The Golang HTTP Filter allows developers to write custom Envoy Filters using the Go language. This framework supports executing Golang code during both request and response flows, making it easier to extend Envoy. Most importantly, Go plugins developed using this framework can be compiled independently of Envoy, which greatly enhances development and deployment flexibility.

注意 Golang Filter require Higress version 2.1.0 or higher to be used.

Features

Support for Golang code execution in both request and response flows
Independent plugin compilation without rebuilding Envoy
Simple and clean API interface
Request/response header modification
Request/response body modification
Synchronous request support

Quick Start

Please refer to Envoy Golang HTTP Filter Example to learn how to develop and run a basic Golang Filter.

Plugin Registration

When developing a new Golang Filter, you need to register your plugin in the init() function of main.go. The registration requires a plugin name, Filter factory function, and configuration parser:

func init() {
    envoyHttp.RegisterHttpFilterFactoryAndConfigParser(
        "your-plugin-name",    // Plugin name
        yourFilterFactory,     // Filter factory function
        &yourConfigParser{},   // Configuration parser
    )
}

Configuration Example

Multiple Golang Filter plugins can be compiled into a single golang-filter.so file, and the desired plugin can be specified using plugin_name. Here's an example configuration:

http_filters:
- name: envoy.filters.http.golang
  typed_config:
    "@type": type.googleapis.com/envoy.extensions.filters.http.golang.v3alpha.Config
    library_id: your-plugin-name
    library_path: "./golang-filter.so"  # Shared library file containing multiple plugins
    plugin_name: your-plugin-name       # Specify which plugin to use, must match the name registered in init()
    plugin_config:
      "@type": type.googleapis.com/xds.type.v3.TypedStruct
      value:
          your_config_here: value

Quick Build

Use the following command to quickly build the golang filter plugin:

make build

If you are on an arm64 architecture, please set GOARCH=arm64:

make build GOARCH=arm64

Alternatively, you can build the Higress Gateway image directly by running make build-gateway-local in the root directory of the Higress project. The golang-filter.so file will be automatically built and included in the image.