rosout_filter: ROS log out put filtering node
=============================================================================

This package contains the rosout_filter node. This nodes reads input from a
rosout logging topic (normally /rosout_agg), passes it through a configurable
chain of filters, and outputs the included messages to another rosout topic
(usually /rosout_filtered).

Requirements
------------
The package requires ROS and yaml-cpp to configure the filter chains.

Configuration
-------------
The node is configured by a YAML file [1]. The file consists of two documents.
The first document contains the general and default configuration values. The
second document defines the filtering chain. In the following we describe the
valid configuration entries.

The General Configuration can contain the following fields:
input-topic (default: /rosout_agg)
  Topic of the rosout logging type to read log messages from.
output-topic (default: /rosout_filtered)
  Topic to write messages to that pass through the filters.
levels (default: [DEBUG, INFO, WARN, ERROR, FATAL])
  Log-levels to include by default
default (default: include)
  Default filter type, either include or exclude. If the message is neither
  accepted nor rejected by a filter this default action applies.

The configuration chain contains one or more filter elements. The elements
can either include or exclude a log message from forwarding. The order of
filters is important, the first one that matches is used and the message is
either included or not, no matter what later rules might state. If a filter
does not apply, the message is passed to the next filter. If no filter
applies, the default type configured in the general section is used. A filter
contains of one or more matchers. The matchers per chain are connected with
a logical "and", meaning that all matchers must apply to consider the filter
as matcher. To create a logical "or" use multiple filter entries. The
following values are possible (entries have no default values!):
type (must be present)
  Type of the filter result, either include or exclude
levels
  Matcher with a list of log levels for which the filter applies.
nodename
  Matcher for name of the sending node.
nodenames
  Matcher for list of names of which any can match to a sending node name.
regex
  Regular expression applied to the message. May contain extended regular
  expressions as known from C.

For an example see example-config.yaml.

References
----------
[1] http://yaml.org/