tosca-parser/toscaparser/functions.py
versus_vv 5860c6f0b0 Update validation of function get_operation_output
Function `get_operation_output` takes Node or Relationship Template
as first argument.

Change-Id: Ifb9ddf2c021408bdc9f2da18a8c7f3958056709e
Closes-Bug: #1901051
2021-01-26 15:35:43 +03:00

899 lines
37 KiB
Python

#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import abc
from toscaparser.common.exception import ExceptionCollector
from toscaparser.common.exception import UnknownInputError
from toscaparser.dataentity import DataEntity
from toscaparser.elements.constraints import Schema
from toscaparser.elements.datatype import DataType
from toscaparser.elements.entity_type import EntityType
from toscaparser.elements.relationshiptype import RelationshipType
from toscaparser.elements.statefulentitytype import StatefulEntityType
from toscaparser.utils.gettextutils import _
GET_PROPERTY = 'get_property'
GET_ATTRIBUTE = 'get_attribute'
GET_INPUT = 'get_input'
GET_OPERATION_OUTPUT = 'get_operation_output'
CONCAT = 'concat'
TOKEN = 'token'
SELF = 'SELF'
HOST = 'HOST'
TARGET = 'TARGET'
SOURCE = 'SOURCE'
HOSTED_ON = 'tosca.relationships.HostedOn'
class Function(object, metaclass=abc.ABCMeta):
"""An abstract type for representing a Tosca template function."""
def __init__(self, tosca_tpl, context, name, args):
self.tosca_tpl = tosca_tpl
self.context = context
self.name = name
self.args = args
self.validate()
@abc.abstractmethod
def result(self):
"""Invokes the function and returns its result
Some methods invocation may only be relevant on runtime (for example,
getting runtime properties) and therefore its the responsibility of
the orchestrator/translator to take care of such functions invocation.
:return: Function invocation result.
"""
return {self.name: self.args}
@abc.abstractmethod
def validate(self):
"""Validates function arguments."""
pass
class GetInput(Function):
"""Get a property value declared within the input of the service template.
Arguments:
* Input name.
Example:
* get_input: port
"""
def validate(self):
if len(self.args) != 1:
ExceptionCollector.appendException(
ValueError(_(
'Expected one argument for function "get_input" but '
'received "%s".') % self.args))
inputs = [input.name for input in self.tosca_tpl.inputs]
if self.args[0] not in inputs:
ExceptionCollector.appendException(
UnknownInputError(input_name=self.args[0]))
def result(self):
if self.tosca_tpl.parsed_params and \
self.input_name in self.tosca_tpl.parsed_params:
return DataEntity.validate_datatype(
self.tosca_tpl.tpl['inputs'][self.input_name]['type'],
self.tosca_tpl.parsed_params[self.input_name])
input = [input_def for input_def in self.tosca_tpl.inputs
if self.input_name == input_def.name][0]
return input.default
@property
def input_name(self):
return self.args[0]
class GetAttribute(Function):
"""Get an attribute value of an entity defined in the service template
Node template attributes values are set in runtime and therefore its the
responsibility of the Tosca engine to implement the evaluation of
get_attribute functions.
Arguments:
* Node template name | HOST.
* Attribute name.
If the HOST keyword is passed as the node template name argument the
function will search each node template along the HostedOn relationship
chain until a node which contains the attribute is found.
