YARN-10374. Create Actions for CS mapping rules. Contributed by Gergely Pollak.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/placement/MappingQueuePath.java

@@ -0,0 +1,108 @@
+/**
+ * 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.
+ */
+
+package org.apache.hadoop.yarn.server.resourcemanager.placement;
+
+import static org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacitySchedulerConfiguration.DOT;
+
+/**
+ * This is a helper class which represents a queue path, and has easy access
+ * methods to get the path's parent or leaf part, or as a whole.
+ */
+public class MappingQueuePath {
+  /**
+   * The parent part of the queue path.
+   */
+  private String parent;
+
+  /**
+   * The leaf part of the parent path.
+   */
+  private String leaf;
+
+  /**
+   * Constructor to create mapping queue path from parent path and leaf name.
+   * @param parent Parent path of the queue
+   * @param leaf Name of the leaf queue
+   */
+  public MappingQueuePath(String parent, String leaf) {
+    this.parent = parent;
+    this.leaf = leaf;
+  }
+
+  /**
+   * Constructor creates a MappingQueuePath object using the queue's full path.
+   * @param fullPath Full path of the queue
+   */
+  public MappingQueuePath(String fullPath) {
+    setFromFullPath(fullPath);
+  }
+
+  /**
+   * This method is responsible for splitting up a full queue path into parent
+   * path and leaf name.
+   * @param fullPath Full path of the queue to be processed
+   */
+  private void setFromFullPath(String fullPath) {
+    parent = null;
+    leaf = fullPath;
+
+    int lastDotIdx = fullPath.lastIndexOf(DOT);
+    if (lastDotIdx > -1) {
+      parent = fullPath.substring(0, lastDotIdx).trim();
+      leaf = fullPath.substring(lastDotIdx + 1).trim();
+    }
+  }
+
+  /**
+   * Getter for the parent part of the path.
+   * @return Parent path of the queue, null if there is no parent.
+   */
+  public String getParent() {
+    return parent;
+  }
+
+  /**
+   * Getter for the leaf part of the path.
+   * @return The leaf queue name
+   */
+  public String getLeafName() {
+    return leaf;
+  }
+
+  /**
+   * Getter for the full path of the queue.
+   * @return Full path of the queue
+   */
+  public String getFullPath() {
+    return hasParent() ? (parent + DOT + leaf) : leaf;
+  }
+
+  /**
+   * Convenience getter to check if the queue has a parent path defined.
+   * @return True if there is a parent path provided
+   */
+  public boolean hasParent() {
+    return parent != null;
+  }
+
+  @Override
+  public String toString() {
+    return getFullPath();
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/placement/MappingRuleAction.java

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+/**
+ * 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.
+ */
+
+package org.apache.hadoop.yarn.server.resourcemanager.placement;
+
+import org.apache.hadoop.yarn.exceptions.YarnException;
+
+/**
+ * This interface represents the action part of a MappingRule, action are
+ * responsible to decide what should happen with the actual application
+ * submission.
+ */
+public interface MappingRuleAction {
+  /**
+   * Returns the fallback action to be taken if the main action (result returned
+   * by the execute method) fails.
+   * e.g. Target queue does not exist, or reference is ambiguous
+   * @return The fallback action to be taken if the main action fails
+   */
+  MappingRuleResult getFallback();
+
+  /**
+   * This method is the main logic of the action, it shall determine based on
+   * the mapping context, what should be the action's result.
+   * @param variables The variable context, which contains all the variables
+   * @return The result of the action
+   */
+  MappingRuleResult execute(VariableContext variables);
+
+
+  /**
+   * Sets the fallback method to reject, if the action cannot be executed the
+   * application will get rejected.
+   * @return MappingRuleAction The same object for method chaining.
+   */
+  MappingRuleAction setFallbackReject();
+
+  /**
+   * Sets the fallback method to skip, if the action cannot be executed
+   * We move onto the next rule, ignoring this one.
+   * @return MappingRuleAction The same object for method chaining.
+   */
+  MappingRuleAction setFallbackSkip();
+
+  /**
+   * Sets the fallback method to place to default, if the action cannot be
+   * executed. The application will be placed into the default queue, if the
+   * default queue does not exist the application will get rejected
+   * @return MappingRuleAction The same object for method chaining.
+   */
+  MappingRuleAction setFallbackDefaultPlacement();
+
+  /**
+   * This method is responsible for config validation, the context contains all
+   * information required for validation, method should throw an exception on
+   * detectable setup errors.
+   * @param ctx Validation context with all the necessary objects and helper
+   *            methods required during validation
+   * @throws YarnException is thrown on validation error
+   */
+  void validate(MappingRuleValidationContext ctx) throws YarnException;
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/placement/MappingRuleActionBase.java

