# Trace filtering#

## Trace filtering#

CARET provides a trace filtering function to exclude specific nodes and topics. Trace data may be discarded when recording a large application like Autoware due to too many data to be recorded, and a warning will occur when validating/analyzing the recorded trace data (See validating). By applying trace filter, unconcerned events like /tf are ignored and the size of recorded data decreases.

## Trace filter configuration#

• Trace filter configuration is performed by setting the following environment variables
• CARET_SELECT_NODES : node names to be recorded
• CARET_IGNORE_NODES : node names to be ignored
• CARET_SELECT_TOPICS : topic names to be recorded
• CARET_IGNORE_TOPICS : topic names to be ignored
• "SELECT" settings override "IGNORE" settings if both are used
• Colon ":" is used to set more than one nodes/topics
• Regular expressions are supported
• These variables need to be set in the same terminal as a target application running
• In most cases, nodes related to /rviz, /clock topic and /parameter_events topic are unnecessary to analyze an application. It's recommended to ignore these nodes/topics

The following shows sample settings

export CARET_IGNORE_NODES="/rviz*"
export CARET_IGNORE_TOPICS="/clock:/parameter_events"


Info

Trace filter doesn't exclude all events of the specified nodes/topics. Events in certain layers, especially DDS layer, won't be ignored. It is one of limitations with current implementation.

## Trace filter setting file#

It will be handy to prepare a trace filter setting file like the following.

# caret_topic_filter.bash
#!/bin/bash

export CARET_IGNORE_NODES=\
"\
/rviz*\
"

export CARET_IGNORE_TOPICS=\
"\
/clock:\
/parameter_events\
"

# if you want to select nodes or topics,
# please remove comment out of the followings.
# export CARET_SELECT_NODES=\
# "\
# /rviz*\
# "

# export CARET_SELECT_TOPICS=\
# "\
# /clock:\
# /parameter_events\
# "