girder · kotfic · Sep 6, 2018 · Sep 10, 2018 · Oct 10, 2018 · Oct 10, 2018
diff --git a/girder_worker_utils/decorators.py b/girder_worker_utils/decorators.py
@@ -1,8 +1,14 @@
 from inspect import getdoc
+
+import deprecation
+
+from girder_worker_utils import __version__
+
 try:
-    from inspect import signature
+    from inspect import signature, Parameter
 except ImportError:  # pragma: nocover
-    from funcsigs import signature
+    from funcsigs import signature, Parameter
+
 import six
 
 
@@ -16,13 +22,210 @@ class MissingInputException(Exception):
 
 def get_description_attribute(func):
     """Get the private description attribute from a function."""
-    func = getattr(func, 'run', func)
-    description = getattr(func, '_girder_description', None)
+    # func = getattr(func, 'run', func)
+    description = getattr(func, GWFuncDesc._func_desc_attr, None)
     if description is None:
         raise MissingDescriptionException('Function is missing description decorators')
     return description
 
 
+class Argument(object):
+    def __init__(self, name, **kwargs):
+        self.name = name
+        for k, v in six.iteritems(kwargs):
+            setattr(self, k, v)
+
+
+# No default value for this argument
+class PositionalArg(Argument):
+    pass
+
+
+# Has a default argument for the value
+class KeywordArg(Argument):
+    pass
+
+
+class VarsArg(Argument):
+    pass
+
+
+class KwargsArg(Argument):
+    pass
+
+# TODO: is there anything we want to try and do with the functions
+# annotated return value?
+# class Return(Argument): pass
+
+
+def _clean_function_doc(f):
+    doc = getdoc(f) or ''
+    if isinstance(doc, bytes):
+        doc = doc.decode('utf-8')
+    return doc
+
+
+class GWFuncDesc(object):
+    _func_desc_attr = "_gw_function_description"
+    _parameter_repr = ['POSITIONAL_ONLY',
+                       'POSITIONAL_OR_KEYWORD',
+                       'VAR_POSITIONAL',
+                       'KEYWORD_ONLY',
+                       'VAR_KEYWORD']
+
+    VarsArgCls = VarsArg
+    KwargsArgCls = KwargsArg
+    PositionalArgCls = PositionalArg
+    KeywordArgCls = KeywordArg
+
+    @classmethod
+    def get_description(cls, func):
+        if cls.has_description(func) and \
+           isinstance(getattr(func, cls._func_desc_attr), cls):
+            return getattr(func, cls._func_desc_attr)
+        return None
+
+    @classmethod
+    def has_description(cls, func):
+        return hasattr(func, cls._func_desc_attr)
+
+    @classmethod
+    def set_description(cls, func):
+        setattr(func, GWFuncDesc._func_desc_attr, cls(func))
+        return None
+
+    def __init__(self, func):
+        self.func_name = func.__name__
+        self.func_help = _clean_function_doc(func)
+        self._metadata = {}
+        self._signature = signature(func)
+
+    def __repr__(self):
+        parameters = []
+        for name in self._signature.parameters:
+            kind = self._signature.parameters[name].kind
+            parameters.append("{}:{}".format(name, self._parameter_repr[kind]))
+
+        return "<{}(".format(self.__class__.__name__) + ", ".join(parameters) + ")>"
+
+    def __getitem__(self, key):
+        return self._construct_argument(
+            self._get_class(self._signature.parameters[key]), key)
+
+    def _construct_argument(self, parameter_cls, name):
+        p = self._signature.parameters[name]
+        metadata = {}
+
+        if p.default != p.empty:
+            metadata['default'] = p.default
+        if p.annotation != p.empty:
+            # TODO: make sure annotation is a type and not just garbage
+            metadata['data_type'] = p.annotation
+
+        metadata.update(self._metadata.get(name, {}))
+
+        return parameter_cls(name, **metadata)
+
+    def _is_varargs(self, p):
+        return p.kind == Parameter.VAR_POSITIONAL
+
+    def _is_kwargs(self, p):
+        return p.kind == Parameter.VAR_KEYWORD
+
+    def _is_kwarg(self, p):
+        return p.kind == Parameter.KEYWORD_ONLY or (
