Online Monitoring plugins
Overview
The Online Monitoring Plugins are used to create histograms that monitor the health of the data in an online environment. The goal is to ensure the quality of the data as it is being read in and to identify any issues quickly so that they can be corrected. The system is deigned using the JANA framework and the plugins will have access to the entire set of sim-recon reconstruction libraries.
The system is made up of a set of plugins allowing individual detector groups to maintain control over the monitoring of their systems. Each detector will have one or more monitoring plugins to generate histograms and, in some cases, provide macros for complex displays of those histograms. The plugins for all detectors will be attached to a single multi-threaded process to optimize efficiency. A small farm of monitoring computer nodes will be used, each processing a portion of the incoming data stream. The events will be distributed to the nodes using the same ET software system that the DAQ system in Hall-D uses.
The system is designed to allow the plugins to be developed completely in an offline environment and then used for online monitoring without any special coding requirements. This is due to RootSpy's ability to read histogram definitions from global memory and publish them to the network. A central program will grab all histograms from all nodes and automatically sum them. A set of initial plugins exists that detector groups should modify. If a new plugin is needed, one can make it using instructions found here.
Getting Started
To develop a plugin for use in the online, there a few steps you will want to follow:
1.) Check out and build the sim-recon code (find instructions here)
2.) Simulate some bggen events to produce an hdgeant_smeared.hddm file (find instructions here)
3.) Convert the HDDM file into EVIO format (find instructions here)
4.) Checkout the online monitoring software package and SBMS system:
> mkdir ONLINE > cd ONLINE > svn co https://halldsvn.jlab.org/repos/trunk/online/packages/monitoring > svn co https://halldsvn.jlab.org/repos/trunk/online/packages/SBMS
5.) Build the plugin of interest. e.g.:
> cd monitoring/plugins/src/BCAL_online > scons -u install
6.) Set your environment to find the plugin and run it along with the DAQ and TTab plugins. e.g.:
> cd ONLINE/monitoring/$BMS_OSNAME
> setenv JANA_PLUGIN_PATH ${PWD}:${JANA_PLUGIN_PATH}
> hd_root -PPLUGINS=DAQ,TTab,BCAL_online rawevent_000002.evio
Histograms will be written to the file hd_root.root
Coupling to RootSpy
The RootSpy system will access and publish ROOT histograms by simply adding the rootspy plugin to the list of plugins. For this system to work though, one needs a cMsg server running.
