gittestserver: Add http middleware support

Add http middleware support to be able to change the behavior of the
server. Usage could be for returning certain response and error or
introducing some delay in the server, etc.
The middlewares can be chained together based on the needs.

Signed-off-by: Sunny <darkowlzz@protonmail.com>

gittestserver/server.go

@@ -20,6 +20,7 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"fmt"
+	"net/http"
 	"net/http/httptest"
 	"net/url"
 	"os"
@@ -60,6 +61,9 @@ func NewGitServer(docroot string) *GitServer {
 	}
 }
 
+// HTTPMiddleware is a git http server middleware.
+type HTTPMiddleware func(http.Handler) http.Handler
+
 // GitServer is a git server for testing purposes.
 // It can serve git repositories over HTTP and SSH.
 type GitServer struct {
@@ -68,6 +72,12 @@ type GitServer struct {
 	sshServer  *gitkit.SSH
 	// Set these to configure HTTP auth
 	username, password string
+	httpMiddlewares    []HTTPMiddleware
+}
+
+// AddHTTPMiddlewares adds http middlewares to the git server.
+func (s *GitServer) AddHTTPMiddlewares(httpMiddlewares ...HTTPMiddleware) {
+	s.httpMiddlewares = append(s.httpMiddlewares, httpMiddlewares...)
 }
 
 // AutoCreate enables the automatic creation of a non-existing Git
@@ -126,7 +136,8 @@ func (s *GitServer) StartHTTP() error {
 	if err := service.Setup(); err != nil {
 		return err
 	}
-	s.httpServer = httptest.NewServer(service)
+	handler := buildHTTPHandler(service, s.httpMiddlewares...)
+	s.httpServer = httptest.NewServer(handler)
 	return nil
 }
 
@@ -142,7 +153,8 @@ func (s *GitServer) StartHTTPS(cert, key, ca []byte, serverName string) error {
 	if err := service.Setup(); err != nil {
 		return err
 	}
-	s.httpServer = httptest.NewUnstartedServer(service)
+	handler := buildHTTPHandler(service, s.httpMiddlewares...)
+	s.httpServer = httptest.NewUnstartedServer(handler)
 
 	config := tls.Config{}
 
@@ -365,3 +377,11 @@ func checkout(repo *gogit.Repository, branch string) error {
 func getLocalURL(localPath string) string {
 	return fmt.Sprintf("file://%s", localPath)
 }
+
+// buildHTTPHandler chains a given http handler with the given middlewares.
+func buildHTTPHandler(handler http.Handler, middlewares ...HTTPMiddleware) http.Handler {
+	for _, middleware := range middlewares {
+		handler = middleware(handler)
+	}
+	return handler
+}

gittestserver/server_test.go

@@ -2,6 +2,7 @@ package gittestserver
 
 import (
 	"fmt"
+	"net/http"
 	"os"
 	"path/filepath"
 	"strings"
@@ -194,3 +195,44 @@ func TestInitRepo(t *testing.T) {
 		})
 	}
 }
+
+func TestGitServer_AddHTTPMiddlewares(t *testing.T) {
+	repoPath := "bar/test-reponame"
+	initBranch := "test-branch"
+
+	srv, err := NewTempGitServer()
+	if err != nil {
+		t.Fatal(err)
+	}
+	srv.Auth("test-user", "test-pswd")
+	defer os.RemoveAll(srv.Root())
+	srv.KeyDir(srv.Root())
+
+	// Add a middleware.
+	middleware := func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			http.Error(w, "something failed", http.StatusInternalServerError)
+		})
+	}
+	srv.AddHTTPMiddlewares(middleware)
+
+	if err = srv.StartHTTP(); err != nil {
+		t.Fatal(err)
+	}
+	defer srv.StopHTTP()
+
+	// Initialize a repo.
+	err = srv.InitRepo("testdata/git/repo1", initBranch, repoPath)
+	if err != nil {
+		t.Fatalf("failed to initialize repo: %v", err)
+	}
+	repoURL := srv.HTTPAddressWithCredentials() + "/" + repoPath
+
+	// Clone the branch.
+	_, err = gogit.PlainClone("some-non-existing-dir", false, &gogit.CloneOptions{
+		URL: repoURL,
+	})
+	if !strings.Contains(err.Error(), "status code: 500") {
+		t.Errorf("expected error status code 500, got: %v", err)
+	}
+}