Addition of MigrationClient (MigrationIWorkflowService & MigrationInterceptor) (#844)

Why

Thin layer on client/worker to migrate workflows from one domain to another.

Logic

Before Migration:
Current domain worker is polling tasks from the current domain.
Current client is querying / canceling / listing / terminating workflows from the current domain.

During Migration:
Current domain worker is polling tasks from the current domain. To migrate cron workflows or continue-as-new workflows, migrationInterceptor needs to be added to the current domain worker.
New domain worker is polling tasks from the new domain.
MigrationClient needs to be used to querying / canceling / listing / terminating workflows, so it coordinates across the new and current domain.

After Migration: Only new Worker is started.

Changes

Added migrationIWorkflowService
Added migrationInterceptor
Moved out TracingInterceptor from WorkflowTest to a separate package
Test

Unit test for MigrationIWorkflowService.
Integration test for MigrationInterceptor.

Author: abhishekj720

src/main/java/com/uber/cadence/migration/MigrationActivities.java

@@ -0,0 +1,31 @@
+/*
+ *  Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *  Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"). You may not
+ *  use this file except in compliance with the License. A copy of the License is
+ *  located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ *  or in the "license" file accompanying this file. This file 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 com.uber.cadence.migration;
+
+import com.uber.cadence.RequestCancelWorkflowExecutionRequest;
+import com.uber.cadence.StartWorkflowExecutionRequest;
+import com.uber.cadence.StartWorkflowExecutionResponse;
+import com.uber.cadence.activity.ActivityMethod;
+
+public interface MigrationActivities {
+  @ActivityMethod
+  StartWorkflowExecutionResponse startWorkflowInNewDomain(StartWorkflowExecutionRequest request);
+
+  @ActivityMethod
+  void cancelWorkflowInCurrentDomain(RequestCancelWorkflowExecutionRequest request);
+}

src/main/java/com/uber/cadence/migration/MigrationActivitiesImpl.java

@@ -0,0 +1,53 @@
+/*
+ *  Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *  Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"). You may not
+ *  use this file except in compliance with the License. A copy of the License is
+ *  located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ *  or in the "license" file accompanying this file. This file 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 com.uber.cadence.migration;
+
+import com.uber.cadence.RequestCancelWorkflowExecutionRequest;
+import com.uber.cadence.StartWorkflowExecutionRequest;
+import com.uber.cadence.StartWorkflowExecutionResponse;
+import com.uber.cadence.client.WorkflowClient;
+import com.uber.cadence.workflow.Workflow;
+
+public class MigrationActivitiesImpl implements MigrationActivities {
+  private final WorkflowClient clientInCurrDomain, clientInNewDomain;
+
+  public MigrationActivitiesImpl(
+      WorkflowClient clientInCurrDomain, WorkflowClient clientInNewDomain) {
+    this.clientInCurrDomain = clientInCurrDomain;
+    this.clientInNewDomain = clientInNewDomain;
+  }
+
+  @Override
+  public StartWorkflowExecutionResponse startWorkflowInNewDomain(
+      StartWorkflowExecutionRequest request) {
+    try {
+      return clientInNewDomain.getService().StartWorkflowExecution(request);
+    } catch (Exception e) {
+      throw Workflow.wrap(e);
+    }
+  }
+
+  @Override
+  public void cancelWorkflowInCurrentDomain(RequestCancelWorkflowExecutionRequest request) {
+    try {
+      clientInCurrDomain.getService().RequestCancelWorkflowExecution(request);
+    } catch (Exception e) {
+      throw Workflow.wrap(e);
+    }
+  }
+}