Feat: Kubectl get implementation

e2e/src/test/groovy/io/kubernetes/client/e2e/kubectl/KubectlApplyTest.groovy

@@ -20,7 +20,10 @@ class KubectlApplyTest extends Specification {
                         .metadata(new V1ObjectMeta().name("apply-foo")))
                 .execute()
         expect:
-        appliedNamespace != null
+        Kubectl.get(V1Namespace.class)
+                .apiClient(apiClient)
+                .name("apply-foo")
+                .execute() != null
     }
 
 }

e2e/src/test/groovy/io/kubernetes/client/e2e/kubectl/KubectlCreateTest.groovy

@@ -18,7 +18,10 @@ class KubectlCreateTest extends Specification {
                         .metadata(new V1ObjectMeta().name("create-foo")))
                 .execute()
         expect:
-        createdNamespace != null
+        Kubectl.get(V1Namespace.class)
+                .apiClient(apiClient)
+                .name("create-foo")
+                .execute() != null
     }
 
 }

extended/src/main/java/io/kubernetes/client/extended/kubectl/Kubectl.java

@@ -28,6 +28,13 @@
  * kubectl commands.
  */
 public class Kubectl {
+
+  /** Equivalent for `kubectl get` */
+  public static <ApiType extends KubernetesObject> KubectlGet<ApiType> get(
+      Class<ApiType> apiTypeClass) {
+    return new KubectlGet<>(apiTypeClass);
+  }
+
   /** Equivalent for `kubectl drain` */
   public static KubectlDrain drain() {
     return new KubectlDrain();
@@ -60,6 +67,7 @@ public static KubectlCreate create() {
   public static KubectlApply apply() {
     return new KubectlApply();
   }
+
   /**
    * Equivalent for `kubectl top`
    *
@@ -198,15 +206,38 @@ protected void refreshDiscovery() throws KubectlException {
       }
     }
 
-    protected GenericKubernetesApi<? extends KubernetesObject, KubernetesListObject> getGenericApi(
-        Class<? extends KubernetesObject> apiTypeClass) {
+    protected <ApiType extends KubernetesObject>
+        GenericKubernetesApi<ApiType, ? extends KubernetesListObject> getGenericApi(
+            Class<ApiType> apiTypeClass) throws KubectlException {
+
+      // load list type class dynamically from class-loader
+      String apiListTypeClassName = apiTypeClass.getName() + "List";
+      try {
+        Class<? extends KubernetesListObject> apiTypeListClass;
+        apiTypeListClass =
+            (Class<? extends KubernetesListObject>)
+                apiTypeClass.getClassLoader().loadClass(apiListTypeClassName);
+        return getGenericApi(apiTypeClass, apiTypeListClass);
+      } catch (ClassNotFoundException e) {
+        throw new KubectlException(
+            new StringBuilder()
+                .append("No such api list type class ")
+                .append(apiListTypeClassName)
+                .append(", consider explicitly load the class by apiListTypeClass()?")
+                .toString());
+      }
+    }
+
+    protected <ApiType extends KubernetesObject, ApiListType extends KubernetesListObject>
+        GenericKubernetesApi<ApiType, ApiListType> getGenericApi(
+            Class<ApiType> apiTypeClass, Class<ApiListType> apiListTypeClass) {
       GroupVersionResource groupVersionResource =
           ModelMapper.getGroupVersionResourceByClass(apiTypeClass);
 
-      GenericKubernetesApi<? extends KubernetesObject, KubernetesListObject> api =
+      GenericKubernetesApi<ApiType, ApiListType> api =
           new GenericKubernetesApi<>(
               apiTypeClass,
-              KubernetesListObject.class,
+              apiListTypeClass,
               groupVersionResource.getGroup(),
               groupVersionResource.getVersion(),
               groupVersionResource.getResource(),
@@ -241,18 +272,7 @@ public T name(String name) {
     }
 
     protected GenericKubernetesApi<ApiType, KubernetesListObject> getGenericApi() {
-      GroupVersionResource groupVersionResource =
-          ModelMapper.getGroupVersionResourceByClass(apiTypeClass);
-
-      GenericKubernetesApi<ApiType, KubernetesListObject> api =
-          new GenericKubernetesApi<>(
-              apiTypeClass,
-              KubernetesListObject.class,
-              groupVersionResource.getGroup(),
-              groupVersionResource.getVersion(),
-              groupVersionResource.getResource(),
-              apiClient);
-      return api;
+      return getGenericApi(apiTypeClass, KubernetesListObject.class);
     }
   }
 

