deb-heat/heat/engine/constraints.py
2014-03-05 16:54:16 +00:00

505 lines
16 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 collections
import numbers
import re
from heat.engine import resources
class InvalidSchemaError(Exception):
pass
class Schema(collections.Mapping):
"""
Schema base class for validating properties or parameters.
Schema objects are serialisable to dictionaries following a superset of
the HOT input Parameter schema using dict().
Serialises to JSON in the form::
{
'type': 'list',
'required': False
'constraints': [
{
'length': {'min': 1},
'description': 'List must not be empty'
}
],
'schema': {
'*': {
'type': 'string'
}
},
'description': 'An example list property.'
}
"""
KEYS = (
TYPE, DESCRIPTION, DEFAULT, SCHEMA, REQUIRED, CONSTRAINTS,
) = (
'type', 'description', 'default', 'schema', 'required', 'constraints',
)
# Keywords for data types; each Schema subclass can define its respective
# type name used in templates
TYPE_KEYS = (
INTEGER_TYPE, STRING_TYPE, NUMBER_TYPE, BOOLEAN_TYPE, MAP_TYPE,
LIST_TYPE,
) = (
'INTEGER', 'STRING', 'NUMBER', 'BOOLEAN', 'MAP',
'LIST',
)
# Default type names for data types used in templates; can be overridden by
# subclasses
TYPES = (
INTEGER, STRING, NUMBER, BOOLEAN, MAP, LIST,
) = (
'Integer', 'String', 'Number', 'Boolean', 'Map', 'List',
)
def __init__(self, data_type, description=None,
default=None, schema=None,
required=False, constraints=[], label=None):
self._len = None
self.label = label
self.type = data_type
if self.type not in self.TYPES:
raise InvalidSchemaError(_('Invalid type (%s)') % self.type)
self.description = description
self.required = required
if isinstance(schema, type(self)):
if self.type != self.LIST:
msg = _('Single schema valid only for '
'%(ltype)s, not %(utype)s') % dict(ltype=self.LIST,
utype=self.type)
raise InvalidSchemaError(msg)
self.schema = AnyIndexDict(schema)
else:
self.schema = schema
if self.schema is not None and self.type not in (self.LIST,
self.MAP):
msg = _('Schema valid only for %(ltype)s or '
'%(mtype)s, not %(utype)s') % dict(ltype=self.LIST,
mtype=self.MAP,
utype=self.type)
raise InvalidSchemaError(msg)
self.constraints = constraints
for c in constraints:
if not self._is_valid_constraint(c):
err_msg = _('%(name)s constraint '
'invalid for %(utype)s') % dict(
name=type(c).__name__,
utype=self.type)
raise InvalidSchemaError(err_msg)
self.default = default
self._validate_default()
def _validate_default(self):
if self.default is not None:
try:
self.validate_constraints(self.default)
except (ValueError, TypeError) as exc:
raise InvalidSchemaError(_('Invalid default '
'%(default)s (%(exc)s)') %
dict(default=self.default, exc=exc))
def set_default(self, default=None):
"""Set the default value for this Schema object."""
self.default = default
def _is_valid_constraint(self, constraint):
valid_types = getattr(constraint, 'valid_types', [])
return any(self.type == getattr(self, t, None) for t in valid_types)
@staticmethod
def str_to_num(value):
"""Convert a string representation of a number into a numeric type."""
if isinstance(value, numbers.Number):
return value
try:
return int(value)
except ValueError:
return float(value)
def validate_constraints(self, value, context=None):
for constraint in self.constraints:
constraint.validate(value, context)
def __getitem__(self, key):
if key == self.TYPE:
return self.type.lower()
elif key == self.DESCRIPTION:
if self.description is not None:
return self.description
elif key == self.DEFAULT:
if self.default is not None:
return self.default
elif key == self.SCHEMA:
if self.schema is not None:
return dict((n, dict(s)) for n, s in self.schema.items())
elif key == self.REQUIRED:
return self.required
elif key == self.CONSTRAINTS:
if self.constraints:
return [dict(c) for c in self.constraints]
raise KeyError(key)
def __iter__(self):
for k in self.KEYS:
try:
self[k]
except KeyError:
pass
else:
yield k
def __len__(self):
if self._len is None:
self._len = len(list(iter(self)))
return self._len
class AnyIndexDict(collections.Mapping):
"""
A Mapping that returns the same value for any integer index.
Used for storing the schema for a list. When converted to a dictionary,
it contains a single item with the key '*'.
"""
ANYTHING = '*'
def __init__(self, value):
self.value = value
def __getitem__(self, key):
if key != self.ANYTHING and not isinstance(key, (int, long)):
raise KeyError(_('Invalid key %s') % str(key))
return self.value
def __iter__(self):
yield self.ANYTHING
def __len__(self):
return 1
class Constraint(collections.Mapping):
"""
Parent class for constraints on allowable values for a Property.
Constraints are serialisable to dictionaries following the HOT input
Parameter constraints schema using dict().
"""
(DESCRIPTION,) = ('description',)
def __init__(self, description=None):
self.description = description
def __str__(self):
def desc():
if self.description:
yield self.description
yield self._str()
return '\n'.join(desc())
def validate(self, value, context=None):
if not self._is_valid(value, context):
if self.description:
err_msg = self.description
else:
err_msg = self._err_msg(value)
raise ValueError(err_msg)
@classmethod
def _name(cls):
return '_'.join(w.lower() for w in re.findall('[A-Z]?[a-z]+',
cls.__name__))
def __getitem__(self, key):
if key == self.DESCRIPTION:
if self.description is None:
raise KeyError(key)
return self.description
if key == self._name():
return self._constraint()
raise KeyError(key)
def __iter__(self):
if self.description is not None:
yield self.DESCRIPTION
yield self._name()
def __len__(self):
return 2 if self.description is not None else 1
class Range(Constraint):
"""
Constrain values within a range.
Serialises to JSON as::
{
'range': {'min': <min>, 'max': <max>},
'description': <description>
}
"""
(MIN, MAX) = ('min', 'max')
valid_types = (Schema.INTEGER_TYPE, Schema.NUMBER_TYPE,)
def __init__(self, min=None, max=None, description=None):
super(Range, self).__init__(description)
self.min = min
self.max = max
for param in (min, max):
if not isinstance(param, (float, int, long, type(None))):
raise InvalidSchemaError(_('min/max must be numeric'))
if min is max is None:
raise InvalidSchemaError(
_('A range constraint must have a min value and/or a max '
'value specified.'))
def _str(self):
if self.max is None:
fmt = _('The value must be at least %(min)s.')
elif self.min is None:
fmt = _('The value must be no greater than %(max)s.')
else:
fmt = _('The value must be in the range %(min)s to %(max)s.')
return fmt % self._constraint()
def _err_msg(self, value):
return '%s is out of range (min: %s, max: %s)' % (value,
self.min,
self.max)
def _is_valid(self, value, context):
value = Schema.str_to_num(value)
if self.min is not None:
if value < self.min:
return False
if self.max is not None:
if value > self.max:
return False
return True
def _constraint(self):
def constraints():
if self.min is not None:
yield self.MIN, self.min
if self.max is not None:
yield self.MAX, self.max
return dict(constraints())
class Length(Range):
"""
Constrain the length of values within a range.
