wlog man page

wLog — WinPR logging facility

Description

wLog is a configurable and flexible logging system used throughout WinPR and FreeRDP.

The primary concept is to have a hierarchy of loggers that can be be configured independently.

Appenders

WLog uses different appenders that define where the log output should be written to. If the application doesn't explicitly configure the appenders the below described variable WLOG_APPENDER can be used to choose one appender.

The following kind of appenders are available:

Binary
Write the log data into a binary format file.
Console
The console appender writes to the console. Depending of the operating system the application runs on, the output might be handled differently. For example on android log print would be used.
File
The file appender writes the textual output to a file.
Udp

This appender sends the logging messages to a pre-defined remote host via UDP.

If no target is set the default one 127.0.0.1:20000 is used. To receive the log messages one can use netcat. To receive the default target the following command can be used: nc -u 127.0.0.1 -p 20000 -l

Syslog
Use syslog for outputting the debug messages.
Journald
This appender outputs messages to journald.

Levels

The WLog are complementary, the higher level always includes the lower ones. The level list below is top down. Top the highest level.

TRACE
print everything including packets dumps
DEBUG
debug messages
INFO
general informations
WARN
warnings
ERROR
errors
FATAL
fatal problems
OFF
completely disable the wlog output

Formats

The format a logger prints has the following possible options:

lv
log level
mn
module name
fl
file name
fn
function
ln
line number
pid
process id
tid
thread id
yr
year
mo
month
dw
day of week
hr
hour
mi
minute
se
second
ml
millisecond

A maximum of 16 options can be used per format string.

An example that generally sets the WLOG_PREFIX for xfreerdp would look like: WLOG_PREFIX="pid=%pid:tid=%tid:fn=%fn -" xfreerdp /v:xxx

Environment

WLOG_APPENDER
The kind of appender, the accepted values are: CONSOLE, FILE, BINARY, SYSLOG, JOURNALD or UDP
WLOG_PREFIX
configure the prefix used for outputting the message (see Format for more details and examples)
WLOG_LEVEL
the level to output messages for
WLOG_FILTER

sets a filter for WLog messages. Only the filtered messages are printed. The format of the filter is a serie of <logger name>:<level> separated by comas

example: WLOG_FILTER=core.channel:DEBUG,dummy:TRACE will display debug messages for the core.channel logger and trace level for the dummy logger

WLOG_FILEAPPENDER_OUTPUT_FILE_PATH
When using the file appender it may contains the output log file's path
WLOG_FILEAPPENDER_OUTPUT_FILE_NAME
When using the file appender it may contains the output log file's name
WLOG_JOURNALD_ID
When using the systemd journal appender, this variable contains the id used with the journal (by default the executable's name)
WLOG_UDP_TARGET
target to use for the UDP appender in the format host:port

Bugs

Please report any bugs using the bug reporting form on the FreeRDP web site

See Also

Additional information and the latest version is available at the web site: http://www.freerdp.com

Author

David Fort <contact@hardening-consulting.com> wrote this manpage from materials written by Bernhard Miklautz <bernhard.miklautz@thincast.com>.

Referenced By

xfreerdp(1).

June 2016 Version 1.0