Fix fabric8io#2701: Add Support for Merge Patch for Kubernetes resources

+ Allow option to configure PatchType in patch operation
+ Use MediaType in PatchType enum + Add merge-patch+json example

CHANGELOG.md

@@ -26,6 +26,7 @@
 * Fix #2980: Add DSL Support for `apps/v1#ControllerRevision` resource
 * Fix #2981: Add DSL support for `storage.k8s.io/v1beta1` CSIDriver, CSINode and VolumeAttachment
 * Fix #2912: Add DSL support for `storage.k8s.io/v1beta1` CSIStorageCapacity
+* Fix #2701: Better support for patching in KuberntesClient
 
 #### _**Note**_: Breaking changes in the API
 ##### DSL Changes:

kubernetes-client/src/main/java/io/fabric8/kubernetes/client/dsl/Patchable.java

@@ -15,8 +15,35 @@
  */
 package io.fabric8.kubernetes.client.dsl;
 
+import io.fabric8.kubernetes.client.dsl.base.PatchContext;
+
 public interface Patchable<T> {
 
+  /**
+   * Update field(s) of a resource using strategic a JSON patch.
+   *
+   * @param item item to be patched with patched values
+   * @return returns deserialized version of api server response
+   */
   T patch(T item);
 
+  /**
+   * Update field(s) of a resource using strategic merge patch or a JSON patch.
+   *
+   * @param patch The patch to be applied to the resource JSON file.
+   * @return returns deserialized version of api server response
+   */
+  default T patch(String patch) {
+    return patch(null, patch);
+  }
+
+  /**
+   * Update field(s) of a resource using type specified in {@link PatchContext}(defaults to strategic merge if not specified).
+   *
+   * @param patchContext {@link PatchContext} for patch request
+   * @param patch The patch to be applied to the resource JSON file.
+   * @return The patch to be applied to the resource JSON file.
+   */
+  T patch(PatchContext patchContext, String patch);
+
 }

kubernetes-client/src/main/java/io/fabric8/kubernetes/client/dsl/base/BaseOperation.java

@@ -98,6 +98,8 @@ public class BaseOperation<T extends HasMetadata, L extends KubernetesResourceLi
   private static final String INVOLVED_OBJECT_RESOURCE_VERSION = "involvedObject.resourceVersion";
   private static final String INVOLVED_OBJECT_API_VERSION = "involvedObject.apiVersion";
   private static final String INVOLVED_OBJECT_FIELD_PATH = "involvedObject.fieldPath";
+  private static final String READ_ONLY_UPDATE_EXCEPTION_MESSAGE = "Cannot update read-only resources";
+  private static final String READ_ONLY_EDIT_EXCEPTION_MESSAGE = "Cannot edit read-only resources";
 
   private final boolean cascading;
   private final T item;
@@ -245,12 +247,12 @@ public RootPaths getRootPaths() {
 
   @Override
   public T edit(UnaryOperator<T> function) {
-    throw new KubernetesClientException("Cannot edit read-only resources");
+    throw new KubernetesClientException(READ_ONLY_EDIT_EXCEPTION_MESSAGE);
   }
 
   @Override
   public T edit(Visitor... visitors) {
-    throw new KubernetesClientException("Cannot edit read-only resources");
+    throw new KubernetesClientException(READ_ONLY_EDIT_EXCEPTION_MESSAGE);
   }
 
   @Override
@@ -270,7 +272,7 @@ public void visit(V item) {
 
   @Override
   public T accept(Consumer<T> consumer) {
-    throw new KubernetesClientException("Cannot edit read-only resources");
+    throw new KubernetesClientException(READ_ONLY_EDIT_EXCEPTION_MESSAGE);
   }
 
   @Override
@@ -848,12 +850,17 @@ public Watch watch(ListOptions options, final Watcher<T> watcher) {
 
   @Override
   public T replace(T item) {
-    throw new KubernetesClientException("Cannot update read-only resources");
+    throw new KubernetesClientException(READ_ONLY_UPDATE_EXCEPTION_MESSAGE);
   }
 
   @Override
   public T patch(T item) {
-    throw new KubernetesClientException("Cannot update read-only resources");
+    throw new KubernetesClientException(READ_ONLY_UPDATE_EXCEPTION_MESSAGE);
+  }
+
+  @Override
+  public T patch(PatchContext patchContext, String patch) {
+    throw new KubernetesClientException(READ_ONLY_UPDATE_EXCEPTION_MESSAGE);
   }
 
   @Override

kubernetes-client/src/main/java/io/fabric8/kubernetes/client/dsl/base/HasMetadataOperation.java

