integration: add forward auth test

integration/forward_auth_test.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"context"
+	"net/http"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/pomerium/pomerium/integration/internal/flows"
+)
+
+func TestForwardAuth(t *testing.T) {
+	ctx := mainCtx
+	ctx, clearTimeout := context.WithTimeout(ctx, time.Second*30)
+	defer clearTimeout()
+
+	client := testcluster.NewHTTPClient()
+	res, err := flows.Authenticate(ctx, client, mustParseURL("https://fa-httpdetails.localhost.pomerium.io/by-user"),
+		flows.WithForwardAuth(true), flows.WithEmail("bob@dogs.test"), flows.WithGroups("user"))
+	if !assert.NoError(t, err, "unexpected http error") {
+		return
+	}
+	defer res.Body.Close()
+	assert.Equal(t, http.StatusOK, res.StatusCode)
+}

integration/internal/flows/flows.go

@@ -27,6 +27,7 @@ type authenticateConfig struct {
 	groups          []string
 	tokenExpiration time.Duration
 	apiPath         string
+	forwardAuth     bool
 }
 
 // An AuthenticateOption is an option for authentication.
@@ -44,6 +45,13 @@ func getAuthenticateConfig(options ...AuthenticateOption) *authenticateConfig {
 	return cfg
 }
 
+// WithForwardAuth enables/disables forward auth.
+func WithForwardAuth(fa bool) AuthenticateOption {
+	return func(cfg *authenticateConfig) {
+		cfg.forwardAuth = fa
+	}
+}
+
 // WithEmail sets the email to use.
 func WithEmail(email string) AuthenticateOption {
 	return func(cfg *authenticateConfig) {
@@ -184,10 +192,28 @@ func Authenticate(ctx context.Context, client *http.Client, url *url.URL, option
 	}
 
 	// (5) finally to callback
-	if req.URL.Path != pomeriumCallbackPath {
+	if !cfg.forwardAuth && req.URL.Path != pomeriumCallbackPath {
 		return nil, fmt.Errorf("expected to redirect back to %s, but got %s", pomeriumCallbackPath, req.URL.String())
 	}
 
+	if cfg.forwardAuth {
+		for {
+			res, err = client.Do(req)
+			if err != nil {
+				return nil, err
+			}
+			defer res.Body.Close()
+			if res.StatusCode != 302 {
+				break
+			}
+			req, err = requestFromRedirectResponse(ctx, res, req)
+			if err != nil {
+				return nil, fmt.Errorf("expected redirect to %s: %w", originalHostname, err)
+			}
+		}
+		return res, err
+	}
+
 	res, err = client.Do(req)
 	if err != nil {
 		return nil, err