Mini Shell
# Copyright 2018 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.
"""This module contains the inteface for controlling how configuration
is loaded.
"""
import logging
import os
from botocore import utils
logger = logging.getLogger(__name__)
#: A default dictionary that maps the logical names for session variables
#: to the specific environment variables and configuration file names
#: that contain the values for these variables.
#: When creating a new Session object, you can pass in your own dictionary
#: to remap the logical names or to add new logical names. You can then
#: get the current value for these variables by using the
#: ``get_config_variable`` method of the :class:`botocore.session.Session`
#: class.
#: These form the keys of the dictionary. The values in the dictionary
#: are tuples of (<config_name>, <environment variable>, <default value>,
#: <conversion func>).
#: The conversion func is a function that takes the configuration value
#: as an argument and returns the converted value. If this value is
#: None, then the configuration value is returned unmodified. This
#: conversion function can be used to type convert config values to
#: values other than the default values of strings.
#: The ``profile`` and ``config_file`` variables should always have a
#: None value for the first entry in the tuple because it doesn't make
#: sense to look inside the config file for the location of the config
#: file or for the default profile to use.
#: The ``config_name`` is the name to look for in the configuration file,
#: the ``env var`` is the OS environment variable (``os.environ``) to
#: use, and ``default_value`` is the value to use if no value is otherwise
#: found.
