YARN-11506. The formatted yarn queue list is displayed on CLI (#5716). Contributed by Lu Yuan.

Reviewed-by: Shilun Fan <slfan1989@apache.org>
Signed-off-by: Ayush Saxena <ayushsaxena@apache.org>

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-client/src/main/java/org/apache/hadoop/yarn/client/cli/QueueCLI.java

@@ -23,6 +23,7 @@ import java.io.PrintWriter;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.text.DecimalFormat;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Set;
 
@@ -36,6 +37,7 @@ import org.apache.hadoop.classification.InterfaceStability.Unstable;
 import org.apache.hadoop.util.ToolRunner;
 import org.apache.hadoop.yarn.api.records.NodeLabel;
 import org.apache.hadoop.yarn.api.records.QueueInfo;
+import org.apache.hadoop.yarn.client.util.FormattingCLIUtils;
 import org.apache.hadoop.yarn.exceptions.YarnException;
 
 import org.apache.hadoop.classification.VisibleForTesting;
@@ -222,27 +224,20 @@ public class QueueCLI extends YarnCLI {
   }
 
   private void printQueueInfos(PrintWriter writer, List<QueueInfo> queueInfos) {
-    writer.print(queueInfos.size() + " queues were found : \n");
-    writer.print("Queue Name\tQueue Path\tState\tCapacity\tCurrent Capacity" +
-        "\tMaximum Capacity\tWeight\tMaximum Parallel Apps\n");
+    String titleString = queueInfos.size() + " queues were found";
+    List<String> headerStrings = Arrays.asList("Queue Name", "Queue Path", "State", "Capacity",
+        "Current Capacity", "Maximum Capacity", "Weight", "Maximum Parallel Apps");
+    FormattingCLIUtils formattingCLIUtils = new FormattingCLIUtils(titleString)
+        .addHeaders(headerStrings);
+    DecimalFormat df = new DecimalFormat("#.00");
     for (QueueInfo queueInfo : queueInfos) {
-      writer.print(queueInfo.getQueueName());
-      writer.print("\t");
-      writer.print(queueInfo.getQueuePath());
-      writer.print("\t");
-      writer.print(queueInfo.getQueueState());
-      DecimalFormat df = new DecimalFormat("#.00");
-      writer.print("\t");
-      writer.print(df.format(queueInfo.getCapacity() * 100) + "%");
-      writer.print("\t");
-      writer.print(df.format(queueInfo.getCurrentCapacity() * 100) + "%");
-      writer.print("\t");
-      writer.print(df.format(queueInfo.getMaximumCapacity() * 100) + "%");
-      writer.print("\t");
-      writer.print(df.format(queueInfo.getWeight()));
-      writer.print("\t");
-      writer.print(queueInfo.getMaxParallelApps());
-      writer.print("\n");
+      formattingCLIUtils.addLine(queueInfo.getQueueName(), queueInfo.getQueuePath(),
+          queueInfo.getQueueState(), df.format(queueInfo.getCapacity() * 100) + "%",
+          df.format(queueInfo.getCurrentCapacity() * 100) + "%",
+          df.format(queueInfo.getMaximumCapacity() * 100) + "%",
+          df.format(queueInfo.getWeight()),
+          queueInfo.getMaxParallelApps());
     }
+    writer.print(formattingCLIUtils.render());
   }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-client/src/main/java/org/apache/hadoop/yarn/client/util/FormattingCLIUtils.java

