from builtins import str, bytes
import inspect
from nipype import logging
from nipype.interfaces.base import (traits, DynamicTraitedSpec, Undefined, isdefined,
BaseInterfaceInputSpec)
from nipype.interfaces.io import IOBase, add_traits
from nipype.utils.filemanip import ensure_list
from nipype.utils.functions import getsource, create_function_from_source
iflogger = logging.getLogger('nipype.interface')
class FunctionInputSpec(DynamicTraitedSpec, BaseInterfaceInputSpec):
function_str = traits.Str(mandatory=True, desc='code for function')
[docs]class Function(IOBase):
"""Runs arbitrary function as an interface
Examples
--------
>>> func = 'def func(arg1, arg2=5): return arg1 + arg2'
>>> fi = Function(input_names=['arg1', 'arg2'], output_names=['out'])
>>> fi.inputs.function_str = func
>>> res = fi.run(arg1=1)
>>> res.outputs.out
6
"""
input_spec = FunctionInputSpec
output_spec = DynamicTraitedSpec
[docs] def __init__(self,
input_names=None,
output_names='out',
function=None,
imports=None,
as_module=False,
**inputs):
"""
Parameters
----------
input_names : single str or list or None
names corresponding to function inputs
if ``None``, derive input names from function argument names
output_names : single str or list
names corresponding to function outputs (default: 'out').
if list of length > 1, has to match the number of outputs
function : callable
callable python object. must be able to execute in an
isolated namespace (possibly in concert with the ``imports``
parameter)
imports : list of strings
list of import statements that allow the function to execute
in an otherwise empty namespace
"""
super(Function, self).__init__(**inputs)
if function:
if as_module:
module = inspect.getmodule(function).__name__
full_name = "%s.%s" % (module, function.__name__)
self.inputs.function_str = full_name
elif hasattr(function, '__call__'):
try:
self.inputs.function_str = getsource(function)
except IOError:
raise Exception('Interface Function does not accept '
'function objects defined interactively '
'in a python session')
else:
if input_names is None:
fninfo = function.__code__
elif isinstance(function, (str, bytes)):
self.inputs.function_str = function
if input_names is None:
fninfo = create_function_from_source(function,
imports).__code__
else:
raise Exception('Unknown type of function')
if input_names is None:
input_names = fninfo.co_varnames[:fninfo.co_argcount]
self.as_module = as_module
self.inputs.on_trait_change(self._set_function_string, 'function_str')
self._input_names = ensure_list(input_names)
self._output_names = ensure_list(output_names)
add_traits(self.inputs, [name for name in self._input_names])
self.imports = imports
self._out = {}
for name in self._output_names:
self._out[name] = None
def _set_function_string(self, obj, name, old, new):
if name == 'function_str':
if self.as_module:
module = inspect.getmodule(new).__name__
full_name = "%s.%s" % (module, new.__name__)
self.inputs.function_str = full_name
elif hasattr(new, '__call__'):
function_source = getsource(new)
fninfo = new.__code__
elif isinstance(new, (str, bytes)):
function_source = new
fninfo = create_function_from_source(new,
self.imports).__code__
self.inputs.trait_set(
trait_change_notify=False, **{
'%s' % name: function_source
})
# Update input traits
input_names = fninfo.co_varnames[:fninfo.co_argcount]
new_names = set(input_names) - set(self._input_names)
add_traits(self.inputs, list(new_names))
self._input_names.extend(new_names)
def _add_output_traits(self, base):
undefined_traits = {}
for key in self._output_names:
base.add_trait(key, traits.Any)
undefined_traits[key] = Undefined
base.trait_set(trait_change_notify=False, **undefined_traits)
return base
def _run_interface(self, runtime):
# Create function handle
if self.as_module:
import importlib
pieces = self.inputs.function_str.split('.')
module = '.'.join(pieces[:-1])
function = pieces[-1]
try:
function_handle = getattr(importlib.import_module(module), function)
except ImportError:
raise RuntimeError('Could not import module: %s' % self.inputs.function_str)
else:
function_handle = create_function_from_source(self.inputs.function_str,
self.imports)
# Get function args
args = {}
for name in self._input_names:
value = getattr(self.inputs, name)
if isdefined(value):
args[name] = value
out = function_handle(**args)
if len(self._output_names) == 1:
self._out[self._output_names[0]] = out
else:
if isinstance(out, tuple) and \
(len(out) != len(self._output_names)):
raise RuntimeError('Mismatch in number of expected outputs')
else:
for idx, name in enumerate(self._output_names):
self._out[name] = out[idx]
return runtime
def _list_outputs(self):
outputs = self._outputs().get()
for key in self._output_names:
outputs[key] = self._out[key]
return outputs
