Get DPID Ryu controller

[J]

Hello, I am developing a project using sFlow, Ryu and mininet, to classify traffic and trigger some actions in the controller according to certain parameters.

One of the actions is deleting a flow entry when some information is received via Sflow, the problem I´m facing is that I need the DPID in order to delete the flow. 

I have seen that in the Ryu DDos example the DPID is obtained using: topologyInterfaceToPort(evt.agent,evt.dataSource). Is there any similar function but in python, not js?

The other solution I was thinking is giving each switch Subagent ID the same value as the DPID, but cant find the way of doing so via the ovs-vsclt commands.

thank you in advance

[Peter Phaal]

You can extend the sFlow-RT API with JavaScript, e.g. create a script called api.js in the sflow-rt home directory:

setHttpHandler(function(req) {

  return topologyInterfaceToPort(req.query.agent,req.query.dataSource);

});

Run sFlow-RT with the script:

./start.sh -Dscript.file=api.js

Now start Mininet:

sudo mn --custom sflow-rt/extras/sflow.py

You can now query for the DPID using the REST API:

curl"http://localhost:8008/script/api.js/json?agent=127.0.0.1&dataSource=27"

{

 "node": "s1",

 "ofport": "1",

 "port": "s1-eth1",

 "dpid": "0000000000000001"

}

This example just contains a single helper function, but you could add additional methods to simplify your Python controller.

See Writing Applications for more information on sFlow-RT's scripting API.