python-botocore/botocore/regions.py
2022-05-25 15:10:07 -07:00

398 lines
14 KiB
Python

# Copyright 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.
"""Resolves regions and endpoints.
This module implements endpoint resolution, including resolving endpoints for a
given service and region and resolving the available endpoints for a service
in a specific AWS partition.
"""
import logging
import re
from botocore.exceptions import (
EndpointVariantError,
NoRegionError,
UnknownRegionError,
)
LOG = logging.getLogger(__name__)
DEFAULT_URI_TEMPLATE = '{service}.{region}.{dnsSuffix}' # noqa
DEFAULT_SERVICE_DATA = {'endpoints': {}}
class BaseEndpointResolver:
"""Resolves regions and endpoints. Must be subclassed."""
def construct_endpoint(self, service_name, region_name=None):
"""Resolves an endpoint for a service and region combination.
:type service_name: string
:param service_name: Name of the service to resolve an endpoint for
(e.g., s3)
:type region_name: string
:param region_name: Region/endpoint name to resolve (e.g., us-east-1)
if no region is provided, the first found partition-wide endpoint
will be used if available.
:rtype: dict
:return: Returns a dict containing the following keys:
- partition: (string, required) Resolved partition name
- endpointName: (string, required) Resolved endpoint name
- hostname: (string, required) Hostname to use for this endpoint
- sslCommonName: (string) sslCommonName to use for this endpoint.
- credentialScope: (dict) Signature version 4 credential scope
- region: (string) region name override when signing.
- service: (string) service name override when signing.
- signatureVersions: (list<string>) A list of possible signature
versions, including s3, v4, v2, and s3v4
- protocols: (list<string>) A list of supported protocols
(e.g., http, https)
- ...: Other keys may be included as well based on the metadata
"""
raise NotImplementedError
def get_available_partitions(self):
"""Lists the partitions available to the endpoint resolver.
:return: Returns a list of partition names (e.g., ["aws", "aws-cn"]).
"""
raise NotImplementedError
def get_available_endpoints(
self, service_name, partition_name='aws', allow_non_regional=False
):
"""Lists the endpoint names of a particular partition.
:type service_name: string
:param service_name: Name of a service to list endpoint for (e.g., s3)
:type partition_name: string
:param partition_name: Name of the partition to limit endpoints to.
(e.g., aws for the public AWS endpoints, aws-cn for AWS China
endpoints, aws-us-gov for AWS GovCloud (US) Endpoints, etc.
:type allow_non_regional: bool
:param allow_non_regional: Set to True to include endpoints that are
not regional endpoints (e.g., s3-external-1,
fips-us-gov-west-1, etc).
:return: Returns a list of endpoint names (e.g., ["us-east-1"]).
"""
raise NotImplementedError
class EndpointResolver(BaseEndpointResolver):
"""Resolves endpoints based on partition endpoint metadata"""
_UNSUPPORTED_DUALSTACK_PARTITIONS = ['aws-iso', 'aws-iso-b']
def __init__(self, endpoint_data):
"""
:param endpoint_data: A dict of partition data.
"""
if 'partitions' not in endpoint_data:
raise ValueError('Missing "partitions" in endpoint data')
self._endpoint_data = endpoint_data
def get_service_endpoints_data(self, service_name, partition_name='aws'):
for partition in self._endpoint_data['partitions']:
if partition['partition'] != partition_name:
continue
services = partition['services']
if service_name not in services:
continue
return services[service_name]['endpoints']
def get_available_partitions(self):
result = []
for partition in self._endpoint_data['partitions']:
result.append(partition['partition'])
return result
def get_available_endpoints(
self,
service_name,
partition_name='aws',
allow_non_regional=False,
endpoint_variant_tags=None,
):
result = []
for partition in self._endpoint_data['partitions']:
if partition['partition'] != partition_name:
continue
services = partition['services']
if service_name not in services:
continue
service_endpoints = services[service_name]['endpoints']
for endpoint_name in service_endpoints:
is_regional_endpoint = endpoint_name in partition['regions']
# Only regional endpoints can be modeled with variants
if endpoint_variant_tags and is_regional_endpoint:
variant_data = self._retrieve_variant_data(
service_endpoints[endpoint_name], endpoint_variant_tags
)
if variant_data:
result.append(endpoint_name)
elif allow_non_regional or is_regional_endpoint:
result.append(endpoint_name)
return result
def get_partition_dns_suffix(
self, partition_name, endpoint_variant_tags=None
):
for partition in self._endpoint_data['partitions']:
if partition['partition'] == partition_name:
if endpoint_variant_tags:
variant = self._retrieve_variant_data(
partition.get('defaults'), endpoint_variant_tags
)
if variant and 'dnsSuffix' in variant:
return variant['dnsSuffix']
else:
return partition['dnsSuffix']
return None
def construct_endpoint(
self,
service_name,
region_name=None,
partition_name=None,
use_dualstack_endpoint=False,
use_fips_endpoint=False,
):
if (
service_name == 's3'
and use_dualstack_endpoint
and region_name is None
):
region_name = 'us-east-1'
if partition_name is not None:
valid_partition = None
for partition in self._endpoint_data['partitions']:
if partition['partition'] == partition_name:
valid_partition = partition
if valid_partition is not None:
result = self._endpoint_for_partition(
valid_partition,
service_name,
region_name,
use_dualstack_endpoint,
use_fips_endpoint,
True,
)
