[GitHub] [helix] junkaixue commented on a change in pull request #1747: New REST api partitionAssignment -- return potential assignment given cluster change

[GitBox <gi...@apache.org>]

junkaixue commented on a change in pull request #1747:
URL: https://github.com/apache/helix/pull/1747#discussion_r643707579



##########
File path: helix-rest/src/main/java/org/apache/helix/rest/server/resources/helix/ResourceAssignmentOptimizerAccessor.java
##########
@@ -0,0 +1,354 @@
+package org.apache.helix.rest.server.resources.helix;
+
+/*
+ * 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.
+ */
+
+import java.security.InvalidParameterException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.stream.Collectors;
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+import javax.ws.rs.PathParam;
+import javax.ws.rs.core.Response;
+
+import com.codahale.metrics.annotation.ResponseMetered;
+import com.codahale.metrics.annotation.Timed;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.type.TypeReference;
+import org.apache.helix.ConfigAccessor;
+import org.apache.helix.HelixDataAccessor;
+import org.apache.helix.controller.rebalancer.strategy.AutoRebalanceStrategy;
+import org.apache.helix.controller.rebalancer.strategy.RebalanceStrategy;
+import org.apache.helix.controller.rebalancer.waged.WagedRebalancer;
+import org.apache.helix.manager.zk.ZkBaseDataAccessor;
+import org.apache.helix.model.ClusterConfig;
+import org.apache.helix.model.IdealState;
+import org.apache.helix.model.InstanceConfig;
+import org.apache.helix.model.ResourceAssignment;
+import org.apache.helix.model.ResourceConfig;
+import org.apache.helix.model.StateModelDefinition;
+import org.apache.helix.rest.common.HttpConstants;
+import org.apache.helix.util.HelixUtil;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+
+@Path("/clusters/{clusterId}/partitionAssignment")
+public class ResourceAssignmentOptimizerAccessor extends AbstractHelixResource {
+  private static Logger LOG = LoggerFactory.getLogger(
+      org.apache.helix.rest.server.resources.helix.ResourceAssignmentOptimizerAccessor.class
+          .getName());
+
+  private static class InputFields {
+    List<String> newInstances = new ArrayList<>();
+    List<String> instancesToRemove = new ArrayList<>();
+    Map<String, String> nodeSwap = new HashMap<>(); // old instance -> new instance.
+    Set<String> instanceFilter = new HashSet<>();
+    Set<String> resourceFilter = new HashSet<>();

Review comment:
       Are these cached? If yes, better cached with some objected instead of static fields. Because the data cached is not synchronized between requests. Shared simple data structure could be problematic.

##########
File path: helix-rest/src/main/java/org/apache/helix/rest/server/ServerContext.java
##########
@@ -278,6 +281,18 @@ public HelixDataAccessor getDataAccessor(String clusterName) {
     return _byteArrayZkBaseDataAccessor;
   }
 
+  public ZkBucketDataAccessor getZkBucketDataAccessor() {
+    if (_zkBucketDataAccessor == null) {
+      synchronized (this) {
+        if (_zkBucketDataAccessor == null) {
+          _zkBucketDataAccessor = new ZkBucketDataAccessor(_zkAddr);

Review comment:
       +1. I was trying to make this comment, for realm aware client, get a dedicated zk address client is not a good idea.

