WebAssembly is binary instruction format for stack based virtual machine.
Fluent Bit currently supports integration of wasm plugins built as wasm/wasi objects for input and filter plugins only. The interface for the WASM filter plugins is currently under development but is functional.
There are no additional requirements to execute WASM plugins.
Currently, fluent-bit supports the following WASM toolchains:
Rust on wasm32-unknown-unknown
.
rustc 1.62.1 (e092d0b6b 2022-07-16) or later
TinyGo on wasm32-wasi
v0.24.0 or later
WASI SDK 13 or later.
Compile Fluent Bit with WASM support, e.g:
Once compiled, we can see new plugins in which handles wasm, e.g:
Currently, Fluent Bit's WASM input assumes WASI ABI that is also known as wasm32-wasi
on Rust target and wasm32-wasi
on TinyGo target.
TinyGo and WASI SDK support wasm target by default. When using Rust's wasm32-wasi
target, users must install wasm32-wasi
via rustup. Then, installing that target components as:
WASM input plugins execute the function that has wasi main function entrypoint. And Fluent Bit's WASM input plugin communicates via stdout on WASM programs.
WASM programs should handle stdout for ingesting logs into Fluent Bit.
Once built, a WASM/WASI program will be available. Then, that built program can be executed with the following Fluent Bit configuration:
For further example that handles structured logs, fluent-bit has a Rust serde-json example: https://github.com/fluent/fluent-bit/tree/master/examples/wasi_serde_json