Jython CLI Library

The JyCLI (Jython CLI) package has been developed to make it easier to create script to create CLI applications using Jython.

application.Application

The application.Application class allows creating CLI applications in a standardized way.

Features

• Automatic exit status: 1 if the return status is a falsy boolean (both bool or just a falsy int), 0 otherwise (None is considered as success);
• Automatic divider to separate the actual script execution from all the previous boilerplate (by default a full-width line consisting of - characters with the application name at the center); can be customized.
• Use hooks to customize the behavior of the application before it closes: on_success (when it ends without errors), on_failure (when it fails because of an exception or falsy return code) and on_finish (always executed at the end before closing the application).
• Define a custom has_failed method if you want to customize when a specific return code should make the application fail (for example, you may want to restrict only to numeric return values).
• Automatically disables colors when it detects the NO_COLOR variable or if the console is not interactive.

Example

Take the following simple application. If you execute this code you'll note that the return code of is set to 0 (which means success in Bash); if you change the return statement in the MyApplication.main() method to return 1==0 (basically False) the RC of the application will be 1 (which means that an error occurred in Bash).

Another thing to take note is that hooks can access local variables defined in the MyApplication.main() using the context.locals dictionary.

from jycli.application import Application, ApplicationContext

class MyApplication(Application):
    """ This is a simple example of a CLI application. """
    title = "My Application"

    divider = "------------------- %(title)s -------------------"

    def main(self):
        text = "Hello World!"
        print(text)
        
        _time.sleep(2)
        return 1==1
    
    def on_success(self, context):
        # type: (ApplicationContext) -> None
        print("Success! Text printed: %s" % context.locals.get("text", None))

    def on_failure(self, context):
        # type: (ApplicationContext) -> None
        print("Failure!")
    
    def on_finish(self, context):
        # type: (ApplicationContext) -> None
        print("\nFinish!")
        print("Context: %s" % context)

        print("\n---> Total execution time: %s seconds (%sh:%sm:%ss)" % (
            context.duration,
            int(context.duration / 3600),
            int(context.duration / 60 % 60),
            int(context.duration % 60)
        ))


app = MyApplication()
app.run()

This code will produce the following output:

------------------- My Application -------------------
Hello World!
------------------- My Application -------------------
Success! Text printed: Hello World!

Finish!
Context: ApplicationContext(duration=2.0, locals={'self': <__main__.MyApplication instance at 1094034428>, 'text': 'Hello World!'}, start_time=1.702979951763E9, return_value=True, end_time=1.702979953763E9, application=<__main__.MyApplication instance at 1094034428>)

---> Total execution time: 2.0 seconds (0h:0m:2s)

table module

The table module exposes the Table class that comes in handy when creating tables that should render nicely (and responsively) in the terminal. It also provides methods for exporting the table data in CSV (.to_csv()) and HTML (.to_html()) format.

Features

• Support for multiple render targets: to terminal (.render()), to CSV (.to_csv()) and to HTML (.to_html());
• Customize the table width when rendering to the terminal (default is full terminal width);
• Wrap lines if they are too long to render on a single line or if they contains a new line (\n).

Example

from jycli.components.table import Table

table = Table("My beautiful table", ["Column1", "Column2"])
table.add_row("Value1", "Value2")
table.add_row("Value3", "Value4")

print(table.render())
# Output:
#   ***********************************************************
#                        My beautiful table
#   ***********************************************************
#   Column1                     | Column2
#   --------------------------- | --------------------------
#   Value1                      | Value2
#   Value3                      | Value4


print(table.to_csv())
# Output:
#   Column1,Column2
#   Value1,Value2
#   Value3,Value4

print(table.to_html())
# Output:
#   <table>
#   <caption>My beautiful table</caption>
#   <thead>
#   <tr>
#   <th>Column1</th>
#   <th>Column2</th>
#   </tr>
#   </thead>
#   <tbody>
#   <tr>
#   <td>Value1</td>
#   <td>Value2</td>
#   </tr>
#   <tr>
#   <td>Value3</td>
#   <td>Value4</td>
#   </tr>
#   </tbody>

console module

The console module as the name suggests allows interacting with the console terminal.

For example, you can get the terminal width and height:

from jycli.console import Console

console = Console()
print("%dh x %dw" % (console.width, console.height))