332 lines
12 KiB
Python
332 lines
12 KiB
Python
|
# Copyright 2012-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
|
||
|
|
#
|
||
|
|
# Licensed under the Apache License, Version 2.0 (the "License"). You
|
||
|
|
# may not use this file except in compliance with the License. A copy of
|
||
|
|
# the License is located at
|
||
|
|
#
|
||
|
|
# http://aws.amazon.com/apache2.0/
|
||
|
|
#
|
||
|
|
# or in the "license" file accompanying this file. This file 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 jmespath
|
||
|
|
import logging
|
||
|
|
import time
|
||
|
|
|
||
|
|
from botocore.utils import get_service_module_name
|
||
|
|
from botocore.docs.docstring import WaiterDocstring
|
||
|
|
from .exceptions import WaiterError, ClientError, WaiterConfigError
|
||
|
|
from . import xform_name
|
||
|
|
|
||
|
|
|
||
|
|
logger = logging.getLogger(__name__)
|
||
|
|
|
||
|
|
|
||
|
|
def create_waiter_with_client(waiter_name, waiter_model, client):
|
||
|
|
"""
|
||
|
|
|
||
|
|
:type waiter_name: str
|
||
|
|
:param waiter_name: The name of the waiter. The name should match
|
||
|
|
the name (including the casing) of the key name in the waiter
|
||
|
|
model file (typically this is CamelCasing).
|
||
|
|
|
||
|
|
:type waiter_model: botocore.waiter.WaiterModel
|
||
|
|
:param waiter_model: The model for the waiter configuration.
|
||
|
|
|
||
|
|
:type client: botocore.client.BaseClient
|
||
|
|
:param client: The botocore client associated with the service.
|
||
|
|
|
||
|
|
:rtype: botocore.waiter.Waiter
|
||
|
|
:return: The waiter object.
|
||
|
|
|
||
|
|
"""
|
||
|
|
single_waiter_config = waiter_model.get_waiter(waiter_name)
|
||
|
|
operation_name = xform_name(single_waiter_config.operation)
|
||
|
|
operation_method = NormalizedOperationMethod(
|
||
|
|
getattr(client, operation_name))
|
||
|
|
|
||
|
|
# Create a new wait method that will serve as a proxy to the underlying
|
||
|
|
# Waiter.wait method. This is needed to attach a docstring to the
|
||
|
|
# method.
|
||
|
|
def wait(self, **kwargs):
|
||
|
|
Waiter.wait(self, **kwargs)
|
||
|
|
|
||
|
|
wait.__doc__ = WaiterDocstring(
|
||
|
|
waiter_name=waiter_name,
|
||
|
|
event_emitter=client.meta.events,
|
||
|
|
service_model=client.meta.service_model,
|
||
|
|
service_waiter_model=waiter_model,
|
||
|
|
include_signature=False
|
||
|
|
)
|
||
|
|
|
||
|
|
# Rename the waiter class based on the type of waiter.
|
||
|
|
waiter_class_name = str('%s.Waiter.%s' % (
|
||
|
|
get_service_module_name(client.meta.service_model),
|
||
|
|
waiter_name))
|
||
|
|
|
||
|
|
# Create the new waiter class
|
||
|
|
documented_waiter_cls = type(
|
||
|
|
waiter_class_name, (Waiter,), {'wait': wait})
|
||
|
|
|
||
|
|
# Return an instance of the new waiter class.
|
||
|
|
return documented_waiter_cls(
|
||
|
|
waiter_name, single_waiter_config, operation_method
|
||
|
|
)
|
||
|
|
|
||
|
|
|
||
|
|
class NormalizedOperationMethod(object):
|
||
|
|
def __init__(self, client_method):
|
||
|
|
self._client_method = client_method
|
||
|
|
|
||
|
|
def __call__(self, **kwargs):
|
||
|
|
try:
|
||
|
|
return self._client_method(**kwargs)
|
||
|
|
except ClientError as e:
|
||
|
|
return e.response
|
||
|
|
|
||
|
|
|
||
|
|
class WaiterModel(object):
|
||
|
|
SUPPORTED_VERSION = 2
|
||
|
|
|
||
|
|
def __init__(self, waiter_config):
|
||
|
|
"""
|
||
|
|
|
||
|
|
Note that the WaiterModel takes ownership of the waiter_config.
