feat: add external authorization service (authzd) with JWT authentication

- Add new authzd gRPC service implementing Envoy's external authorization API
- Integrate JWT authentication filter in Envoy configuration with claim extraction
- Update middleware to support both cookie-based and header-based user authentication
- Add comprehensive test coverage for authorization service and server
- Configure proper service orchestration with authzd, sparkled, and Envoy
- Update build system and Docker configuration for multi-service deployment
- Add grpcurl tool for gRPC service debugging and testing

This enables fine-grained authorization control through Envoy's ext_authz filter
while maintaining backward compatibility with existing cookie-based authentication.

1 files changed, 86 insertions, 0 deletions

diff --git a/pkg/authz/server_test.go b/pkg/authz/server_test.go
new file mode 100644
index 0000000..6fa4eee
--- /dev/null
+++ b/pkg/authz/server_test.go
@@ -0,0 +1,86 @@
+package authz
+
+import (
+	"context"
+	"net"
+	"strings"
+	"testing"
+
+	auth "github.com/envoyproxy/go-control-plane/envoy/service/auth/v3"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/test/bufconn"
+)
+
+func TestServer(t *testing.T) {
+	socket := bufconn.Listen(1024 * 1024)
+	srv := New(t.Context())
+
+	defer srv.GracefulStop()
+	go func() {
+		require.NoError(t, srv.Serve(socket))
+	}()
+
+	connection, err := grpc.DialContext(
+		t.Context(),
+		"bufnet",
+		grpc.WithContextDialer(func(context.Context, string) (net.Conn, error) {
+			return socket.Dial()
+		}),
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+	)
+	require.NoError(t, err)
+	defer connection.Close()
+
+	client := auth.NewAuthorizationClient(connection)
+	idToken := "eyJ0eXAiOiJKV1QiLCJraWQiOiJ0ZDBTbWRKUTRxUGg1cU5Lek0yNjBDWHgyVWgtd2hHLU1Eam9PS1dmdDhFIiwiYWxnIjoiUlMyNTYifQ.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.TjTrGS5FjfPoY0HWkSLvgjogBxB27jX2beosOZAkwXi_gO3q9DTnL0csOgxjoF1UR8baPNfMFBqL1ipLxBdY9vvDxZve-sOhoSptjzLGkCi7uQKeu7r8wNyFWNWhcLwmbinZyENGSZqIDSkHy0lGdo9oj7qqnH6sYqU46jtWACDGSHTFjNNuo1s_P2SZgkaq4c4v4jdlVV_C_Qlvtl7-eaWV1LzTpB4Mz0VWGsRx1pk3-KnS24crhBjxSE383z4Nar4ZhrsrTK-bOj33l6U32gRKNb4g6GxrPXaRQ268n37spQmbQn0aDwmUOABv-aBRy203bCCZca8BJ0XBur8t6w"
+	accessToken := "f88f60df11e458b594c80b299aee05f8e5805c65c3e779cc6fbc606c4ac36227"
+	refreshToken := "0847d325d6e4f021c4baaae0ddb425dbd8795807a4751cd2131bec8e8a9aee24"
+
+	cookies := []string{
+		"bearer_token=" + accessToken + ";",
+		"id_token=" + idToken + ";",
+		"refresh_token=" + refreshToken,
+	}
+	loggedInHeaders := map[string]string{"cookie": strings.Join(cookies, "; ")}
+
+	t.Run("CheckRequest", func(t *testing.T) {
+		tt := []struct {
+			http   *auth.AttributeContext_HttpRequest
+			status codes.Code
+		}{
+			{status: codes.OK, http: &auth.AttributeContext_HttpRequest{Method: "GET", Path: "/"}},
+			{status: codes.OK, http: &auth.AttributeContext_HttpRequest{Method: "GET", Path: "/application.js"}},
+			{status: codes.OK, http: &auth.AttributeContext_HttpRequest{Method: "GET", Path: "/callback"}},
+			{status: codes.OK, http: &auth.AttributeContext_HttpRequest{Method: "GET", Path: "/dashboard", Headers: loggedInHeaders}},
+			{status: codes.OK, http: &auth.AttributeContext_HttpRequest{Method: "GET", Path: "/dashboard/nav"}},
+			{status: codes.OK, http: &auth.AttributeContext_HttpRequest{Method: "GET", Path: "/favicon.ico"}},
+			{status: codes.OK, http: &auth.AttributeContext_HttpRequest{Method: "GET", Path: "/favicon.png"}},
+			{status: codes.OK, http: &auth.AttributeContext_HttpRequest{Method: "GET", Path: "/health"}},
+			{status: codes.OK, http: &auth.AttributeContext_HttpRequest{Method: "GET", Path: "/index.html"}},
+			{status: codes.OK, http: &auth.AttributeContext_HttpRequest{Method: "GET", Path: "/logo.png"}},
+			{status: codes.OK, http: &auth.AttributeContext_HttpRequest{Method: "GET", Path: "/signout"}},
+			{status: codes.OK, http: &auth.AttributeContext_HttpRequest{Method: "GET", Path: "/sparkles"}},
+			{status: codes.OK, http: &auth.AttributeContext_HttpRequest{Method: "POST", Path: "/sparkles/restore"}},
+			{status: codes.PermissionDenied, http: &auth.AttributeContext_HttpRequest{Method: "GET", Path: "/dashboard"}},
+			{status: codes.PermissionDenied, http: &auth.AttributeContext_HttpRequest{Method: "POST", Path: "/sparkles"}},
+		}
+
+		for _, example := range tt {
+			t.Run(example.http.Path, func(t *testing.T) {
+				response, err := client.Check(t.Context(), &auth.CheckRequest{
+					Attributes: &auth.AttributeContext{
+						Request: &auth.AttributeContext_Request{
+							Http: example.http,
+						},
+					},
+				})
+				require.NoError(t, err)
+				assert.Equal(t, int32(example.status), response.Status.Code)
+			})
+		}
+	})
+}