BOTOCORE_DEFAUT_SESSION_VARIABLES = {
# logical: config_file, env_var, default_value, conversion_func
'profile': (None, ['AWS_DEFAULT_PROFILE', 'AWS_PROFILE'], None, None),
'region': ('region', 'AWS_DEFAULT_REGION', None, None),
'data_path': ('data_path', 'AWS_DATA_PATH', None, None),
'config_file': (None, 'AWS_CONFIG_FILE', '~/.aws/config', None),
'ca_bundle': ('ca_bundle', 'AWS_CA_BUNDLE', None, None),
'api_versions': ('api_versions', None, {}, None),
# This is the shared credentials file amongst sdks.
'credentials_file': (None, 'AWS_SHARED_CREDENTIALS_FILE',
'~/.aws/credentials', None),
# These variables only exist in the config file.
# This is the number of seconds until we time out a request to
# the instance metadata service.
'metadata_service_timeout': (
'metadata_service_timeout',
'AWS_METADATA_SERVICE_TIMEOUT', 1, int),
# This is the number of request attempts we make until we give
# up trying to retrieve data from the instance metadata service.
'metadata_service_num_attempts': (
'metadata_service_num_attempts',
'AWS_METADATA_SERVICE_NUM_ATTEMPTS', 1, int),
'ec2_metadata_service_endpoint': (
'ec2_metadata_service_endpoint',
'AWS_EC2_METADATA_SERVICE_ENDPOINT',
None, None),
'imds_use_ipv6': (
'imds_use_ipv6',
'AWS_IMDS_USE_IPV6',
False, None),
'parameter_validation': ('parameter_validation', None, True, None),
# Client side monitoring configurations.
# Note: These configurations are considered internal to botocore.
# Do not use them until publicly documented.
'csm_enabled': (
'csm_enabled', 'AWS_CSM_ENABLED', False, utils.ensure_boolean),
'csm_host': ('csm_host', 'AWS_CSM_HOST', '127.0.0.1', None),
'csm_port': ('csm_port', 'AWS_CSM_PORT', 31000, int),
'csm_client_id': ('csm_client_id', 'AWS_CSM_CLIENT_ID', '', None),
# Endpoint discovery configuration
'endpoint_discovery_enabled': (
'endpoint_discovery_enabled', 'AWS_ENDPOINT_DISCOVERY_ENABLED',
'auto', None),
'sts_regional_endpoints': (
'sts_regional_endpoints', 'AWS_STS_REGIONAL_ENDPOINTS', 'legacy',
None
),
'retry_mode': ('retry_mode', 'AWS_RETRY_MODE', 'legacy', None),
# We can't have a default here for v1 because we need to defer to
# whatever the defaults are in _retry.json.
'max_attempts': ('max_attempts', 'AWS_MAX_ATTEMPTS', None, int),
}
# A mapping for the s3 specific configuration vars. These are the configuration
# vars that typically go in the s3 section of the config file. This mapping
# follows the same schema as the previous session variable mapping.
DEFAULT_S3_CONFIG_VARS = {
'addressing_style': (
('s3', 'addressing_style'), None, None, None),
'use_accelerate_endpoint': (
('s3', 'use_accelerate_endpoint'), None, None, utils.ensure_boolean
),
'use_dualstack_endpoint': (
('s3', 'use_dualstack_endpoint'), None, None, utils.ensure_boolean
),
'payload_signing_enabled': (
('s3', 'payload_signing_enabled'), None, None, utils.ensure_boolean
),
'use_arn_region': (
['s3_use_arn_region',
('s3', 'use_arn_region')],
'AWS_S3_USE_ARN_REGION', None, utils.ensure_boolean
),
'us_east_1_regional_endpoint': (
['s3_us_east_1_regional_endpoint',
('s3', 'us_east_1_regional_endpoint')],
'AWS_S3_US_EAST_1_REGIONAL_ENDPOINT', None, None
)
}
# A mapping for the proxy specific configuration vars. These are
# used to configure how botocore interacts with proxy setups while
# sending requests.
DEFAULT_PROXIES_CONFIG_VARS = {
'proxy_ca_bundle': ('proxy_ca_bundle', None, None, None),
'proxy_client_cert': ('proxy_client_cert', None, None, None),
'proxy_use_forwarding_for_https': (
'proxy_use_forwarding_for_https', None, None, utils.normalize_boolean),
}
def create_botocore_default_config_mapping(session):
chain_builder = ConfigChainFactory(session=session)
config_mapping = _create_config_chain_mapping(
chain_builder, BOTOCORE_DEFAUT_SESSION_VARIABLES)
config_mapping['s3'] = SectionConfigProvider(
's3', session, _create_config_chain_mapping(
chain_builder, DEFAULT_S3_CONFIG_VARS)
)
config_mapping['proxies_config'] = SectionConfigProvider(
'proxies_config', session, _create_config_chain_mapping(
chain_builder, DEFAULT_PROXIES_CONFIG_VARS)
)
return config_mapping
def _create_config_chain_mapping(chain_builder, config_variables):
mapping = {}
for logical_name, config in config_variables.items():
mapping[logical_name] = chain_builder.create_config_chain(
instance_name=logical_name,
env_var_names=config[1],
config_property_names=config[0],
default=config[2],
conversion_func=config[3]
)
return mapping
class ConfigChainFactory(object):
"""Factory class to create our most common configuration chain case.
This is a convenience class to construct configuration chains that follow
our most common pattern. This is to prevent ordering them incorrectly,
and to make the config chain construction more readable.
"""
def __init__(self, session, environ=None):
"""Initialize a ConfigChainFactory.
:type session: :class:`botocore.session.Session`
:param session: This is the session that should be used to look up
values from the config file.
:type environ: dict
:param environ: A mapping to use for environment variables. If this
is not provided it will default to use os.environ.
"""
self._session = session
if environ is None:
environ = os.environ
self._environ = environ
def create_config_chain(self, instance_name=None, env_var_names=None,
config_property_names=None, default=None,
conversion_func=None):
"""Build a config chain following the standard botocore pattern.
In botocore most of our config chains follow the the precendence:
session_instance_variables, environment, config_file, default_value.
This is a convenience function for creating a chain that follow
that precendence.
:type instance_name: str
:param instance_name: This indicates what session instance variable
corresponds to this config value. If it is None it will not be
added to the chain.
:type env_var_names: str or list of str or None
:param env_var_names: One or more environment variable names to
search for this value. They are searched in order. If it is None
it will not be added to the chain.
:type config_property_names: str/tuple or list of str/tuple or None
:param config_property_names: One of more strings or tuples
representing the name of the key in the config file for this
config option. They are searched in order. If it is None it will
not be added to the chain.
:type default: Any
:param default: Any constant value to be returned.
:type conversion_func: None or callable
:param conversion_func: If this value is None then it has no effect on
the return type. Otherwise, it is treated as a function that will
conversion_func our provided type.
:rvalue: ConfigChain
:returns: A ConfigChain that resolves in the order env_var_names ->
config_property_name -> default. Any values that were none are
omitted form the chain.