Examples:
* { get_attribute: [ server, private_address ] }
* { get_attribute: [ HOST, private_address ] }
* { get_attribute: [ HOST, private_address, 0 ] }
* { get_attribute: [ HOST, private_address, 0, some_prop] }
"""
def validate(self):
if len(self.args) < 2:
ExceptionCollector.appendException(
ValueError(_('Illegal arguments for function "{0}". Expected '
'arguments: "node-template-name", "req-or-cap"'
'(optional), "property name"'
).format(GET_ATTRIBUTE)))
return
elif len(self.args) == 2:
self._find_node_template_containing_attribute()
else:
node_tpl = self._find_node_template(self.args[0])
if node_tpl is None:
return
index = 2
attrs = node_tpl.type_definition.get_attributes_def()
found = [attrs[self.args[1]]] if self.args[1] in attrs else []
if found:
attr = found[0]
else:
index = 3
# then check the req or caps
attr = self._find_req_or_cap_attribute(self.args[1],
self.args[2])
if not attr:
return
value_type = attr.schema['type']
if len(self.args) > index:
for elem in self.args[index:]:
if value_type == "list":
if not isinstance(elem, int):
ExceptionCollector.appendException(
ValueError(_('Illegal arguments for function'
' "{0}". "{1}" Expected positive'
' integer argument'
).format(GET_ATTRIBUTE, elem)))
value_type = attr.schema['entry_schema']['type']
elif value_type == "map":
value_type = attr.schema['entry_schema']['type']
elif value_type in Schema.PROPERTY_TYPES:
ExceptionCollector.appendException(
ValueError(_('Illegal arguments for function'
' "{0}". Unexpected attribute/'
'index value "{1}"'
).format(GET_ATTRIBUTE, elem)))
return
else: # It is a complex type
data_type = DataType(value_type)
props = data_type.get_all_properties()
found = [props[elem]] if elem in props else []
if found:
prop = found[0]
value_type = prop.schema['type']
else:
ExceptionCollector.appendException(
KeyError(_('Illegal arguments for function'
' "{0}". Attribute name "{1}" not'
' found in "{2}"'
).format(GET_ATTRIBUTE,
elem,
value_type)))
def result(self):
return self
def get_referenced_node_template(self):
"""Gets the NodeTemplate instance the get_attribute function refers to.
If HOST keyword was used as the node template argument, the node
template which contains the attribute along the HostedOn relationship
chain will be returned.
"""
return self._find_node_template_containing_attribute()
# Attributes can be explicitly created as part of the type definition
# or a property name can be implicitly used as an attribute name
def _find_node_template_containing_attribute(self):
node_tpl = self._find_node_template(self.args[0])
if node_tpl and \
not self._attribute_exists_in_type(node_tpl.type_definition) \
and self.attribute_name not in node_tpl.get_properties():
ExceptionCollector.appendException(
KeyError(_('Attribute "%(att)s" was not found in node '
'template "%(ntpl)s".') %
{'att': self.attribute_name,
'ntpl': node_tpl.name}))
return node_tpl
def _attribute_exists_in_type(self, type_definition):
attrs_def = type_definition.get_attributes_def()
found = [attrs_def[self.attribute_name]] \
if self.attribute_name in attrs_def else []
return len(found) == 1
def _find_host_containing_attribute(self, node_template_name=SELF):
node_template = self._find_node_template(node_template_name)
if node_template:
hosted_on_rel = EntityType.TOSCA_DEF[HOSTED_ON]
for r in node_template.requirements:
for requirement, target_name in r.items():
target_node = self._find_node_template(target_name)
target_type = target_node.type_definition
for capability in target_type.get_capabilities_objects():
if capability.inherits_from(
hosted_on_rel['valid_target_types']):
if self._attribute_exists_in_type(target_type):
return target_node
return self._find_host_containing_attribute(
target_name)
def _find_node_template(self, node_template_name):
# if the node_template_name has the long format
if isinstance(node_template_name, dict):
# get only the node name
if 'node' in node_template_name:
node_template_name = node_template_name['node']
else:
ExceptionCollector.appendException(
ValueError(_(' No node name in the relationship.')))
return
if node_template_name == HOST:
# Currently this is the only way to tell whether the function
# is used within the outputs section of the TOSCA template.
if isinstance(self.context, list):
ExceptionCollector.appendException(
ValueError(_(
'"get_attribute: [ HOST, ... ]" is not allowed in '
'"outputs" section of the TOSCA template.')))
return
node_tpl = self._find_host_containing_attribute()
if not node_tpl:
ExceptionCollector.appendException(
ValueError(_(
'"get_attribute: [ HOST, ... ]" was used in node '
'template "{0}" but "{1}" was not found in '
'the relationship chain.').format(self.context.name,
HOSTED_ON)))
return
return node_tpl
if node_template_name == TARGET:
if not isinstance(self.context.type_definition, RelationshipType):
ExceptionCollector.appendException(
KeyError(_('"TARGET" keyword can only be used in context'
' to "Relationships" target node')))
return
return self.context.target
if node_template_name == SOURCE:
if not isinstance(self.context.type_definition, RelationshipType):
ExceptionCollector.appendException(
KeyError(_('"SOURCE" keyword can only be used in context'
' to "Relationships" source node')))
return
return self.context.source
name = self.context.name \
if node_template_name == SELF and \
not isinstance(self.context, list) \
else node_template_name
for node_template in self.tosca_tpl.nodetemplates:
if node_template.name == name:
return node_template
ExceptionCollector.appendException(
KeyError(_(
'Node template "{0}" was not found.'