Serialises to JSON as::
{
'length': {'min': <min>, 'max': <max>},
'description': <description>
}
"""
valid_types = (Schema.STRING_TYPE, Schema.LIST_TYPE, Schema.MAP_TYPE,)
def __init__(self, min=None, max=None, description=None):
if min is max is None:
raise InvalidSchemaError(
_('A length constraint must have a min value and/or a max '
'value specified.'))
super(Length, self).__init__(min, max, description)
for param in (min, max):
if not isinstance(param, (int, long, type(None))):
msg = _('min/max length must be integral')
raise InvalidSchemaError(msg)
def _str(self):
if self.max is None:
fmt = _('The length must be at least %(min)s.')
elif self.min is None:
fmt = _('The length must be no greater than %(max)s.')
else:
fmt = _('The length must be in the range %(min)s to %(max)s.')
return fmt % self._constraint()
def _err_msg(self, value):
return 'length (%d) is out of range (min: %s, max: %s)' % (len(value),
self.min,
self.max)
def _is_valid(self, value, context):
return super(Length, self)._is_valid(len(value), context)
class AllowedValues(Constraint):
"""
Constrain values to a predefined set.
Serialises to JSON as::
{
'allowed_values': [<allowed1>, <allowed2>, ...],
'description': <description>
}
"""
valid_types = (Schema.STRING_TYPE, Schema.INTEGER_TYPE, Schema.NUMBER_TYPE,
Schema.BOOLEAN_TYPE, Schema.LIST_TYPE,)
def __init__(self, allowed, description=None):
super(AllowedValues, self).__init__(description)
if (not isinstance(allowed, collections.Sequence) or
isinstance(allowed, basestring)):
raise InvalidSchemaError(_('AllowedValues must be a list'))
self.allowed = tuple(allowed)
def _str(self):
allowed = ', '.join(str(a) for a in self.allowed)
return _('Allowed values: %s') % allowed
def _err_msg(self, value):
allowed = '[%s]' % ', '.join(str(a) for a in self.allowed)
return '"%s" is not an allowed value %s' % (value, allowed)
def _is_valid(self, value, context):
# For list values, check if all elements of the list are contained
# in allowed list.
if isinstance(value, list):
return all(v in self.allowed for v in value)
return value in self.allowed
def _constraint(self):
return list(self.allowed)
class AllowedPattern(Constraint):
"""
Constrain values to a predefined regular expression pattern.
Serialises to JSON as::
{
'allowed_pattern': <pattern>,
'description': <description>
}
"""
valid_types = (Schema.STRING_TYPE,)
def __init__(self, pattern, description=None):
super(AllowedPattern, self).__init__(description)
if not isinstance(pattern, basestring):
raise InvalidSchemaError(_('AllowedPattern must be a string'))
self.pattern = pattern
self.match = re.compile(pattern).match
def _str(self):
return _('Value must match pattern: %s') % self.pattern
def _err_msg(self, value):
return '"%s" does not match pattern "%s"' % (value, self.pattern)
def _is_valid(self, value, context):
match = self.match(value)
return match is not None and match.end() == len(value)
def _constraint(self):
return self.pattern
class CustomConstraint(Constraint):
"""
A constraint delegating validation to an external class.
"""
valid_types = (Schema.STRING_TYPE, Schema.INTEGER_TYPE, Schema.NUMBER_TYPE,
Schema.BOOLEAN_TYPE, Schema.LIST_TYPE)
def __init__(self, name, description=None, environment=None):
super(CustomConstraint, self).__init__(description)
self.name = name
self._environment = environment
self._custom_constraint = None
def _constraint(self):
return self.name
@property
def custom_constraint(self):
if self._custom_constraint is None:
if self._environment is None:
self._environment = resources.global_env()
constraint_class = self._environment.get_constraint(self.name)
if constraint_class:
self._custom_constraint = constraint_class()
return self._custom_constraint
def _str(self):
message = getattr(self.custom_constraint, "message", None)
if not message:
message = _('Value must be of type %s') % self.name
return message
def _err_msg(self, value):
constraint = self.custom_constraint
if constraint is None:
return _('"%(value)s" does not validate %(name)s '
'(constraint not found)') % {
"value": value, "name": self.name}
error = getattr(constraint, "error", None)
if error:
return error(value)
return _('"%(value)s" does not validate %(name)s') % {
"value": value, "name": self.name}
def _is_valid(self, value, context):
constraint = self.custom_constraint
if not constraint:
return False
return constraint.validate(value, context)