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+/**
+ * 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.
+ */
+
+package org.apache.hadoop.yarn.server.resourcemanager.placement;
+
+/**
+ * This class implements the fallback logic for MappingRuleActions, this can
+ * be extended to implement the actual logic of the actions, this should be
+ * a base class for most actions.
+ */
+public abstract class MappingRuleActionBase implements MappingRuleAction {
+  /**
+   * The default fallback method is reject, so if the action fails
+   * We will reject the application. However this behaviour can be overridden
+   * on a per rule basis
+   */
+  private MappingRuleResult fallback = MappingRuleResult.createRejectResult();
+
+  /**
+   * Returns the fallback action to be taken if the main action (result returned
+   * by the execute method) fails.
+   * e.g. Target queue does not exist, or reference is ambiguous
+   * @return The fallback action to be taken if the main action fails
+   */
+  public MappingRuleResult getFallback() {
+    return fallback;
+  }
+
+  /**
+   * Sets the fallback method to reject, if the action cannot be executed the
+   * application will get rejected.
+   * @return MappingRuleAction The same object for method chaining.
+   */
+  public MappingRuleAction setFallbackReject() {
+    fallback = MappingRuleResult.createRejectResult();
+    return this;
+  }
+
+  /**
+   * Sets the fallback method to skip, if the action cannot be executed
+   * We move onto the next rule, ignoring this one.
+   * @return MappingRuleAction The same object for method chaining.
+   */
+  public MappingRuleAction setFallbackSkip() {
+    fallback = MappingRuleResult.createSkipResult();
+    return this;
+  }
+
+  /**
+   * Sets the fallback method to place to default, if the action cannot be
+   * executed the application will be placed into the default queue, if the
+   * default queue does not exist the application will get rejected.
+   * @return MappingRuleAction The same object for method chaining.
+   */
+  public MappingRuleAction setFallbackDefaultPlacement() {
+    fallback = MappingRuleResult.createDefaultPlacementResult();
+    return this;
+  }
+
+  /**
+   * This method is the main logic of the action, it shall determine based on
+   * the mapping context, what should be the action's result.
+   * @param variables The variable context, which contains all the variables
+   * @return The result of the action
+   */
+  public abstract MappingRuleResult execute(VariableContext variables);
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/placement/MappingRuleActions.java

@@ -0,0 +1,236 @@
+/**
+ * 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.
+ */
+
+package org.apache.hadoop.yarn.server.resourcemanager.placement;
+
+import org.apache.hadoop.yarn.exceptions.YarnException;
+
+/**
+ * This class contains all the actions and some helper methods to generate them.
+ */
+public final class MappingRuleActions {
+  public static final String DEFAULT_QUEUE_VARIABLE = "%default";
+
+  /**
+   * Utility class, hiding constructor.
+   */
+  private MappingRuleActions() {}
+
+  /**
+   * PlaceToQueueAction represents a placement action, contains the pattern of
+   * the queue name or path in which the path variables will be substituted
+   * with the variable context's respective values.
+   */
+  public static class PlaceToQueueAction extends MappingRuleActionBase {
+    /**
+     * We store the queue pattern in this variable, it may contain substitutable
+     * variables.
+     */
+    private String queuePattern;
+
+    /**
+     * Constructor.
+     * @param queuePattern The queue pattern in which the application will be
+     *                     placed if this action is fired. The pattern may
+     *                     contain variables. eg. root.%primary_group.%user
+     */
+    PlaceToQueueAction(String queuePattern) {
+      this.queuePattern = queuePattern == null ? "" : queuePattern;
+    }
+
+    /**
+     * This method is the main logic of the action, it will replace all the
+     * variables in the queuePattern with their respective values, then returns
+     * a placementResult with the final queue name.
+     * @param variables The variable context, which contains all the variables
+     * @return The result of the action
+     */
+    @Override
+    public MappingRuleResult execute(VariableContext variables) {
+      String substituted = variables.replacePathVariables(queuePattern);
+      return MappingRuleResult.createPlacementResult(substituted);
+    }
+
+    /**
+     * This method is responsible for config validation, we use the validation
+     * context's helper method to validate if our path is valid. From the
+     * point of the action all paths are valid, that is why we need to use
+     * an external component which is aware of the queue structure and know
+     * when a queue placement is valid in that context. This way this calass can
+     * stay independent of the capacity scheduler's internal queue placement
+     * logic, yet it is able to obey it's rules.
+     * @param ctx Validation context with all the necessary objects and helper
+     *            methods required during validation
+     * @throws YarnException is thrown on validation error
+     */
+    @Override
+    public void validate(MappingRuleValidationContext ctx)
+        throws YarnException {
+      ctx.validateQueuePath(this.queuePattern);
+    }
+
+    @Override
+    public String toString() {
+      return "PlaceToQueueAction{" +
+          "queueName='" + queuePattern + '\'' +
+          '}';
+    }
+  }
+
+  /**
+   * RejectAction represents the action when the application is rejected, this
+   * simply will throw an error on the user's side letting it know the
+   * submission was rejected.
+   */
+  public static class RejectAction extends MappingRuleActionBase {
+    /**
+     * Reject action will unconditionally return a reject result.
+     * @param variables The variable context, which contains all the variables
+     * @return Always a REJECT MappingRuleResut
+     */
+    @Override
+    public MappingRuleResult execute(VariableContext variables) {
+      return MappingRuleResult.createRejectResult();
+    }
+
+    /**
+     * Reject action is always valid, so it is just an empty implementation
+     * of the defined interface method.
+     * @param ctx Validation context with all the necessary objects and helper
+     *            methods required during validation
+     * @throws YarnException is thrown on validation error
+     */
+    @Override
+    public void validate(MappingRuleValidationContext ctx) throws
+        YarnException {}
+
+    @Override
+    public String toString() {
+      return "RejectAction";
+    }
+  }
+
+  /**
+   * VariableUpdateAction represents the action which alters one of the
+   * mutable variables in the variable context, but doesn't do anything with
+   * the application. This can be used to change the default queue or define
+   * custom variables to be used later.
+   */
+  public static class VariableUpdateAction extends MappingRuleActionBase {
+    /**
+     * Name of the variable to be updated (in it's full form) eg. %custom
+     */
+    private final String variableName;
+    /**
+     * The variable's new value pattern, this may contain additional variables
+     * which will be evaluated on execution.
+     */
+    private final String variableValue;
+
+    /**
+     * Constructor.
+     * @param variableName Name of the variable to be updated in the variable
+     *                     context
+     * @param variableValue
+     */
+    VariableUpdateAction(String variableName, String variableValue) {
+      this.variableName = variableName;
+      this.variableValue = variableValue;
+    }
+
+    /**
+     * This execute is a bit special, compared to other actions, since it does
+     * not affect the placement of the application, but changes the variable
+     * context. So it always returns a skip result in order to ensure the
+     * rule evalutaion continues after the variable update.
+     * The exectute method will do the update to the variable context the
+     * variable name stored in variableName will be updated with the value
+     * stored in variableValue, but all variables in the variableValue will
+     * gets resolved first, so this way dynamic updates are possible.
+     * @param variables The variable context, which contains all the variables
+     * @return Always a skip result.
+     */
+    @Override
+    public MappingRuleResult execute(VariableContext variables) {
+      variables.put(variableName, variables.replaceVariables(variableValue));
+      return MappingRuleResult.createSkipResult();
+    }
+
+    /**
+     * During the validation process we add the variable set by this action
+     * to the known variables, to make sure the context is aware that we might
+     * introduce a new custom variable. All rules after this may use this
+     * variable. If the variable cannot be added (eg. it is already added as
+     * immutable), an exception will be thrown, and the validation will fail.
+     * @param ctx Validation context with all the necessary objects and helper
+     *            methods required during validation
+     * @throws YarnException If the variable cannot be added to the context
+     */
+    @Override
+    public void validate(MappingRuleValidationContext ctx)
+        throws YarnException {
+      ctx.addVariable(this.variableName);
+    }
+
+    @Override
+    public String toString() {
+      return "VariableUpdateAction{" +
+          "variableName='" + variableName + '\'' +
+          ", variableValue='" + variableValue + '\'' +
+          '}';
+    }
+  }
+
+  /**
+   * Convenience method to create an action which changes the default queue.
+   * @param queue The new value of the default queue
+   * @return VariableUpdateAction which will change the default queue on execute
+   */
+  public static MappingRuleAction createUpdateDefaultAction(String queue) {
+    return new VariableUpdateAction(DEFAULT_QUEUE_VARIABLE, queue);
+  }
+
+  /**
+   * Convenience method to create an action which places the application to a
+   * queue.
+   * @param queue The name of the queue the application should be placed to
+   * @return PlaceToQueueAction which will place the application to the
+   * specified queue on execute
+   */
+  public static MappingRuleAction createPlaceToQueueAction(String queue) {
+    return new PlaceToQueueAction(queue);
+  }
+
+  /**
+   * Convenience method to create an action which places the application to the
+   * DEFAULT queue.
+   * @return PlaceToQueueAction which will place the application to the
+   * DEFAULT queue on execute
+   */
+  public static MappingRuleAction createPlaceToDefaultAction() {
+    return createPlaceToQueueAction(DEFAULT_QUEUE_VARIABLE);
+  }
+
+  /**
+   * Convenience method to create an action rejects the application.
+   * @return RejectAction which will reject the application on execute
+   */
+  public static MappingRuleAction createRejectAction() {
+    return new RejectAction();
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/placement/MappingRuleResult.java

