The daemon represents the main system service responsible for the network node management. The daemon does not provide any special functionality expect the base system support necessary to keep it operational such as possibility to load/unload plugins, manage the daemon include possibility of remote upgrades, and allowing sharing the system resources on host. The Management Agent’s plugins are capable to add new functionality to the daemon.
Nsys Daemon Architecture
The Management Agent is the first of the two major subsystems hosted within daemon and it is responsible for the plugins management (component Manager). The first subsystem is providing access to the host resources (responsibility of the component Core), interacting with other daemons through web service (REST, SOAP), and providing cooperation with the Data Processor subsystem. The second subsystem, the Data Processor is responsible for the data processing of the specific management agent plugin. The NeuralBag is the basic unit used for communication between daemons and it contains data for processing inside of the data processor. The results are store to storage which can be for instance a database or it can be send to another daemon for additional processing.
The daemon uses the bag for information exchange between other daemons in the framework infrastructure. The management agent is accepting and sending bags to infrastructure through the Grid component.
Each Management Agent plugin is capable to use for data processing the stages representing individual phases in data processor. The stages are used for the intercommunication of the bags during each phase.
Good example of the data processor stages usage is the plugin implementing web crawler functionality which has three different stages in data processor. The first stage is responsible for a web page download, the page content is stored in the bag, the second stage does a web page analyze based on data received from bag, and the last stage does storing of the results of the previously analyzed page to a storage.