+            p.kind == Parameter.POSITIONAL_OR_KEYWORD and p.default != p.empty)
+
+    def _is_posarg(self, p):
+        return p.kind == Parameter.POSITIONAL_ONLY or (
+            p.kind == Parameter.POSITIONAL_OR_KEYWORD and p.default == p.empty)
+
+    def _get_class(self, p):
+        if self._is_varargs(p):
+            return self.VarsArgCls
+        elif self._is_kwargs(p):
+            return self.KwargsArgCls
+        elif self._is_posarg(p):
+            return self.PositionalArgCls
+        elif self._is_kwarg(p):
+            return self.KeywordArgCls
+        else:
+            raise RuntimeError("Could not determine parameter type!")
+
+    def init_metadata(self, name):
+        if name not in self._metadata:
+            self._metadata[name] = {}
+
+    def set_metadata(self, name, key, value):
+        if name not in self._signature.parameters:
+            raise RuntimeError("{} is not a valid argument to this function!".format(name))
+
+        self.init_metadata(name)
+
+        self._metadata[name][key] = value
+
+    @property
+    def arguments(self):
+        return [
+            self._construct_argument(
+                self._get_class(self._signature.parameters[name]), name)
+            for name in self._signature.parameters]
+
+    @property
+    def varargs(self):
+        for name in self._signature.parameters:
+            if self._is_varargs(self._signature.parameters[name]):
+                return self._construct_argument(VarsArg, name)
+        return None
+
+    @property
+    def kwargs(self):
+        for name in self._signature.parameters:
+            if self._is_kwargs(self._signature.parameters[name]):
+                return self._construct_argument(KeywordArg, name)
+        return None
+
+    @property
+    def positional_args(self):
+        return [arg for arg in self.arguments if isinstance(arg, PositionalArg)]
+
+    @property
+    def keyword_args(self):
+        return [arg for arg in self.arguments if isinstance(arg, KeywordArg)]
+
+
+def parameter(name, **kwargs):
+    if not isinstance(name, six.string_types):
+        raise TypeError('Expected argument name to be a string')
+
+    data_type = kwargs.get("data_type", None)
+    if callable(data_type):
+        kwargs['data_type'] = data_type(name, **kwargs)
+
+    def argument_wrapper(func):
+        if not GWFuncDesc.has_description(func):
+            GWFuncDesc.set_description(func)
+
+        desc = GWFuncDesc.get_description(func)
+
+        # Make sure the metadata key exists even if we don't set any
+        # values on it.  This ensures that metadata's keys represent
+        # the full list of parameters that have been identified by the
+        # user (even if there is no actual metadata associated with
+        # the argument).
+        desc.init_metadata(name)
+
+        for key, value in six.iteritems(kwargs):
+            desc.set_metadata(name, key, value)
+
+        return func
+
+    return argument_wrapper
+
+
+@deprecation.deprecated(deprecated_in="0.8.5", removed_in="0.9.0",
+                        current_version=__version__,
+                        details="Use 'parameter' decorator instead")
 def argument(name, data_type, *args, **kwargs):
     """Describe an argument to a function as a function decorator.
 
@@ -38,8 +241,10 @@ def argument(name, data_type, *args, **kwargs):
         data_type = data_type(name, *args, **kwargs)
 
     def argument_wrapper(func):
-        func._girder_description = getattr(func, '_girder_description', {})
-        args = func._girder_description.setdefault('arguments', [])
+        setattr(func, GWFuncDesc._func_desc_attr,
+                getattr(func, GWFuncDesc._func_desc_attr, {}))
+
+        args = getattr(func, GWFuncDesc._func_desc_attr).setdefault('arguments', [])
         sig = signature(func)
 
         if name not in sig.parameters:

diff --git a/girder_worker_utils/tests/conftest.py b/girder_worker_utils/tests/conftest.py
@@ -0,0 +1,5 @@
+import six
+
+collect_ignore = []
+if six.PY2:
+    collect_ignore.append("py3_decorators_test.py")