@@ -21,13 +21,19 @@
 import io.fabric8.kubernetes.api.model.KubernetesResourceList;
 import io.fabric8.kubernetes.client.KubernetesClientException;
 import io.fabric8.kubernetes.client.dsl.Resource;
+
+import java.io.IOException;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
 import java.util.function.UnaryOperator;
 
+import static io.fabric8.kubernetes.client.utils.IOHelpers.convertToJson;
+
 public class HasMetadataOperation<T extends HasMetadata, L extends KubernetesResourceList<T>, R extends Resource<T>> extends BaseOperation< T, L, R> {
   public static final DeletionPropagation DEFAULT_PROPAGATION_POLICY = DeletionPropagation.BACKGROUND;
   public static final long DEFAULT_GRACE_PERIOD_IN_SECONDS = -1L;
+  private static final String PATCH_OPERATION = "patch";
 
   public HasMetadataOperation(OperationContext ctx) {
     super(ctx);
@@ -119,7 +125,7 @@ public T patch(T item) {
             resource.getMetadata().setResourceVersion(resourceVersion);
             return handlePatch(got, resource);
           } catch (Exception e) {
-            throw KubernetesClientException.launderThrowable(forOperationType("patch"), e);
+            throw KubernetesClientException.launderThrowable(forOperationType(PATCH_OPERATION), e);
           }
         };
         return visitor.apply(item);
@@ -142,6 +148,22 @@ public T patch(T item) {
         caught = e;
       }
     }
-    throw KubernetesClientException.launderThrowable(forOperationType("patch"), caught);
+    throw KubernetesClientException.launderThrowable(forOperationType(PATCH_OPERATION), caught);
+  }
+
+  @Override
+  public T patch(PatchContext patchContext, String patch) {
+    try {
+      final T got = fromServer().get();
+      if (got == null) {
+        return null;
+      }
+      return handlePatch(patchContext, got, convertToJson(patch), getType());
+    } catch (InterruptedException interruptedException) {
+      Thread.currentThread().interrupt();
+      throw KubernetesClientException.launderThrowable(forOperationType(PATCH_OPERATION), interruptedException);
+    } catch (IOException | ExecutionException e) {
+      throw KubernetesClientException.launderThrowable(forOperationType(PATCH_OPERATION), e);
+    }
   }
 }

kubernetes-client/src/main/java/io/fabric8/kubernetes/client/dsl/base/OperationSupport.java

@@ -55,6 +55,7 @@ public class OperationSupport {
   public static final MediaType JSON = MediaType.parse("application/json");
   public static final MediaType JSON_PATCH = MediaType.parse("application/json-patch+json");
   public static final MediaType STRATEGIC_MERGE_JSON_PATCH = MediaType.parse("application/strategic-merge-patch+json");
+  public static final MediaType JSON_MERGE_PATCH = MediaType.parse("application/merge-patch+json");
   protected static final ObjectMapper JSON_MAPPER = Serialization.jsonMapper();
   protected static final ObjectMapper YAML_MAPPER = Serialization.yamlMapper();
   private static final String CLIENT_STATUS_FLAG = "CLIENT_STATUS_FLAG";
@@ -174,6 +175,23 @@ public URL getResourceURLForWriteOperation(URL resourceURL) throws MalformedURLE
     return resourceURL;
   }
 
+  public URL getResourceURLForPatchOperation(URL resourceUrl, PatchContext patchContext) throws MalformedURLException {
+    if (patchContext != null) {
+      String url = resourceUrl.toString();
+      if (patchContext.getForce() != null) {
+        url = URLUtils.join(url, "?force=" + patchContext.getForce());
+      }
+      if ((patchContext.getDryRun() != null && !patchContext.getDryRun().isEmpty()) || dryRun) {
+        url = URLUtils.join(url, "?dryRun=All");
+      }
+      if (patchContext.getFieldManager() != null) {
+        url = URLUtils.join(url, "?fieldManager=" + patchContext.getFieldManager());
+      }
+      return new URL(url);
+    }
+    return resourceUrl;
+  }
+
   protected <T> String checkNamespace(T item) {
     String operationNs = getNamespace();
     String itemNs = (item instanceof HasMetadata && ((HasMetadata)item).getMetadata() != null) ? ((HasMetadata) item).getMetadata().getNamespace() : null;
@@ -344,6 +362,26 @@ protected <T> T handlePatch(T current, Map<String, Object> patchForUpdate, Class
     return handleResponse(requestBuilder, type, Collections.<String, String>emptyMap());
   }
 
