YARN-5443. Add support for docker inspect command. Contributed by Shane Kumpf.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/linux/runtime/docker/DockerInspectCommand.java

@@ -0,0 +1,41 @@
+/*
+ * *
+ *  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.nodemanager.containermanager.linux.runtime.docker;
+
+/**
+ * Encapsulates the docker inspect command and its command
+ * line arguments.
+ */
+public class DockerInspectCommand extends DockerCommand {
+  private static final String INSPECT_COMMAND = "inspect";
+  private String containerName;
+
+  public DockerInspectCommand(String containerName) {
+    super(INSPECT_COMMAND);
+    this.containerName = containerName;
+  }
+
+  public DockerInspectCommand getContainerStatus() {
+    super.addCommandArguments("--format='{{.State.Status}}'");
+    super.addCommandArguments(containerName);
+    return this;
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/linux/runtime/docker/TestDockerInspectCommand.java

@@ -0,0 +1,50 @@
+/*
+ * 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.nodemanager.containermanager.linux.runtime.docker;
+
+import static org.junit.Assert.assertEquals;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Tests the docker inspect command and its command
+ * line arguments.
+ */
+public class TestDockerInspectCommand {
+
+  private DockerInspectCommand dockerInspectCommand;
+
+  private static final String CONTAINER_NAME = "foo";
+
+  @Before
+  public void setup() {
+    dockerInspectCommand = new DockerInspectCommand(CONTAINER_NAME);
+  }
+
+  @Test
+  public void testGetCommandOption() {
+    assertEquals("inspect", dockerInspectCommand.getCommandOption());
+  }
+
+  @Test
+  public void testGetContainerStatus() throws Exception {
+    dockerInspectCommand.getContainerStatus();
+    assertEquals("inspect --format='{{.State.Status}}' foo",
+        dockerInspectCommand.getCommandWithArguments());
+  }
+}