@@ -0,0 +1,165 @@
+/**
+ * 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.
+ */
+
+package org.apache.hadoop.yarn.server.resourcemanager.placement;
+
+/**
+ * This class represents the outcome of an action.
+ */
+public final class MappingRuleResult {
+  /**
+   * The name of the queue we should place our application into.
+   * Only valid if result == PLACE.
+   */
+  private final String queue;
+
+  /**
+   * The normalized name of the queue, since CS allows users to reference queues
+   * by only their leaf name, we need to normalize those queues to have full
+   * reference.
+   */
+  private String normalizedQueue;
+
+  /**
+   * The result of the action.
+   */
+  private MappingRuleResultType result;
+
+  /**
+   * To the reject result has no variable field, so we don't have to create
+   * a new instance all the time.
+   * This is THE instance which will be used to represent REJECT
+   */
+  private static final MappingRuleResult RESULT_REJECT
+      = new MappingRuleResult(null, MappingRuleResultType.REJECT);
+
+  /**
+   * To the skip result has no variable field, so we don't have to create
+   * a new instance all the time.
+   * This is THE instance which will be used to represent SKIP
+   */
+  private static final MappingRuleResult RESULT_SKIP
+      = new MappingRuleResult(null, MappingRuleResultType.SKIP);
+
+  /**
+   * To the default placement result has no variable field, so we don't have to
+   * create a new instance all the time.
+   * This is THE instance which will be used to represent default placement
+   */
+  private static final MappingRuleResult RESULT_DEFAULT_PLACEMENT
+      = new MappingRuleResult(null, MappingRuleResultType.PLACE_TO_DEFAULT);
+
+  /**
+   * Constructor is private to force the user to use the predefined generator
+   * methods to create new instances in order to avoid inconsistent states.
+   * @param queue Name of the queue in which the application is supposed to be
+   *              placed, only valid if result == PLACE
+   *              otherwise it should be null
+   * @param result The type of the result
+   */
+  private MappingRuleResult(String queue, MappingRuleResultType result) {
+    this.queue = queue;
+    this.normalizedQueue = queue;
+    this.result = result;
+  }
+
+  /**
+   * This method returns the result queue. Currently only makes sense when
+   * result == PLACE.
+   * @return the queue this result is about
+   */
+  public String getQueue() {
+    return queue;
+  }
+
+  /**
+   * External interface for setting the normalized version of the queue. This
+   * class cannot normalize on it's own, but provides a way to store the
+   * normalized name of the target queue.
+   * @param normalizedQueueName The normalized name of the queue
+   */
+  public void updateNormalizedQueue(String normalizedQueueName) {
+    this.normalizedQueue = normalizedQueueName;
+  }
+
+  /**
+   * This method returns the normalized name of the result queue.
+   * Currently only makes sense when result == PLACE
+   * Normalized value must be set externally, this class cannot normalize
+   * it just provides a way to store the normalized name of a queue
+   * @return the queue name this result is about
+   */
+  public String getNormalizedQueue() {
+    return normalizedQueue;
+  }
+
+  /**
+   * Returns the type of the result.
+   * @return the type of the result.
+   */
+  public MappingRuleResultType getResult() {
+    return result;
+  }
+
+  /**
+   * Generator method for place results.
+   * @param queue The name of the queue in which we shall place the application
+   * @return The generated MappingRuleResult
+   */
+  public static MappingRuleResult createPlacementResult(String queue) {
+    return new MappingRuleResult(queue, MappingRuleResultType.PLACE);
+  }
+
+  /**
+   * Generator method for reject results.
+   * @return The generated MappingRuleResult
+   */
+  public static MappingRuleResult createRejectResult() {
+    return RESULT_REJECT;
+  }
+
+  /**
+   * Generator method for skip results.
+   * @return The generated MappingRuleResult
+   */
+  public static MappingRuleResult createSkipResult() {
+    return RESULT_SKIP;
+  }
+
+  /**
+   * Generator method for default placement results. It is a specialized
+   * placement result which will only use the "%default" as a queue name.
+   * @return The generated MappingRuleResult
+   */
+  public static MappingRuleResult createDefaultPlacementResult() {
+    return RESULT_DEFAULT_PLACEMENT;
+  }
+
+  /**
+   * Returns the string representation of the object.
+   * @return the string representation of the object
+   */
+  @Override
+  public String toString() {
+    if (result == MappingRuleResultType.PLACE) {
+      return result.name() + ": '" + normalizedQueue + "' ('" + queue + "')";
+    } else {
+      return result.name();
+    }
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/placement/MappingRuleResultType.java

