Thanks Matt for the explanation.  I will try groovy but before i try what format of data we get in inputstream( byte array)? i will try to see if i can decode in native lua.

On Wed, May 4, 2016 at 1:21 PM, Matt Burgess <mattyb149@gmail.com> wrote:
Madhu,

Unfortunately, the LuaJ script engine resolves classes using the
system class loader as a parent class loader, rather than the current
thread's context class loader. This means LuaJ only has access to the
classes defined in JARs in the lib/ folder (not even lib/bootstrap).
The Module Directory property is useless for LuaJ at present, meaning
even if you add that JAR to the Module Directory property it still
won't work. Theoretically you'd add the JARs you want to the lib/
folder and restart NiFi, but then you're risking all sorts of bad news
and interactions.

The bottom line is that LuaJ should probably only be used to leverage
business logic written in Lua, not Java. If you want access to Java
libraries, I'd use another script engine such as Groovy.

Regards,
Matt

On Wed, May 4, 2016 at 11:39 AM, Madhukar Thota
<madhukar.thota@gmail.com> wrote:
> Hey Matt,
>
> Do you know how to call java classes in lua?
>
> i am trying to call java class org.apache.commons.io.IOUtils  like this:
>
> local io = luajava.bindClass("org.apache.commons.io.IOUtils")
>
> but nifi execurescript processor is complaning class not found.
>
> failed to process session due to org.luaj.vm2.LuaError: script:98 vm error:
> java.lang.ClassNotFoundException: org.apache.commons.io.IOUtils:
> org.luaj.vm2.LuaError: script:98 vm error: java.lang.ClassNotFoundException:
> org.apache.commons.io.IOUtils
>
>
>
> Any help here?
>
> On Thu, Apr 21, 2016 at 10:58 AM, Madhukar Thota <madhukar.thota@gmail.com>
> wrote:
>>
>> Made some progess on loading the lua files from modules directory. In my
>> case all my lua files and .so files are in modules diretory. I placed the
>> directory in nifi installation folder.
>>
>> Eg: lua_modules/common_log_format.lua
>>
>> in my script i am calling the luascript as follows:
>>
>> local clf = require 'lua_modules.common_log_format'
>>
>> It is reading the lua script without any issue, now the problem is
>> common_log_format.lua is dependent on lpeg module which is .so file (
>> lpeg.so). The question is, Can we read .so files in nifi luaj libarary. If
>> so how can i parse .so files?
>>
>>
>> On Wed, Apr 20, 2016 at 5:21 PM, Madhukar Thota <madhukar.thota@gmail.com>
>> wrote:
>>>
>>> I am trying to read the lua file this way, but its not working. How to
>>> read the lua files from module directory and use it in execution?
>>>
>>> luajava.LuaState = luajava.LuaStateFactory.newLuaState()
>>>
>>>
>>> luajava.LuaState.openLibs()
>>> luajava.LuaState.LdoFile("common_log_format.lua");
>>>
>>>
>>> On Wed, Apr 20, 2016 at 4:29 PM, Madhukar Thota
>>> <madhukar.thota@gmail.com> wrote:
>>>>
>>>> Thanks Matt. This will be helpful to get started. I will definitely
>>>> contribute back to community once i have working script. One more question,
>>>> Can i call the lua modues in the script with require statement like this
>>>> local lpeg = require "lpeg"?
>>>>
>>>> -Madhu
>>>>
>>>>
>>>>
>>>> On Wed, Apr 20, 2016 at 3:11 PM, Matt Burgess <mattyb149@gmail.com>
>>>> wrote:
>>>>>
>>>>> Madhu,
>>>>>
>>>>> I know very little about Lua, so I haven't tried making a Lua version
>>>>> of my JSON-to-JSON scripts/blogs (funnifi.blogspot.com), but here's
>>>>> something that works to get you started. The following Luaj script creates a
>>>>> flow file, writes to it, adds an attribute, then transfers it to success.
>>>>> Hopefully you can use your Lua scripts inline by calling their functions and
>>>>> such from the OutputStreamCallback proxy (the process method below). If you
>>>>> get something working and would like to share, I would very much appreciate
>>>>> it!
>>>>>
>>>>> local writecb =
>>>>> luajava.createProxy("org.apache.nifi.processor.io.OutputStreamCallback", {
>>>>> process = function(outputStream)
>>>>> outputStream:write("This is flow file content from Lua")
>>>>> end
>>>>> })
>>>>> flowFile = session:create()
>>>>> flowFile = session:putAttribute(flowFile, "lua.attrib", "Hello from
>>>>> Lua!")
>>>>> flowFile = session:write(flowFile, writecb)
>>>>> session:transfer(flowFile, REL_SUCCESS)
>>>>>
>>>>>
>>>>> Regards,
>>>>> Matt
>>>>>
>>>>> On Tue, Apr 19, 2016 at 1:15 PM, Madhukar Thota
>>>>> <madhukar.thota@gmail.com> wrote:
>>>>>>
>>>>>> Friends,
>>>>>>
>>>>>> Can anyone share an sample example on how to use Lua in ExecuteScript
>>>>>> Processor? We have bunch of lua scripts which we would like to use for data
>>>>>> processing.
>>>>>>
>>>>>> Any help is appreciated.
>>>>>>
>>>>>> Thanks
>>>>>> Madhu
>>>>>
>>>>>
>>>>
>>>
>>
>