Use Wasm programs as a filter

Wasm Filter allows you to modify the incoming records using Wasm technology.

Due to the necessity to have a flexible filtering mechanism, it is now possible to extend Calyptia Fluent Bit capabilities by writing custom filters using built Wasm programs and its runtime. A Wasm-based filter takes two steps:

  1. (Optional) Compiled as AOT (Ahead Of Time) objects to optimize Wasm execution pipeline

  2. Configure the Filter in the main configuration

  3. Prepare a Wasm program that will be used by the Filter

Configuration Parameters

The plugin supports the following configuration parameters:



Path to the built Wasm program that will be used. This can be a relative path against the main configuration file.


Wasm function name that will be triggered to do filtering. It's assumed that the function is built inside the Wasm program specified above.


Specify the whilelist of paths to be able to access paths from WASM programs.

Configuration Examples

Here is a configuration example.

    Name   dummy
    Tag    dummy.local

    Name wasm
    Match dummy.*
    WASM_Path /path/to/wasm_program.wasm
    Function_Name filter_function_name
    Accessible_Paths .,/path/to/accessible

    Name   stdout
    Match  *

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