@@ -0,0 +1,277 @@
+/**
+ * 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.client.util;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * The main core class that generates the ASCII TABLE.
+ */
+public final class FormattingCLIUtils {
+  /** Table title. */
+  private String title;
+  /** Last processed row type. */
+  private TableRowType lastTableRowType;
+  /** StringBuilder object used to concatenate strings. */
+  private StringBuilder join;
+  /** An ordered Map that holds each row of data. */
+  private List<TableRow> tableRows;
+  /** Maps the maximum length of each column. */
+  private Map<Integer, Integer> maxColMap;
+
+  /**
+   * Contains the title constructor.
+   * @param title titleName
+   */
+  public FormattingCLIUtils(String title) {
+    this.init();
+    this.title = title;
+  }
+
+  /**
+   * Initialize the data.
+   */
+  private void init() {
+    this.join = new StringBuilder();
+    this.tableRows = new ArrayList<>();
+    this.maxColMap = new HashMap<>();
+  }
+
+  /**
+   * Adds elements from the collection to the header data in the table.
+   * @param headers Header data
+   * @return FormattingCLIUtils object
+   */
+  public FormattingCLIUtils addHeaders(List<?> headers) {
+    return this.appendRows(TableRowType.HEADER, headers.toArray());
+  }
+
+  /**
+   * Adds a row of normal data to the table.
+   * @param objects Common row data
+   * @return FormattingCLIUtils object
+   */
+  public FormattingCLIUtils addLine(Object... objects) {
+    return this.appendRows(TableRowType.LINE, objects);
+  }
+
+  /**
+   * Adds the middle row of data to the table.
+   * @param tableRowType TableRowType
+   * @param objects Table row data
+   * @return FormattingCLIUtils object
+   */
+  private FormattingCLIUtils appendRows(TableRowType tableRowType, Object... objects) {
+    if (objects != null && objects.length > 0) {
+      int len = objects.length;
+      if (this.maxColMap.size() > len) {
+        throw new IllegalArgumentException("The number of columns that inserted a row " +
+            "of data into the table is different from the number of previous columns, check!");
+      }
+      List<String> lines = new ArrayList<>();
+      for (int i = 0; i < len; i++) {
+        Object o = objects[i];
+        String value = o == null ? "null" : o.toString();
+        lines.add(value);
+        Integer maxColSize = this.maxColMap.get(i);
+        if (maxColSize == null) {
+          this.maxColMap.put(i, value.length());
+          continue;
+        }
+        if (value.length() > maxColSize) {
+          this.maxColMap.put(i, value.length());
+        }
+      }
+      this.tableRows.add(new TableRow(tableRowType, lines));
+    }
+    return this;
+  }
+
+  /**
+   * Builds the string for the row of the table title.
+   */
+  private void buildTitle() {
+    if (this.title != null) {
+      int maxTitleSize = 0;
+      for (Integer maxColSize : this.maxColMap.values()) {
+        maxTitleSize += maxColSize;
+      }
+      maxTitleSize += 3 * (this.maxColMap.size() - 1);
+      if (this.title.length() > maxTitleSize) {
+        this.title = this.title.substring(0, maxTitleSize);
+      }
+      this.join.append("+");
+      for (int i = 0; i < maxTitleSize + 2; i++) {
+        this.join.append("-");
+      }
+      this.join.append("+\n")
+          .append("|")
+          .append(StrUtils.center(this.title, maxTitleSize + 2, ' '))
+          .append("|\n");
+      this.lastTableRowType = TableRowType.TITLE;
+    }
+  }
+
+  /**
+   * Build the table, first build the title, and then walk through each row of data to build.
+   */
+  private void buildTable() {
+    this.buildTitle();
+    for (int i = 0, len = this.tableRows.size(); i < len; i++) {
+      List<String> data = this.tableRows.get(i).data;
+      switch (this.tableRows.get(i).tableRowType) {
+      case HEADER:
+        if (this.lastTableRowType != TableRowType.HEADER) {
+          this.buildRowBorder(data);
+        }
+        this.buildRowLine(data);
+        this.buildRowBorder(data);
+        break;
+      case LINE:
+        this.buildRowLine(data);
+        if (i == len - 1) {
+          this.buildRowBorder(data);
+        }
+        break;
+      default:
+        break;
+      }
+    }
+  }
+
+  /**
+   * Method to build a border row.
+   * @param data dataLine
+   */
+  private void buildRowBorder(List<String> data) {
+    this.join.append("+");
+    for (int i = 0, len = data.size(); i < len; i++) {
+      for (int j = 0; j < this.maxColMap.get(i) + 2; j++) {
+        this.join.append("-");
+      }
+      this.join.append("+");
+    }
+    this.join.append("\n");
+  }
+
+  /**
+   * A way to build rows of data.
+   * @param data dataLine
+   */
+  private void buildRowLine(List<String> data) {
+    this.join.append("|");
+    for (int i = 0, len = data.size(); i < len; i++) {
+      this.join.append(StrUtils.center(data.get(i), this.maxColMap.get(i) + 2, ' '))
+          .append("|");
+    }
+    this.join.append("\n");
+  }
+
+  /**
+   * Rendering is born as a result.
+   * @return ASCII string of Table
+   */
+  public String render() {
+    this.buildTable();
+    return this.join.toString();
+  }
+
+  /**
+   * The type of each table row and the entity class of the data.
+   */
+  private static class TableRow {
+    private TableRowType tableRowType;
+    private List<String> data;
+    TableRow(TableRowType tableRowType, List<String> data) {
+      this.tableRowType = tableRowType;
+      this.data = data;
+    }
+  }
+
+  /**
+   * An enumeration class that distinguishes between table headers and normal table data.
+   */
+  private enum TableRowType {
+    TITLE, HEADER, LINE
+  }
+
+  /**
+   * String utility class.
+   */
+  private static final class StrUtils {
+    /**
+     * Puts a string in the middle of a given size.
+     * @param str Character string
+     * @param size Total size
+     * @param padChar Fill character
+     * @return String result
+     */
+    private static String center(String str, int size, char padChar) {
+      if (str != null && size > 0) {
+        int strLen = str.length();
+        int pads = size - strLen;
+        if (pads > 0) {
+          str = leftPad(str, strLen + pads / 2, padChar);
+          str = rightPad(str, size, padChar);
+        }
+      }
+      return str;
+    }
+
+    /**
+     * Left-fill the given string and size.
+     * @param str String
+     * @param size totalSize
+     * @param padChar Fill character
+     * @return String result
+     */
+    private static String leftPad(final String str, int size, char padChar) {
+      int pads = size - str.length();
+      return pads <= 0 ? str : repeat(padChar, pads).concat(str);
+    }
+
+    /**
+     * Right-fill the given string and size.
+     * @param str String
+     * @param size totalSize
+     * @param padChar Fill character
+     * @return String result
+     */
+    private static String rightPad(final String str, int size, char padChar) {
+      int pads = size - str.length();
+      return pads <= 0 ? str : str.concat(repeat(padChar, pads));
+    }
+
+    /**
+     * Re-fill characters as strings.
+     * @param ch String
+     * @param repeat Number of repeats
+     * @return String
+     */
+    private static String repeat(char ch, int repeat) {
+      char[] buf = new char[repeat];
+      for (int i = repeat - 1; i >= 0; i--) {
+        buf[i] = ch;
+      }
+      return new String(buf);
+    }
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-client/src/test/java/org/apache/hadoop/yarn/client/cli/TestYarnCLI.java