|
||
|
|
It may or may not mutate the waiter_config. If this is a concern,
|
||
|
|
it is best to make a copy of the waiter config before passing it to
|
||
|
|
the WaiterModel.
|
||
|
|
|
||
|
|
:type waiter_config: dict
|
||
|
|
:param waiter_config: The loaded waiter config
|
||
|
|
from the <service>*.waiters.json file. This can be
|
||
|
|
obtained from a botocore Loader object as well.
|
||
|
|
|
||
|
|
"""
|
||
|
|
self._waiter_config = waiter_config['waiters']
|
||
|
|
|
||
|
|
# These are part of the public API. Changing these
|
||
|
|
# will result in having to update the consuming code,
|
||
|
|
# so don't change unless you really need to.
|
||
|
|
version = waiter_config.get('version', 'unknown')
|
||
|
|
self._verify_supported_version(version)
|
||
|
|
self.version = version
|
||
|
|
self.waiter_names = list(sorted(waiter_config['waiters'].keys()))
|
||
|
|
|
||
|
|
def _verify_supported_version(self, version):
|
||
|
|
if version != self.SUPPORTED_VERSION:
|
||
|
|
raise WaiterConfigError(
|
||
|
|
error_msg=("Unsupported waiter version, supported version "
|
||
|
|
"must be: %s, but version of waiter config "
|
||
|
|
"is: %s" % (self.SUPPORTED_VERSION,
|
||
|
|
version)))
|
||
|
|
|
||
|
|
def get_waiter(self, waiter_name):
|
||
|
|
try:
|
||
|
|
single_waiter_config = self._waiter_config[waiter_name]
|
||
|
|
except KeyError:
|
||
|
|
raise ValueError("Waiter does not exist: %s" % waiter_name)
|
||
|
|
return SingleWaiterConfig(single_waiter_config)
|
||
|
|
|
||
|
|
|
||
|
|
class SingleWaiterConfig(object):
|
||
|
|
"""Represents the waiter configuration for a single waiter.
|
||
|
|
|
||
|
|
A single waiter is considered the configuration for a single
|
||
|
|
value associated with a named waiter (i.e TableExists).
|
||
|
|
|
||
|
|
"""
|
||
|
|
def __init__(self, single_waiter_config):
|
||
|
|
self._config = single_waiter_config
|
||
|
|
|
||
|
|
# These attributes are part of the public API.
|
||
|
|
self.description = single_waiter_config.get('description', '')
|
||
|
|
# Per the spec, these three fields are required.
|
||
|
|
self.operation = single_waiter_config['operation']
|
||
|
|
self.delay = single_waiter_config['delay']
|
||
|
|
self.max_attempts = single_waiter_config['maxAttempts']
|
||
|
|
|
||
|
|
@property
|
||
|
|
def acceptors(self):
|
||
|
|
acceptors = []
|
||
|
|
for acceptor_config in self._config['acceptors']:
|
||
|
|
acceptor = AcceptorConfig(acceptor_config)
|
||
|
|
acceptors.append(acceptor)
|
||
|
|
return acceptors
|
||
|
|
|
||
|
|
|
||
|
|
class AcceptorConfig(object):
|
||
|
|
def __init__(self, config):
|
||
|
|
self.state = config['state']
|
||
|
|
self.matcher = config['matcher']
|
||
|
|
self.expected = config['expected']
|
||
|
|
self.argument = config.get('argument')
|
||
|
|
self.matcher_func = self._create_matcher_func()
|
||
|
|
|
||
|
|
def _create_matcher_func(self):