@@ -0,0 +1,43 @@
+/**
+ * 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.
+ */
+
+package org.apache.hadoop.yarn.server.resourcemanager.placement;
+
+public enum MappingRuleResultType {
+  /**
+   * Represents a result where we simply ignore the current rule
+   * and move onto the next one.
+   */
+  SKIP,
+
+  /**
+   * Represents a result where the application gets rejected.
+   */
+  REJECT,
+
+  /**
+   * Represents a result where the application gets placed into a queue.
+   */
+  PLACE,
+
+  /**
+   * Special placement, which means the application is to be placed to the
+   * queue marked by %default variable.
+   */
+  PLACE_TO_DEFAULT
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/placement/MappingRuleValidationContext.java

@@ -0,0 +1,75 @@
+/**
+ * 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.
+ */
+
+package org.apache.hadoop.yarn.server.resourcemanager.placement;
+
+import org.apache.hadoop.yarn.exceptions.YarnException;
+
+import java.util.Set;
+
+/**
+ * This interface represents a context which contains all methods and data
+ * required by the mapping rules to validate the initial configuration. The
+ * reason this is moved to a separate interface is to minimize the dependencies
+ * of the MappingRules, MappingRuleMatchers and MappingRule actions. This
+ * interface should contain all validation related data and functions, this way
+ * schedulers or engines can be changed without changing the MappingRules.
+ */
+interface MappingRuleValidationContext {
+  /**
+   * This method should determine if the provided queue path can result in
+   * a possible placement. It should fail if the provided path cannot be placed
+   * into any of the known queues regardless of the variable context.
+   * @param queuePath The path to check
+   * @return true if the validation was successful
+   * @throws YarnException if the provided queue path is invalid
+   */
+  boolean validateQueuePath(String queuePath) throws YarnException;
+
+  /**
+   * Method to determine if the provided queue path contains any dynamic parts
+   * A part is dynamic if a known variable is referenced in it.
+   * @param queuePath The path to check
+   * @return true if no dynamic parts were found
+   */
+  boolean isPathStatic(String queuePath);
+
+  /**
+   * This method will add a known variable to the validation context, known
+   * variables can be used to determine if a path is static or dynamic.
+   * @param variable Name of the variable
+   * @throws YarnException If the variable to be added has already added as an
+   * immutable one, an exception is thrown
+   */
+  void addVariable(String variable) throws YarnException;
+
+  /**
+   * This method will add a known immutable variable to the validation context,
+   * known variables can be used to determine if a path is static or dynamic.
+   * @param variable Name of the immutable variable
+   * @throws YarnException If the variable to be added has already added as a
+   * regular, mutable variable an exception is thrown
+   */
+  void addImmutableVariable(String variable) throws YarnException;
+
+  /**
+   * This method will return all the known variables.
+   * @return Set of the known variables
+   */
+  Set<String> getVariables();
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/placement/MappingRuleValidationContextImpl.java

