arrow-left

All pages
gitbookPowered by GitBook
1 of 1

Loading...

Format and Schema

Fluent Bit might optionally use a configuration file to define how the service will behave.

Before proceeding we need to understand how the configuration schema works.

The schema is defined by three concepts:

  • Sections

  • Entries: Key/Value

  • Indented Configuration Mode

A simple example of a configuration file is as follows:

hashtag
Sections

A section is defined by a name or title inside brackets. Looking at the example above, a Service section has been set using [SERVICE] definition. Section rules:

  • All section content must be indented (4 spaces ideally).

  • Multiple sections can exist on the same file.

  • A section is expected to have comments and entries, it cannot be empty.

hashtag
Entries: Key/Value

A section may contain Entries, an entry is defined by a line of text that contains a Key and a Value, using the above example, the [SERVICE] section contains two entries, one is the key Daemon with value off and the other is the key Log_Level with the value debug. Entries rules:

  • An entry is defined by a key and a value.

  • A key must be indented.

  • A key must contain a value which ends in the breakline.

Also commented lines are set prefixing the # character, those lines are not processed but they must be indented too.

hashtag
Indented Configuration Mode

Fluent Bit configuration files are based in a strict Indented Mode, that means that each configuration file must follow the same pattern of alignment from left to right when writing text. By default an indentation level of four spaces from left to right is suggested. Example:

As you can see there are two sections with multiple entries and comments, note also that empty lines are allowed and they do not need to be indented.

Any commented line under a section, must be indented too.
  • End-of-line comments are not supported, only full-line comments.

  • Multiple keys with the same name can exist.
    [SERVICE]
        # This is a commented line
        Daemon    off
        log_level debug
    [FIRST_SECTION]
        # This is a commented line
        Key1  some value
        Key2  another value
        # more comments
    
    [SECOND_SECTION]
        KeyN  3.14