lago.plugins package

exception lago.plugins.NoSuchPluginError

Bases: lago.plugins.PluginError

lago.plugins.PLUGIN_ENTRY_POINTS = {'vm': 'lago.plugins.vm', 'vm-service': 'lago.plugins.vm_service', 'vm-provider': 'lago.plugins.vm_provider', 'cli': 'lago.plugins.cli', 'out': 'lago.plugins.output'}

Map of plugin type string -> setuptools entry point

class lago.plugins.Plugin

Bases: object

Base class for all the plugins

exception lago.plugins.PluginError

Bases: exceptions.Exception

lago.plugins.load_plugins(namespace, instantiate=True)

Loads all the plugins for the given namespace

Parameters:

• namespace (str) – Namespace string, as in the setuptools entry_points
• instantiate (bool) – If true, will instantiate the plugins too

Returns:

Returns the list of loaded plugins

Return type:

dict of str, object

Submodules

lago.plugins.cli module

About CLIPlugins

A CLIPlugin is a subcommand of the lagocli command, it’s ment to group actions together in a logical sense, for example grouping all the actions done to templates.

To create a new subcommand for testenvcli you just have to subclass the CLIPlugin abstract class and declare it in the setuptools as an entry_point, see this module’s setup.py/setup.cfg for an example:

class NoopCLIplugin(CLIPlugin):
    init_args = {
        'help': 'dummy help string',
    }

    def populate_parser(self, parser):
        parser.addArgument('--dummy-flag', action='store_true')

    def do_run(self, args):
        if args.dummy_flag:
            print "Dummy flag passed to noop subcommand!"
        else:
            print "Dummy flag not passed to noop subcommand!"

You can also use decorators instead, an equivalent is:

@cli_plugin_add_argument('--dummy-flag', action='store_true')
@cli_plugin(help='dummy help string')
def my_fancy_plugin_func(dummy_flag, **kwargs):
    if dummy_flag:
        print "Dummy flag passed to noop subcommand!"
    else:
        print "Dummy flag not passed to noop subcommand!"

Or:

@cli_plugin_add_argument('--dummy-flag', action='store_true')
def my_fancy_plugin_func(dummy_flag, **kwargs):
    "dummy help string"
    if dummy_flag:
        print "Dummy flag passed to noop subcommand!"
    else:
        print "Dummy flag not passed to noop subcommand!"

Then you will need to add an entry_points section in your setup.py like:

setup(
    ...
    entry_points={
        'lago.plugins.cli': [
            'noop=noop_module:my_fancy_plugin_func',
        ],
    }
    ...
)

Or in your setup.cfg like:

[entry_points]
lago.plugins.cli =
    noop=noop_module:my_fancy_plugin_func

Any of those will add a new subcommand to the lagocli command that can be run as:

$ lagocli noop
Dummy flag not passed to noop subcommand!

TODO: Allow per-plugin namespacing to get rid of the **kwargs parameter

class lago.plugins.cli.CLIPlugin

Bases: lago.plugins.Plugin

_abc_cache = <_weakrefset.WeakSet object>

_abc_negative_cache = <_weakrefset.WeakSet object>

_abc_negative_cache_version = 33

_abc_registry = <_weakrefset.WeakSet object>

do_run(args)

Execute any actions given the arguments

Parameters:args (Namespace) – with the arguments Returns:None

init_args

Dictionary with the argument to initialize the cli parser (for example, the help argument)

populate_parser(parser)

Add any required arguments to the parser

Parameters:parser (ArgumentParser) – parser to add the arguments to Returns:None

class lago.plugins.cli.CLIPluginFuncWrapper(do_run=None, init_args=None)

Bases: lago.plugins.cli.CLIPlugin

Special class to handle decorated cli plugins, take into account that the decorated functions have some limitations on what arguments can they define actually, if you need something complicated, used the abstract class CLIPlugin instead.

Keep in mind that right now the decorated function must use **kwargs as param, as it will be passed all the members of the parser, not just whatever it defined

__call__(*args, **kwargs)

Keep the original function interface, so it can be used elsewhere

_abc_cache = <_weakrefset.WeakSet object>

_abc_negative_cache = <_weakrefset.WeakSet object>

_abc_negative_cache_version = 33

_abc_registry = <_weakrefset.WeakSet object>

add_argument(*argument_args, **argument_kwargs)

do_run(args)

init_args

populate_parser(parser)

set_help(help=None)

set_init_args(init_args)

lago.plugins.cli.cli_plugin(func=None, **kwargs)

Decorator that wraps the given function in a CLIPlugin

Parameters:

• func (callable) – function/class to decorate
• **kwargs – Any other arg to use when initializing the parser (like help, or prefix_chars)

Returns:

cli plugin that handles that method

Return type:

CLIPlugin

Notes

It can be used as a decorator or as a decorator generator, if used as a decorator generator don’t pass any parameters

Examples

>>> @cli_plugin
... def test(**kwargs):
...     print 'test'
...
>>> print test.__class__
<class 'cli.CLIPluginFuncWrapper'>

>>> @cli_plugin()
... def test(**kwargs):
...     print 'test'
>>> print test.__class__
<class 'cli.CLIPluginFuncWrapper'>

>>> @cli_plugin(help='dummy help')
... def test(**kwargs):
...     print 'test'
>>> print test.__class__
<class 'cli.CLIPluginFuncWrapper'>
>>> print test.init_args['help']
'dummy help'

lago.plugins.cli.cli_plugin_add_argument(*args, **kwargs)

Decorator generator that adds an argument to the cli plugin based on the decorated function

Parameters:

• *args – Any args to be passed to argparse.ArgumentParser.add_argument()
• *kwargs – Any keyword args to be passed to argparse.ArgumentParser.add_argument()

Returns:

Decorator that builds or extends the cliplugin for the

decorated function, adding the given argument definition

Return type:

function

Examples

>>> @cli_plugin_add_argument('-m', '--mogambo', action='store_true')
... def test(**kwargs):
...     print 'test'
...
>>> print test.__class__
<class 'cli.CLIPluginFuncWrapper'>
>>> print test._parser_args
[(('-m', '--mogambo'), {'action': 'store_true'})]

>>> @cli_plugin_add_argument('-m', '--mogambo', action='store_true')
... @cli_plugin_add_argument('-b', '--bogabmo', action='store_false')
... @cli_plugin
... def test(**kwargs):
...     print 'test'
...
>>> print test.__class__
<class 'cli.CLIPluginFuncWrapper'>
>>> print test._parser_args 
[(('-b', '--bogabmo'), {'action': 'store_false'}),
 (('-m', '--mogambo'), {'action': 'store_true'})]

lago.plugins.cli.cli_plugin_add_help(help)

Decorator generator that adds the cli help to the cli plugin based on the decorated function

Parameters:help (str) – help string for the cli plugin Returns:

Decorator that builds or extends the cliplugin for the

decorated function, setting the given help

Return type:function

Examples

>>> @cli_plugin_add_help('my help string')
... def test(**kwargs):
...     print 'test'
...
>>> print test.__class__
<class 'cli.CLIPluginFuncWrapper'>
>>> print test.help
my help string

>>> @cli_plugin_add_help('my help string')
... @cli_plugin()
... def test(**kwargs):
...     print 'test'
>>> print test.__class__
<class 'cli.CLIPluginFuncWrapper'>
>>> print test.help
my help string

lago.plugins.output module

About OutFormatPlugins

An OutFormatPlugin is used to format the output of the commands that extract information from the perfixes, like status.