"""
providers = []
if instance_name is not None:
providers.append(
InstanceVarProvider(
instance_var=instance_name,
session=self._session
)
)
if env_var_names is not None:
providers.extend(self._get_env_providers(env_var_names))
if config_property_names is not None:
providers.extend(
self._get_scoped_config_providers(config_property_names)
)
if default is not None:
providers.append(ConstantProvider(value=default))
return ChainProvider(
providers=providers,
conversion_func=conversion_func,
)
def _get_env_providers(self, env_var_names):
env_var_providers = []
if not isinstance(env_var_names, list):
env_var_names = [env_var_names]
for env_var_name in env_var_names:
env_var_providers.append(
EnvironmentProvider(name=env_var_name, env=self._environ)
)
return env_var_providers
def _get_scoped_config_providers(self, config_property_names):
scoped_config_providers = []
if not isinstance(config_property_names, list):
config_property_names = [config_property_names]
for config_property_name in config_property_names:
scoped_config_providers.append(
ScopedConfigProvider(
config_var_name=config_property_name,
session=self._session,
)
)
return scoped_config_providers
class ConfigValueStore(object):
"""The ConfigValueStore object stores configuration values."""
def __init__(self, mapping=None):
"""Initialize a ConfigValueStore.
:type mapping: dict
:param mapping: The mapping parameter is a map of string to a subclass
of BaseProvider. When a config variable is asked for via the
get_config_variable method, the corresponding provider will be
invoked to load the value.
"""
self._overrides = {}
self._mapping = {}
if mapping is not None:
for logical_name, provider in mapping.items():
self.set_config_provider(logical_name, provider)
def get_config_variable(self, logical_name):
"""
Retrieve the value associeated with the specified logical_name
from the corresponding provider. If no value is found None will
be returned.
:type logical_name: str
:param logical_name: The logical name of the session variable
you want to retrieve. This name will be mapped to the
appropriate environment variable name for this session as
well as the appropriate config file entry.
:returns: value of variable or None if not defined.
"""
if logical_name in self._overrides:
return self._overrides[logical_name]
if logical_name not in self._mapping:
return None
provider = self._mapping[logical_name]
return provider.provide()
def set_config_variable(self, logical_name, value):
"""Set a configuration variable to a specific value.
By using this method, you can override the normal lookup
process used in ``get_config_variable`` by explicitly setting
a value. Subsequent calls to ``get_config_variable`` will
use the ``value``. This gives you per-session specific
configuration values.
::
>>> # Assume logical name 'foo' maps to env var 'FOO'
>>> os.environ['FOO'] = 'myvalue'
>>> s.get_config_variable('foo')
'myvalue'
>>> s.set_config_variable('foo', 'othervalue')
>>> s.get_config_variable('foo')
'othervalue'
:type logical_name: str
:param logical_name: The logical name of the session variable
you want to set. These are the keys in ``SESSION_VARIABLES``.
:param value: The value to associate with the config variable.
"""
self._overrides[logical_name] = value
def clear_config_variable(self, logical_name):
"""Remove an override config variable from the session.
:type logical_name: str
:param logical_name: The name of the parameter to clear the override
value from.
"""
self._overrides.pop(logical_name, None)
def set_config_provider(self, logical_name, provider):
"""Set the provider for a config value.
This provides control over how a particular configuration value is
loaded. This replaces the provider for ``logical_name`` with the new
``provider``.
:type logical_name: str
:param logical_name: The name of the config value to change the config
provider for.
:type provider: :class:`botocore.configprovider.BaseProvider`
:param provider: The new provider that should be responsible for
providing a value for the config named ``logical_name``.
"""
self._mapping[logical_name] = provider
class BaseProvider(object):
"""Base class for configuration value providers.
A configuration provider has some method of providing a configuration
value.
"""
def provide(self):
"""Provide a config value."""
raise NotImplementedError('provide')
class ChainProvider(BaseProvider):
"""This provider wraps one or more other providers.
Each provider in the chain is called, the first one returning a non-None
value is then returned.
"""
def __init__(self, providers=None, conversion_func=None):
"""Initalize a ChainProvider.
:type providers: list
:param providers: The initial list of providers to check for values
when invoked.
:type conversion_func: None or callable
:param conversion_func: If this value is None then it has no affect on
the return type. Otherwise, it is treated as a function that will
transform provided value.
