Add GrpcWeb middleware

Co-authored-by: Kevin Pollet <pollet.kevin@gmail.com>

pkg/config/dynamic/middlewares.go

@@ -34,12 +34,23 @@ type Middleware struct {
 	PassTLSClientCert *PassTLSClientCert `json:"passTLSClientCert,omitempty" toml:"passTLSClientCert,omitempty" yaml:"passTLSClientCert,omitempty" export:"true"`
 	Retry             *Retry             `json:"retry,omitempty" toml:"retry,omitempty" yaml:"retry,omitempty" export:"true"`
 	ContentType       *ContentType       `json:"contentType,omitempty" toml:"contentType,omitempty" yaml:"contentType,omitempty" export:"true"`
+	GrpcWeb           *GrpcWeb           `json:"grpcWeb,omitempty" toml:"grpcWeb,omitempty" yaml:"grpcWeb,omitempty" export:"true"`
 
 	Plugin map[string]PluginConf `json:"plugin,omitempty" toml:"plugin,omitempty" yaml:"plugin,omitempty" export:"true"`
 }
 
 // +k8s:deepcopy-gen=true
 
+// GrpcWeb holds the gRPC web middleware configuration.
+// This middleware converts a gRPC web request to an HTTP/2 gRPC request.
+type GrpcWeb struct {
+	// AllowOrigins is a list of allowable origins.
+	// Can also be a wildcard origin "*".
+	AllowOrigins []string `json:"allowOrigins,omitempty" toml:"allowOrigins,omitempty" yaml:"allowOrigins,omitempty"`
+}
+
+// +k8s:deepcopy-gen=true
+
 // ContentType holds the content-type middleware configuration.
 // This middleware exists to enable the correct behavior until at least the default one can be changed in a future version.
 type ContentType struct {

pkg/config/dynamic/zz_generated.deepcopy.go

@@ -353,6 +353,27 @@ func (in *ForwardingTimeouts) DeepCopy() *ForwardingTimeouts {
 	return out
 }
 
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *GrpcWeb) DeepCopyInto(out *GrpcWeb) {
+	*out = *in
+	if in.AllowOrigins != nil {
+		in, out := &in.AllowOrigins, &out.AllowOrigins
+		*out = make([]string, len(*in))
+		copy(*out, *in)
+	}
+	return
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new GrpcWeb.
+func (in *GrpcWeb) DeepCopy() *GrpcWeb {
+	if in == nil {
+		return nil
+	}
+	out := new(GrpcWeb)
+	in.DeepCopyInto(out)
+	return out
+}
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *HTTPConfiguration) DeepCopyInto(out *HTTPConfiguration) {
 	*out = *in
@@ -734,6 +755,11 @@ func (in *Middleware) DeepCopyInto(out *Middleware) {
 		*out = new(ContentType)
 		**out = **in
 	}
+	if in.GrpcWeb != nil {
+		in, out := &in.GrpcWeb, &out.GrpcWeb
+		*out = new(GrpcWeb)
+		(*in).DeepCopyInto(*out)
+	}
 	if in.Plugin != nil {
 		in, out := &in.Plugin, &out.Plugin
 		*out = make(map[string]PluginConf, len(*in))

pkg/middlewares/grpcweb/grpcweb.go

@@ -0,0 +1,27 @@
+package grpcweb
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/improbable-eng/grpc-web/go/grpcweb"
+	"github.com/traefik/traefik/v2/pkg/config/dynamic"
+	"github.com/traefik/traefik/v2/pkg/log"
+	"github.com/traefik/traefik/v2/pkg/middlewares"
+)
+
+const typeName = "grpc-web"
+
+// New builds a new gRPC web request converter.
+func New(ctx context.Context, next http.Handler, config dynamic.GrpcWeb, name string) http.Handler {
+	log.FromContext(middlewares.GetLoggerCtx(ctx, name, typeName)).Debug("Creating middleware")
+
+	return grpcweb.WrapHandler(next, grpcweb.WithCorsForRegisteredEndpointsOnly(false), grpcweb.WithOriginFunc(func(origin string) bool {
+		for _, originCfg := range config.AllowOrigins {
+			if originCfg == "*" || originCfg == origin {
+				return true
+			}
+		}
+		return false
+	}))
+}

pkg/provider/kubernetes/crd/kubernetes.go

@@ -279,6 +279,7 @@ func (p *Provider) loadConfigurationFromCRD(ctx context.Context, client Client)
 			PassTLSClientCert: middleware.Spec.PassTLSClientCert,
 			Retry:             retry,
 			ContentType:       middleware.Spec.ContentType,
+			GrpcWeb:           middleware.Spec.GrpcWeb,
 			Plugin:            plugin,
 		}
 	}

pkg/provider/kubernetes/crd/traefik/v1alpha1/middleware.go

@@ -48,6 +48,7 @@ type MiddlewareSpec struct {
 	PassTLSClientCert *dynamic.PassTLSClientCert `json:"passTLSClientCert,omitempty"`
 	Retry             *Retry                     `json:"retry,omitempty"`
 	ContentType       *dynamic.ContentType       `json:"contentType,omitempty"`
+	GrpcWeb           *dynamic.GrpcWeb           `json:"grpcWeb,omitempty"`
 	// Plugin defines the middleware plugin configuration.
 	// More info: https://doc.traefik.io/traefik/plugins/
 	Plugin map[string]apiextensionv1.JSON `json:"plugin,omitempty"`

pkg/provider/kubernetes/crd/traefik/v1alpha1/zz_generated.deepcopy.go

@@ -769,6 +769,11 @@ func (in *MiddlewareSpec) DeepCopyInto(out *MiddlewareSpec) {
 		*out = new(dynamic.ContentType)
 		**out = **in
 	}
+	if in.GrpcWeb != nil {
+		in, out := &in.GrpcWeb, &out.GrpcWeb
+		*out = new(dynamic.GrpcWeb)
+		(*in).DeepCopyInto(*out)
+	}
 	if in.Plugin != nil {
 		in, out := &in.Plugin, &out.Plugin
 		*out = make(map[string]v1.JSON, len(*in))

pkg/server/middleware/middlewares.go

@@ -17,6 +17,7 @@ import (
 	"github.com/traefik/traefik/v2/pkg/middlewares/circuitbreaker"
 	"github.com/traefik/traefik/v2/pkg/middlewares/compress"
 	"github.com/traefik/traefik/v2/pkg/middlewares/customerrors"
+	"github.com/traefik/traefik/v2/pkg/middlewares/grpcweb"
 	"github.com/traefik/traefik/v2/pkg/middlewares/headers"
 	"github.com/traefik/traefik/v2/pkg/middlewares/inflightreq"
 	"github.com/traefik/traefik/v2/pkg/middlewares/ipallowlist"
@@ -219,6 +220,16 @@ func (b *Builder) buildConstructor(ctx context.Context, middlewareName string) (
 		}
 	}
 
+	// GrpcWeb
+	if config.GrpcWeb != nil {
+		if middleware != nil {
+			return nil, badConf
+		}
+		middleware = func(next http.Handler) (http.Handler, error) {
+			return grpcweb.New(ctx, next, *config.GrpcWeb, middlewareName), nil
+		}
+	}
+
 	// Headers
 	if config.Headers != nil {
 		if middleware != nil {