@@ -0,0 +1,252 @@
+/**
+ * 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.
+ */
+package org.apache.hadoop.yarn.server.resourcemanager.placement;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
+import org.apache.hadoop.yarn.exceptions.YarnException;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CSQueue;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacitySchedulerQueueManager;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.LeafQueue;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.ManagedParentQueue;
+
+import java.util.Set;
+
+public class MappingRuleValidationContextImpl
+    implements MappingRuleValidationContext {
+  /**
+   * We store all known variables in this set.
+   */
+  private Set<String> knownVariables = Sets.newHashSet();
+
+  /**
+   * This set is to determine which variables are immutable.
+   */
+  private Set<String> immutableVariables = Sets.newHashSet();
+
+  /**
+   * For queue path validations we need an instance of the queue manager
+   * to look up queues and their parents.
+   */
+  private final CapacitySchedulerQueueManager queueManager;
+
+  MappingRuleValidationContextImpl(CapacitySchedulerQueueManager qm) {
+    queueManager = qm;
+  }
+
+  /**
+   * This method will determine if a static queue path is valid.
+   * @param path The static path of the queue
+   * @return true of the path is valid
+   * @throws YarnException if the path is invalid
+   */
+  private boolean validateStaticQueuePath(MappingQueuePath path)
+      throws YarnException {
+    //Try getting queue by its full path name, if it exists it is a static
+    //leaf queue indeed, without any auto creation magic
+    CSQueue queue = queueManager.getQueue(path.getFullPath());
+    if (queue == null) {
+      //We might not be able to find the queue, because the reference was
+      // ambiguous this should only happen if the queue was referenced by
+      // leaf name only
+      if (queueManager.isAmbiguous(path.getFullPath())) {
+        throw new YarnException(
+            "Target queue is an ambiguous leaf queue '" +
+            path.getFullPath() + "'");
+      }
+
+      //if leaf queue does not exist,
+      //we need to check if the parent exists and is a managed parent
+      if (!path.hasParent()) {
+        throw new YarnException(
+            "Target queue does not exist and has no parent defined '" +
+            path.getFullPath() + "'");
+      }
+
+      CSQueue parentQueue = queueManager.getQueue(path.getParent());
+      if (parentQueue == null) {
+        if (queueManager.isAmbiguous(path.getParent())) {
+          throw new YarnException("Target queue path '" + path +
+              "' contains an ambiguous parent queue '" +
+              path.getParent() + "' reference");
+        } else {
+          throw new YarnException("Target queue path '" + path + "' " +
+              "contains an invalid parent queue '" + path.getParent() + "'.");
+        }
+      }
+
+      if (!(parentQueue instanceof ManagedParentQueue)) {
+        //If the parent path was referenced by short name, and it is not
+        // managed, we look up if there is a queue under it with the leaf
+        // queue's name
+        String normalizedParentPath = parentQueue.getQueuePath() + "."
+            + path.getLeafName();
+        CSQueue normalizedQueue = queueManager.getQueue(normalizedParentPath);
+        if (normalizedQueue instanceof LeafQueue) {
+          return true;
+        }
+
+        if (normalizedQueue == null) {
+          throw new YarnException(
+              "Target queue '" + path.getFullPath() + "' does not exist" +
+              " and has a non-managed parent queue defined.");
+        } else {
+          throw new YarnException("Target queue '" + path + "' references" +
+              "a non-leaf queue, target queues must always be " +
+              "leaf queues.");
+        }
+
+      }
+
+    } else {
+      // if queue exists, validate if its an instance of leaf queue
+      if (!(queue instanceof LeafQueue)) {
+        throw new YarnException("Target queue '" + path + "' references" +
+            "a non-leaf queue, target queues must always be " +
+            "leaf queues.");
+      }
+    }
+    return true;
+  }
+
+  /**
+   * This method will determine if a dynamic queue path (a path which contains
+   * variables) is valid.
+   * @param path The dynamic path of the queue
+   * @return true of the path is valid
+   * @throws YarnException if the path is invalid
+   */
+  private boolean validateDynamicQueuePath(MappingQueuePath path)
+      throws YarnException{
+    //if the queue is dynamic and we don't have a parent path, we cannot do
+    //any validation, since the dynamic part can be substituted to anything
+    //and that is the only part
+    if (!path.hasParent()) {
+      return true;
+    }
+
+    String parent = path.getParent();
+    //if the parent path has dynamic parts, we cannot do any more validations
+    if (!isPathStatic(parent)) {
+      return true;
+    }
+
+    //We check if the parent queue exists
+    CSQueue parentQueue = queueManager.getQueue(parent);
+    if (parentQueue == null) {
+      throw new YarnException("Target queue path '" + path + "' contains an " +
+          "invalid parent queue");
+    }
+
+    if (!(parentQueue instanceof ManagedParentQueue)) {
+      for (CSQueue queue : parentQueue.getChildQueues()) {
+        if (queue instanceof LeafQueue) {
+          //if a non managed parent queue has at least one leaf queue, this
+          //mapping can be valid, we cannot do any more checks
+          return true;
+        }
+      }
+
+      //There is no way we can place anything into the queue referenced by the
+      // rule, because we cannot auto create, and we don't have any leaf queues
+      //Actually this branch is not accessibe with the current queue hierarchy,
+      //there should be no parents without any leaf queues. This condition says
+      //for sanity checks
+      throw new YarnException("Target queue path '" + path + "' has" +
+          "a non-managed parent queue which has no LeafQueues either.");
+    }
+
+    return true;
+  }
+
+
+  /**
+   * This method should determine if the provided queue path can result in
+   * a possible placement. It should fail if the provided path cannot be placed
+   * into any of the known queues regardless of the variable context.
+   * @param queuePath The path to check
+   * @return true if the validation was successful
+   * @throws YarnException if the provided queue path is invalid
+   */
+  public boolean validateQueuePath(String queuePath) throws YarnException {
+    MappingQueuePath path = new MappingQueuePath(queuePath);
+
+    if (isPathStatic(queuePath)) {
+      return validateStaticQueuePath(path);
+    } else {
+      return validateDynamicQueuePath(path);
+    }
+  }
+
+  /**
+   * Method to determine if the provided queue path contains any dynamic parts
+   * A part is dynamic if a known variable is referenced in it.
+   * @param queuePath The path to check
+   * @return true if no dynamic parts were found
+   */
+  public boolean isPathStatic(String queuePath) {
+    String[] parts = queuePath.split("\\.");
+    for (int i = 0; i < parts.length; i++) {
+      if (knownVariables.contains(parts[i])) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  /**
+   * This method will add a known variable to the validation context, known
+   * variables can be used to determine if a path is static or dynamic.
+   * @param variable Name of the variable
+   * @throws YarnException If the variable to be added has already added as an
+   * immutable one, an exception is thrown
+   */
+  public void addVariable(String variable) throws YarnException {
+    if (immutableVariables.contains(variable)) {
+      throw new YarnException("Variable '" + variable + "' is immutable " +
+          "cannot add to the modified variable list.");
+    }
+    knownVariables.add(variable);
+  }
+
+  /**
+   * This method will add a known immutable variable to the validation context,
+   * known variables can be used to determine if a path is static or dynamic.
+   * @param variable Name of the immutable variable
+   * @throws YarnException If the variable to be added has already added as a
+   * regular, mutable variable an exception is thrown
+   */
+  public void addImmutableVariable(String variable) throws YarnException {
+    if (knownVariables.contains(variable) &&
+        !immutableVariables.contains(variable)) {
+      throw new YarnException("Variable '" + variable + "' already " +
+          "added as a mutable variable cannot set it to immutable.");
+    }
+    knownVariables.add(variable);
+    immutableVariables.add(variable);
+  }
+
+  /**
+   * This method will return all the known variables.
+   * @return Set of the known variables
+   */
+  public Set<String> getVariables() {
+    return ImmutableSet.copyOf(knownVariables);
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/placement/MockQueueHierarchyBuilder.java

