This crate aims to build output plugins for Fluent-bit. It is based on the Go interface for writting output plugins.
This crate is still in heavy development. At this point, Multiple-instance plugin is not supported but it would be added very soon.
A simple Hello world example which prints data to stdout, it involves following three steps:
- Create a struct/enum with the data you might use for processing the incoming buffer from Fluent-bit
- Implement the trait FLBPluginMethods for that struct/enum.
- After steps 1 and 2, call the macro create_boilerplate!() which will generate the boilerplate code that every plugin should have, taking care of the unsafe safe code and abstracting it into a safe Rust style. This macro will accept as an argument any type which implements the FLBPluginMethods trait
And that's all. Compile your plugin as a dynamic library by adding this line to your Cargo.toml
[lib]
crate-type=["cdylib"]
Another thing that is worth to mention is that Fluent-bit should be able to load Go plugins even though your plugin was written in Rust. To enable external plugins' support you have to compile Fluent-bit with Goland support, e.g:
$ cd build/
$ cmake -DFLB_DEBUG=On -DFLB_PROXY_GO=On ../
$ make && mske install
Once compiled, you can see a new option in the binary -e which stands for external plugin, e.g:
$ bin/fluent-bit -h
Usage: fluent-bit [OPTION]
Available Options
-c --config=FILE specify an optional configuration file
-d, --daemon run Fluent Bit in background mode
-f, --flush=SECONDS flush timeout in seconds (default: 5)
-i, --input=INPUT set an input
-m, --match=MATCH set plugin match, same as '-p match=abc'
-o, --output=OUTPUT set an output
-p, --prop="A=B" set plugin configuration property
-e, --plugin=FILE load an external plugin (shared lib)
...
Now here is a simple output plugin
extern crate fluentbit;
use fluentbit::*;
extern crate rmpv;
extern crate serde_json;
extern crate serde;
#[derive(Default)]
struct JsonExample{}
impl FLBPluginMethods for JsonExample{
fn plugin_register(&mut self, info: &mut PluginInfo) -> FLBResult{
info.name = "rustout".into();
info.description = "This is a default description".into();
Ok(())
}
fn plugin_init(&mut self) -> FLBResult{
println!("default init");
Ok(())
}
fn plugin_flush(&mut self, data: &[u8]) -> FLBResult{
let mut value = data.clone();
let value: rmpv::Value = rmpv::decode::value::read_value(&mut value).unwrap();
let json = serde_json::to_string_pretty(&value).unwrap();
println!("\n{}", json);
Ok(())
}
fn plugin_exit(&mut self) -> FLBResult{
println!("exiting");
Ok(())
}
}
create_boilerplate!(JsonExample::default());
cargo build --release
fluent-bit -e target/release/libjson.so -i cpu -o "rustout"
fluentbit is licensed under either
- Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)
at your option.
Any kinds of contributions are welcome as a pull request.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in fluentbit by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.