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aws_service.py

aws_service.py demonstrates how to create an API Gateway REST interface to an AWS service.

# Copyright 2010-2019 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 argparse import json import logging import os import boto3 from botocore.exceptions import ClientError import requests # Amazon Translate target language code # To translate text to another language, change this setting to the desired code TARGET_LANGUAGE_CODE = 'fr' # Configuration settings. Change as desired REGION = 'us-east-1' # AWS region in which to create resources API_NAME = 'AmazonTranslateAPI' # API name in API Gateway API_RESOURCE_NAME = 'translate' # As in https:/my_api/translate API_STAGE = 'dev' # API Gateway stage API_QUERY_PARAM = 'text' # Required query parameter API_TRANSLATE_IAM_ROLE = 'apigateway_translate_role' # IAM role name CONFIG_FILENAME = 'config.txt' # Disk file to store API settings def create_iam_role_for_apigateway(iam_role_name): """Create an IAM role to enable the API Gateway to call the Amazon Translate service :param iam_role_name: Name of IAM role :return: ARN of IAM role. If error, returns None. """ # API Gateway trusted relationship policy document apigateway_assume_role = { 'Version': '2012-10-17', 'Statement': [ { 'Sid': '', 'Effect': 'Allow', 'Principal': { 'Service': 'apigateway.amazonaws.com' }, 'Action': 'sts:AssumeRole' } ] } iam_client = boto3.client('iam') try: result = iam_client.create_role(RoleName=iam_role_name, AssumeRolePolicyDocument=json.dumps(apigateway_assume_role)) except ClientError as e: logging.error(e) return None apigateway_role_arn = result['Role']['Arn'] # Attach the AWS-managed TranslateReadOnly policy to the role apigateway_policy_arn = 'arn:aws:iam::aws:policy/TranslateReadOnly' try: iam_client.attach_role_policy(RoleName=iam_role_name, PolicyArn=apigateway_policy_arn) except ClientError as e: logging.error(e) return None ''' # Debug: Verify policy is attached to the role try: response = iam_client.list_attached_role_policies(RoleName=iam_role_name) except ClientError as e: logging.error(e) else: for policy in response['AttachedPolicies']: logging.debug(f'Role: {iam_role_name}, ' f'Attached Policy: {policy["PolicyName"]}, ' f'ARN: {policy["PolicyArn"]}') ''' # Return the ARN of the created IAM role return apigateway_role_arn def delete_iam_role(role_name): """Detach all managed policies from an IAM role and delete the role :param role_name: String name of IAM role to delete """ # Retrieve all policies attached to the role iam_client = boto3.client('iam') try: response = iam_client.list_attached_role_policies(RoleName=role_name) except ClientError as e: logging.error(e) return # Detach each policy while True: for policy in response['AttachedPolicies']: try: iam_client.detach_role_policy(RoleName=role_name, PolicyArn=policy['PolicyArn']) except ClientError as e: logging.error(e) # Process next attached policy # Is there another batch of policies? if response['IsTruncated']: # Get another batch try: response = iam_client.list_attached_role_policies(Marker=response['Marker']) except ClientError as e: logging.error(e) break else: logging.info(f'Detached all policies from IAM role {role_name}') break # Delete the role try: iam_client.delete_role(RoleName=role_name) except ClientError as e: logging.error(e) else: logging.info(f'Deleted IAM role: {role_name}') def create_rest_api_for_aws_service(api_name, region): """Create a REST API for the Amazon Translate service The REST API defines a child called API_RESOURCE_NAME and a stage called API_STAGE. The service infrastructure creates an API key, which must be included in an X-API-Key header of each API call. :param api_name: Name of the REST API :param region: Region in which to create the API resources :return: URL of API. If error, returns None. """ # Create initial REST API api_client = boto3.client('apigateway', region_name=REGION) try: result = api_client.create_rest_api(name=api_name, apiKeySource='HEADER') except ClientError as e: logging.error(e) return None api_id = result['id'] logging.info(f'Created REST API: {result["name"]}, ID: {api_id}') # Get the ID of the API's root resource try: result = api_client.get_resources(restApiId=api_id) except ClientError as e: logging.error(e) return None root_id = None for item in result['items']: if item['path'] == '/': root_id = item['id'] break if root_id is None: logging.error('Could not retrieve the ID of the API\'s root resource.') return None # Define a child resource called API_RESOURCE_NAME under the root resource try: result = api_client.create_resource(restApiId=api_id, parentId=root_id, pathPart=API_RESOURCE_NAME) except ClientError as e: logging.error(e) return None resource_id = result['id'] # Create a request validator to validate the query string parameters # and headers try: result = api_client.create_request_validator(restApiId=api_id, name='TranslateAPIValidator', # validateRequestBody=False, validateRequestParameters=True) except ClientError as e: logging.error(e) return None validator_id = result['id'] # Define a GET method on the /API_RESOURCE_NAME resource # The method accepts a required 'text' query parameter. request_parameters = {f'method.request.querystring.