Custom VILLAS Human Readable

This is a simple human-readable format commonly used for logging or debugging: The format is similar to a conventional CSV (comma separated values) file. Every line in a file correspondents to a message / sample of simulation data. The columns of a line are separated by whitespaces (tabs or spaces). The columns are defined as follows:

seconds.nanoseconds+offset(sequenceno) value0 value1 ... valueN

1. The first column contains a timestamp which is composed of up to 4 parts:

   • Number of seconds after 1970-01-01 00:00:00 UTC
   • A dot: '.'
   • Number of nano seconds of the current second (optional)
   • An offset between the point in time when a message was sent and received (optional)
   • The sequence number of the message (optional)

   A valid timestamp can be generated by the following Unix command: date +%s.%N. Important: The second field is not the fractional part of the second!!!

2. Maximum MSG_VALUES floating point values per sample. The values are separated by whitespaces as well.

Implementation

The source code of the format-type is available here: https://github.com/VILLASframework/node/blob/master/lib/formats/villas_human.cpp

Configuration

delimiter	string Default: "\\n" The character that separates lines.
header	boolean Default: true Whether or not to emit a header.
skip_first_line	boolean Default: false Whether or not to skip the first line of the input.
comment_prefix	string Default: "#" Lines starting with this prefix are ignored.
real_precision	integer Default: 17 Output all real numbers with at most n digits of precision. The valid range for this setting is between 0 and 31 (inclusive), and other values result in an undefined behavior. By default, the precision is 17, to correctly and losslessly encode all IEEE 754 double precision floating point numbers.
ts_origin	boolean Default: true If set, include the origin timestamp in the output.
ts_received	boolean Default: true If set, include the received timestamp in the output.
sequence	boolean Default: true If set, include the sequence number in the output.
data	boolean Default: true If set, include the data in the output.
offset	boolean Default: true If set, include the offset between origin and received timestamp in the output.

{

• "delimiter": "\\n",
• "header": true,
• "skip_first_line": false,
• "comment_prefix": "#",
• "real_precision": 17,
• "ts_origin": true,
• "ts_received": true,
• "sequence": true,
• "data": true,
• "offset": true

}

Example Configuration

node/etc/examples/formats/villas-human.conf

nodes = {
    node = {
        type = "file"
        uri = "/dev/null"

        format = {
            type = "villas.human"

            comment_prefix = "#"
            header = false
        }
    }
}

Example Payload

This example shows a dump with three values per sample:

# seconds.nanoseconds(sequence)	signal0 signal1 signal2
1438959964.162102394(6)	3.489760	-1.882725	0.860070