##########
File path: helix-rest/src/main/java/org/apache/helix/rest/server/resources/helix/ResourceAssignmentOptimizerAccessor.java
##########
@@ -0,0 +1,354 @@
+package org.apache.helix.rest.server.resources.helix;
+
+/*
+ * 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.
+ */
+
+import java.security.InvalidParameterException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.stream.Collectors;
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+import javax.ws.rs.PathParam;
+import javax.ws.rs.core.Response;
+
+import com.codahale.metrics.annotation.ResponseMetered;
+import com.codahale.metrics.annotation.Timed;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.type.TypeReference;
+import org.apache.helix.ConfigAccessor;
+import org.apache.helix.HelixDataAccessor;
+import org.apache.helix.controller.rebalancer.strategy.AutoRebalanceStrategy;
+import org.apache.helix.controller.rebalancer.strategy.RebalanceStrategy;
+import org.apache.helix.controller.rebalancer.waged.WagedRebalancer;
+import org.apache.helix.manager.zk.ZkBaseDataAccessor;
+import org.apache.helix.model.ClusterConfig;
+import org.apache.helix.model.IdealState;
+import org.apache.helix.model.InstanceConfig;
+import org.apache.helix.model.ResourceAssignment;
+import org.apache.helix.model.ResourceConfig;
+import org.apache.helix.model.StateModelDefinition;
+import org.apache.helix.rest.common.HttpConstants;
+import org.apache.helix.util.HelixUtil;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+
+@Path("/clusters/{clusterId}/partitionAssignment")
+public class ResourceAssignmentOptimizerAccessor extends AbstractHelixResource {
+  private static Logger LOG = LoggerFactory.getLogger(
+      org.apache.helix.rest.server.resources.helix.ResourceAssignmentOptimizerAccessor.class
+          .getName());
+
+  private static class InputFields {
+    List<String> newInstances = new ArrayList<>();
+    List<String> instancesToRemove = new ArrayList<>();
+    Map<String, String> nodeSwap = new HashMap<>(); // old instance -> new instance.
+    Set<String> instanceFilter = new HashSet<>();
+    Set<String> resourceFilter = new HashSet<>();
+  }
+
+  private static class ClusterState {
+    List<InstanceConfig> instanceConfigs = new ArrayList<>();
+    ClusterConfig clusterConfig;
+    List<String> resources = new ArrayList<>();
+    List<String> instances;        // cluster LiveInstance + addInstances - instancesToRemove.
+  }
+
+  // Result format: Map of resource -> partition -> instance -> state.
+  private static class AssignmentResult extends HashMap<String, Map<String, Map<String, String>>> {
+    public AssignmentResult() {
+      super();
+    }
+  }
+
+  public static final String INSTANCE_CHANGE = "InstanceChange";
+  public static final String INSTANCE_CHANGE_ADD_INSTANCES = "AddInstances";
+  public static final String INSTANCE_CHANGE_REMOVE_INSTANCES = "RemoveInstances";
+  public static final String INSTANCE_CHANGE_SWAP_INSTANCES = "SwapInstances";
+  public static final String OPTIONS = "Options";
+  public static final String OPTIONS_INSTANCE_FLT = "InstanceFilter";
+  public static final String OPTIONS_RESOURCE_FLT = "ResourceFilter";
+
+  @ResponseMetered(name = HttpConstants.WRITE_REQUEST)
+  @Timed(name = HttpConstants.WRITE_REQUEST)
+  @POST
+  public Response computePotentialAssignment(@PathParam("clusterId") String clusterId,
+      String content) {
+
+    InputFields inputFields;
+    ClusterState clusterState;
+    AssignmentResult result;
+
+    try {
+      // 1.  Try to parse the content string. If parseable, use it as a KV map. Otherwise, return a REASON String
+      inputFields = readInput(content);
+      // 2. Read cluster status from ZK.
+      clusterState = readClusterStateAndValidateInput(clusterId, inputFields);
+      // 3. Call rebalancer tools for each resource.
+      result = computeOptimalAssignmentForResources(inputFields, clusterState, clusterId);
+      // 4. Serialize result to JSON and return.
+      return JSONRepresentation(result);
+    } catch (InvalidParameterException ex) {
+      return badRequest(ex.getMessage());
+    } catch (JsonProcessingException e) {
+      return badRequest("Invalid input: Input can not be parsed into a KV map." + e.getMessage());
+    } catch (OutOfMemoryError e) {
+      LOG.error("OutOfMemoryError while calling partitionAssignment" + Arrays
+          .toString(e.getStackTrace()));
+      return badRequest(
+          "Response size is too large to serialize. Please query by resources or instance filter");
+    } catch (Exception e) {
+      LOG.error("Failed to compute partition assignment:" + Arrays.toString(e.getStackTrace()));
+      return badRequest("Failed to compute partition assignment: " + e);
+    }
+  }
+
+  private InputFields readInput(String content)
+      throws InvalidParameterException, JsonProcessingException {
+
+    Map<String, Map<String, Object>> customFieldsMap;
+    InputFields inputMap = new InputFields();
+    customFieldsMap =
+        OBJECT_MAPPER.readValue(content, new TypeReference<HashMap<String, Map<String, Object>>>() {
+        });
+
+    // Content is given as a KV mapping.
+    for (Map.Entry<String, Map<String, Object>> entry : customFieldsMap.entrySet()) {
+      String key = entry.getKey();
+      switch (key) {
+        case INSTANCE_CHANGE:
+          for (Map.Entry<String, Object> instanceChange : entry.getValue().entrySet()) {
+            String instanceChangeKey = instanceChange.getKey();
+            if (instanceChangeKey.equals(INSTANCE_CHANGE_ADD_INSTANCES) && (instanceChange

Review comment:
       Can we have nested switch case for here? That could be easy for us to read.

