proxy: add skipping invoice creation on request

proxy/proxy.go

@@ -172,6 +172,7 @@ func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	// Determine auth level required to access service and dispatch request
 	// accordingly.
 	authLevel := target.AuthRequired(r)
+	skipInvoiceCreation := target.SkipInvoiceCreation(r)
 	switch {
 	case authLevel.IsOn():
 		// Determine if the header contains the authentication
@@ -181,6 +182,16 @@ func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		// resources.
 		acceptAuth := p.authenticator.Accept(&r.Header, resourceName)
 		if !acceptAuth {
+			if skipInvoiceCreation {
+				addCorsHeaders(w.Header())
+				sendDirectResponse(
+					w, r, http.StatusUnauthorized,
+					"unauthorized",
+				)
+
+				return
+			}
+
 			price, err := target.pricer.GetPrice(r.Context(), r)
 			if err != nil {
 				prefixLog.Errorf("error getting "+

proxy/proxy_test.go

@@ -48,10 +48,11 @@ var (
 )
 
 type testCase struct {
-	name           string
-	auth           auth.Level
-	authWhitelist  []string
-	wantBackendErr bool
+	name                         string
+	auth                         auth.Level
+	authWhitelist                []string
+	authSkipInvoiceCreationPaths []string
+	wantBackendErr               bool
 }
 
 // helloServer is a simple server that implements the GreeterServer interface.
@@ -98,6 +99,15 @@ func TestProxyHTTP(t *testing.T) {
 		name:          "with whitelist",
 		auth:          "on",
 		authWhitelist: []string{"^/http/white.*$"},
+	}, {
+		name:                         "no whitelist with skip",
+		auth:                         "on",
+		authSkipInvoiceCreationPaths: []string{"^/http/skip.*$"},
+	}, {
+		name:                         "with whitelist with skip",
+		auth:                         "on",
+		authWhitelist:                []string{"^/http/white.*$"},
+		authSkipInvoiceCreationPaths: []string{"^/http/skip.*$"},
 	}}
 
 	for _, tc := range testCases {
@@ -182,12 +192,13 @@ func TestProxyHTTPBlocklist(t *testing.T) {
 func runHTTPTest(t *testing.T, tc *testCase, method string) {
 	// Create a list of services to proxy between.
 	services := []*proxy.Service{{
-		Address:            testTargetServiceAddress,
-		HostRegexp:         testHostRegexp,
-		PathRegexp:         testPathRegexpHTTP,
-		Protocol:           "http",
-		Auth:               tc.auth,
-		AuthWhitelistPaths: tc.authWhitelist,
+		Address:                      testTargetServiceAddress,
+		HostRegexp:                   testHostRegexp,
+		PathRegexp:                   testPathRegexpHTTP,
+		Protocol:                     "http",
+		Auth:                         tc.auth,
+		AuthWhitelistPaths:           tc.authWhitelist,
+		AuthSkipInvoiceCreationPaths: tc.authSkipInvoiceCreationPaths,
 	}}
 
 	mockAuth := auth.NewMockAuthenticator()
@@ -261,8 +272,33 @@ func runHTTPTest(t *testing.T, tc *testCase, method string) {
 		require.EqualValues(t, len(bodyBytes), resp.ContentLength)
 	}
 