@@ -23,6 +23,7 @@
 import org.apache.commons.compress.utils.Lists;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.*;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -38,6 +39,7 @@ class MockQueueHierarchyBuilder {
   private Set<String> ambiguous = Sets.newHashSet();
   private Map<String, String> shortNameMapping = Maps.newHashMap();
   private CapacitySchedulerQueueManager queueManager;
+  private Map<String, List<CSQueue>> childrenMap = Maps.newHashMap();
 
   public static MockQueueHierarchyBuilder create() {
     return new MockQueueHierarchyBuilder();
@@ -164,12 +166,20 @@ private AbstractCSQueue addLeafQueueAsChildOf(ParentQueue parent,
 
   private void setQueueFields(ParentQueue parent, AbstractCSQueue newQueue,
       String queueName) {
-    String fullPathOfQueue = parent.getQueuePath() + QUEUE_SEP + queueName;
+    String fullPathOfParent = parent.getQueuePath();
+    String fullPathOfQueue = fullPathOfParent + QUEUE_SEP + queueName;
     addQueueToQueueManager(queueName, newQueue, fullPathOfQueue);
 
+    if (childrenMap.get(fullPathOfParent) == null) {
+      childrenMap.put(fullPathOfParent, new ArrayList<>());
+    }
+    childrenMap.get(fullPathOfParent).add(newQueue);
+    when(parent.getChildQueues()).thenReturn(childrenMap.get(fullPathOfParent));
+
     when(newQueue.getParent()).thenReturn(parent);
     when(newQueue.getQueuePath()).thenReturn(fullPathOfQueue);
     when(newQueue.getQueueName()).thenReturn(queueName);
+
   }
 
   private void addQueueToQueueManager(String queueName, AbstractCSQueue queue,

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/placement/TestMappingRuleActions.java

