VILLASnode/doc/Configuration.md

Configuration

The VILLASnode configuration is completly contained in a single file. Take a look at the example configuration: server/etc/example.conf.

The configuration file consists of three sections:

Global

The global section consists of some global configuration parameters:

debug (integer)

debug expects an integer number (0-10) which determines the verbosity of debug messages during the execution of the server. Use this with care! Producing a lot of IO might decrease the performance of the server. Omitting this setting or setting it to zero will disable debug messages completely.

stats (float)

stats specifies the rate in which statistics about the actives paths will be printed to the screen. Setting this value to 5, will print 5 lines per second. A line of includes information such as:

• Source and Destination of path
• Messages received
• Messages sent
• Messaged dropped

affinity (integer)

The affinity setting allows to restrict the exeuction of the daemon to certain CPU cores. This technique, also called 'pinning', improves the determinism of the server by isolating the daemon processes on exclusive cores.

priority (integer)

The priority setting allows to adjust the scheduling priority of the deamon processes. By default, the daemon uses a real-time optimized FIFO scheduling algorithm.

name (integer)

By default the name of a VILLASnode instance is equalt to the hostname of the machine it is running on. Some node types are using this name to identify themselves agains their remotes. An example is the ngsi node type which adds a metadata attribute source to its updates.

Nodes

The node section is a directory of nodes (clients) which are connected to the VILLASnode instance. The directory is indexed by the name of the node:

nodes = {
    "sintef_node" = {
    type = "socket"
    ....
}
}

There are multiple diffrent type of nodes. But all types have the following settings in common:

type ("socket" | "gtfpga" | "file" | "ngsi")

type sets the type of the node. This should be one of:

• socket which refers to a Socket node.
• gtfpga which refers to a GTFPGA node.
• opal which refers to a OPAL Asynchronous Process node.
• file which refers to a File node.

The remaining settings per node a depending on type. Take a look a the specific pages for details.

Paths

The path section consists of a list of paths:

paths = [
    {
        in = "rtds",
        out = "broker",
        reverse = false,
        poolsize = 32,
        msgsize = 16,
        vectorize = 4,
        hook = [ "print", "ts" ]
    }
]

Every path is allowed to have the following settings:

in & out (string)

The in and out settings expect the name of the source and destination node.

The out setting itself is allowed to be list of nodes. This enables 1-to-n distribution of simulation data.

enabled (boolean)

The optional enabled setting can be used to temporarily disable a path. If omitted, the path is enabled by default.

reverse (boolean)

By default, the path is unidirectional. Meaning, that it only forwards samples from the source to the destination. Sometimes a bidirectional path is needed. This can be accomplished by setting reverse to true.

vectorize (integer)

This setting allows to send multiple samples in a single message to the destination nodes. Currently this is only supported by the file and socket node-types.

The value of this setting determines how many samples will be combined into one packet.

Important: Please make sure that the value of this setting is smaller or equal to the poolsize setting of this path.

rate (float)

A non-zero value for this setting will change this path to an asynchronous mode. In this mode VILLASnode will send with a fixed rate to all destination nodes. It will always send the latest value it received, possible skipping values which have been received in between. If vectorize is larger than 1, it will send the last vectorize samples at once.

Important: Please note that there is no correlation between the time of arrival and time of departure in this mode. It might increase the latency of this path by up to 1 / rate seconds!

poolsize (integer)

Every path manages a circular buffer to keep a history of past samples. This setting specifies the size of this circular buffer.

Important: There are some hook functions (or the vectorize setting) which require a minimum poolsize (for example the finite-impulse-response fir hook).

hook (list of strings)

A list of hook functions which will be executed for this path.

Please consult the hook chapter of this documentation for more details.