##########
File path: helix-rest/src/main/java/org/apache/helix/rest/server/resources/helix/ResourceAssignmentOptimizerAccessor.java
##########
@@ -0,0 +1,354 @@
+package org.apache.helix.rest.server.resources.helix;
+
+/*
+ * 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.
+ */
+
+import java.security.InvalidParameterException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.stream.Collectors;
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+import javax.ws.rs.PathParam;
+import javax.ws.rs.core.Response;
+
+import com.codahale.metrics.annotation.ResponseMetered;
+import com.codahale.metrics.annotation.Timed;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.type.TypeReference;
+import org.apache.helix.ConfigAccessor;
+import org.apache.helix.HelixDataAccessor;
+import org.apache.helix.controller.rebalancer.strategy.AutoRebalanceStrategy;
+import org.apache.helix.controller.rebalancer.strategy.RebalanceStrategy;
+import org.apache.helix.controller.rebalancer.waged.WagedRebalancer;
+import org.apache.helix.manager.zk.ZkBaseDataAccessor;
+import org.apache.helix.model.ClusterConfig;
+import org.apache.helix.model.IdealState;
+import org.apache.helix.model.InstanceConfig;
+import org.apache.helix.model.ResourceAssignment;
+import org.apache.helix.model.ResourceConfig;
+import org.apache.helix.model.StateModelDefinition;
+import org.apache.helix.rest.common.HttpConstants;
+import org.apache.helix.util.HelixUtil;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+
+@Path("/clusters/{clusterId}/partitionAssignment")
+public class ResourceAssignmentOptimizerAccessor extends AbstractHelixResource {
+  private static Logger LOG = LoggerFactory.getLogger(
+      org.apache.helix.rest.server.resources.helix.ResourceAssignmentOptimizerAccessor.class
+          .getName());
+
+  private static class InputFields {
+    List<String> newInstances = new ArrayList<>();
+    List<String> instancesToRemove = new ArrayList<>();
+    Map<String, String> nodeSwap = new HashMap<>(); // old instance -> new instance.
+    Set<String> instanceFilter = new HashSet<>();
+    Set<String> resourceFilter = new HashSet<>();
+  }
+
+  private static class ClusterState {
+    List<InstanceConfig> instanceConfigs = new ArrayList<>();
+    ClusterConfig clusterConfig;
+    List<String> resources = new ArrayList<>();
+    List<String> instances;        // cluster LiveInstance + addInstances - instancesToRemove.
+  }
+
+  // Result format: Map of resource -> partition -> instance -> state.
+  private static class AssignmentResult extends HashMap<String, Map<String, Map<String, String>>> {
+    public AssignmentResult() {
+      super();
+    }
+  }
+
+  public static final String INSTANCE_CHANGE = "InstanceChange";
+  public static final String INSTANCE_CHANGE_ADD_INSTANCES = "AddInstances";
+  public static final String INSTANCE_CHANGE_REMOVE_INSTANCES = "RemoveInstances";
+  public static final String INSTANCE_CHANGE_SWAP_INSTANCES = "SwapInstances";
+  public static final String OPTIONS = "Options";
+  public static final String OPTIONS_INSTANCE_FLT = "InstanceFilter";
+  public static final String OPTIONS_RESOURCE_FLT = "ResourceFilter";
+
+  @ResponseMetered(name = HttpConstants.WRITE_REQUEST)
+  @Timed(name = HttpConstants.WRITE_REQUEST)
+  @POST
+  public Response computePotentialAssignment(@PathParam("clusterId") String clusterId,
+      String content) {
+
+    InputFields inputFields;
+    ClusterState clusterState;
+    AssignmentResult result;
+
+    try {
+      // 1.  Try to parse the content string. If parseable, use it as a KV map. Otherwise, return a REASON String
+      inputFields = readInput(content);
+      // 2. Read cluster status from ZK.
+      clusterState = readClusterStateAndValidateInput(clusterId, inputFields);
+      // 3. Call rebalancer tools for each resource.
+      result = computeOptimalAssignmentForResources(inputFields, clusterState, clusterId);
+      // 4. Serialize result to JSON and return.
+      return JSONRepresentation(result);
+    } catch (InvalidParameterException ex) {
+      return badRequest(ex.getMessage());
+    } catch (JsonProcessingException e) {
+      return badRequest("Invalid input: Input can not be parsed into a KV map." + e.getMessage());
+    } catch (OutOfMemoryError e) {
+      LOG.error("OutOfMemoryError while calling partitionAssignment" + Arrays
+          .toString(e.getStackTrace()));
+      return badRequest(
+          "Response size is too large to serialize. Please query by resources or instance filter");
+    } catch (Exception e) {
+      LOG.error("Failed to compute partition assignment:" + Arrays.toString(e.getStackTrace()));
+      return badRequest("Failed to compute partition assignment: " + e);
+    }
+  }
+
+  private InputFields readInput(String content)
+      throws InvalidParameterException, JsonProcessingException {
+
+    Map<String, Map<String, Object>> customFieldsMap;
+    InputFields inputMap = new InputFields();