class lago.plugins.output.DefaultOutFormatPlugin

Bases: lago.plugins.output.OutFormatPlugin

_abc_cache = <_weakrefset.WeakSet object>

_abc_negative_cache = <_weakrefset.WeakSet object>

_abc_negative_cache_version = 33

_abc_registry = <_weakrefset.WeakSet object>

format(info_obj, indent='')

indent_unit = ' '

class lago.plugins.output.FlatOutFormatPlugin

Bases: lago.plugins.output.OutFormatPlugin

_abc_cache = <_weakrefset.WeakSet object>

_abc_negative_cache = <_weakrefset.WeakSet object>

_abc_negative_cache_version = 33

_abc_registry = <_weakrefset.WeakSet object>

format(info_dict, delimiter='/')

This formatter will take a data structure that represent a tree and will print all the paths from the root to the leaves

in our case it will print each value and the keys that needed to get to it, for example:

vm0:

net: lago memory: 1024

will be output as:

vm0/net/lago vm0/memory/1024

Args:

info_dict (dict): information to reformat delimiter (str): a delimiter for the path components

Returns:

str: String representing the formatted info

class lago.plugins.output.JSONOutFormatPlugin

Bases: lago.plugins.output.OutFormatPlugin

_abc_cache = <_weakrefset.WeakSet object>

_abc_negative_cache = <_weakrefset.WeakSet object>

_abc_negative_cache_version = 33

_abc_registry = <_weakrefset.WeakSet object>

format(info_dict)

class lago.plugins.output.OutFormatPlugin

Bases: lago.plugins.Plugin

_abc_cache = <_weakrefset.WeakSet object>

_abc_negative_cache = <_weakrefset.WeakSet object>

_abc_negative_cache_version = 33

_abc_registry = <_weakrefset.WeakSet object>

format(info_dict)

Execute any actions given the arguments

Parameters:info_dict (dict) – information to reformat Returns:String representing the formatted info Return type:str

class lago.plugins.output.YAMLOutFormatPlugin

Bases: lago.plugins.output.OutFormatPlugin

_abc_cache = <_weakrefset.WeakSet object>

_abc_negative_cache = <_weakrefset.WeakSet object>

_abc_negative_cache_version = 33

_abc_registry = <_weakrefset.WeakSet object>

format(info_dict)

lago.plugins.service module

Service Plugin

This plugins are used in order to manage services in the vms

class lago.plugins.service.ServicePlugin(vm, name)

Bases: lago.plugins.Plugin

BIN_PATH

Path to the binary used to manage services in the vm, will be checked for existence when trying to decide if the serviece is supported on the VM (see func:is_supported).

Returns:Full path to the binary insithe the domain Return type:str

_abc_cache = <_weakrefset.WeakSet object>

_abc_negative_cache = <_weakrefset.WeakSet object>

_abc_negative_cache_version = 33

_abc_registry = <_weakrefset.WeakSet object>

_request_start()

Low level implementation of the service start request, used by the func:start method

Returns:True if the service succeeded to start, False otherwise Return type:bool

_request_stop()

Low level implementation of the service stop request, used by the func:stop method

Returns:True if the service succeeded to stop, False otherwise Return type:bool

alive()

exists()

classmethod is_supported(vm)

start()

state()

Check the current status of the service

Returns:Which state the service is at right now Return type:ServiceState

stop()

class lago.plugins.service.ServiceState

Bases: enum.Enum

ACTIVE = 2

INACTIVE = 1

MISSING = 0

This state corresponds to a service that is not available in the domain

_member_map_ = OrderedDict([('MISSING', <ServiceState.MISSING: 0>), ('INACTIVE', <ServiceState.INACTIVE: 1>), ('ACTIVE', <ServiceState.ACTIVE: 2>)])

_member_names_ = ['MISSING', 'INACTIVE', 'ACTIVE']

_member_type_

alias of object

_value2member_map_ = {0: <ServiceState.MISSING: 0>, 1: <ServiceState.INACTIVE: 1>, 2: <ServiceState.ACTIVE: 2>}

lago.plugins.vm module