import logging import os from aws_lambda_powertools.shared.version import VERSION powertools_version = VERSION inject_header = True try: import botocore except ImportError: # if botocore failed to import, user might be using custom runtime and we can't inject header inject_header = False logger = logging.getLogger(__name__) EXEC_ENV = os.environ.get("AWS_EXECUTION_ENV", "NA") TARGET_SDK_EVENT = "request-created" FEATURE_PREFIX = "PT" DEFAULT_FEATURE = "no-op" HEADER_NO_OP = f"{FEATURE_PREFIX}/{DEFAULT_FEATURE}/{powertools_version} PTEnv/{EXEC_ENV}" def _initializer_botocore_session(session): """ This function is used to add an extra header for the User-Agent in the Botocore session, as described in the pull request: https://github.com/boto/botocore/pull/2682 Parameters ---------- session : botocore.session.Session The Botocore session to which the user-agent function will be registered. Raises ------ Exception If there is an issue while adding the extra header for the User-Agent. """ try: session.register(TARGET_SDK_EVENT, _create_feature_function(DEFAULT_FEATURE)) except Exception: logger.debug("Can't add extra header User-Agent") def _create_feature_function(feature): """ Create and return the `add_powertools_feature` function. The `add_powertools_feature` function is designed to be registered in boto3's event system. When registered, it appends the given feature string to the User-Agent header of AWS SDK requests. Parameters ---------- feature : str The feature string to be appended to the User-Agent header. Returns ------- add_powertools_feature : Callable The `add_powertools_feature` function that modifies the User-Agent header. """ def add_powertools_feature(request, **kwargs): try: headers = request.headers header_user_agent = ( f"{headers['User-Agent']} {FEATURE_PREFIX}/{feature}/{powertools_version} PTEnv/{EXEC_ENV}" ) # This function is exclusive to client and resources objects created in Powertools # and must remove the no-op header, if present if HEADER_NO_OP in headers["User-Agent"] and feature != DEFAULT_FEATURE: # Remove HEADER_NO_OP + space header_user_agent = header_user_agent.replace(f"{HEADER_NO_OP} ", "") headers["User-Agent"] = f"{header_user_agent}" except Exception: logger.debug("Can't find User-Agent header") return add_powertools_feature # Add feature user-agent to given sdk boto3.session def register_feature_to_session(session, feature): """ Register the given feature string to the event system of the provided boto3 session and append the feature to the User-Agent header of the request Parameters ---------- session : boto3.session.Session The boto3 session to which the feature will be registered. feature : str The feature string to be appended to the User-Agent header, e.g., "streaming" in Powertools. Raises ------ AttributeError If the provided session does not have an event system. """ try: session.events.register(TARGET_SDK_EVENT, _create_feature_function(feature)) except AttributeError as e: logger.debug(f"session passed in doesn't have a event system:{e}") # Add feature user-agent to given sdk botocore.session.Session def register_feature_to_botocore_session(botocore_session, feature): """ Register the given feature string to the event system of the provided botocore session Please notice this function is for patching botocore session and is different from previous one which is for patching boto3 session Parameters ---------- botocore_session : botocore.session.Session The botocore session to which the feature will be registered. feature : str The feature string to be appended to the User-Agent header, e.g., "data-masking" in Powertools. Raises ------ AttributeError If the provided session does not have an event system. Examples -------- **register data-masking user-agent to botocore session** >>> from aws_lambda_powertools.shared.user_agent import ( >>> register_feature_to_botocore_session >>> ) >>> >>> session = botocore.session.Session() >>> register_feature_to_botocore_session(botocore_session=session, feature="data-masking") >>> key_provider = StrictAwsKmsMasterKeyProvider(key_ids=self.keys, botocore_session=session) """ try: botocore_session.register(TARGET_SDK_EVENT, _create_feature_function(feature)) except AttributeError as e: logger.debug(f"botocore session passed in doesn't have a event system:{e}") # Add feature user-agent to given sdk boto3.client def register_feature_to_client(client, feature): """ Register the given feature string to the event system of the provided boto3 client and append the feature to the User-Agent header of the request Parameters ---------- client : boto3.session.Session.client The boto3 client to which the feature will be registered. feature : str The feature string to be appended to the User-Agent header, e.g., "streaming" in Powertools. Raises ------ AttributeError If the provided client does not have an event system. """ try: client.meta.events.register(TARGET_SDK_EVENT, _create_feature_function(feature)) except AttributeError as e: logger.debug(f"session passed in doesn't have a event system:{e}") # Add feature user-agent to given sdk boto3.resource def register_feature_to_resource(resource, feature): """ Register the given feature string to the event system of the provided boto3 resource and append the feature to the User-Agent header of the request Parameters ---------- resource : boto3.session.Session.resource The boto3 resource to which the feature will be registered. feature : str The feature string to be appended to the User-Agent header, e.g., "streaming" in Powertools. Raises ------ AttributeError If the provided resource does not have an event system. """ try: resource.meta.client.meta.events.register(TARGET_SDK_EVENT, _create_feature_function(feature)) except AttributeError as e: logger.debug(f"resource passed in doesn't have a event system:{e}") def inject_user_agent(): if inject_header: # Some older botocore versions doesn't support register_initializer. In those cases, we disable the feature. if not hasattr(botocore, "register_initializer"): return # Customize botocore session to inject Powertools header # See: https://github.com/boto/botocore/pull/2682 botocore.register_initializer(_initializer_botocore_session)