|
||
|
|
# An acceptor function is a callable that takes a single value. The
|
||
|
|
# parsed AWS response. Note that the parsed error response is also
|
||
|
|
# provided in the case of errors, so it's entirely possible to
|
||
|
|
# handle all the available matcher capabilities in the future.
|
||
|
|
# There's only three supported matchers, so for now, this is all
|
||
|
|
# contained to a single method. If this grows, we can expand this
|
||
|
|
# out to separate methods or even objects.
|
||
|
|
|
||
|
|
if self.matcher == 'path':
|
||
|
|
return self._create_path_matcher()
|
||
|
|
elif self.matcher == 'pathAll':
|
||
|
|
return self._create_path_all_matcher()
|
||
|
|
elif self.matcher == 'pathAny':
|
||
|
|
return self._create_path_any_matcher()
|
||
|
|
elif self.matcher == 'status':
|
||
|
|
return self._create_status_matcher()
|
||
|
|
elif self.matcher == 'error':
|
||
|
|
return self._create_error_matcher()
|
||
|
|
else:
|
||
|
|
raise WaiterConfigError(
|
||
|
|
error_msg="Unknown acceptor: %s" % self.matcher)
|
||
|
|
|
||
|
|
def _create_path_matcher(self):
|
||
|
|
expression = jmespath.compile(self.argument)
|
||
|
|
expected = self.expected
|
||
|
|
|
||
|
|
def acceptor_matches(response):
|
||
|
|
if 'Error' in response:
|
||
|
|
return
|
||
|
|
return expression.search(response) == expected
|
||
|
|
return acceptor_matches
|
||
|
|
|
||
|
|
def _create_path_all_matcher(self):
|
||
|
|
expression = jmespath.compile(self.argument)
|
||
|
|
expected = self.expected
|
||
|
|
|
||
|
|
def acceptor_matches(response):
|
||
|
|
if 'Error' in response:
|
||
|
|
return
|
||
|
|
result = expression.search(response)
|
||
|
|
if not isinstance(result, list) or not result:
|
||
|
|
# pathAll matcher must result in a list.
|
||
|
|
# Also we require at least one element in the list,
|
||
|
|
# that is, an empty list should not result in this
|
||
|
|
# acceptor match.
|
||
|
|
return False
|
||
|
|
for element in result:
|
||
|
|
if element != expected:
|
||
|
|
return False
|
||
|
|
return True
|
||
|
|
return acceptor_matches
|
||
|
|
|
||
|
|
def _create_path_any_matcher(self):
|
||
|
|
expression = jmespath.compile(self.argument)
|
||
|
|
expected = self.expected
|
||
|
|
|
||
|
|
def acceptor_matches(response):
|
||
|
|
if 'Error' in response:
|
||
|
|
return
|
||
|
|
result = expression.search(response)
|
||
|
|
if not isinstance(result, list) or not result:
|
||
|
|
# pathAny matcher must result in a list.
|
||
|
|
# Also we require at least one element in the list,
|
||
|
|
# that is, an empty list should not result in this
|
||
|
|
# acceptor match.
|
||
|
|
return False
|
||
|
|
for element in result:
|
||
|
|
if element == expected:
|
||
|
|
return True
|
||
|
|
return False
|
||
|
|
return acceptor_matches
|
||
|
|
|
||
|
|
def _create_status_matcher(self):
|
||
|
|
expected = self.expected
|
||
|
|
|
||
|
|
def acceptor_matches(response):
