Fluent Bit currently supports integration of Golang plugins built as shared objects for output plugins only. The interface for the Golang plugins is currently under development but is functional.
Getting Started
Compile Fluent Bit with Golang support, e.g:
$ cd build/
$ cmake -DFLB_DEBUG=On -DFLB_PROXY_GO=On ../
$ make
Once compiled, we 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)
...
Build a Go Plugin
The fluent-bit-go package is available to assist developers in creating Go plugins.
packagemainimport"github.com/fluent/fluent-bit-go/output"//export FLBPluginRegisterfuncFLBPluginRegister(def unsafe.Pointer) int {// Gets called only once when the plugin.so is loadedreturn output.FLBPluginRegister(ctx, "gstdout", "Stdout GO!")}//export FLBPluginInitfuncFLBPluginInit(plugin unsafe.Pointer) int {// Gets called only once for each instance you have configured.return output.FLB_OK}//export FLBPluginFlushCtxfuncFLBPluginFlushCtx(ctx, data unsafe.Pointer, length C.int, tag *C.char) int {// Gets called with a batch of records to be written to an instance.return output.FLB_OK}//export FLBPluginExitfuncFLBPluginExit() int {return output.FLB_OK}funcmain() {}
the code above is a template to write an output plugin, it's really important to keep the package name as main and add an explicit main() function. This is a requirement as the code will be build as a shared library.
Once built, a shared library called out\_gstdout.so will be available. It's really important to double check the final .so file is what we expect. Doing a ldd over the library we should see something similar to this: