Don't dump a stacktrace for invalid patterns when executing elasticsearch-croneval (#49744) (#50578)

Co-authored-by: bellengao <gbl_long@163.com>

docs/reference/commands/croneval.asciidoc

@@ -31,6 +31,10 @@ This command is provided in the `$ES_HOME/bin` directory.
   The number of future times this expression will be triggered. The default
   value is `10`.
 
+`-d, --detail`::
+  Shows detail for invalid cron expression. It will print the stacktrace if the
+  expression is not valid.
+
 `-h, --help`::
   Returns all of the command parameters.
 

x-pack/plugin/watcher/src/main/java/org/elasticsearch/xpack/watcher/trigger/schedule/tool/CronEvalTool.java

@@ -37,13 +37,16 @@ public class CronEvalTool extends LoggingAwareCommand {
 
     private final OptionSpec<Integer> countOption;
     private final OptionSpec<String> arguments;
+    private final OptionSpec<Void> detailOption;
 
     CronEvalTool() {
         super("Validates and evaluates a cron expression");
-        this.countOption = parser.acceptsAll(Arrays.asList("c", "count"),
+        this.countOption = parser.acceptsAll(Arrays.asList("c", "count"), "The number of future times this expression will be triggered")
-            "The number of future times this expression will be triggered")
+            .withRequiredArg()
-            .withRequiredArg().ofType(Integer.class).defaultsTo(10);
+            .ofType(Integer.class)
+            .defaultsTo(10);
         this.arguments = parser.nonOptions("expression");
+        this.detailOption = parser.acceptsAll(Arrays.asList("d", "detail"), "Show detail for invalid cron expression");
 
         parser.accepts("E", "Unused. Only for compatibility with other CLI tools.").withRequiredArg();
     }
@@ -55,10 +58,12 @@ public class CronEvalTool extends LoggingAwareCommand {
         if (args.size() != 1) {
             throw new UserException(ExitCodes.USAGE, "expecting a single argument that is the cron expression to evaluate");
         }
-        execute(terminal, args.get(0), count);
+        boolean printDetail = options.has(detailOption);
+        execute(terminal, args.get(0), count, printDetail);
     }
 
-    private void execute(Terminal terminal, String expression, int count) throws Exception {
+    private void execute(Terminal terminal, String expression, int count, boolean printDetail) throws Exception {
+        try {
             Cron.validate(expression);
             terminal.println("Valid!");
 
@@ -67,7 +72,9 @@ public class CronEvalTool extends LoggingAwareCommand {
             if (isLocalTimeUTC) {
                 terminal.println("Now is [" + UTC_FORMATTER.format(date) + "] in UTC");
             } else {
-            terminal.println("Now is [" + UTC_FORMATTER.format(date) + "] in UTC, local time is [" + LOCAL_FORMATTER.format(date) + "]");
+                terminal.println(
+                    "Now is [" + UTC_FORMATTER.format(date) + "] in UTC, local time is [" + LOCAL_FORMATTER.format(date) + "]"
+                );
 
             }
             terminal.println("Here are the next " + count + " times this cron expression will trigger:");
@@ -80,11 +87,16 @@ public class CronEvalTool extends LoggingAwareCommand {
                 time = cron.getNextValidTimeAfter(time);
                 if (time < 0) {
                     if (i == 0) {
-                    throw new UserException(ExitCodes.OK, "Could not compute future times since ["
+                        throw new UserException(
-                            + UTC_FORMATTER.format(Instant.ofEpochMilli(prevTime)) + "] " + "(perhaps the cron expression only points to " +
+                            ExitCodes.OK,
-                        "times in the" +
+                            "Could not compute future times since ["
-                        " " +
+                                + UTC_FORMATTER.format(Instant.ofEpochMilli(prevTime))
-                        "past?)");
+                                + "] "
+                                + "(perhaps the cron expression only points to "
+                                + "times in the"
+                                + " "
+                                + "past?)"
+                        );
                     }
                     break;
                 }
@@ -96,5 +108,13 @@ public class CronEvalTool extends LoggingAwareCommand {
                     terminal.println("\t" + LOCAL_FORMATTER.format(Instant.ofEpochMilli(time)));
                 }
             }
+        } catch (Exception e) {
+            if (printDetail) {
+                throw e;
+            } else {
+                throw new UserException(ExitCodes.OK, e.getMessage() + (e.getCause() == null ? "" : ": " + e.getCause().getMessage()));
+            }
+
+        }
     }
 }