).format(node_template_name)))
def _find_req_or_cap_attribute(self, req_or_cap, attr_name):
node_tpl = self._find_node_template(self.args[0])
# Find attribute in node template's requirements
for r in node_tpl.requirements:
for req, node_name in r.items():
if req == req_or_cap:
node_template = self._find_node_template(node_name)
return self._get_capability_attribute(
node_template,
req,
attr_name)
# If requirement was not found, look in node template's capabilities
return self._get_capability_attribute(node_tpl,
req_or_cap,
attr_name)
def _get_capability_attribute(self,
node_template,
capability_name,
attr_name):
"""Gets a node template capability attribute."""
caps = node_template.get_capabilities()
if caps and capability_name in caps.keys():
cap = caps[capability_name]
attribute = None
attrs = cap.definition.get_attributes_def()
if attrs and attr_name in attrs.keys():
attribute = attrs[attr_name]
if not attribute:
ExceptionCollector.appendException(
KeyError(_('Attribute "%(attr)s" was not found in '
'capability "%(cap)s" of node template '
'"%(ntpl1)s" referenced from node template '
'"%(ntpl2)s".') % {'attr': attr_name,
'cap': capability_name,
'ntpl1': node_template.name,
'ntpl2': self.context.name}))
return attribute
msg = _('Requirement/Capability "{0}" referenced from node template '
'"{1}" was not found in node template "{2}".').format(
capability_name,
self.context.name,
node_template.name)
ExceptionCollector.appendException(KeyError(msg))
@property
def node_template_name(self):
return self.args[0]
@property
def attribute_name(self):
return self.args[1]
class GetProperty(Function):
"""Get a property value of an entity defined in the same service template.
Arguments:
* Node template name | SELF | HOST | SOURCE | TARGET.
* Requirement or capability name (optional).
* Property name.
If requirement or capability name is specified, the behavior is as follows:
The req or cap name is first looked up in the specified node template's
requirements.
If found, it would search for a matching capability
of an other node template and get its property as specified in function
arguments.
Otherwise, the req or cap name would be looked up in the specified
node template's capabilities and if found, it would return the property of
the capability as specified in function arguments.
Examples:
* { get_property: [ mysql_server, port ] }
* { get_property: [ SELF, db_port ] }
* { get_property: [ SELF, database_endpoint, port ] }
* { get_property: [ SELF, database_endpoint, port, 1 ] }
"""
def validate(self):
if len(self.args) < 2:
ExceptionCollector.appendException(
ValueError(_(
'Expected arguments: "node-template-name", "req-or-cap" '
'(optional), "property name".')))
return
if len(self.args) == 2:
found_prop = self._find_property(self.args[1])
if not found_prop:
return
prop = found_prop.value
if not isinstance(prop, Function):
get_function(self.tosca_tpl, self.context, prop)
elif len(self.args) >= 3:
# do not use _find_property to avoid raise KeyError
# if the prop is not found
# First check if there is property with this name
node_tpl = self._find_node_template(self.args[0])
props = node_tpl.get_properties() if node_tpl else []
index = 2
found = [props[self.args[1]]] if self.args[1] in props else []
if found:
property_value = found[0].value
else:
index = 3
# then check the req or caps
property_value = self._find_req_or_cap_property(self.args[1],
self.args[2])
if len(self.args) > index:
for elem in self.args[index:]:
if isinstance(property_value, list):
int_elem = int(elem)
property_value = self._get_index_value(property_value,
int_elem)
else:
property_value = self._get_attribute_value(
property_value,
elem)
def _find_req_or_cap_property(self, req_or_cap, property_name):
node_tpl = self._find_node_template(self.args[0])
if node_tpl is None:
return None
# Find property in node template's requirements
for r in node_tpl.requirements:
for req, node_name in r.items():
if req == req_or_cap:
node_template = self._find_node_template(node_name)
return self._get_capability_property(
node_template,
req,
property_name)
# If requirement was not found, look in node template's capabilities
return self._get_capability_property(node_tpl,
req_or_cap,
property_name)
def _get_capability_property(self,
node_template,
capability_name,
property_name,
throw_errors=True):
"""Gets a node template capability property."""
