Test: Allow CliTool to write out stacktraces

In order to have the possibility of debugging on the command line, the user
now can either set the es.cli.debug system property
which results in stack traces being written to to the terminal.

Closes #7222

src/main/java/org/elasticsearch/common/cli/CliTool.java

@@ -144,13 +144,13 @@ public final int execute(String... args) {
             return command.execute(settings, env).status;
 
         } catch (IOException ioe) {
-            terminal.printError(ioe.getMessage());
+            terminal.printError(ioe);
             return ExitStatus.IO_ERROR.status;
         } catch (IllegalArgumentException | ElasticsearchIllegalArgumentException ilae) {
-            terminal.printError(ilae.getMessage());
+            terminal.printError(ilae);
             return ExitStatus.USAGE.status;
         } catch (Throwable t) {
-            terminal.printError(t.getMessage());
+            terminal.printError(t);
             if (command == null) {
                 return ExitStatus.USAGE.status;
             }

src/main/java/org/elasticsearch/common/cli/Terminal.java

@@ -29,6 +29,8 @@
 */
 public abstract class Terminal {
 
+    public static final String DEBUG_SYSTEM_PROPERTY = "es.cli.debug";
+
     public static final Terminal DEFAULT = ConsoleTerminal.supported() ? new ConsoleTerminal() : new SystemTerminal();
 
     public static enum Verbosity {
@@ -56,14 +58,15 @@ public static Verbosity resolve(CommandLine cli) {
     }
 
     private Verbosity verbosity = Verbosity.NORMAL;
-
+    private final boolean isDebugEnabled;
 
     public Terminal() {
         this(Verbosity.NORMAL);
     }
 
     public Terminal(Verbosity verbosity) {
         this.verbosity = verbosity;
+        this.isDebugEnabled = "true".equals(System.getProperty(DEBUG_SYSTEM_PROPERTY, "false"));
     }
 
     public void verbosity(Verbosity verbosity) {
@@ -78,6 +81,8 @@ public Verbosity verbosity() {
 
     public abstract char[] readSecret(String text, Object... args);
 
+    protected abstract void printStackTrace(Throwable t);
+
     public void println() {
         println(Verbosity.NORMAL);
     }
@@ -108,6 +113,13 @@ public void printError(String msg, Object... args) {
         println(Verbosity.SILENT, "ERROR: " + msg, args);
     }
 
+    public void printError(Throwable t) {
+        printError("%s", t.getMessage());
+        if (isDebugEnabled) {
+            printStackTrace(t);
+        }
+    }
+
     protected abstract void doPrint(String msg, Object... args);
 
     public abstract PrintWriter writer();
@@ -141,6 +153,10 @@ public PrintWriter writer() {
             return console.writer();
         }
 
+        @Override
+        public void printStackTrace(Throwable t) {
+            t.printStackTrace(console.writer());
+        }
     }
 
     private static class SystemTerminal extends Terminal {
@@ -168,6 +184,11 @@ public char[] readSecret(String text, Object... args) {
             return readText(text, args).toCharArray();
         }
 
+        @Override
+        public void printStackTrace(Throwable t) {
+            t.printStackTrace(printWriter);
+        }
+
         @Override
         public PrintWriter writer() {
             return printWriter;

src/test/java/org/elasticsearch/common/cli/CliToolTestCase.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.common.cli;
 
+import org.elasticsearch.ExceptionsHelper;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.test.ElasticsearchTestCase;
 
@@ -74,6 +75,11 @@ public char[] readSecret(String text, Object... args) {
         public void print(String msg, Object... args) {
         }
 
+        @Override
+        public void printStackTrace(Throwable t) {
+            return;
+        }
+
         @Override
         public PrintWriter writer() {
             return DEV_NULL;
@@ -120,6 +126,11 @@ public void print(String msg, Object... args) {
             doPrint(msg, args);
         }
 
+        @Override
+        public void printStackTrace(Throwable t) {
+            terminalOutput.add(ExceptionsHelper.stackTrace(t));
+        }
+
         public List<String> getTerminalOutput() {
             return terminalOutput;
         }

src/test/java/org/elasticsearch/common/cli/CliToolTests.java

@@ -21,6 +21,7 @@
 
 import com.google.common.collect.ImmutableMap;
 import org.apache.commons.cli.CommandLine;
+import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.env.Environment;
 import org.junit.Test;
@@ -224,6 +225,34 @@ public CliTool.ExitStatus execute(Settings settings, Environment env) throws Exc
         assertThat(terminal.getTerminalOutput(), hasItem(containsString("cmd1 help")));
     }
 
+    @Test
+    public void testThatThrowExceptionCanBeLogged() throws Exception {
+        CaptureOutputTerminal terminal = new CaptureOutputTerminal();
+        NamedCommand cmd = new NamedCommand("cmd", terminal) {
+            @Override
+            public CliTool.ExitStatus execute(Settings settings, Environment env) throws Exception {
+                throw new ElasticsearchException("error message");
+            }
+        };
+        SingleCmdTool tool = new SingleCmdTool("tool", terminal, cmd);
+        assertStatus(tool.execute(), CliTool.ExitStatus.CODE_ERROR);
+        assertThat(terminal.getTerminalOutput(), hasSize(1));
+        assertThat(terminal.getTerminalOutput(), hasItem(containsString("error message")));
+
+        // set env... and log stack trace
+        try {
+            System.setProperty(Terminal.DEBUG_SYSTEM_PROPERTY, "true");
+            terminal = new CaptureOutputTerminal();
+            assertStatus(new SingleCmdTool("tool", terminal, cmd).execute(), CliTool.ExitStatus.CODE_ERROR);
+            assertThat(terminal.getTerminalOutput(), hasSize(2));
+            assertThat(terminal.getTerminalOutput(), hasItem(containsString("error message")));
+            // This class must be part of the stack strace
+            assertThat(terminal.getTerminalOutput(), hasItem(containsString(getClass().getName())));
+        } finally {
+            System.clearProperty(Terminal.DEBUG_SYSTEM_PROPERTY);
+        }
+    }
+
     private void assertStatus(int status, CliTool.ExitStatus expectedStatus) {
         assertThat(status, is(expectedStatus.status()));
     }