return result
return None
# Iterate over each partition until a match is found.
for partition in self._endpoint_data['partitions']:
if use_dualstack_endpoint and (
partition['partition']
in self._UNSUPPORTED_DUALSTACK_PARTITIONS
):
continue
result = self._endpoint_for_partition(
partition,
service_name,
region_name,
use_dualstack_endpoint,
use_fips_endpoint,
)
if result:
return result
def get_partition_for_region(self, region_name):
for partition in self._endpoint_data['partitions']:
if self._region_match(partition, region_name):
return partition['partition']
raise UnknownRegionError(
region_name=region_name,
error_msg='No partition found for provided region_name.',
)
def _endpoint_for_partition(
self,
partition,
service_name,
region_name,
use_dualstack_endpoint,
use_fips_endpoint,
force_partition=False,
):
partition_name = partition["partition"]
if (
use_dualstack_endpoint
and partition_name in self._UNSUPPORTED_DUALSTACK_PARTITIONS
):
error_msg = (
"Dualstack endpoints are currently not supported"
" for %s partition" % partition_name
)
raise EndpointVariantError(tags=['dualstack'], error_msg=error_msg)
# Get the service from the partition, or an empty template.
service_data = partition['services'].get(
service_name, DEFAULT_SERVICE_DATA
)
# Use the partition endpoint if no region is supplied.
if region_name is None:
if 'partitionEndpoint' in service_data:
region_name = service_data['partitionEndpoint']
else:
raise NoRegionError()
resolve_kwargs = {
'partition': partition,
'service_name': service_name,
'service_data': service_data,
'endpoint_name': region_name,
'use_dualstack_endpoint': use_dualstack_endpoint,
'use_fips_endpoint': use_fips_endpoint,
}
# Attempt to resolve the exact region for this partition.
if region_name in service_data['endpoints']:
return self._resolve(**resolve_kwargs)
# Check to see if the endpoint provided is valid for the partition.
if self._region_match(partition, region_name) or force_partition:
# Use the partition endpoint if set and not regionalized.
partition_endpoint = service_data.get('partitionEndpoint')
is_regionalized = service_data.get('isRegionalized', True)
if partition_endpoint and not is_regionalized:
LOG.debug(
'Using partition endpoint for %s, %s: %s',
service_name,
region_name,
partition_endpoint,
)
resolve_kwargs['endpoint_name'] = partition_endpoint
return self._resolve(**resolve_kwargs)
LOG.debug(
'Creating a regex based endpoint for %s, %s',
service_name,
region_name,
)
return self._resolve(**resolve_kwargs)
def _region_match(self, partition, region_name):
if region_name in partition['regions']:
return True
if 'regionRegex' in partition:
return re.compile(partition['regionRegex']).match(region_name)
return False
def _retrieve_variant_data(self, endpoint_data, tags):
variants = endpoint_data.get('variants', [])
for variant in variants:
if set(variant['tags']) == set(tags):
result = variant.copy()
return result
def _create_tag_list(self, use_dualstack_endpoint, use_fips_endpoint):
tags = []
if use_dualstack_endpoint:
tags.append('dualstack')
if use_fips_endpoint:
tags.append('fips')
return tags
def _resolve_variant(
self, tags, endpoint_data, service_defaults, partition_defaults
):
result = {}
for variants in [endpoint_data, service_defaults, partition_defaults]:
variant = self._retrieve_variant_data(variants, tags)
if variant:
self._merge_keys(variant, result)
return result
def _resolve(
self,
partition,
service_name,
service_data,
endpoint_name,
use_dualstack_endpoint,
use_fips_endpoint,
):
endpoint_data = service_data.get('endpoints', {}).get(
endpoint_name, {}
)
if endpoint_data.get('deprecated'):
LOG.warning(
'Client is configured with the deprecated endpoint: %s'
% (endpoint_name)
)
service_defaults = service_data.get('defaults', {})
partition_defaults = partition.get('defaults', {})
tags = self._create_tag_list(use_dualstack_endpoint, use_fips_endpoint)
if tags:
result = self._resolve_variant(
tags, endpoint_data, service_defaults, partition_defaults
)
if result == {}:
error_msg = (
f"Endpoint does not exist for {service_name} "
f"in region {endpoint_name}"
)
raise EndpointVariantError(tags=tags, error_msg=error_msg)
self._merge_keys(endpoint_data, result)
else:
result = endpoint_data
# If dnsSuffix has not already been consumed from a variant definition
if 'dnsSuffix' not in result:
result['dnsSuffix'] = partition['dnsSuffix']
result['partition'] = partition['partition']
result['endpointName'] = endpoint_name
# Merge in the service defaults then the partition defaults.
self._merge_keys(service_defaults, result)
self._merge_keys(partition_defaults, result)
result['hostname'] = self._expand_template(
partition,
result['hostname'],
service_name,
endpoint_name,
result['dnsSuffix'],
)
if 'sslCommonName' in result:
result['sslCommonName'] = self._expand_template(
partition,
result['sslCommonName'],
service_name,
endpoint_name,
result['dnsSuffix'],
)
return result
def _merge_keys(self, from_data, result):
for key in from_data:
if key not in result:
result[key] = from_data[key]
def _expand_template(
self, partition, template, service_name, endpoint_name, dnsSuffix
):
return template.format(
service=service_name, region=endpoint_name, dnsSuffix=dnsSuffix
)