Main settings:

  • REMOTE_USER: session attribute used for logging user access

  • REMOTE_CUSTOM: can be used for logging an another user attribute or a macro (optional)

  • Hidden attributes: session attributes never displayed or sent.

Changed in version 2.17.0: Since version 2.17.0 hidden attributes parameter supports regular expressions. You can hide attributes by listing them or by providing one or more regexps. By example: _password, _session_id, /^notification_/ /^real\d+$/  _oidcConsents


Regexp must start and end with a slash / character.

LemonLDAP::NG provides 5 levels of error and has two kinds of logs:

  • technical logs

  • user actions logs

Each category can be handle by a different logging framework. You can choose between:

  • Lemonldap::NG::Common::Logger::Std: standard output (mapped in web server logs, see below)

  • Lemonldap::NG::Common::Logger::Syslog: syslog logging

  • Lemonldap::NG::Common::Logger::Apache2: use Apache2 logging, levels are stored in Apache2 logs and the log level is defined by LogLevel Apache parameter

  • Lemonldap::NG::Common::Logger::Log4perl: use Log4perl framework to log (inspired by Java Log4J)

  • Lemonldap::NG::Common::Logger::Sentry (experimental): use Sentry to store logs

  • Lemonldap::NG::Common::Logger::Dispatch: dispatch logs in other backends depending on log level


Except for Apache2 and Log4Perl, log level is defined by logLevel parameter set in lemonldap-ng.ini file. Logger configurations are defined in lemonldap-ng.ini. Example:

logger     = Lemonldap::NG::Common::Logger::Log4perl
userLogger = Lemonldap::NG::Common::Logger::Syslog
logLevel   = notice

You can also modify these values in each lemonldap-ng.ini section to have different values for portal, manager and handlers.

Therefore, LLNG provides a username that can be used by web servers in their access logs. To configure the user identifier to write into access logs, go to Manager, General Parameters > Logging > REMOTE_USER.

User log samples


The user name set in user log messages is set with whatToTrace parameter, except for messages corresponding to failed authentifications, when the user name logged is the login used by the user.


[info] User dwho successfully authenticated at level 2
[info] User dwho connected from LDAP (

Failed authentication:

[warn] foo.bar was not found in LDAP directory (
[warn] Bad password for dwho (

Failed authentication with Combination module:

[warn] All schemes failed for user dwho (


[notice] User dwho has been disconnected from LDAP (

Password change:

[notice] Password changed for dwho (

Access to a CAS application non registered in configuration (when CAS server is open):

[notice] User dwho is redirected to https://cas.service.url

Access to a CAS application whose configuration key is app-example:

[notice] User dwho is authorized to access to app-example

Access to an SAML SP whose configuration key is sp-example:

[notice] User dwho is authorized to access to sp-example

Access to an OIDC RP whose configuration key is rp-example:

[notice] User dwho is authorized to access to rp-example

Access to a Get application whose vhost configuration key is host.example.com:

[notice] User dwho is authorized to access to host.example.com

Default loggers

  • Apache handlers use by default Apache2 logger. This logger can not be used for other LLNG components

  • Except when launched by LLNG FastCGI server (used by Nginx), Portal and Manager use Std logger by default

  • All components launched by LLNG FastCGI server use Syslog by default

Log levels

Technical log levels

  • error is used for problems that must be reported to administrator and needs an action. In this case, some features may not work

  • warn is used for problems that do not block LLNG features but should be solved

  • notice is used for actions that must be logged

  • info displays some technical information

  • debug generates lot of debugging logs

Log levels for user actions

  • error is used for logging bad user actions that seem malicious

  • warn is used for logging some errors like “bad password”

  • notice is used for actions that must be logged for accounting (connections, logout and so on)

  • info displays some useful information like handler authorizations (at least one for each HTTP hit)

  • debug not relevant

Logger configuration

Std logger

Nothing to configure except logLevel.

Apache2 logger

The log level can be set with Apache LogLevel parameter. It can be configured globally, or inside a virtual host.

See http://httpd.apache.org/docs/current/mod/core.html#loglevel for more information.


You can choose facility in lemonldap-ng.ini file. Default values:

syslogFacility     = daemon
userSyslogFacility = auth

You can also override options. Default values:

syslogOptions      = cons,pid,ndelay
userSyslogOptions  = cons,pid,ndelay


You can find more information on Syslog options in Sys::Syslog Perl module.


You can define the Log4perl configuration file and classes to use. Default values:

log4perlConfFile   = /etc/log4perl.conf
log4perlLogger     = LLNG
log4perlUserLogger = LLNGuser

Sample log4perl.conf file

log4perl.logger.LLNG = DEBUG, Syslog
log4perl.logger.LLNGuser = INFO, Syslog
log4perl.appender.Syslog = Log::Dispatch::Syslog
log4perl.appender.Syslog.ident = LLNG
log4perl.appender.Syslog.layout = PatternLayout
log4perl.appender.Syslog.layout.ConversionPattern = [%p] %m

For additional information, please read the Log4Perl documentation

New in version 2.0.14: The following special formatters have been added to standard PatternLayout placeholders

  • %Q{address}: IP address of the request

  • %Q{user}: Username of the current user

  • %Q{id}: Session ID of the current user

  • %E{ENV_VAR}: content of the ENV_VAR variable

New in version 2.17.

  • %S{mail}: content of the mail session variable

New in version 2.19.

  • %Q{request_id}: Unique request ID, from UNIQUE_ID environment variable, or generated by LemonLDAP::NG if UNIQUE_ID is not found.


You just have to give your DSN:

sentryDsn = https://...


This experimental logger requires Sentry::Raven Perl module.


Use it to enable more than one logger. Example:

logger               = Lemonldap::NG::Common::Logger::Dispatch
userLogger           = Lemonldap::NG::Common::Logger::Dispatch
logDispatchError     = Lemonldap::NG::Common::Logger::Sentry
logDispatchNotice    = Lemonldap::NG::Common::Logger::Syslog
userLogDispatchError = Lemonldap::NG::Common::Logger::Sentry
; Other parameters
syslogFacility    = daemon
sentryDsn         = https://...


At least logDispatchError (or userLogDispatchError for user logs) must be defined. All sub level will be dispatched on it, until another lever is declared. In the above example, Sentry collects error and warn levels and all user actions, while syslog stores technical notice, info and debug logs.

Audit logs

New in version 2.19.

beta This feature may change in a future version, event codes and format should not be considered stable.

LemonLDAP::NG user logs (see above) are being replaced with a new facility: Audit logs.

Audit logs are structured logs that are meant to be easier to process than the current log messages.

At the moment, audit logs are transmitted by default to the configured userLogger. But you can plug-in your own custom implementation.


Your logger class can look something like this:

package My::Logger::Class;
use Scalar::Util qw(weaken);

sub new {
    my ( $class, $psgi_or_handler ) = @_;
    my $self = bless {}, $class;

    # Populate $self with options read from $psgi_or_handler
    # ...

    return $self;

sub log {
    my ( $self, $req, %fields ) = @_;

    # Your logging actions here. %fields is the structured
    # data from the logging context, which you can enrich with
    # data from the HTTP request ($req).
    # The "code" field generally contains an upper case event code such as

    # my $code = $fields{code};
    # ...