@@ -40,6 +40,7 @@ import java.io.PrintWriter;
 import java.io.UnsupportedEncodingException;
 import java.text.DecimalFormat;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.Date;
 import java.util.EnumSet;
@@ -82,6 +83,7 @@ import org.apache.hadoop.yarn.api.records.SignalContainerCommand;
 import org.apache.hadoop.yarn.api.records.YarnApplicationAttemptState;
 import org.apache.hadoop.yarn.api.records.YarnApplicationState;
 import org.apache.hadoop.yarn.client.api.YarnClient;
+import org.apache.hadoop.yarn.client.util.FormattingCLIUtils;
 import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.exceptions.ApplicationAttemptNotFoundException;
 import org.apache.hadoop.yarn.exceptions.ApplicationNotFoundException;
@@ -1774,28 +1776,21 @@ public class TestYarnCLI {
     verify(client).getAllQueues();
     ByteArrayOutputStream baos = new ByteArrayOutputStream();
     PrintWriter writer = new PrintWriter(baos);
-    writer.print(queueInfos.size() + " queues were found : \n");
-    writer.print("Queue Name\tQueue Path\tState\tCapacity\tCurrent Capacity\t" +
-        "Maximum Capacity\tWeight\tMaximum Parallel Apps\n");
+    String titleString = queueInfos.size() + " queues were found";
+    List<String> headerStrings = Arrays.asList("Queue Name", "Queue Path", "State", "Capacity",
+        "Current Capacity", "Maximum Capacity", "Weight", "Maximum Parallel Apps");
+    FormattingCLIUtils formattingCLIUtils = new FormattingCLIUtils(titleString)
+        .addHeaders(headerStrings);
+    DecimalFormat df = new DecimalFormat("#.00");
     for (QueueInfo queueInfoe : queueInfos) {
-      writer.print(queueInfoe.getQueueName());
-      writer.print("\t");
-      writer.print(queueInfoe.getQueuePath());
-      writer.print("\t");
-      writer.print(queueInfoe.getQueueState());
-      DecimalFormat df = new DecimalFormat("#.00");
-      writer.print("\t");
-      writer.print(df.format(queueInfoe.getCapacity() * 100) + "%");
-      writer.print("\t");
-      writer.print(df.format(queueInfoe.getCurrentCapacity() * 100) + "%");
-      writer.print("\t");
-      writer.print(df.format(queueInfoe.getMaximumCapacity() * 100) + "%");
-      writer.print("\t");
-      writer.print(df.format(queueInfoe.getWeight()));
-      writer.print("\t");
-      writer.print(queueInfoe.getMaxParallelApps());
-      writer.print("\n");
+      formattingCLIUtils.addLine(queueInfoe.getQueueName(), queueInfoe.getQueuePath(),
+          queueInfoe.getQueueState(), df.format(queueInfoe.getCapacity() * 100) + "%",
+          df.format(queueInfoe.getCurrentCapacity() * 100) + "%",
+          df.format(queueInfoe.getMaximumCapacity() * 100) + "%",
+          df.format(queueInfoe.getWeight()),
+          queueInfoe.getMaxParallelApps());
     }
+    writer.print(formattingCLIUtils.render());
     writer.close();
     String queueInfoStr = baos.toString("UTF-8");
     Assert.assertEquals(queueInfoStr, sysOutStream.toString());