feat: add Basic Auth middleware for management API

pkg/service/handlers/auth_middleware.go

@@ -0,0 +1,23 @@
+package handlers
+
+import (
+	"crypto/subtle"
+	"net/http"
+)
+
+// BasicAuthMiddleware returns a chi middleware that enforces HTTP Basic Authentication.
+func BasicAuthMiddleware(username, password string) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			u, p, ok := r.BasicAuth()
+			if !ok ||
+				subtle.ConstantTimeCompare([]byte(u), []byte(username)) != 1 ||
+				subtle.ConstantTimeCompare([]byte(p), []byte(password)) != 1 {
+				w.Header().Set("WWW-Authenticate", `Basic realm="Management API"`)
+				http.Error(w, "Unauthorized", http.StatusUnauthorized)
+				return
+			}
+			next.ServeHTTP(w, r)
+		})
+	}
+}

pkg/service/handlers/auth_middleware_test.go

@@ -0,0 +1,102 @@
+package handlers
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestBasicAuthMiddleware_ValidCredentials(t *testing.T) {
+	handler := BasicAuthMiddleware("admin", "secret123")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte("OK"))
+	}))
+
+	req := httptest.NewRequest(http.MethodGet, "/mgmt/test", nil)
+	req.SetBasicAuth("admin", "secret123")
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+
+	if rr.Code != http.StatusOK {
+		t.Errorf("expected status %d, got %d", http.StatusOK, rr.Code)
+	}
+	if rr.Body.String() != "OK" {
+		t.Errorf("expected body 'OK', got %q", rr.Body.String())
+	}
+}
+
+func TestBasicAuthMiddleware_WrongUsername(t *testing.T) {
+	handler := BasicAuthMiddleware("admin", "secret123")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Error("handler should not be called with wrong username")
+	}))
+
+	req := httptest.NewRequest(http.MethodGet, "/mgmt/test", nil)
+	req.SetBasicAuth("wrong", "secret123")
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+
+	if rr.Code != http.StatusUnauthorized {
+		t.Errorf("expected status %d, got %d", http.StatusUnauthorized, rr.Code)
+	}
+	if rr.Header().Get("WWW-Authenticate") == "" {
+		t.Error("expected WWW-Authenticate header to be set")
+	}
+}
+
+func TestBasicAuthMiddleware_WrongPassword(t *testing.T) {
+	handler := BasicAuthMiddleware("admin", "secret123")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Error("handler should not be called with wrong password")
+	}))
+
+	req := httptest.NewRequest(http.MethodGet, "/mgmt/test", nil)
+	req.SetBasicAuth("admin", "wrongpass")
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+
+	if rr.Code != http.StatusUnauthorized {
+		t.Errorf("expected status %d, got %d", http.StatusUnauthorized, rr.Code)
+	}
+	if rr.Header().Get("WWW-Authenticate") == "" {
+		t.Error("expected WWW-Authenticate header to be set")
+	}
+}
+
+func TestBasicAuthMiddleware_MissingAuthHeader(t *testing.T) {
+	handler := BasicAuthMiddleware("admin", "secret123")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Error("handler should not be called without auth header")
+	}))
+
+	req := httptest.NewRequest(http.MethodGet, "/mgmt/test", nil)
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+
+	if rr.Code != http.StatusUnauthorized {
+		t.Errorf("expected status %d, got %d", http.StatusUnauthorized, rr.Code)
+	}
+	if rr.Header().Get("WWW-Authenticate") == "" {
+		t.Error("expected WWW-Authenticate header to be set")
+	}
+}
+
+func TestBasicAuthMiddleware_EmptyCredentials(t *testing.T) {
+	handler := BasicAuthMiddleware("admin", "secret123")(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Error("handler should not be called with empty credentials")
+	}))
+
+	req := httptest.NewRequest(http.MethodGet, "/mgmt/test", nil)
+	req.SetBasicAuth("", "")
+	rr := httptest.NewRecorder()
+
+	handler.ServeHTTP(rr, req)
+
+	if rr.Code != http.StatusUnauthorized {
+		t.Errorf("expected status %d, got %d", http.StatusUnauthorized, rr.Code)
+	}
+	if rr.Header().Get("WWW-Authenticate") == "" {
+		t.Error("expected WWW-Authenticate header to be set")
+	}
+}