org.freedesktop.LogControl1

systemd
org.freedesktop.LogControl1 5
org.freedesktop.LogControl1 D-Bus interface to query and set logging configuration

## Introduction

org.freedesktop.LogControl1 is a generic interface that is intended to be used by any daemon which allows the log level and target to be set over D-Bus. It is implemented by various daemons that are part of the systemd 1 suite.

It is assumed that those settings are global for the whole program, so a fixed object path is used. The interface should always be available under the path `/org/freedesktop/LogControl1`.

## Description

The following interface is exposed:

    node /org/freedesktop/LogControl1 {
      interface org.freedesktop.LogControl1 {
        properties:
          @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
          @org.freedesktop.systemd1.Privileged("true")
          readwrite s LogLevel = '...';
          @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
          @org.freedesktop.systemd1.Privileged("true")
          readwrite s LogTarget = '...';
          @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
          readonly s SyslogIdentifier = '...';
      };
      interface org.freedesktop.DBus.Peer { ... };
      interface org.freedesktop.DBus.Introspectable { ... };
      interface org.freedesktop.DBus.Properties { ... };
    };

### Properties

`LogLevel` describes the syslog 3-style log-level, and should be one of `emerg`, `alert`, `crit`, `err`, `warning`, `notice`, `info`, `debug`, in order of increasing verbosity.

`LogTarget` describes the log target (mechanism). It should be one of `console` (log to the console or standard output), `kmsg` (log to the kernel ring buffer), `journal` (log to the journal natively, see systemd-journald.service 8), `syslog` (log using the syslog 3 call).

Those two properties are writable, so they may be set by sufficiently privileged users.

`SyslogIdentifier` is a read-only property that shows the "syslog identifier". It is a short string that identifies the program that is the source of log messages that is passed to the syslog 3 call.

## Tools

`journalctl` option `-p`/`--priority=` may be used to filter log messages by log level, option `-t`/`--identifier=` may be used to by the syslog identifier, and filters like `_TRANSPORT=syslog`, `_TRANSPORT=journal`, and `_TRANSPORT=kernel` may be used to filter messages by the mechanism through which they reached `systemd-journald`.

`systemctl log-level` and `systemctl log-target` verbs may be used to query and set the `LogLevel` and `LogTarget` properties of the service manager. `systemctl service-log-level` and `systemctl service-log-target` may similarly be used for individual services. (Services must have the `BusName=` property set and must implement the interface described here. See systemd.service 5 for details about `BusName=`.)

## See Also

systemd 1, journalctl 1, systemctl 1, systemd.service 5, syslog 3