|
||
|
|
# We don't have any requirements on the expected incoming data
|
||
|
|
# other than it is a dict, so we don't assume there's
|
||
|
|
# a ResponseMetadata.HTTPStatusCode.
|
||
|
|
status_code = response.get('ResponseMetadata', {}).get(
|
||
|
|
'HTTPStatusCode')
|
||
|
|
return status_code == expected
|
||
|
|
return acceptor_matches
|
||
|
|
|
||
|
|
def _create_error_matcher(self):
|
||
|
|
expected = self.expected
|
||
|
|
|
||
|
|
def acceptor_matches(response):
|
||
|
|
# When the client encounters an error, it will normally raise
|
||
|
|
# an exception. However, the waiter implementation will catch
|
||
|
|
# this exception, and instead send us the parsed error
|
||
|
|
# response. So response is still a dictionary, and in the case
|
||
|
|
# of an error response will contain the "Error" and
|
||
|
|
# "ResponseMetadata" key.
|
||
|
|
return response.get("Error", {}).get("Code", "") == expected
|
||
|
|
return acceptor_matches
|
||
|
|
|
||
|
|
|
||
|
|
class Waiter(object):
|
||
|
|
def __init__(self, name, config, operation_method):
|
||
|
|
"""
|
||
|
|
|
||
|
|
:type name: string
|
||
|
|
:param name: The name of the waiter
|
||
|
|
|
||
|
|
:type config: botocore.waiter.SingleWaiterConfig
|
||
|
|
:param config: The configuration for the waiter.
|
||
|
|
|
||
|
|
:type operation_method: callable
|
||
|
|
:param operation_method: A callable that accepts **kwargs
|
||
|
|
and returns a response. For example, this can be
|
||
|
|
a method from a botocore client.
|
||
|
|
|
||
|
|
"""
|
||
|
|
self._operation_method = operation_method
|
||
|
|
# The two attributes are exposed to allow for introspection
|
||
|
|
# and documentation.
|
||
|
|
self.name = name
|
||
|
|
self.config = config
|
||
|
|
|
||
|
|
def wait(self, **kwargs):
|
||
|
|
acceptors = list(self.config.acceptors)
|
||
|
|
current_state = 'waiting'
|
||
|
|
# pop the invocation specific config
|
||
|
|
config = kwargs.pop('WaiterConfig', {})
|
||
|
|
sleep_amount = config.get('Delay', self.config.delay)
|
||
|
|
max_attempts = config.get('MaxAttempts', self.config.max_attempts)
|
||
|
|
num_attempts = 0
|
||
|
|
|
||
|
|
while True:
|
||
|
|
response = self._operation_method(**kwargs)
|
||
|
|
num_attempts += 1
|
||
|
|
for acceptor in acceptors:
|
||
|
|
if acceptor.matcher_func(response):
|
||
|
|
current_state = acceptor.state
|
||
|
|
break
|
||
|
|
else:
|
||
|
|
# If none of the acceptors matched, we should
|
||
|
|
# transition to the failure state if an error
|
||
|
|
# response was received.
|
||
|
|
if 'Error' in response:
|
||
|
|
# Transition to a failure state, which we
|
||
|
|
# can just handle here by raising an exception.
|
||
|
|
raise WaiterError(
|
||
|
|
name=self.name,
|
||
|
|
reason=response['Error'].get('Message', 'Unknown'),
|
||
|
|
last_response=response
|
||
|
|
)
|
||
|
|
if current_state == 'success':
|
||
|
|
logger.debug("Waiting complete, waiter matched the "
|
||
|
|
"success state.")
|
||
|
|
return
|
||
|
|
if current_state == 'failure':
|
||
|
|
raise WaiterError(
|
||
|
|
name=self.name,
|
||
|
|
reason='Waiter encountered a terminal failure state',
|
||
|
|
last_response=response,
|
||
|
|
)
|
||
|
|
if num_attempts >= max_attempts:
|
||
|
|
raise WaiterError(
|
||
|
|
name=self.name,
|
||
|
|
reason='Max attempts exceeded',
|
||
|
|
last_response=response
|
||
|
|
)
|
||
|
|
time.sleep(sleep_amount)
|