+    customFieldsMap =
+        OBJECT_MAPPER.readValue(content, new TypeReference<HashMap<String, Map<String, Object>>>() {
+        });
+
+    // Content is given as a KV mapping.
+    for (Map.Entry<String, Map<String, Object>> entry : customFieldsMap.entrySet()) {
+      String key = entry.getKey();
+      switch (key) {
+        case INSTANCE_CHANGE:
+          for (Map.Entry<String, Object> instanceChange : entry.getValue().entrySet()) {
+            String instanceChangeKey = instanceChange.getKey();
+            if (instanceChangeKey.equals(INSTANCE_CHANGE_ADD_INSTANCES) && (instanceChange
+                .getValue() instanceof List)) {
+              inputMap.newInstances.addAll((List<String>) instanceChange.getValue());
+            } else if (instanceChangeKey.equals(INSTANCE_CHANGE_REMOVE_INSTANCES) && (instanceChange
+                .getValue() instanceof List)) {
+              inputMap.instancesToRemove.addAll((List<String>) instanceChange.getValue());
+            } else if (instanceChangeKey.equals(INSTANCE_CHANGE_SWAP_INSTANCES) && (instanceChange
+                .getValue() instanceof Map)) {
+              for (Map.Entry<String, String> swapPair : ((Map<String, String>) instanceChange
+                  .getValue()).entrySet()) {
+                inputMap.nodeSwap.put(swapPair.getKey(), swapPair.getValue());
+              }
+            } else {
+              throw new InvalidParameterException(
+                  "Unsupported command or invalid format for InstanceChange : "
+                      + instanceChangeKey);
+            }
+          }
+          break;
+        case OPTIONS:
+          for (Map.Entry<String, Object> option : entry.getValue().entrySet()) {
+            String optionKey = option.getKey();
+            if (optionKey.equals(OPTIONS_RESOURCE_FLT) && (option.getValue() instanceof List)) {
+              inputMap.resourceFilter.addAll((List<String>) option.getValue());
+            } else if (optionKey.equals(OPTIONS_INSTANCE_FLT) && (option.getValue() instanceof List)) {
+              inputMap.instanceFilter.addAll((List<String>) option.getValue());
+            } else {
+              throw new InvalidParameterException(
+                  "Unsupported command or invalid format for Options : " + option);
+            }
+          }
+          break;
+        default:
+          throw new InvalidParameterException(
+              "Unsupported command for partitionAssignment : " + key);
+      }
+    }
+    return inputMap;
+  }
+
+  private ClusterState readClusterStateAndValidateInput(String clusterId, InputFields inputFields)
+      throws InvalidParameterException {
+
+    ClusterState clusterState = new ClusterState();
+    ConfigAccessor cfgAccessor = getConfigAccessor();
+    HelixDataAccessor dataAccessor = getDataAccssor(clusterId);
+    clusterState.resources = dataAccessor.getChildNames(dataAccessor.keyBuilder().idealStates());
+    // Add existing live instances and new instances from user input to instances list.
+    clusterState.instances = dataAccessor.getChildNames(dataAccessor.keyBuilder().liveInstances());
+    clusterState.instances.addAll(inputFields.newInstances);
+
+    // Check if to be removed instances and old instances in swap node exist in live instance.
+    if (!inputFields.nodeSwap.isEmpty() || !inputFields.instancesToRemove.isEmpty()) {
+      Set<String> liveInstanceSet = new HashSet<>(clusterState.instances);
+      for (Map.Entry<String, String> nodeSwapPair : inputFields.nodeSwap.entrySet()) {
+        if (!liveInstanceSet.contains(nodeSwapPair.getKey())) {
+          throw new InvalidParameterException("Invalid input: instance [" + nodeSwapPair.getKey()
+              + "] in SwapInstances does not exist in cluster.");
+        }
+      }
+      for (String instanceToRemove : inputFields.instancesToRemove) {
+        if (!liveInstanceSet.contains(instanceToRemove)) {
+          throw new InvalidParameterException("Invalid input: instance [" + instanceToRemove
+              + "] in RemoveInstances does not exist in cluster.");
+        }
+      }
+      if (!inputFields.instancesToRemove.isEmpty()) {
+        clusterState.instances.removeIf(inputFields.instancesToRemove::contains);
+      }
+    }
+
+    // Read instance and cluster config.
+    // It will throw exception if there is no instanceConfig for newly added instance.
+    for (String instance : clusterState.instances) {
+      InstanceConfig config = cfgAccessor.getInstanceConfig(clusterId, instance);
+      clusterState.instanceConfigs.add(config);
+    }
+    clusterState.clusterConfig = cfgAccessor.getClusterConfig(clusterId);
+    return clusterState;
+  }
+
+  private AssignmentResult computeOptimalAssignmentForResources(InputFields inputFields,

Review comment:
       Shall we move the logic into HelixUtil or RebalanceUtil? Because this could be something leveraged by Java API as well.




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