+	// Make sure that if we query a URL that is on the skip invoice
+	// creation list, we get a 401 if auth fails.
+	if len(tc.authSkipInvoiceCreationPaths) > 0 {
+		urlToSkip := fmt.Sprintf("http://%s/http/skip", testProxyAddr)
+		reqToSkip, err := http.NewRequest(method, urlToSkip, nil)
+		require.NoError(t, err)
+
+		if method == "POST" {
+			reqToSkip.Header.Add("Content-Type", "application/json")
+			reqToSkip.Body = io.NopCloser(strings.NewReader(`{}`))
+		}
+
+		respSkipped, err := client.Do(reqToSkip)
+		require.NoError(t, err)
+
+		require.Equal(t, http.StatusUnauthorized, respSkipped.StatusCode)
+		require.Equal(t, "401 Unauthorized", respSkipped.Status)
+
+		bodySkippedContent, err := io.ReadAll(respSkipped.Body)
+		require.NoError(t, err)
+		require.Equal(t, "unauthorized\n", string(bodySkippedContent))
+		require.EqualValues(t, len(bodySkippedContent), respSkipped.ContentLength)
+		_ = respSkipped.Body.Close()
+	}
+
 	// Make sure that if the Auth header is set, the client's request is
-	// proxied to the backend service.
+	// proxied to the backend service for a non-skipped, non-whitelisted path.
 	req, err = http.NewRequest(method, url, nil)
 	require.NoError(t, err)
 	req.Header.Add("Authorization", "foobar")
@@ -297,6 +333,12 @@ func TestProxyGRPC(t *testing.T) {
 		authWhitelist: []string{
 			"^/proxy_test\\.Greeter/SayHelloNoAuth.*$",
 		},
+	}, {
+		name: "gRPC no whitelist with skip for SayHello",
+		auth: "on",
+		authSkipInvoiceCreationPaths: []string{
+			`^/proxy_test[.]Greeter/SayHello.*$`,
+		},
 	}}
 
 	for _, tc := range testCases {
@@ -343,13 +385,14 @@ func runGRPCTest(t *testing.T, tc *testCase) {
 
 	// Create a list of services to proxy between.
 	services := []*proxy.Service{{
-		Address:            testTargetServiceAddress,
-		HostRegexp:         testHostRegexp,
-		PathRegexp:         testPathRegexpGRPC,
-		Protocol:           "https",
-		TLSCertPath:        certFile,
-		Auth:               tc.auth,
-		AuthWhitelistPaths: tc.authWhitelist,
+		Address:                      testTargetServiceAddress,
+		HostRegexp:                   testHostRegexp,
+		PathRegexp:                   testPathRegexpGRPC,
+		Protocol:                     "https",
+		TLSCertPath:                  certFile,
+		Auth:                         tc.auth,
+		AuthWhitelistPaths:           tc.authWhitelist,
+		AuthSkipInvoiceCreationPaths: tc.authSkipInvoiceCreationPaths,
 	}}
 
 	// Create the proxy server and start serving on TLS.
@@ -393,17 +436,24 @@ func runGRPCTest(t *testing.T, tc *testCase) {
 		grpc.Trailer(&captureMetadata),
 	)
 	require.Error(t, err)
-	require.True(t, l402.IsPaymentRequired(err))
+	if len(tc.authSkipInvoiceCreationPaths) > 0 {
+		statusErr, ok := status.FromError(err)
+		require.True(t, ok)
+		require.Equal(t, codes.Internal, statusErr.Code())
+		require.Equal(t, "unauthorized", statusErr.Message())
+	} else {
+		require.True(t, l402.IsPaymentRequired(err))
 
-	// We expect the WWW-Authenticate header field to be set to an L402
-	// auth response.
-	expectedHeaderContent, _ := mockAuth.FreshChallengeHeader("", 0)
-	capturedHeader := captureMetadata.Get("WWW-Authenticate")
-	require.Len(t, capturedHeader, 2)
-	require.Equal(
-		t, expectedHeaderContent.Values("WWW-Authenticate"),
-		capturedHeader,
-	)
+		// We expect the WWW-Authenticate header field to be set to an L402
+		// auth response.
+		expectedHeaderContent, _ := mockAuth.FreshChallengeHeader("", 0)
+		capturedHeader := captureMetadata.Get("WWW-Authenticate")
+		require.Len(t, capturedHeader, 2)
+		require.Equal(
+			t, expectedHeaderContent.Values("WWW-Authenticate"),
+			capturedHeader,
+		)
+	}
 
 	// Make sure that if we query an URL that is on the whitelist, we don't
 	// get the 402 response.