Reworks plugin loading and structure

Implements #4358

scripts/plugins/examples/example/user_scripts/flow/example.lua

@@ -0,0 +1,134 @@
+--
+-- (C) 2019-20 - ntop.org
+--
+
+local flow_consts = require("flow_consts")
+
+-- This is a user script executed by scripts/callbacks/interface/flow.lua .
+-- Changes to this script must be applied by reloading the plugins from
+-- http://127.0.0.1:3000/lua/plugins_overview.lua
+
+local global_state = nil
+
+-- #################################################################
+
+local script = {
+  -- Script category, see user_scripts.script_categories for all available categories
+  category = user_scripts.script_categories.other,
+
+  -- This module is enabled by default
+  default_enabled = true,
+
+  -- The default configuration for this plugin. The current configuration
+  -- is passed to the script hooks as the second parameter.
+  default_value = {
+    -- This configuration is specific of this script
+    exclude_ports = {[80] = true},
+  },
+
+  -- A user script must be attached some hooks in order to be executed.
+  -- This is only a placeholder, see below for the hooks definitions.
+  -- NOTE: the "all" hook is a virtual hook which causes the script to
+  -- be attached to all the available hooks.
+  hooks = {},
+
+  -- GUI specific stuff. If this section is missing, the user script
+  -- will not be shown in the gui.
+  gui = {
+    -- A title for this user script
+    i18n_title = "example.flow_script_title",
+
+    -- A description for this user script
+    i18n_description = "example.flow_script_description",
+  },
+
+  ----------------------------------------------------------------------
+
+  -- If true, the script will be automatically disabled when alerts are
+  -- disabled.
+  is_alert = false,
+
+  -- If true, this script will only be executed on packet interfaces
+  packet_interface_only = false,
+
+  -- If true, this script will only be executed in nEdge
+  nedge_only = false,
+
+  -- If true, this script will not be executed in nEdge
+  nedge_exclude = false,
+
+  -- If true, this script will not be available on Windows.
+  windows_exclude = false,
+
+  ----------------------------------------------------------------------
+
+  -- The frequency for the periodicUpdate hook invocation. Must be
+  -- multiple of 30 seconds.
+  periodic_update_seconds = 30,
+
+  -- If true, the script will be executed on TCP flows only after the three
+  -- way handshake is completed
+  three_way_handshake_ok = false,
+
+  -- If set, the script will only be called on flows with the specified
+  -- L7 protocol name (application or master protocol).
+  -- Run "ntopng --print-ndpi-protocols" to get a list of protocol names.
+  l7_proto = nil,
+
+  -- If set, the script will only be called on flows with the specified
+  -- L4 protocol name. Supported values: udp, tcp, icmp
+  l4_proto = nil,
+}
+
+-- #################################################################
+
+-- @brief Called when the script is going to be loaded.
+-- @return true if the script should be loaded, false otherwise
+-- @note Can be used to init some script global state or to skip the script
+-- execution on some particular conditions
+function script.setup()
+  local is_enabled = true -- your custom condition here
+
+  global_state = {}
+
+  return(is_enabled)
+end
+
+-- #################################################################
+
+-- An hook executed after the protocol of a flow has been detected
+function script.hooks.protocolDetected(now, config)
+  local flow_info = flow.getInfo()
+
+  print("flow:protocolDetected hook called: " .. shortFlowLabel(flow_info))
+
+  -- Check if the server port is not in the configured exclusion list
+  if not config["exclude_ports"][flow_info["srv.port"]] then
+    -- Set an invalid status on the flow and trigger the corresponding alert
+    flow.triggerStatus(flow_consts.status_types.status_example, {
+      bad_port = flow_info["srv.port"]
+    }, 60--[[ flow score]], 50--[[ cli score ]], 10--[[ srv score ]])
+  else
+    -- A previosly set status can be cleared
+    -- flow.clearStatus(flow_consts.status_types.status_example)
+  end
+end
+
+-- #################################################################
+
+-- An hook executed when the flow is considered closed
+function script.hooks.flowEnd(now, config)
+  print("flow:protocolDetected hook called: " .. shortFlowLabel(flow.getInfo()))
+end
+
+-- #################################################################
+
+-- An hook executed periodically. The update frequency is specified via the
+-- periodic_update_seconds parameter.
+function script.hooks.periodicUpdate(now, config)
+  print("flow:periodicUpdate hook called: " .. shortFlowLabel(flow.getInfo()))
+end
+
+-- #################################################################
+
+return script