caps = node_template.get_capabilities()
if caps and capability_name in caps.keys():
cap = caps[capability_name]
property = None
props = cap.get_properties()
if props and property_name in props.keys():
property = props[property_name].value
if property is None and throw_errors:
ExceptionCollector.appendException(
KeyError(_('Property "%(prop)s" was not found in '
'capability "%(cap)s" of node template '
'"%(ntpl1)s" referenced from node template '
'"%(ntpl2)s".') % {'prop': property_name,
'cap': capability_name,
'ntpl1': node_template.name,
'ntpl2': self.context.name}))
return property
if throw_errors:
msg = _('Requirement/Capability "{0}" referenced from '
'node template "{1}" was not found in node template'
' "{2}".').format(capability_name,
self.context.name,
node_template.name)
ExceptionCollector.appendException(KeyError(msg))
else:
return None
def _find_property(self, property_name):
node_tpl = self._find_node_template(self.args[0])
if not node_tpl:
return
props = node_tpl.get_properties()
found = [props[property_name]] if property_name in props else []
if len(found) == 0:
ExceptionCollector.appendException(
KeyError(_('Property "%(prop)s" was not found in node '
'template "%(ntpl)s".') %
{'prop': property_name,
'ntpl': node_tpl.name}))
return None
return found[0]
def _find_node_template(self, node_template_name):
# if the node_template_name has the long format
if isinstance(node_template_name, dict):
# get only the node name
if 'node' in node_template_name:
node_template_name = node_template_name['node']
else:
ExceptionCollector.appendException(
ValueError(_(' No node name in the relationship.')))
return
if node_template_name == SELF:
return self.context
# enable the HOST value in the function
if node_template_name == HOST:
node = self._find_host_containing_property()
if node is None:
ExceptionCollector.appendException(
KeyError(_(
"Property '{0}' not found in capability/requirement"
" '{1}' referenced from node template {2}").
format(self.args[2],
self.args[1],
self.context.name)))
return None
else:
return node
if node_template_name == TARGET:
if not isinstance(self.context.type_definition, RelationshipType):
ExceptionCollector.appendException(
KeyError(_('"TARGET" keyword can only be used in context'
' to "Relationships" target node')))
return
return self.context.target
if node_template_name == SOURCE:
if not isinstance(self.context.type_definition, RelationshipType):
ExceptionCollector.appendException(
KeyError(_('"SOURCE" keyword can only be used in context'
' to "Relationships" source node')))
return
return self.context.source
if not hasattr(self.tosca_tpl, 'nodetemplates'):
return
for node_template in self.tosca_tpl.nodetemplates:
if node_template.name == node_template_name:
return node_template
ExceptionCollector.appendException(
KeyError(_(
'Node template "{0}" was not found.'
' referenced from node template {1}'
).format(node_template_name,
self.context.name)))
def _get_index_value(self, value, index):
if isinstance(value, list):
if index < len(value):
return value[index]
else:
ExceptionCollector.appendException(
KeyError(_(
"Property '{0}' found in capability '{1}'"
" referenced from node template {2}"
" must have an element with index {3}.").
format(self.args[2],
self.args[1],
self.context.name,
index)))
else:
ExceptionCollector.appendException(
KeyError(_(
"Property '{0}' found in capability '{1}'"
" referenced from node template {2}"
" must be a list.").format(self.args[2],
self.args[1],
self.context.name)))
def _get_attribute_value(self, value, attibute):
if isinstance(value, dict):
if attibute in value:
return value[attibute]
else:
ExceptionCollector.appendException(
KeyError(_(
"Property '{0}' found in capability '{1}'"
" referenced from node template {2}"
" must have an attribute named {3}.").
