class Command(object):
"""Base class for ``Command``
A ``Command`` is interface agnostic, knows how to run itself and knows
about the arguments that it can take (via ``Parameters``).
"""
BriefDescription = "" # 1 sentence description
LongDescription = """""" # longer, more detailed description
CommandIns = ParameterCollection([])
CommandOuts = ParameterCollection([])
def __init__(self, **kwargs):
""" """
self._logger = NullLogger()
def __call__(self, **kwargs):
"""Safely execute a ``Command``"""
self_str = str(self.__class__)
self._logger.info('Starting command: %s' % self_str)
self._validate_kwargs(kwargs)
self._set_defaults(kwargs)
try:
result = self.run(**kwargs)
except Exception, e:
self._logger.fatal('Error executing command: %s' % self_str)
raise e
else:
def __init__(self, **kwargs):
""" """
self._logger = NullLogger()
class Command(object):
"""Base class for ``Command``
A ``Command`` is interface agnostic, knows how to run itself and knows
about the arguments that it can take (via ``Parameters``).
"""
BriefDescription = "" # 1 sentence description
LongDescription = """""" # longer, more detailed description
CommandIns = ParameterCollection([])
CommandOuts = ParameterCollection([])
def __init__(self, **kwargs):
""" """
self._logger = NullLogger()
def __call__(self, **kwargs):
"""Safely execute a ``Command``"""
self_str = str(self.__class__)
self._logger.info('Starting command: %s' % self_str)
self._validate_kwargs(kwargs)
self._set_defaults(kwargs)
try:
result = self.run(**kwargs)
except Exception:
self._logger.fatal('Error executing command: %s' % self_str)
raise
else:
self._logger.info('Completed command: %s' % self_str)
# verify the result type
if not isinstance(result, dict):
self._logger.fatal('Unsupported result return type for command: '
'%s' % self_str)
raise InvalidReturnTypeError("Unsupported result return type. "
"Results must be stored in a "
"dictionary.")
self._validate_result(result)
return result
def _validate_kwargs(self, kwargs):
"""Validate input kwargs prior to executing a ``Command``
This method can be overridden by subclasses. The baseclass defines only
a basic validation.
"""
self_str = str(self.__class__)
# check required parameters
for p in self.CommandIns.values():
if p.Required and p.Name not in kwargs:
err_msg = 'Missing required CommandIn %s in %s' % (p.Name,
self_str)
self._logger.fatal(err_msg)
raise MissingParameterError(err_msg)
if p.Name in kwargs and p.ValidateValue:
if not p.ValidateValue(kwargs[p.Name]):
err_msg = "CommandIn %s cannot take value %s in %s" % \
(p.Name, kwargs[p.Name], self_str)
self._logger.fatal(err_msg)
raise ValueError(err_msg)
# make sure we only have things we expect
for opt in kwargs:
if opt not in self.CommandIns:
err_msg = 'Unknown CommandIn %s in %s' % (opt, self_str)
self._logger.fatal(err_msg)
raise UnknownParameterError(err_msg)
def _validate_result(self, result):
"""Validate the result from a ``Command.run``"""
self_str = str(self.__class__)
for p in self.CommandOuts.values():
if p.Name not in result:
err_msg = "CommandOut %s not in %s" % (p.Name, self_str)
self._logger.fatal(err_msg)
raise UnknownParameterError(err_msg)
for k in result:
if k not in self.CommandOuts:
err_msg = "Unknown CommandOut %s in %s" % (k, self_str)
self._logger.fatal(err_msg)
raise UnknownParameterError(err_msg)
def _set_defaults(self, kwargs):
"""Set defaults for optional parameters"""
for p in self.CommandIns.values():
if not p.Required and p.Name not in kwargs:
kwargs[p.Name] = p.Default
def run(self, **kwargs):
"""Exexcute a ``Command``
A ``Command`` must accept **kwargs to run, and must return a ``dict``
as a result.
"""
raise NotImplementedError("All subclasses must implement run.")
def __init__(self, **kwargs):
""" """
self._logger = NullLogger()
class Command(object):
"""Base class for ``Command``
A ``Command`` is interface agnostic, knows how to run itself and knows
about the arguments that it can take (via ``Parameters``).
"""
BriefDescription = "" # 1 sentence description
LongDescription = """""" # longer, more detailed description
CommandIns = ParameterCollection([])
CommandOuts = ParameterCollection([])
def __init__(self, **kwargs):
""" """
self._logger = NullLogger()
def __call__(self, **kwargs):
"""Safely execute a ``Command``"""
self_str = str(self.__class__)
self._logger.info('Starting command: %s' % self_str)
self._validate_kwargs(kwargs)
self._set_defaults(kwargs)
try:
result = self.run(**kwargs)
except Exception:
self._logger.fatal('Error executing command: %s' % self_str)
raise
else:
self._logger.info('Completed command: %s' % self_str)
# verify the result type
if not isinstance(result, dict):
self._logger.fatal('Unsupported result return type for command: '
'%s' % self_str)
raise InvalidReturnTypeError("Unsupported result return type. "
"Results must be stored in a "
"dictionary.")
self._validate_result(result)
return result
def _validate_kwargs(self, kwargs):
"""Validate input kwargs prior to executing a ``Command``
This method can be overridden by subclasses. The baseclass defines only
a basic validation.
"""
self_str = str(self.__class__)
# check required parameters
for p in self.CommandIns.values():
if p.Required and p.Name not in kwargs:
err_msg = 'Missing required CommandIn %s in %s' % (p.Name,
self_str)
self._logger.fatal(err_msg)
raise MissingParameterError(err_msg)
if p.Name in kwargs and p.ValidateValue:
if not p.ValidateValue(kwargs[p.Name]):
err_msg = "CommandIn %s cannot take value %s in %s" % \
(p.Name, kwargs[p.Name], self_str)
self._logger.fatal(err_msg)
raise ValueError(err_msg)
# make sure we only have things we expect
for opt in kwargs:
if opt not in self.CommandIns:
err_msg = 'Unknown CommandIn %s in %s' % (opt, self_str)
self._logger.fatal(err_msg)
raise UnknownParameterError(err_msg)
def _validate_result(self, result):
"""Validate the result from a ``Command.run``"""
self_str = str(self.__class__)
for p in self.CommandOuts.values():
if p.Name not in result:
err_msg = "CommandOut %s not in %s" % (p.Name, self_str)
self._logger.fatal(err_msg)
raise UnknownParameterError(err_msg)
for k in result:
if k not in self.CommandOuts:
err_msg = "Unknown CommandOut %s in %s" % (k, self_str)
self._logger.fatal(err_msg)
raise UnknownParameterError(err_msg)
def _set_defaults(self, kwargs):
"""Set defaults for optional parameters"""
for p in self.CommandIns.values():
if not p.Required and p.Name not in kwargs:
kwargs[p.Name] = p.Default
def run(self, **kwargs):
"""Exexcute a ``Command``
A ``Command`` must accept **kwargs to run, and must return a ``dict``
as a result.
"""
raise NotImplementedError("All subclasses must implement run.")
