---
title: "Generating configuration blocks from a script"
url: "https://axoflow.com/docs/axosyslog-core/4.28/chapter-configuration-file/large-configs/generating-configuration-blocks/"
last_modified: "2024-02-07T19:12:41+01:00"
---

> For the complete documentation index, see [llms.txt](https://axoflow.com/docs/axosyslog-core/4.28/llms.txt).

# Generating configuration blocks from a script

## Purpose:

The AxoSyslog application can automatically execute scripts when it is started, and can include the output of such script in the configuration file. To create and use a script that generates a part of the AxoSyslog configuration file (actually, a configuration block), complete the following steps. The steps include examples for collecting Apache access log files (`access.log`) from subdirectories, but you can create any script that creates a valid AxoSyslog configuration snippet.

## Steps:

1. Navigate to the directory where you have installed AxoSyslog (for example, `/opt/syslog-ng/share/include/scl/`), and create a new directory, for example, `apache-access-logs`. The name of the directory will be used in the AxoSyslog configuration file as well, so use a descriptive name.
2. Create a file called `plugin.conf` in this new directory.
3. Edit the `plugin.conf` file and add the following line:

   ```shell
       @module confgen context(source) name(<directory-name>) exec("`scl-root`/<directory-name>/<my-script>")
   ```

   Replace `<directory-name>` with the name of the directory (for example, `apache-access-logs`), and `<my-script>` with the filename of your script (for example, `apache-access-logs.sh`). You can reference the script in your AxoSyslog configuration file as a configuration block using the value `name` option.

   The `context` option determines the type of the configuration snippet that the script generates, and must be one of the following: `destination`, `filter`, `log`, `parser`, `rewrite`, `root`, `source`. The `root` blocks can be used in the “root” context of the configuration file, that is, outside any other statements. In the example, `context(source)` means that the output of the script will be used within a source statement.

   You can pass parameters to the script. In the script these parameters are available as environment variables, and have the `confgen_` prefix. For example, passing the `--myparameter` parameter becomes available in the script as the `confgen_myparameter` environment variable.
4. Write a script that generates the output you need, and formats it to a configuration snippet that AxoSyslog can use. The filename of the script must match with the filename used in `plugin.conf`, for example, `apache-access-logs.sh`.

   The following example checks the `/var/log/apache2/` directory and its subdirectories, and creates a source driver for every directory that contains an `access.log` file.

   ```shell
       #!/bin/bash
       for i in `find /var/log/apache2/ -type d`; do
           echo "file(\"$i/access.log\" flags(no-parse) program-override(\"apache2\"));";
       done;
   ```

   The script generates an output similar to this one, where `service*` is the actual name of a subdirectory:

   ```shell
       file("/var/log/apache2/service1/access.log" flags(no-parse) program-override("apache2"));
       file("/var/log/apache2/service2/access.log" flags(no-parse) program-override("apache2"));
   ```
5. Include the `plugin.conf` file in the `syslog-ng.conf` file — or a file already included into `syslog-ng.conf`. Version 3.7 and newer automatically includes the `*.conf` files from the `<directory-where-syslog-ng-is-installed>/scl/*/` directories. For details on including configuration files, see [Including configuration files](https://axoflow.com/docs/axosyslog-core/4.28/chapter-configuration-file/large-configs/including-config-files/index.md).
6. Add the block you defined in the `plugin.conf` file to your AxoSyslog configuration file. You can reference the block using the value of the `name` option from the `plugin.conf` file, followed by parentheses, for example, `apache-access-logs()`. Make sure to use the block in the appropriate context of the configuration file, for example, within a source statement if the value of the `context` option in the `plugin.conf` file is source.

   ```shell
       @include "scl.conf"
       ...
       source s_apache {
           file("/var/log/apache2/access.log" flags(no-parse) program-override("apache2"));
           file("/var/log/apache2/error.log" flags(no-parse) program-override("apache2"));
           file("/var/log/apache2/ssl.log" flags(no-parse) program-override("apache2"));
           apache-access-logs();
       };

       log {
           source(s_apache); destination(d_central);
       };
       ...
   ```
7. Check if your modified AxoSyslog configuration file is syntactically correct using the `syslog-ng --syntax-only` command.
8. If your modified configuration is syntactically correct, load the new configuration file using the `syslog-ng-ctl reload` command.

Last modified February 7, 2024: [Formatting fixes (05f0c76f)](https://github.com/axoflow/axosyslog-core-docs/commit/05f0c76f9ce2c4e89876911f4ae9abcbd267e2e9)