How to trigger system exit with a given return code and Feature request

Dear,

Firstly, thanks for your awesome library.

I would like to follow as much as possible standard return type on *NIX . Thus I defined some constants (see below ) and use picocli through a Runnable class .

In order to capture exception throw by picocli I invoke CommandLine.populateCommand method followed by App.run . And inside the run method I can do some checks on both options and parameters and return an error code if it is needed.

But I fail to catch MissingParameterException and seem to be consumed by CommandLine::handleParseException and CommandLine::internalHandleParseException

So what is the recommended way to capture all errors events in order to exit with the proper system exit code ?

Any improvement of the current library in order to ease custom/standard status code usage is welcome.

@CommandLine.Command(name = "Foo")
public final class App implements Runnable {

    @CommandLine.Option(names = {"-v", "--verbose"}, description = "Turn-on informative messages. " +
                                                                   "Multiple -v options increase the verbosity.")
    private boolean[] verbose = new boolean[0];

    @CommandLine.Parameters(index = "0", paramLabel = "Input", description = "Input to load.")
    private File input;

    @CommandLine.Parameters(index = "1", paramLabel = "LOG DIR", description = "Directory to store log files.")
    private File logDir;

    public static void exit(final int status) {
        new Thread("App-exit") {
            @Override
            public void run() {
                System.exit(status);
            }
        }.start();
    }
    public static void main(final String[] args) {
        // Configure the number of columns used for the help message
        int width = Integer.parseInt(System.getProperty("picocli.usage.width", String.valueOf(DEFAULT_USAGE_WIDTH)));
        System.setProperty("picocli.usage.width", String.valueOf(width));

        try {
            final App app = CommandLine.populateCommand(new App(), args);
            app.run();
        }
        catch (CommandLine.MissingParameterException e){
            System.err.printf("Error missing parameter: %s%n%n", e.getMessage());
            CommandLine.usage(new App(), System.err);
            exit(SysExit.USAGE);
        }
        catch (CommandLine.ParameterException e){
            System.err.printf("Error: %s%n%n", e.getMessage());
            CommandLine.usage(new App(), System.err);
            exit(SysExit.USAGE);
        }
        catch (Exception e){
            System.err.printf("Unknown Error: %s%n%n", e.getMessage());
            CommandLine.usage(new App(), System.err);
            exit(SysExit.USAGE);
        }

    }


    @Override
    public void run() {

        if (!model.exists()) {
            System.err.printf("The file " + input+ " do not exists!%n%n");
            new CommandLine(this).usage(System.err);
            exit(SysExit.IO_ERROR);
        } else if (!model.isFile()) {
            System.err.printf("The item " + input+ " is not a file!%n%n");
            new CommandLine(this).usage(System.err);
            exit(SysExit.USAGE);
        }
        else if( model == null ) {
            System.err.printf("Missing required parameter: INPUT%n%n");
            new CommandLine(this).usage(System.err);
            exit(SysExit.USAGE);
        }

        if (!logDir.exists()) {
            System.err.printf("The directory " + logDir + " do not exists!%n%n");
            new CommandLine(this).usage(System.err);
            exit(SysExit.IO_ERROR);
        } else if (!logDir.isDirectory()) {
            System.err.printf("The item " + logDir + " is not a directory!%n%n");
            new CommandLine(this).usage(System.err);
            exit(SysExit.USAGE);
        }
        else if( logDir == null ) {
            System.err.printf("Missing required parameter: LOG DIR!%n%n");
            new CommandLine(this).usage(System.err);
            exit(SysExit.USAGE);
        }

        final Logger root = (Logger) LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME);
        switch (verbose.length) {
            case 0:
                root.setLevel(Level.OFF);
            case 1:
                root.setLevel(Level.INFO);
            case 2:
                root.setLevel(Level.WARN);
            case 3:
                root.setLevel(Level.DEBUG);
            default:
                root.setLevel(Level.DEBUG);
        }
    }
}

// FROM /usr/include/sysexits.h
public final class SysExit {
    public static final int OK = 0;
    public static final int GENERIC_ERROR = 1;
    public static final int BASE = 64;
    public static final int USAGE = 64;
    public static final int NO_DATA = 65;
    public static final int NO_INPUT = 66;
    public static final int NO_USER = 67;
    public static final int NO_HOST = 68;
    public static final int UNAVAILLABLE = 69;
    public static final int SOFTWARE = 70;
    public static final int OS_ERROR = 71;
    public static final int OS_FILE = 72;
    public static final int CAN_NOT_CREATE = 73;
    public static final int IO_ERROR = 74;
    public static final int TEMP_FAIL = 75;
    public static final int PROTOCOL = 76;
    public static final int NO_PERM = 77;
    public static final int CONFIG = 78;
}

Thanks for your insight

[remkop]

@gerardbosch Would you mind creating a new ticket?

[remkop]

Yes I’m also not 100% happy about exit code handling as it stands. I don’t have a good answer on how to fix it yet, need to think about this more.