main.go

package main

import (
	"fmt"

	"github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm"
	"github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm/types"
)

func main() {
	proxywasm.SetVMContext(&vmContext{})
}

type vmContext struct {
	// Embed the default VM context here,
	// so that we don't need to reimplement all the methods.
	types.DefaultVMContext
}

// Override types.DefaultVMContext.
func (*vmContext) NewPluginContext(contextID uint32) types.PluginContext {
	return &pluginContext{}
}

type pluginContext struct {
	// Embed the default plugin context here,
	// so that we don't need to reimplement all the methods.
	types.DefaultPluginContext
}

// Override types.DefaultPluginContext.
func (*pluginContext) NewHttpContext(contextID uint32) types.HttpContext {
	return &httpHeaders{contextID: contextID}
}

type httpHeaders struct {
	// Embed the default http context here,
	// so that we don't need to reimplement all the methods.
	types.DefaultHttpContext
	contextID uint32
}

func (ctx *httpHeaders) OnHttpRequestHeaders(numHeaders int, endOfStream bool) types.Action {
	hs, err := proxywasm.GetHttpRequestHeaders()
	if err != nil {
		panic(err)
	}
	for _, h := range hs {
		fmt.Printf("%s: %s", h[0], h[1])
	}
	return types.ActionContinue
}

// Additional headers supposed to be injected to response headers.
var additionalResponseHeaders = map[string]string{
	"istio-weekly": "#14",
}

func (ctx *httpHeaders) OnHttpResponseHeaders(numHeaders int, endOfStream bool) types.Action {
	for key, value := range additionalResponseHeaders {
		proxywasm.AddHttpResponseHeader(key, value)
	}
	return types.ActionContinue
}