Couldn't send metadata inside buffer from one custom plugin to another custom plugin

Aswin aswin.prabhakaran at
Tue Jun 8 16:30:35 UTC 2021

Hi Team , 

I have built custom plugins in python for my use case where one of the
plugins sends the following metadata in the buffer :

{ "key 1" : int, "key 2" : [list of 20 elements]}, 
{ "key 1" : int, "key 2" : [list of 20 elements]}, 
{ "key 1" : int, "key 2" : [list of 20 elements]}, 
{ "key 1" : int, "key 2" : [list of 20 elements]}

Note : The above structure is in Python

I am able to encode this data as ctypes & put it into buffer. 

The immediate downstream plugin gets the buffer & decodes the metadata.

The problem is when i decode the buffer in downstream plugin, it gives an
empty list. But when i decode in the same plugin which encodes, i am able to
decode & get the same data as sent.

I also found that we have to register the Metadata info. I have not
registered any metadata info yet in C. Does this fails because of that
reason where I dont have any Structure registered ??

Also i found the metadata API as an alternative. Firstly how to register one
such API in python ? And secondly which is best - 1) API for metadata or 2)
Registering the structure in C & generating ".so" file for it.

So far i am following this thread :

This thread talks about encoding data into buffer.

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