Tracer

The Tracer application is one of the HELICS apps available with the library Its purpose is to provide a easy way to display data from a federation It acts as a federate that can “capture” values or messages from specific publications or direct endpoints or cloned endpoints which exist elsewhere and either trigger callbacks or display it to a screen The main use is a simple visual indicator and a monitoring app

Command line arguments

allowed options:

command line only:
  -? [ --help ]          produce help message
  -v [ --version ]       display a version string
  --config-file arg      specify a configuration file to use

configuration:
  --stop arg             the time to stop recording
  --tags arg             tags to record, this argument may be specified any
                         number of times
  --endpoints arg        endpoints to capture, this argument may be specified
                         multiple time
  --sourceclone arg      existing endpoints to capture generated packets from,
                         this argument may be specified multiple time
  --destclone arg        existing endpoints to capture all packets with the
                         specified endpoint as a destination, this argument may
                         be specified multiple time
  --clone arg            existing endpoints to clone all packets to and from
  --capture arg          capture all the publications of a particular federate
                         capture="fed1;fed2"  supports multiple arguments or a
                         semicolon/comma separated list
  -o [ --output ] arg    the output file for recording the data
  --mapfile arg          write progress to a memory mapped file


federate configuration
  -b [ --broker ] arg    address of the broker to connect
  -n [ --name ] arg      name of the player federate
  --corename arg         the name of the core to create or find
  -c [ --core ] arg      type of the core to connect to
  --offset arg           the offset of the time steps
  --period arg           the period of the federate
  --timedelta arg        the time delta of the federate
  -i [ --coreinit ] arg  the core initialization string
  --inputdelay arg       the input delay on incoming communication of the
                         federate
  --outputdelay arg      the output delay for outgoing communication of the
                         federate
  -f [ --flags ] arg     named flags for the federate

also permissible are all arguments allowed for federates and any specific broker specified:

Command line reference

the tracer executable also takes an untagged argument of a file name for example

helics_app tracer tracer_file.txt --stop 5

Tracers support both delimited text files and JSON files some examples can be found in, they are otherwise the same as options for recorders.

Tracer configuration examples

Config File Detail

subscriptions

a simple example of a recorder file specifying some subscriptions

#FederateName topic1

sub pub1
subscription pub2

# signifies a comment

if only a single column is specified it is assumed to be a subscription

for two column rows the second is the identifier arguments with spaces should be enclosed in quotes

interface	description
s, sub, subscription	subscribe to a particular publication
endpoint, ept, e	generate an endpoint to capture all targeted packets
source, sourceclone,src	capture all messages coming from a particular endpoint
dest, destination, destclone	capture all message going to a particular endpoint
capture	capture all data coming from a particular federate
clone	capture all message going from or to a particular endpoint

for 3 column rows the first must be either clone or capture for clone the second can be either source or destination and the third the endpoint name [for capture it can be either “endpoints” or “subscriptions”]

JSON configuration

Tracers can also be specified via JSON files

here are two examples of the text format and equivalent JSON

#list publications and endpoints for a recorder

pub1
pub2
e src1

JSON example

{
  "subscriptions": [
    {
      "key": "pub1",
      "type": "double"
    },
    {
      "key": "pub2",
      "type": "double"
    }
  ],
  "endpoints": [
    {
      "name": "src1",
      "global": true
    }
  ]
}

some configuration can also be done through JSON through elements of “stop”,”local”,”separator”,”timeunits” and file elements can be used to load up additional files