wLog

Section: 2.0 (7)
Updated: June 2016
Page Index

NAME

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 information
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 series 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

AUTHOR

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