="{{ i18n('discord_alert_endpoint.validation.invalid_username') }}"
+	data-pattern="username" name="discord_username" type="text" class="form-control" />
+        <small class="text-muted">{{ i18n('discord_alert_endpoint.message_sender') }}</small>
+    </div>
+</div>