@@ -0,0 +1,173 @@
+/**
+ * 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.
+ */
+
+package org.apache.hadoop.yarn.server.resourcemanager.placement;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class TestMappingRuleActions {
+  void assertRejectResult(MappingRuleResult result) {
+    assertSame(MappingRuleResultType.REJECT, result.getResult());
+  }
+
+
+  void assertSkipResult(MappingRuleResult result) {
+    assertSame(MappingRuleResultType.SKIP, result.getResult());
+  }
+
+  void assertPlaceDefaultResult(MappingRuleResult result) {
+    assertSame(MappingRuleResultType.PLACE_TO_DEFAULT, result.getResult());
+  }
+
+  void assertPlaceResult(MappingRuleResult result, String queue) {
+    assertSame(MappingRuleResultType.PLACE, result.getResult());
+    assertEquals(queue, result.getQueue());
+  }
+
+  @Test
+  public void testRejectAction() {
+    VariableContext variables = new VariableContext();
+    MappingRuleAction reject = new MappingRuleActions.RejectAction();
+    MappingRuleAction rejectHelper = MappingRuleActions.createRejectAction();
+
+    assertRejectResult(reject.execute(variables));
+    assertRejectResult(rejectHelper.execute(variables));
+  }
+
+  @Test
+  public void testActionFallbacks() {
+    MappingRuleActionBase action =
+        new MappingRuleActions.PlaceToQueueAction("a");
+
+    action.setFallbackDefaultPlacement();
+    assertPlaceDefaultResult(action.getFallback());
+
+    action.setFallbackReject();
+    assertRejectResult(action.getFallback());
+
+    action.setFallbackSkip();
+    assertSkipResult(action.getFallback());
+  }
+
+  @Test
+  public void testVariableUpdateAction() {
+    VariableContext variables = new VariableContext();
+    variables.put("%default", "root.default");
+    variables.put("%immutable", "immutable");
+    variables.put("%empty", "");
+    variables.put("%null", null);
+    variables.put("%sub", "xxx");
+    variables.setImmutables("%immutable");
+
+    MappingRuleAction updateDefaultManual =
+        new MappingRuleActions.VariableUpdateAction("%default", "root.%sub");
+    MappingRuleAction updateDefaultHelper =
+        MappingRuleActions.createUpdateDefaultAction("root.%sub%sub");
+    MappingRuleAction updateImmutable =
+        new MappingRuleActions.VariableUpdateAction("%immutable", "changed");
+    MappingRuleAction updateEmpty =
+        new MappingRuleActions.VariableUpdateAction("%empty", "something");
+    MappingRuleAction updateNull =
+        new MappingRuleActions.VariableUpdateAction("%null", "non-null");
+
+    MappingRuleResult result;
+
+    result = updateDefaultManual.execute(variables);
+    assertSkipResult(result);
+    assertEquals("root.xxx", variables.get("%default"));
+
+    result = updateDefaultHelper.execute(variables);
+    assertSkipResult(result);
+    assertEquals("root.xxxxxx", variables.get("%default"));
+
+    result = updateEmpty.execute(variables);
+    assertSkipResult(result);
+    assertEquals("something", variables.get("%empty"));
+    result = updateNull.execute(variables);
+    assertSkipResult(result);
+    assertEquals("non-null", variables.get("%null"));
+
+    try {
+      updateImmutable.execute(variables);
+      fail("Should've failed with exception");
+    } catch (Exception e){
+      assertTrue(e instanceof IllegalStateException);
+    }
+  }
+
+  @Test
+  public void testPlaceToQueueAction() {
+    VariableContext variables = new VariableContext();
+    variables.put("%default", "root.default");
+    variables.put("%immutable", "immutable");
+    variables.put("%empty", "");
+    variables.put("%null", null);
+    variables.put("%sub", "xxx");
+    variables.setImmutables("%immutable");
+
+    MappingRuleAction placeToStatic =
+        new MappingRuleActions.PlaceToQueueAction("root.static.queue");
+
+    MappingRuleAction placeToDynamic =
+        new MappingRuleActions.PlaceToQueueAction("root.%sub.%immutable");
+
+    MappingRuleAction placeToDynamicDoubleSub =
+        MappingRuleActions.createPlaceToQueueAction("root.%sub%sub.%immutable");
+
+    MappingRuleAction placeToNull =
+        MappingRuleActions.createPlaceToQueueAction(null);
+
+    MappingRuleAction placeToEmpty =
+        MappingRuleActions.createPlaceToQueueAction("");
+
+    MappingRuleAction placeToNulRef =
+        new MappingRuleActions.PlaceToQueueAction("%null");
+
+    MappingRuleAction placeToEmptyRef =
+        new MappingRuleActions.PlaceToQueueAction("%empty");
+
+    MappingRuleAction placeToDefaultRef =
+        new MappingRuleActions.PlaceToQueueAction("%default");
+
+    assertPlaceResult(placeToStatic.execute(variables), "root.static.queue");
+    assertPlaceResult(placeToDynamic.execute(variables), "root.xxx.immutable");
+    assertPlaceResult(placeToDynamicDoubleSub.execute(variables),
+        "root.%sub%sub.immutable");
+
+    assertPlaceResult(placeToNull.execute(variables), "");
+    assertPlaceResult(placeToEmpty.execute(variables), "");
+    assertPlaceResult(placeToNulRef.execute(variables), "");
+    assertPlaceResult(placeToEmptyRef.execute(variables), "");
+    assertPlaceResult(placeToDefaultRef.execute(variables), "root.default");
+  }
+
+  @Test
+  public void testToStrings() {
+    MappingRuleAction place = new MappingRuleActions.PlaceToQueueAction(
+        "queue");
+    MappingRuleAction varUpdate = new MappingRuleActions.VariableUpdateAction(
+        "%var", "value");
+    MappingRuleAction reject = new MappingRuleActions.RejectAction();
+
+    assertEquals("PlaceToQueueAction{queueName='queue'}", place.toString());
+    assertEquals("VariableUpdateAction{variableName='%var'" +
+            ", variableValue='value'}", varUpdate.toString());
+    assertEquals("RejectAction", reject.toString());
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/placement/TestMappingRuleValidationContextImpl.java