+  /**
+   * Send an http patch and handle the response.
+   *
+   * @param patchContext patch options for patch request
+   * @param current current object
+   * @param patchForUpdate Patch string
+   * @param type type of object
+   * @param <T> template argument provided
+   * @return returns de-serialized version of api server response
+   * @throws ExecutionException Execution Exception
+   * @throws InterruptedException Interrupted Exception
+   * @throws IOException IOException in case of network errors
+   */
+  protected <T> T handlePatch(PatchContext patchContext, T current, String patchForUpdate, Class<T> type) throws ExecutionException, InterruptedException, IOException {
+    MediaType bodyMediaType = getMediaTypeFromPatchContextOrDefault(patchContext);
+    RequestBody body = RequestBody.create(bodyMediaType, patchForUpdate);
+    Request.Builder requestBuilder = new Request.Builder().patch(body).url(getResourceURLForPatchOperation(getResourceUrl(checkNamespace(current), checkName(current)), patchContext));
+    return handleResponse(requestBuilder, type, Collections.emptyMap());
+  }
+
   /**
    * Replace Scale of specified Kubernetes Resource
    *
@@ -611,4 +649,11 @@ protected static <T> Map getObjectValueAsMap(T object) {
   public Config getConfig() {
     return config;
   }
+
+  private MediaType getMediaTypeFromPatchContextOrDefault(PatchContext patchContext) {
+    if (patchContext != null && patchContext.getPatchType() != null) {
+      return patchContext.getPatchType().getMediaType();
+    }
+    return STRATEGIC_MERGE_JSON_PATCH;
+  }
 }

kubernetes-client/src/main/java/io/fabric8/kubernetes/client/dsl/base/PatchContext.java

@@ -0,0 +1,68 @@
+/**
+ * Copyright (C) 2015 Red Hat, Inc.
+ *
+ * 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.fabric8.kubernetes.client.dsl.base;
+
+import io.sundr.builder.annotations.Buildable;
+
+import java.util.List;
+
+@Buildable(editableEnabled = false, validationEnabled = false, generateBuilderPackage = false, lazyCollectionInitEnabled = false, builderPackage = "io.fabric8.kubernetes.api.builder")
+public class PatchContext {
+  private List<String> dryRun;
+  private String fieldManager;
+  private Boolean force;
+  private PatchType patchType;
+
+  public PatchContext(List<String> dryRun, String fieldManager, Boolean force, PatchType patchType) {
+    this.dryRun = dryRun;
+    this.fieldManager = fieldManager;
+    this.force = force;
+    this.patchType = patchType;
+  }
+
+  public List<String> getDryRun() {
+    return dryRun;
+  }
+
+  public void setDryRun(List<String> dryRun) {
+    this.dryRun = dryRun;
+  }
+
+  public String getFieldManager() {
+    return fieldManager;
+  }
+
+  public void setFieldManager(String fieldManager) {
+    this.fieldManager = fieldManager;
+  }
+
+  public Boolean getForce() {
+    return force;
+  }
+
+  public void setForce(Boolean force) {
+    this.force = force;
+  }
+
+  public PatchType getPatchType() {
+    return patchType;
+  }
+
+  public void setPatchType(PatchType patchType) {
+    this.patchType = patchType;
+  }
+
+}

kubernetes-client/src/main/java/io/fabric8/kubernetes/client/dsl/base/PatchType.java

@@ -0,0 +1,41 @@
+/**
+ * Copyright (C) 2015 Red Hat, Inc.
+ *
+ * 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.fabric8.kubernetes.client.dsl.base;
+
+import okhttp3.MediaType;
+
+import static io.fabric8.kubernetes.client.dsl.base.OperationSupport.JSON_PATCH;
+import static io.fabric8.kubernetes.client.dsl.base.OperationSupport.JSON_MERGE_PATCH;
+import static io.fabric8.kubernetes.client.dsl.base.OperationSupport.STRATEGIC_MERGE_JSON_PATCH;
+
+/**
+ * Enum for different Patch types supported by Patch
+ */
+public enum PatchType {
+  JSON(JSON_PATCH),
+  JSON_MERGE(JSON_MERGE_PATCH),
+  STRATEGIC_MERGE(STRATEGIC_MERGE_JSON_PATCH);
+
+  private final MediaType mediaType;
+
+  PatchType(MediaType mediaType) {
+    this.mediaType = mediaType;
+  }
+
+  public MediaType getMediaType() {
+    return this.mediaType;
+  }
+}

kubernetes-client/src/main/java/io/fabric8/kubernetes/client/utils/IOHelpers.java

@@ -75,4 +75,11 @@ public static String convertYamlToJson(String yaml) throws IOException {
     return jsonWriter.writeValueAsString(obj);
   }
 
+  public static String convertToJson(String jsonOrYaml) throws IOException {
+      if (isJSONValid(jsonOrYaml)) {
+        return jsonOrYaml;
+      }
+      return convertYamlToJson(jsonOrYaml);
+  }
+
 }