format(self.args[2],
self.args[1],
self.context.name,
attibute)))
else:
ExceptionCollector.appendException(
KeyError(_(
"Property '{0}' found in capability '{1}'"
" referenced from node template {2}"
" must be a dict.").format(self.args[2],
self.args[1],
self.context.name)))
# Add this functions similar to get_attribute case
def _find_host_containing_property(self, node_template_name=SELF):
node_template = self._find_node_template(node_template_name)
hosted_on_rel = EntityType.TOSCA_DEF[HOSTED_ON]
for r in node_template.requirements:
for requirement, target_name in r.items():
target_node = self._find_node_template(target_name)
target_type = target_node.type_definition
for capability in target_type.get_capabilities_objects():
if capability.inherits_from(
hosted_on_rel['valid_target_types']):
if self._property_exists_in_type(target_type):
return target_node
# If requirement was not found, look in node
# template's capabilities
if (len(self.args) > 2 and
self._get_capability_property(target_node,
self.args[1],
self.args[2],
False)
is not None):
return target_node
return self._find_host_containing_property(
target_name)
return None
def _property_exists_in_type(self, type_definition):
props_def = type_definition.get_properties_def()
found = [props_def[self.args[1]]] \
if self.args[1] in props_def else []
return len(found) == 1
def result(self):
if len(self.args) >= 3:
# First check if there is property with this name
node_tpl = self._find_node_template(self.args[0])
props = node_tpl.get_properties() if node_tpl else []
index = 2
found = [props[self.args[1]]] if self.args[1] in props else []
if found:
property_value = found[0].value
else:
index = 3
# then check the req or caps
property_value = self._find_req_or_cap_property(self.args[1],
self.args[2])
if len(self.args) > index:
for elem in self.args[index:]:
if isinstance(property_value, list):
int_elem = int(elem)
property_value = self._get_index_value(property_value,
int_elem)
else:
property_value = self._get_attribute_value(
property_value,
elem)
else:
property_value = self._find_property(self.args[1]).value
if isinstance(property_value, Function):
return property_value.result()
return get_function(self.tosca_tpl,
self.context,
property_value)
@property
def node_template_name(self):
return self.args[0]
@property
def property_name(self):
if len(self.args) > 2:
return self.args[2]
return self.args[1]
@property
def req_or_cap(self):
if len(self.args) > 2:
return self.args[1]
return None
class GetOperationOutput(Function):
def validate(self):
if len(self.args) == 4:
template_name = self.args[0]
interface_name = self.args[1]
operation_name = self.args[2]
template = None
node_template = self._find_node_template(template_name)
if node_template:
template = node_template
else:
relationship_template = \
self._find_relationship_template(template_name)
if relationship_template:
template = relationship_template
if not template:
ExceptionCollector.appendException(
KeyError(_(
'Node or relationship template "{0}" was not found.'
).format(template_name)))
return
if hasattr(template, template.INTERFACES):
operation = self._find_operation_name(interface_name,
operation_name,
template.interfaces)
if operation:
return
ExceptionCollector.appendException(
ValueError(_(
'Node or relationship template "{0}" has not '
'interface "{1}" or operation "{2}".'
).format(template_name, interface_name, operation_name)))
else:
ExceptionCollector.appendException(
ValueError(_('Illegal arguments for function "{0}". Expected '
'arguments: "template_name","interface_name",'
'"operation_name","output_variable_name"'
).format(GET_OPERATION_OUTPUT)))
return
def _find_operation_name(self, interface_name, operation_name,
interfaces=None):
if(interface_name == 'Configure' or
interface_name == 'tosca.interfaces.node.relationship.Configure'):
if(operation_name in
StatefulEntityType.