@@ -0,0 +1,216 @@
+/**
+ * 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.
+ */
+
+package org.apache.hadoop.yarn.server.resourcemanager.placement;
+
+import org.apache.hadoop.yarn.exceptions.YarnException;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacitySchedulerQueueManager;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+import static org.mockito.ArgumentMatchers.isNull;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class TestMappingRuleValidationContextImpl {
+  @Test
+  public void testContextVariables() {
+    //Setting up queue manager and emulated queue hierarchy
+    CapacitySchedulerQueueManager qm =
+        mock(CapacitySchedulerQueueManager.class);
+
+    MockQueueHierarchyBuilder.create()
+        .withQueueManager(qm)
+        .withQueue("root.unmanaged")
+        .build();
+    when(qm.getQueue(isNull())).thenReturn(null);
+
+    MappingRuleValidationContextImpl ctx =
+        new MappingRuleValidationContextImpl(qm);
+
+    //in the beginning there were no variables
+    assertEquals(0, ctx.getVariables().size());
+    //hence all quese were considered static
+    assertTrue(ctx.isPathStatic("root.%user"));
+    try {
+      //but then suddenly there was a variable
+      ctx.addVariable("%user");
+      ctx.addVariable("%user");
+      assertEquals(1, ctx.getVariables().size());
+      //and suddenly previously static queues became dynamic
+      assertFalse(ctx.isPathStatic("root.%user"));
+      //as time passed, more and more variables joined the void
+      ctx.addVariable("%primary_group");
+      ctx.addVariable("%default");
+    } catch (YarnException e) {
+      fail("We don't expect the add variable to fail: " + e.getMessage());
+    }
+    assertEquals(3, ctx.getVariables().size());
+    //making more and more dynamic queues possible
+    assertFalse(ctx.isPathStatic("root.%primary_group.something"));
+    assertFalse(ctx.isPathStatic("root.something.%default"));
+    //but the majority of the queues remained static
+    assertTrue(ctx.isPathStatic("root.static"));
+    assertTrue(ctx.isPathStatic("root.static.%nothing"));
+    assertTrue(ctx.isPathStatic("root"));
+
+    assertTrue(ctx.getVariables().contains("%user"));
+    assertTrue(ctx.getVariables().contains("%primary_group"));
+    assertTrue(ctx.getVariables().contains("%default"));
+    assertFalse(ctx.getVariables().contains("%nothing"));
+  }
+
+  void assertValidPath(MappingRuleValidationContext ctx, String path) {
+    try {
+      ctx.validateQueuePath(path);
+    } catch (YarnException e) {
+      fail("Path '" + path + "' should be VALID");
+    }
+  }
+
+  void assertInvalidPath(MappingRuleValidationContext ctx, String path) {
+    try {
+      ctx.validateQueuePath(path);
+      fail("Path '" + path + "' should be INVALID");
+    } catch (YarnException e) {
+      //Exception is expected
+    }
+  }
+
+  @Test
+  public void testDynamicQueueValidation() {
+    //Setting up queue manager and emulated queue hierarchy
+    CapacitySchedulerQueueManager qm =
+        mock(CapacitySchedulerQueueManager.class);
+
+    MockQueueHierarchyBuilder.create()
+        .withQueueManager(qm)
+        .withQueue("root.unmanaged")
+        .withManagedParentQueue("root.managed")
+        .withQueue("root.unmanagedwithchild.child")
+        .withQueue("root.leaf")
+        .build();
+    when(qm.getQueue(isNull())).thenReturn(null);
+
+    MappingRuleValidationContextImpl ctx =
+        new MappingRuleValidationContextImpl(qm);
+    try {
+      ctx.addVariable("%dynamic");
+      ctx.addVariable("%user");
+    } catch (YarnException e) {
+      fail("We don't expect the add variable to fail: " + e.getMessage());
+    }
+
+    assertValidPath(ctx, "%dynamic");
+    assertValidPath(ctx, "root.%dynamic");
+    assertValidPath(ctx, "%user.%dynamic");
+    assertValidPath(ctx, "root.managed.%dynamic");
+    assertValidPath(ctx, "managed.%dynamic");
+
+    assertInvalidPath(ctx, "root.invalid.%dynamic");
+    assertInvalidPath(ctx, "root.umanaged.%dynamic");
+
+    assertValidPath(ctx, "root.unmanagedwithchild.%user");
+    assertValidPath(ctx, "unmanagedwithchild.%user");
+  }
+
+  @Test
+  public void testStaticQueueValidation() {
+    //Setting up queue manager and emulated queue hierarchy
+    CapacitySchedulerQueueManager qm =
+        mock(CapacitySchedulerQueueManager.class);
+
+    MockQueueHierarchyBuilder.create()
+        .withQueueManager(qm)
+        .withQueue("root.unmanaged")
+        .withManagedParentQueue("root.managed")
+        .withQueue("root.deep.queue.path")
+        .withQueue("root.ambi.ambileaf")
+        .withQueue("root.deep.ambi.ambileaf")
+        .build();
+    when(qm.getQueue(isNull())).thenReturn(null);
+
+    MappingRuleValidationContextImpl ctx =
+        new MappingRuleValidationContextImpl(qm);
+
+    assertValidPath(ctx, "root.unmanaged");
+    assertValidPath(ctx, "unmanaged");
+    assertInvalidPath(ctx, "root");
+    assertInvalidPath(ctx, "managed");
+    assertInvalidPath(ctx, "root.managed");
+    assertInvalidPath(ctx, "fail");
+
+    assertInvalidPath(ctx, "ambi");
+    assertInvalidPath(ctx, "ambileaf");
+    assertInvalidPath(ctx, "ambi.ambileaf");
+    assertValidPath(ctx, "root.ambi.ambileaf");
+
+
+    assertValidPath(ctx, "root.managed.a");
+    assertInvalidPath(ctx, "root.deep");
+    assertInvalidPath(ctx, "deep");
+    assertInvalidPath(ctx, "deep.queue");
+    assertInvalidPath(ctx, "root.deep.queue");
+    assertInvalidPath(ctx, "deep.queue.path");
+    assertValidPath(ctx, "queue.path");
+    assertInvalidPath(ctx, "queue.invalidPath");
+    assertValidPath(ctx, "path");
+    assertValidPath(ctx, "root.deep.queue.path");
+  }
+
+  @Test
+  public void testImmutableVariablesInContext() {
+    CapacitySchedulerQueueManager qm =
+        mock(CapacitySchedulerQueueManager.class);
+
+    MappingRuleValidationContextImpl ctx =
+        new MappingRuleValidationContextImpl(qm);
+
+    try {
+      ctx.addVariable("mutable");
+      ctx.addVariable("mutable");
+    } catch (YarnException e) {
+      fail("We should be able to add a mutable variable multiple times: "
+          + e.getMessage());
+    }
+
+    try {
+      ctx.addImmutableVariable("mutable");
+      fail("We should receive an exception if an already added mutable" +
+          " variable is being marked as immutable");
+    } catch (YarnException e) {
+      //An exception is expected
+    }
+
+    try {
+      ctx.addImmutableVariable("immutable");
+      ctx.addImmutableVariable("immutable");
+    } catch (YarnException e) {
+      fail("We should be able to add a immutable variable multiple times: "
+          + e.getMessage());
+    }
+
+    try {
+      ctx.addVariable("immutable");
+      fail("We should receive an exception if we try to add a variable as " +
+          "mutable when it was previously added as immutable");
+    } catch (YarnException e) {
+      //An exception is expected
+    }
+  }
+}