fix(admin): initialise V1Scale spec before setting replicas (#7698)

shenyu-admin/src/main/java/org/apache/shenyu/admin/scale/scaler/KubernetesScaler.java

@@ -71,7 +71,7 @@ public void scaleByAction(final ScaleAction action) throws Exception {
     public void scaleByNum(final int replicaCount) {
         try {
             V1Scale scale = new V1Scale();
-            Objects.requireNonNull(scale.getSpec()).setReplicas(replicaCount);
+            scale.setSpec(new V1ScaleSpec().replicas(replicaCount));
 
             appsV1Api.replaceNamespacedDeploymentScale(
                     deploymentProperties.getName(),

shenyu-admin/src/test/java/org/apache/shenyu/admin/scale/scaler/KubernetesScalerTest.java

@@ -0,0 +1,108 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.shenyu.admin.scale.scaler;
+
+import io.kubernetes.client.openapi.apis.AppsV1Api;
+import io.kubernetes.client.openapi.models.V1Scale;
+import io.kubernetes.client.openapi.models.V1ScaleSpec;
+import org.apache.shenyu.admin.config.properties.DeploymentProperties;
+import org.apache.shenyu.admin.scale.scaler.dynamic.ScaleAction;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.mockito.junit.jupiter.MockitoSettings;
+import org.mockito.quality.Strictness;
+
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.ArgumentMatchers.isNull;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+@MockitoSettings(strictness = Strictness.LENIENT)
+public final class KubernetesScalerTest {
+
+    private static final String DEPLOY_NAME = "shenyu-bootstrap";
+
+    private static final String DEPLOY_NAMESPACE = "shenyu";
+
+    @Mock
+    private AppsV1Api appsV1Api;
+
+    private KubernetesScaler kubernetesScaler;
+
+    @BeforeEach
+    public void setUp() {
+        final DeploymentProperties deploymentProperties = new DeploymentProperties();
+        deploymentProperties.setName(DEPLOY_NAME);
+        deploymentProperties.setNamespace(DEPLOY_NAMESPACE);
+        kubernetesScaler = new KubernetesScaler(Optional.of(appsV1Api), deploymentProperties);
+    }
+
+    /**
+     * A freshly built {@link V1Scale} carries a null spec, so the previous
+     * {@code requireNonNull(scale.getSpec())} threw before the replace call.
+     */
+    @Test
+    public void testScaleByNumSetsSpecBeforeReplace() throws Exception {
+        kubernetesScaler.scaleByNum(3);
+
+        final ArgumentCaptor<V1Scale> captor = ArgumentCaptor.forClass(V1Scale.class);
+        verify(appsV1Api).replaceNamespacedDeploymentScale(
+                eq(DEPLOY_NAME),
+                eq(DEPLOY_NAMESPACE),
+                captor.capture(),
+                isNull(),
+                isNull(),
+                isNull(),
+                isNull());
+
+        final V1Scale sent = captor.getValue();
+        assertNotNull(sent.getSpec(), "scale spec must be initialised before the replace call");
+        assertEquals(3, sent.getSpec().getReplicas());
+    }
+
+    @Test
+    public void testScaleByActionReadsCurrentAndAppliesDelta() throws Exception {
+        final V1Scale current = new V1Scale();
+        current.setSpec(new V1ScaleSpec().replicas(2));
+        when(appsV1Api.readNamespacedDeploymentScale(eq(DEPLOY_NAME), eq(DEPLOY_NAMESPACE), any()))
+                .thenReturn(current);
+
+        kubernetesScaler.scaleByAction(new ScaleAction(ScaleAction.ActionType.SCALE_UP));
+
+        final ArgumentCaptor<V1Scale> captor = ArgumentCaptor.forClass(V1Scale.class);
+        verify(appsV1Api).replaceNamespacedDeploymentScale(
+                eq(DEPLOY_NAME),
+                eq(DEPLOY_NAMESPACE),
+                captor.capture(),
+                isNull(),
+                isNull(),
+                isNull(),
+                isNull());
+        assertEquals(3, captor.getValue().getSpec().getReplicas());
+    }
+}