274 lines
9.3 KiB
Python
274 lines
9.3 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import collections
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import re
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from heat.engine import template
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PARAMETER_KEYS = (
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TYPE, DEFAULT, NO_ECHO, VALUES, PATTERN,
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MAX_LENGTH, MIN_LENGTH, MAX_VALUE, MIN_VALUE,
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DESCRIPTION, CONSTRAINT_DESCRIPTION
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) = (
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'Type', 'Default', 'NoEcho', 'AllowedValues', 'AllowedPattern',
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'MaxLength', 'MinLength', 'MaxValue', 'MinValue',
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'Description', 'ConstraintDescription'
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)
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PARAMETER_TYPES = (
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STRING, NUMBER, COMMA_DELIMITED_LIST
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) = (
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'String', 'Number', 'CommaDelimitedList'
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)
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(PARAM_STACK_NAME, PARAM_REGION) = ('AWS::StackName', 'AWS::Region')
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class Parameter(object):
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'''A template parameter.'''
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def __new__(cls, name, schema, value=None):
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'''Create a new Parameter of the appropriate type.'''
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if cls is not Parameter:
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return super(Parameter, cls).__new__(cls)
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param_type = schema[TYPE]
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if param_type == STRING:
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ParamClass = StringParam
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elif param_type == NUMBER:
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ParamClass = NumberParam
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elif param_type == COMMA_DELIMITED_LIST:
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ParamClass = CommaDelimitedListParam
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else:
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raise ValueError('Invalid Parameter type "%s"' % param_type)
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return ParamClass(name, schema, value)
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def __init__(self, name, schema, value=None):
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'''
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Initialise the Parameter with a name, schema and optional user-supplied
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value.
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'''
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self.name = name
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self.schema = schema
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self.user_value = value
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self._constraint_error = self.schema.get(CONSTRAINT_DESCRIPTION)
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if self.has_default():
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self._validate(self.default())
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if self.user_value is not None:
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self._validate(self.user_value)
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def _error_msg(self, message):
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return '%s %s' % (self.name, self._constraint_error or message)
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def _validate(self, value):
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if VALUES in self.schema:
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allowed = self.schema[VALUES]
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if value not in allowed:
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message = '%s not in %s %s' % (value, VALUES, allowed)
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raise ValueError(self._error_msg(message))
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def value(self):
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'''Get the parameter value, optionally sanitising it for output.'''
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if self.user_value is not None:
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return self.user_value
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if self.has_default():
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return self.default()
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raise KeyError('Missing parameter %s' % self.name)
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def no_echo(self):
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'''
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Return whether the parameter should be sanitised in any output to
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the user.
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'''
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return self.schema.get(NO_ECHO, 'false').lower() == 'true'
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def description(self):
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'''Return the description of the parameter.'''
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return self.schema.get(DESCRIPTION, '')
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def has_default(self):
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'''Return whether the parameter has a default value.'''
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return DEFAULT in self.schema
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def default(self):
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'''Return the default value of the parameter.'''
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return self.schema.get(DEFAULT)
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def __str__(self):
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'''Return a string representation of the parameter'''
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value = self.value()
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if self.no_echo():
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return '******'
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else:
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return value
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class NumberParam(Parameter):
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'''A template parameter of type "Number".'''
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@staticmethod
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def str_to_num(s):
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'''Convert a string to an integer (if possible) or float.'''
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try:
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return int(s)
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except ValueError:
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return float(s)
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def _validate(self, value):
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'''Check that the supplied value is compatible with the constraints.'''
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num = self.str_to_num(value)
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minn = self.str_to_num(self.schema.get(MIN_VALUE, value))
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maxn = self.str_to_num(self.schema.get(MAX_VALUE, value))
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if num > maxn or num < minn:
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raise ValueError(self._error_msg('%s is out of range' % value))
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Parameter._validate(self, value)
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def __int__(self):
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'''Return an integer representation of the parameter'''
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return int(self.value())
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def __float__(self):
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'''Return a float representation of the parameter'''
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return float(self.value())
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class StringParam(Parameter):
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'''A template parameter of type "String".'''
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def _validate(self, value):
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'''Check that the supplied value is compatible with the constraints'''
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if not isinstance(value, basestring):
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raise ValueError(self._error_msg('value must be a string'))
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length = len(value)
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if MAX_LENGTH in self.schema:
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max_length = int(self.schema[MAX_LENGTH])
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if length > max_length:
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message = 'length (%d) overflows %s %s' % (length,
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MAX_LENGTH,
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max_length)
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raise ValueError(self._error_msg(message))
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if MIN_LENGTH in self.schema:
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min_length = int(self.schema[MIN_LENGTH])
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if length < min_length:
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message = 'length (%d) underflows %s %d' % (length,
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MIN_LENGTH,
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min_length)
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raise ValueError(self._error_msg(message))
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if PATTERN in self.schema:
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pattern = self.schema[PATTERN]
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match = re.match(pattern, value)
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if match is None or match.end() != length:
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message = '"%s" does not match %s "%s"' % (value,
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PATTERN,
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pattern)
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raise ValueError(self._error_msg(message))
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Parameter._validate(self, value)
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class CommaDelimitedListParam(Parameter, collections.Sequence):
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'''A template parameter of type "CommaDelimitedList".'''
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def _validate(self, value):
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'''Check that the supplied value is compatible with the constraints'''
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try:
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sp = value.split(',')
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except AttributeError:
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raise ValueError('Value must be a comma-delimited list string')
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for li in self:
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Parameter._validate(self, li)
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def __len__(self):
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'''Return the length of the list'''
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return len(self.value().split(','))
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def __getitem__(self, index):
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'''Return an item from the list'''
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return self.value().split(',')[index]
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class Parameters(collections.Mapping):
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'''
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The parameters of a stack, with type checking, defaults &c. specified by
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the stack's template.
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'''
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def __init__(self, stack_name, tmpl, user_params={}):
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'''
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Create the parameter container for a stack from the stack name and
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template, optionally setting the user-supplied parameter values.
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'''
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def parameters():
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if stack_name is not None:
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yield Parameter(PARAM_STACK_NAME,
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{TYPE: STRING,
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DESCRIPTION: 'Stack Name',
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DEFAULT: stack_name})
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yield Parameter(PARAM_REGION,
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{TYPE: STRING,
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DEFAULT: 'ap-southeast-1',
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VALUES: ['us-east-1',
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'us-west-1', 'us-west-2',
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'sa-east-1',
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'eu-west-1',
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'ap-southeast-1',
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'ap-northeast-1']})
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for name, schema in tmpl[template.PARAMETERS].iteritems():
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yield Parameter(name, schema, user_params.get(name))
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self.params = dict((p.name, p) for p in parameters())
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def __contains__(self, key):
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'''Return whether the specified parameter exists'''
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return key in self.params
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def __iter__(self):
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'''Return an iterator over the parameter names.'''
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return iter(self.params)
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def __len__(self):
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'''Return the number of parameters defined'''
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return len(self.params)
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def __getitem__(self, key):
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'''Get a parameter value.'''
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return self.params[key].value()
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def map(self, func, filter_func=lambda p: True):
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'''
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Map the supplied filter function onto each Parameter (with an
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optional filter function) and return the resulting dictionary.
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'''
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return dict((n, func(p)) for n, p in self.params.iteritems()
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if filter_func(p))
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def user_parameters(self):
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'''
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Return a dictionary of all the parameters passed in by the user
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'''
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return self.map(lambda p: p.user_value,
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lambda p: p.user_value is not None)
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