[HUDI-2422] Adding rollback plan and rollback requested instant (#3651)

- This patch introduces rollback plan and rollback.requested instant. Rollback will be done in two phases, namely rollback plan and rollback action. In planning, we prepare the rollback plan and serialize it to rollback.requested. In the rollback action phase, we fetch details from the plan and just delete the files as per the plan. This will ensure final rollback commit metadata will contain all files that got rolled back even if rollback failed midway and retried again.

hudi-common/src/main/avro/HoodieRollbackPlan.avsc

@@ -0,0 +1,76 @@
+/*
+ * 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.
+ */
+{
+  "namespace": "org.apache.hudi.avro.model",
+  "type": "record",
+  "name": "HoodieRollbackPlan",
+  "fields": [
+     {
+           "name": "instantToRollback",
+           "doc": "Hoodie instant that needs to be rolled back",
+           "type": ["null", "HoodieInstantInfo"],
+           "default": null
+    },
+    {
+      "name": "RollbackRequests",
+      "type":["null", {
+                "type":"array",
+                "items":{
+                 "type": "record",
+                         "name": "HoodieRollbackRequest",
+                         "fields": [
+                            {"name": "partitionPath", "type": "string"},
+                            {"name": "fileId",
+                              "type":["null", "string"],
+                              "default": null
+                             },
+                            {"name": "latestBaseInstant",
+                              "type":["null", "string"],
+                              "default": null
+                            },
+                            {"name": "filesToBeDeleted",
+                             "default": [],
+                             "type": {
+                                       "type": "array",
+                                       "default": [],
+                                       "items": "string"
+                                    }
+                            },
+                            {"name": "logBlocksToBeDeleted",
+                             "type": ["null", {
+                               "type": "map",
+                               "doc": "Log blocks that need to be deleted as part of the rollback",
+                               "values": {
+                                   "type": "long",
+                                   "doc": "Size of this file/block in bytes"
+                               }
+                             }],
+                             "default":null
+                            }
+                         ]
+                }
+                }],
+       "default" : null
+    },
+    {
+       "name":"version",
+       "type":["int", "null"],
+       "default": 1
+    }
+  ]
+}