syslog-ng Open Source Edition 3.30 - Administration Guide

Listing configuration options

Starting with syslog-ng OSE 3.25, you can use the syslog-ng-cfg-db.py utility to list the available options of configuration objects. For example, you can list all the options that can be set in the file source, and so on.

The syslog-ng-cfg-db.py utility has the following options:

• The following command lists the contexts that the utility supports.

  syslog-ng-cfg-db.py

  NOTE: Currently, sources and destinations are supported.

• The following command lists the available drivers of a context:

  syslog-ng-cfg-db.py -c <source|destination>

• The following command lists the available options of a specific driver and specifies the context and the driver:

  syslog-ng-cfg-db.py -c <source|destination> -d <driver>

  For example, to list the options of the kafka-c() destination driver:

  syslog-ng-cfg-db.py -c destination -d kafka-c

  The output includes the available options of the driver in alphabetical order, and the type of the option. For example:

  destination kafka-c(
      bootstrap-servers/kafka-bootstrap-servers(<string>)
      client-lib-dir(<string>)
      config/option()
      config/option(<string> <arrow> <string-or-number>)
      config/option(<string> <string-or-number>)
      flush-timeout-on-reload(<number>)
      flush-timeout-on-shutdown(<number>)
      frac-digits(<number>)
      key(<string>)
      local-time-zone/time-zone(<string>)
      log-fifo-size(<number>)
      message/template(<string>)
      on-error(<string>)
      persist-name(<string>)
      poll-timeout(<number>)
      properties-file(<path>)
      send-time-zone(<string>)
      sync-send(<yesno>)
      throttle(<number>)
      time-zone(<string>)
      topic(<string>)
      ts-format(<string>)
      workers(<number>)
      config/option(
          <string>(<string-or-number>)
      )
      key(
          <identifier>(<string>)
      )
      message/template(
          <identifier>(<string>)
      )
  )

  NOTE: The script caches the list of the options, so if you want to rebuild the database, you have to use the -r option.

Visualize the configuration

Starting with syslog-ng OSE 3.25, you can visualize the configuration of a running syslog-ng OSE instance using the syslog-ng-ctl --export-config-graph command. The command walks through the effective configuration, and exports it as a graph into a JSON structure.

The resulting JSON file can be converted into DOT file format that visualization tools (for example, Graphviz) can use. The package includes a Python script to convert the exported JSON file into DOT format: <syslog-ng-installation-directory>/contrib/scripts/config-graph-json-to-dot.py

You can convert the DOT file into PNG or PDF format using external tools.

Managing complex syslog-ng configurations

The following sections describe some methods that can be useful to simplify the management of large-scale syslog-ng installations.

Including configuration files

The syslog-ng application supports including external files in its configuration file, so parts of its configuration can be managed separately. To include the contents of a file in the syslog-ng configuration, use the following syntax:

@include "<filename>"

This imports the entire file into the configuration of syslog-ng OSE, at the location of the include statement. The <filename> can be one of the following:

• A filename, optionally with full path. The filename (not the path) can include UNIX-style wildcard characters (*, ?). When using wildcard characters, syslog-ng OSE will include every matching file. For details on using wildcard characters, see Options of regular expressions.

• A directory. When including a directory, syslog-ng OSE will try to include every file from the directory, except files beginning with a ~ (tilde) or a . (dot) character. Including a directory is not recursive. The files are included in alphabetic order, first files beginning with uppercase characters, then files beginning with lowercase characters. For example, if the directory contains the a.conf, B. conf, c.conf, D.conf files, they will be included in the following order: B.conf, D. conf, a.conf, c.conf.

When including configuration files, consider the following points:

• The default path where syslog-ng OSE looks for the file depends on where syslog-ng OSE is installed. The syslog-ng --version command displays this path as Include-Path.

• Defining an object twice is not allowed, unless you use the @define allow-config-dups 1 definition in the configuration file. If an object is defined twice (for example, the original syslog-ng configuration file and the file imported into this configuration file both define the same option, source, or other object), then the object that is defined later in the configuration file will be effective. For example, if you set a global option at the beginning of the configuration file, and later include a file that defines the same option with a different value, then the option defined in the imported file will be used.

• Files can be embedded into each other: the included files can contain include statements as well, up to a maximum depth of 15 levels.

• You cannot include complete configuration files into each other, only configuration snippets can be included. This means that the included file cannot have a @version statement.

• Include statements can only be used at top level of the configuration file. For example, the following is correct:

  @version: 3.30
  @include "example.conf"

  But the following is not:

  source s_example {
      @include "example.conf"
  };