"""
if providers is None:
providers = []
self._providers = providers
self._conversion_func = conversion_func
def provide(self):
"""Provide the value from the first provider to return non-None.
Each provider in the chain has its provide method called. The first
one in the chain to return a non-None value is the returned from the
ChainProvider. When no non-None value is found, None is returned.
"""
for provider in self._providers:
value = provider.provide()
if value is not None:
return self._convert_type(value)
return None
def _convert_type(self, value):
if self._conversion_func is not None:
return self._conversion_func(value)
return value
def __repr__(self):
return '[%s]' % ', '.join([str(p) for p in self._providers])
class InstanceVarProvider(BaseProvider):
"""This class loads config values from the session instance vars."""
def __init__(self, instance_var, session):
"""Initialize InstanceVarProvider.
:type instance_var: str
:param instance_var: The instance variable to load from the session.
:type session: :class:`botocore.session.Session`
:param session: The botocore session to get the loaded configuration
file variables from.
"""
self._instance_var = instance_var
self._session = session
def provide(self):
"""Provide a config value from the session instance vars."""
instance_vars = self._session.instance_variables()
value = instance_vars.get(self._instance_var)
return value
def __repr__(self):
return 'InstanceVarProvider(instance_var=%s, session=%s)' % (
self._instance_var,
self._session,
)
class ScopedConfigProvider(BaseProvider):
def __init__(self, config_var_name, session):
"""Initialize ScopedConfigProvider.
:type config_var_name: str or tuple
:param config_var_name: The name of the config variable to load from
the configuration file. If the value is a tuple, it must only
consist of two items, where the first item represents the section
and the second item represents the config var name in the section.
:type session: :class:`botocore.session.Session`
:param session: The botocore session to get the loaded configuration
file variables from.
"""
self._config_var_name = config_var_name
self._session = session
def provide(self):
"""Provide a value from a config file property."""
scoped_config = self._session.get_scoped_config()
if isinstance(self._config_var_name, tuple):
section_config = scoped_config.get(self._config_var_name[0])
if not isinstance(section_config, dict):
return None
return section_config.get(self._config_var_name[1])
return scoped_config.get(self._config_var_name)
def __repr__(self):
return 'ScopedConfigProvider(config_var_name=%s, session=%s)' % (
self._config_var_name,
self._session,
)
class EnvironmentProvider(BaseProvider):
"""This class loads config values from environment variables."""
def __init__(self, name, env):
"""Initialize with the keys in the dictionary to check.
:type name: str
:param name: The key with that name will be loaded and returned.
:type env: dict
:param env: Environment variables dictionary to get variables from.
"""
self._name = name
self._env = env
def provide(self):
"""Provide a config value from a source dictionary."""
if self._name in self._env:
return self._env[self._name]
return None
def __repr__(self):
return 'EnvironmentProvider(name=%s, env=%s)' % (self._name, self._env)
class SectionConfigProvider(BaseProvider):
"""Provides a dictionary from a section in the scoped config
This is useful for retrieving scoped config variables (i.e. s3) that have
their own set of config variables and resolving logic.
"""
def __init__(self, section_name, session, override_providers=None):
self._section_name = section_name
self._session = session
self._scoped_config_provider = ScopedConfigProvider(
self._section_name, self._session)
self._override_providers = override_providers
if self._override_providers is None:
self._override_providers = {}
def provide(self):
section_config = self._scoped_config_provider.provide()
if section_config and not isinstance(section_config, dict):
logger.debug("The %s config key is not a dictionary type, "
"ignoring its value of: %s", self._section_name,
section_config)
return None
for section_config_var, provider in self._override_providers.items():
provider_val = provider.provide()
if provider_val is not None:
if section_config is None:
section_config = {}
section_config[section_config_var] = provider_val
return section_config
def __repr__(self):
return (
'SectionConfigProvider(section_name=%s, '
'session=%s, override_providers=%s)' % (
self._section_name, self._session,
self._override_providers,
)
)
class ConstantProvider(BaseProvider):
"""This provider provides a constant value."""
def __init__(self, value):
self._value = value
def provide(self):
"""Provide the constant value given during initialization."""
return self._value
def __repr__(self):
return 'ConstantProvider(value=%s)' % self._value
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