perfSONAR User Q&A and Other Discussion

[Mark Feit <>]

Cong Wang writes:

    We are trying to build a platform to collect perfSonar measurement data 
from multiple sites in real time. Is there a way to programmatically retrieve 
the data from the perfSonar web interface, e.g., through RESTful API? We plan 
to collect throughput, latency and packet loss if it works.

To expand a bit on what Dan said:

All test activity in perfSONAR 4.0 is coordinated by pScheduler, which, as 
Dan mentioned, has a REST API for creating measurement tasks and retrieving 
the results.  It’s stable but not officially documented.  You’re the first 
person outside the project to ask about it, which will probably light a fire 
under me to get it done.  All data is JSON and is easy to deal with.  If you 
want to do ad hoc measurements, where your platform tells pScheduler to do a 
measurement on demand, this is the way to go.  The same API can be used to 
start repeating tasks, and by keeping the URL it returns, you can find and 
retrieve the results.  If you (or anyone else) is interested, I could do a 
brief, informal workshop to go over it and supply some snippets of Python 
code that can help get you started.  

One of the other new features pScheduler brought with it is a system of 
plugins that allows us to have multiple ways to dispose of measurement 
results.  This would mean you don’t have to retrieve the results yourself; 
pScheduler can be directed to send them directly to you and retry if it 
fails.  4.0 shipped with plugins that can post results to an HTTP server, 
RabbitMQ, the system log or Esmond, which should give you enough options that 
developing something custom won’t be necessary.  Information on how to use 
archivers with pScheduler can be found here:  
https://github.com/perfsonar/pscheduler/wiki/Archivers.

The one limitation is that meshconfig can’t be used to configure measurements 
that use any archiver other than Esmond.  This is a holdover from earlier 
versions of perfSONAR, and we’re working on ways to expose pScheduler’s 
additional features to meshconfig.  You can still use the API to run your own 
tests in parallel, though.

--Mark