interfaces_relationship_configure_operations):
return operation_name
else:
ExceptionCollector.appendException(
ValueError(_('Enter an operation of Configure interface'
).format(GET_OPERATION_OUTPUT)))
return
elif(interface_name == 'Standard' or
interface_name == 'tosca.interfaces.node.lifecycle.Standard'):
if(operation_name in
StatefulEntityType.interfaces_node_lifecycle_operations):
return operation_name
else:
ExceptionCollector.appendException(
ValueError(_('Enter an operation of Standard interface'
).format(GET_OPERATION_OUTPUT)))
return
elif interfaces:
for interface_obj in interfaces:
if interface_obj.name == operation_name and \
interface_obj.type == interface_name:
return operation_name
else:
ExceptionCollector.appendException(
ValueError(_('Enter a valid operation name'
).format(GET_OPERATION_OUTPUT)))
return
def _find_node_template(self, node_template_name):
if node_template_name == TARGET:
if not isinstance(self.context.type_definition, RelationshipType):
ExceptionCollector.appendException(
KeyError(_('"TARGET" keyword can only be used in context'
' to "Relationships" target node')))
return
return self.context.target
if node_template_name == SOURCE:
if not isinstance(self.context.type_definition, RelationshipType):
ExceptionCollector.appendException(
KeyError(_('"SOURCE" keyword can only be used in context'
' to "Relationships" source node')))
return
return self.context.source
name = self.context.name \
if node_template_name == SELF and \
not isinstance(self.context, list) \
else node_template_name
for node_template in self.tosca_tpl.nodetemplates:
if node_template.name == name:
return node_template
def _find_relationship_template(self, relationship_template_name):
for rel_template in self.tosca_tpl.relationship_templates:
if rel_template.name == relationship_template_name:
return rel_template
def result(self):
return self
class Concat(Function):
"""Validate the function and provide an instance of the function
Concatenation of values are supposed to be produced at runtime and
therefore its the responsibility of the TOSCA engine to implement the
evaluation of Concat functions.
Arguments:
* List of strings that needs to be concatenated
Example:
[ 'http://',
get_attribute: [ server, public_address ],
':' ,
get_attribute: [ server, port ] ]
"""
def validate(self):
if len(self.args) < 1:
ExceptionCollector.appendException(
ValueError(_('Invalid arguments for function "{0}". Expected '
'at least one arguments.').format(CONCAT)))
def result(self):
return self
class Token(Function):
"""Validate the function and provide an instance of the function
The token function is used within a TOSCA service template on a string to
parse out (tokenize) substrings separated by one or more token characters
within a larger string.
Arguments:
* The composite string that contains one or more substrings separated by
token characters.
* The string that contains one or more token characters that separate
substrings within the composite string.
* The integer indicates the index of the substring to return from the
composite string. Note that the first substring is denoted by using
the '0' (zero) integer value.
Example:
[ get_attribute: [ my_server, data_endpoint, ip_address ], ':', 1 ]
"""
def validate(self):
if len(self.args) < 3:
ExceptionCollector.appendException(
ValueError(_('Invalid arguments for function "{0}". Expected '
'at least three arguments.').format(TOKEN)))
else:
if not isinstance(self.args[1], str) or len(self.args[1]) != 1:
ExceptionCollector.appendException(
ValueError(_('Invalid arguments for function "{0}". '
'Expected single char value as second '
'argument.').format(TOKEN)))
if not isinstance(self.args[2], int):
ExceptionCollector.appendException(
ValueError(_('Invalid arguments for function "{0}". '
'Expected integer value as third '
'argument.').format(TOKEN)))
def result(self):
return self
function_mappings = {
GET_PROPERTY: GetProperty,
GET_INPUT: GetInput,
GET_ATTRIBUTE: GetAttribute,
GET_OPERATION_OUTPUT: GetOperationOutput,
CONCAT: Concat,
TOKEN: Token
}
def is_function(function):
"""Returns True if the provided function is a Tosca intrinsic function.
Examples:
* "{ get_property: { SELF, port } }"
* "{ get_input: db_name }"
* Function instance
:param function: Function as string or a Function instance.
:return: True if function is a Tosca intrinsic function, otherwise False.
"""
if isinstance(function, dict) and len(function) == 1:
func_name = list(function.keys())[0]
return func_name in function_mappings
return isinstance(function, Function)
def get_function(tosca_tpl, node_template, raw_function):
"""Gets a Function instance representing the provided template function.
If the format provided raw_function format is not relevant for template
functions or if the function name doesn't exist in function mapping the
method returns the provided raw_function.
:param tosca_tpl: The tosca template.
:param node_template: The node template the function is specified for.
:param raw_function: The raw function as dict.
:return: Template function as Function instance or the raw_function if
parsing was unsuccessful.
"""
if is_function(raw_function):
if isinstance(raw_function, dict):
func_name = list(raw_function.keys())[0]
if func_name in function_mappings:
func = function_mappings[func_name]
func_args = list(raw_function.values())[0]
if not isinstance(func_args, list):
func_args = [func_args]
return func(tosca_tpl, node_template, func_name, func_args)
return raw_function