YARN-5339. Fixed "yarn logs" to fail when a file is passed to -out option instead of a directory. Contributed by Xuan Gong.

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

@@ -18,6 +18,7 @@
 
 package org.apache.hadoop.yarn.client.cli;
 
+import java.io.File;
 import java.io.IOException;
 import java.io.PrintStream;
 import java.util.ArrayList;
@@ -197,6 +198,15 @@ private int runCommand(String[] args) throws Exception {
       return -1;
     }
 
+    if (localDir != null) {
+      File file = new File(localDir);
+      if (file.exists() && file.isFile()) {
+        System.err.println("Invalid value for -out option. "
+            + "Please provide a directory.");
+        return -1;
+      }
+    }
+
     LogCLIHelpers logCliHelper = new LogCLIHelpers();
     logCliHelper.setConf(getConf());
 

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

@@ -711,6 +711,64 @@ public void testFetchApplictionLogsAsAnotherUser() throws Exception {
     }
   }
 
+  @Test (timeout = 5000)
+  public void testLogsCLIWithInvalidArgs() throws Exception {
+    String localDir = "target/SaveLogs";
+    Path localPath = new Path(localDir);
+    Configuration configuration = new Configuration();
+    FileSystem fs = FileSystem.get(configuration);
+    ApplicationId appId = ApplicationId.newInstance(0, 1);
+    YarnClient mockYarnClient =
+        createMockYarnClient(YarnApplicationState.FINISHED,
+        UserGroupInformation.getCurrentUser().getShortUserName());
+    LogsCLI cli = new LogsCLIForTest(mockYarnClient);
+    cli.setConf(configuration);
+
+    // Specify an invalid applicationId
+    int exitCode = cli.run(new String[] {"-applicationId",
+        "123"});
+    assertTrue(exitCode == -1);
+    assertTrue(sysErrStream.toString().contains(
+        "Invalid ApplicationId specified"));
+    sysErrStream.reset();
+
+    // Specify an invalid containerId
+    exitCode = cli.run(new String[] {"-containerId",
+        "123"});
+    assertTrue(exitCode == -1);
+    assertTrue(sysErrStream.toString().contains(
+        "Invalid ContainerId specified"));
+    sysErrStream.reset();
+
+    // Specify show_container_log_info and show_application_log_info
+    // at the same time
+    exitCode = cli.run(new String[] {"-applicationId", appId.toString(),
+        "-show_container_log_info", "-show_application_log_info"});
+    assertTrue(exitCode == -1);
+    assertTrue(sysErrStream.toString().contains("Invalid options. "
+        + "Can only accept one of show_application_log_info/"
+        + "show_container_log_info."));
+    sysErrStream.reset();
+
+    // Specify a file name to the option -out
+    try {
+      fs.mkdirs(localPath);
+      Path tmpFilePath = new Path(localPath, "tmpFile");
+      if (!fs.exists(tmpFilePath)) {
+        fs.createNewFile(tmpFilePath);
+      }
+      exitCode = cli.run(new String[] {"-applicationId",
+          appId.toString(),
+          "-out" , tmpFilePath.toString()});
+      assertTrue(exitCode == -1);
+      assertTrue(sysErrStream.toString().contains(
+          "Invalid value for -out option. Please provide a directory."));
+    } finally {
+      fs.delete(localPath, true);
+    }
+  }
+
+
   @Test (timeout = 15000)
   public void testSaveContainerLogsLocally() throws Exception {
     String remoteLogRootDir = "target/logs/";
@@ -845,13 +903,6 @@ public void testPrintContainerLogMetadata() throws Exception {
     LogsCLI cli = new LogsCLIForTest(mockYarnClient);
     cli.setConf(configuration);
 
-    int result = cli.run(new String[] {"-applicationId", appId.toString(),
-        "-show_container_log_info", "-show_application_log_info"});
-    assertTrue(result == -1);
-    assertTrue(sysErrStream.toString().contains("Invalid options. "
-        + "Can only accept one of show_application_log_info/"
-        + "show_container_log_info."));
-
     cli.run(new String[] {"-applicationId", appId.toString(),
         "-show_container_log_info"});
     assertTrue(sysOutStream.toString().contains(