Implemented lua caching to speedump hostname and interface mapping lookup

scripts/lua/modules/cache_utils.lua

@@ -0,0 +1,106 @@
+--
+-- (C) 2013-25 - ntop.org
+--
+
+--
+-- Volatile (across ntopng restarts) in-memory cache
+--
+
+local dirs = ntop.getDirs()
+package.path = dirs.installdir .. "/scripts/lua/modules/?.lua;" .. package.path
+
+local json = require "dkjson"
+
+local cache_utils = {}
+
+-- ##############################################
+
+-- Loaded at startup
+function cache_utils.initialize()
+   local basename = "ntopng.cachedsnmp."
+   local len  = string.len(basename)
+
+   -- system
+   local keys = ntop.getKeysCache(basename.."*.system")
+
+   for k,_ in pairs(keys) do
+      local system = json.decode(ntop.getCache(k))
+      local ipaddr = string.sub(k, len+1, string.len(k)-7)
+
+      cache_utils.sethostname(ipaddr, system.name)
+   end
+
+   -- interfaces
+   keys = ntop.getKeysCache(basename.."*.interfaces")
+
+   for k,_ in pairs(keys) do
+      local ifaces = json.decode(ntop.getCache(k))
+      local ipaddr = string.sub(k, len+1, string.len(k)-11)
+
+      -- tprint("Loading "..ipaddr)
+      for if_id,if_v in pairs(ifaces) do
+	 local val = if_v.alias or if_v.ifname or if_v.name
+
+	 if(val ~= nil) then
+	    cache_utils.setifname(ipaddr, if_id, val)
+	 end
+      end
+   end
+
+   -- Debug
+   -- tprint(ntop.dumpLuaCache())
+end
+
+-- ##############################################
+
+function cache_utils.gethostname(ipaddr)
+   return(ntop.getLuaCache("host."..ipaddr))
+end
+
+-- ##############################################
+
+function cache_utils.sethostname(ipaddr, name)
+   if(debugme) then
+      tprint("cache_utils.sethostname(".. ipaddr .. ", ".. name..")")
+   end
+   
+   return(ntop.setLuaCache("host."..ipaddr, name or ipaddr))
+end
+
+-- ##############################################
+
+function cache_utils.getifname(ipaddr, ifid)
+   local ret = ntop.getLuaCache("iface."..ipaddr.."@"..ifid)
+
+   if(isEmptyString(ret)) then
+      ret = ifid
+   end
+
+   if(debugme) then
+      tprint(debug.traceback())
+      tprint("cache_utils.getifname(".. ipaddr .. ", ".. ifid..") = "..ret)
+   end
+   
+   return(ret)
+end
+
+-- ##############################################
+
+function cache_utils.setifname(ipaddr, ifid, ifname)
+   if(ifname == nil) then
+      tprint("cache_utils.setifname() ERROR on interface "..ipaddr.." / "..ifid)
+      tprint(debug.traceback())
+   end
+   
+   return(ntop.setLuaCache("iface."..ipaddr.."@"..ifid, ifname or ifid))
+end
+
+-- ##############################################
+
+function cache_utils.set(key, val)
+   ntop.setLuaCache(key, val)
+end
+
+-- ##############################################
+
+return cache_utils