Rosendale YAML Output Handler Plugin

The YAML Output Plugin provides similar functionality to the builtin ‘–json’ output_handler, but outputs yaml. The following features are included:

* --yaml option causes output to be rendered strictly as yaml

The yaml plugin is Open Source and distributed under The MIT License. Please see the LICENSE file included with The Rosendale Project.

Installation

Stable versions of the rosendale.yaml plugin are available via PyPi and can be installed by easy_install, pip, or similar:

$ easy_install rosendale.yaml

You will want to add ‘rosendale.yaml’ to your applications ‘setup.py’ under the section ‘install_requires’.

Configuration

The yaml_output plugin can be enabled in any application built on Cement, however due to its tight integration with Cement internals it can not be loaded dynamically. It MUST be included during your applications root bootstrap process by adding the following to <youapp>/bootstrap/root.py:

from rosendale.bootstrap import yaml_output

This plugin does not honor any other config settings and does not require a plugin config file.

Usage Within Your Application

To demonstrate usage we have created a fresh ‘helloworld’ application via the paster cement-app helper. We’ve then enabled the rosendale yaml plugin by adding a permanent import to helloworld/bootstrap/root.py as listed above. We now have:

$ helloworld --help
Usage:   helloworld <COMMAND> [ARGS] --(OPTIONS)

Commands:
    get-started, cmd1

Help?  try '[COMMAND]-help' OR '[NAMESPACE] --help'

Options:
    --version          show program's version number and exit
    -h, --help         show this help message and exit
    -R, --root-option  Example root option
    --json             render output as json (CLI-API)
    --debug            toggle debug output
    --quiet            disable console logging
    --yaml             render output as yaml

You can see the additional option ‘–yaml’.

Rendering Command Output as YAML

The ‘–yaml’ flag simply overrides your applications ‘output_handler_override’ config option on execution. Therefore, all commands function normally but the output is rendered as YAML. The following is the example command we are going to run:

class RootController(CementController):
    @expose('helloworld.templates.root.cmd1')
    def cmd1(self):
        foo = 'In helloworld.controllers.root.cmd1()'
        if self.cli_opts.enable_yaml:
            print 'The --yaml option was passed'

        items = ['one', 'two', 'three']
        return dict(foo=foo, items=items)

And this is the output:

$ helloworld cmd1

In helloworld.controllers.root.cmd1()

    * one
    * two
    * three


$ helloworld cmd1 --yaml
foo: In helloworld.controllers.root.cmd1()
items: [one, two, three]
stderr: ''
stdout: 'The --yaml option was passed

Note that, just as the ‘–json’ option, all STDOUT output is captured and passed via YAML as well. Meaning, the output from the command is pure YAML and not corrupted by spurious output.