extended/src/main/java/io/kubernetes/client/extended/kubectl/KubectlGet.java

@@ -0,0 +1,135 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+Licensed 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 io.kubernetes.client.extended.kubectl;
+
+import io.kubernetes.client.common.KubernetesListObject;
+import io.kubernetes.client.common.KubernetesObject;
+import io.kubernetes.client.extended.kubectl.exception.KubectlException;
+import io.kubernetes.client.openapi.ApiException;
+import io.kubernetes.client.util.generic.GenericKubernetesApi;
+import io.kubernetes.client.util.generic.options.ListOptions;
+import java.util.List;
+import org.apache.commons.lang.StringUtils;
+
+public class KubectlGet<ApiType extends KubernetesObject>
+    extends Kubectl.ApiClientBuilder<KubectlGet<ApiType>>
+    implements Kubectl.Executable<List<ApiType>> {
+
+  private String namespace;
+  private ListOptions listOptions;
+  private Class<ApiType> apiTypeClass;
+  private Class<? extends KubernetesListObject> apiTypeListClass;
+
+  KubectlGet(Class<ApiType> apiTypeClass) {
+    this.apiTypeClass = apiTypeClass;
+    this.listOptions = new ListOptions();
+  }
+
+  public KubectlGet<ApiType> apiListTypeClass(
+      Class<? extends KubernetesListObject> apiTypeListClass) {
+    this.apiTypeListClass = apiTypeListClass;
+    return this;
+  }
+
+  public KubectlGet<ApiType> options(ListOptions listOptions) {
+    this.listOptions = listOptions;
+    return this;
+  }
+
+  public KubectlGet<ApiType> namespace(String namespace) {
+    this.namespace = namespace;
+    return this;
+  }
+
+  public KubectlGetSingle name(String name) {
+    return new KubectlGetSingle(name);
+  }
+
+  @Override
+  public List<ApiType> execute() throws KubectlException {
+    GenericKubernetesApi<ApiType, ? extends KubernetesListObject> api =
+        apiTypeListClass == null
+            ? getGenericApi(apiTypeClass)
+            : getGenericApi(apiTypeClass, apiTypeListClass);
+    try {
+      if (isNamespaced()) {
+        return (List<ApiType>)
+            api.list(namespace, listOptions)
+                .onFailure(
+                    errorStatus -> {
+                      throw new ApiException(errorStatus.toString());
+                    })
+                .getObject()
+                .getItems();
+
+      } else {
+        return (List<ApiType>)
+            api.list(listOptions)
+                .onFailure(
+                    errorStatus -> {
+                      throw new ApiException(errorStatus.toString());
+                    })
+                .getObject()
+                .getItems();
+      }
+    } catch (ApiException e) {
+      throw new KubectlException(e);
+    }
+  }
+
+  private boolean isNamespaced() {
+    return !StringUtils.isEmpty(namespace);
+  }
+
+  public class KubectlGetSingle extends Kubectl.ResourceBuilder<ApiType, KubectlGetSingle>
+      implements Kubectl.Executable<ApiType> {
+
+    private KubectlGetSingle(String name) {
+      super(KubectlGet.this.apiTypeClass);
+      KubectlGetSingle.this.name = name;
+      KubectlGetSingle.this.namespace = KubectlGet.this.namespace;
+      KubectlGetSingle.this.apiClient = KubectlGet.this.apiClient;
+      KubectlGetSingle.this.skipDiscovery = KubectlGet.this.skipDiscovery;
+    }
+
+    private boolean isNamespaced() {
+      return !StringUtils.isEmpty(namespace);
+    }
+
+    @Override
+    public ApiType execute() throws KubectlException {
+      GenericKubernetesApi<ApiType, ? extends KubernetesListObject> api =
+          getGenericApi(KubectlGetSingle.this.apiTypeClass);
+      try {
+        if (isNamespaced()) {
+          return api.get(KubectlGetSingle.this.namespace, KubectlGetSingle.this.name)
+              .onFailure(
+                  errorStatus -> {
+                    throw new ApiException(errorStatus.toString());
+                  })
+              .getObject();
+
+        } else {
+          return api.get(KubectlGetSingle.this.name)
+              .onFailure(
+                  errorStatus -> {
+                    throw new ApiException(errorStatus.toString());
+                  })
+              .getObject();
+        }
+      } catch (ApiException e) {
+        throw new KubectlException(e);
+      }
+    }
+  }
+}