Add http-wasm plugin support to Traefik

pkg/plugins/middlewarewasm.go

@@ -0,0 +1,81 @@
+package plugins
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"os"
+	"path/filepath"
+	"reflect"
+
+	"github.com/http-wasm/http-wasm-host-go/handler"
+	wasm "github.com/http-wasm/http-wasm-host-go/handler/nethttp"
+	"github.com/tetratelabs/wazero"
+	"github.com/traefik/traefik/v3/pkg/logs"
+	"github.com/traefik/traefik/v3/pkg/middlewares"
+)
+
+type wasmMiddlewareBuilder struct {
+	path string
+}
+
+func newWasmMiddlewareBuilder(goPath string, moduleName, wasmPath string) *wasmMiddlewareBuilder {
+	return &wasmMiddlewareBuilder{path: filepath.Join(goPath, "src", moduleName, wasmPath)}
+}
+
+func (b wasmMiddlewareBuilder) newMiddleware(config map[string]interface{}, middlewareName string) (pluginMiddleware, error) {
+	return &WasmMiddleware{
+		middlewareName: middlewareName,
+		config:         reflect.ValueOf(config),
+		builder:        b,
+	}, nil
+}
+
+func (b wasmMiddlewareBuilder) newHandler(ctx context.Context, next http.Handler, cfg reflect.Value, middlewareName string) (http.Handler, error) {
+	code, err := os.ReadFile(b.path)
+	if err != nil {
+		return nil, fmt.Errorf("loading Wasm binary: %w", err)
+	}
+
+	logger := middlewares.GetLogger(ctx, middlewareName, "wasm")
+
+	opts := []handler.Option{
+		handler.ModuleConfig(wazero.NewModuleConfig().WithSysWalltime()),
+		handler.Logger(logs.NewWasmLogger(logger)),
+	}
+
+	i := cfg.Interface()
+	if i != nil {
+		config, ok := i.(map[string]interface{})
+		if !ok {
+			return nil, fmt.Errorf("could not type assert config: %T", i)
+		}
+
+		data, err := json.Marshal(config)
+		if err != nil {
+			return nil, fmt.Errorf("marshaling config: %w", err)
+		}
+
+		opts = append(opts, handler.GuestConfig(data))
+	}
+
+	mw, err := wasm.NewMiddleware(context.Background(), code, opts...)
+	if err != nil {
+		return nil, err
+	}
+
+	return mw.NewHandler(ctx, next), nil
+}
+
+// WasmMiddleware is an HTTP handler plugin wrapper.
+type WasmMiddleware struct {
+	middlewareName string
+	config         reflect.Value
+	builder        wasmMiddlewareBuilder
+}
+
+// NewHandler creates a new HTTP handler.
+func (m WasmMiddleware) NewHandler(ctx context.Context, next http.Handler) (http.Handler, error) {
+	return m.builder.newHandler(ctx, next, m.config, m.middlewareName)
+}