{API_QUERY_PARAM}': True} try: api_client.put_method(restApiId=api_id, resourceId=resource_id, httpMethod='GET', authorizationType='NONE', apiKeyRequired=True, requestParameters=request_parameters, requestValidatorId=validator_id) except ClientError as e: logging.error(e) return None # Set the content-type of the API's GET method response to JSON content_type = {'application/json': 'Empty'} try: api_client.put_method_response(restApiId=api_id, resourceId=resource_id, httpMethod='GET', statusCode='200', responseModels=content_type) except ClientError as e: logging.error(e) return None # Create IAM role with permissions to access the Amazon Translate service iam_role_arn = create_iam_role_for_apigateway(API_TRANSLATE_IAM_ROLE) if iam_role_arn is None: return None # Construct the URI for the Amazon Translate.TranslateText service # Note: A bug exists in the processing of the Translate URI. Specifically, # passing the correct service value of 'translate' to put_integration() # does not link the integration to the Translate service. Instead, to link # the integration, the service must be specified as 'Translate' (uppercase # 'T'). However, having 'Translate' in the URI causes the subsequent call # to create_deployment() to fail with an unrecognized service. The # workaround is to use the 'translate' service in the URI for both # put_integration() and create_deployment(). Then to link the integration # to the service, call update_integration() to replace the URI to use # 'Translate'. After this bug is fixed, the translate_uri_updated variable # defined below can be removed, along with the call to update_integration() # later in this function. translate_uri = f'arn:aws:apigateway:{region}:translate:action/TranslateText' translate_uri_updated = f'arn:aws:apigateway:{region}:Translate:action/TranslateText' # Specify the request headers that the Translate service requires # Other AWS services would have their own unique requirements request_parameters = {'integration.request.header.Content-Type': "'application/x-amz-json-1.1'", 'integration.request.header.X-Amz-Target': "'AWSShineFrontendService_20170701.TranslateText'"} # Define the TranslateText arguments translate_args = { 'SourceLanguageCode': 'auto', 'TargetLanguageCode': TARGET_LANGUAGE_CODE, 'Text': f"$input.params('{API_QUERY_PARAM}')" } request_templates = {'application/json': json.dumps(translate_args)} try: api_client.put_integration(restApiId=api_id, resourceId=resource_id, httpMethod='GET', type='AWS', integrationHttpMethod='POST', credentials=iam_role_arn, requestParameters=request_parameters, requestTemplates=request_templates, uri=translate_uri, passthroughBehavior='WHEN_NO_TEMPLATES') except ClientError as e: logging.error(e) return None # Set the content-type of the TranslateText function to JSON content_type = {'application/json': ''} try: api_client.put_integration_response(restApiId=api_id, resourceId=resource_id, httpMethod='GET', statusCode='200', responseTemplates=content_type) except ClientError as e: logging.error(e) return None # Deploy the API try: api_client.create_deployment(restApiId=api_id, stageName=API_STAGE) except ClientError as e: logging.error(e) return None # Create an API key try: result = api_client.create_api_key(name='TranslateAPIKey', description=f'API key for {API_NAME}', enabled=True) except ClientError as e: logging.error(e) return None api_key_id = result['id'] api_key_value = result['value'] # Create a usage plan api_stages = [ { 'apiId': api_id, 'stage': API_STAGE, 'throttle': { f'/{API_RESOURCE_NAME}/GET': { 'burstLimit': 100, 'rateLimit': 10.0, } } } ] throttle = { 'burstLimit': 100, 'rateLimit': 10.0, } quota = { 'limit': 100, 'period': 'DAY', } try: result = api_client.create_usage_plan(name='TranslateAPIUsagePlan', description=f'Usage plan for {API_NAME}', apiStages=api_stages, throttle=throttle, quota=quota) except ClientError as e: logging.error(e) return None usage_plan_id = result['id'] # Attach the API key to the usage plan try: result = api_client.create_usage_plan_key(usagePlanId=usage_plan_id, keyId=api_key_id, keyType='API_KEY') except ClientError as e: logging.error(e) return None # Workaround for the 'translate/Translate' bug patch_uri = [{ 'path': '/uri', 'value': translate_uri_updated, 'op': 'replace' }] try: api_client.update_integration(restApiId=api_id, resourceId=resource_id, httpMethod='GET', patchOperations=patch_uri) except ClientError as e: logging.error(e) # Note: When the bug is fixed, this operation will be unnecessary and # will probably fail. Thus, in the case of failure, rather than # returning None here, we instead continue program execution. # Construct the API URL api_url = f'https://{api_id}.execute-api.{region}.amazonaws.com/{API_STAGE}/{API_RESOURCE_NAME}' logging.info(f'API base URL: {api_url}') # Save the API settings for subsequent use and deletion save_config_file(api_url, api_key_id, api_key_value, usage_plan_id) return api_url def get_rest_api_id(api_name, region): """Retrieve the ID of an API Gateway REST API :param api_name: Name of API Gateway REST API :param region: Region API is located :return: Retrieved API ID. If API not found or error, returns None. """ # Retrieve a batch of APIs api_client = boto3.client('apigateway', region_name=region) try: apis = api_client.get_rest_apis() except ClientError as e: logging.error(e) return None # Search the batch while True: for api in apis['items']: if api['name'] == api_name: # Found the API we're searching for return api['id'] # Is there another batch of APIs? if 'position' in apis: # Get another batch try: apis = api_client.get_rest_apis(position=apis['position']) except ClientError as e: logging.error(e) return None else: # API not found logging.error(f'API {api_name} was not found.') return None def delete_rest_api(api_name, region): """Delete an API Gateway API object, including all resources, stages, etc. :param api_name: Name of API object to delete :param region: Region API is located """ # Delete all versions of the API Gateway object and associated resources api_client = boto3.client('apigateway', region_name=region) api_id = get_rest_api_id(api_name, region) if api_id is not None: try: api_client.delete_rest_api(restApiId=api_id) except ClientError as e: logging.error(e) # Delete the API Gateway-Translate IAM role delete_iam_role(API_TRANSLATE_IAM_ROLE) # Delete the usage plan and API key config_settings = load_config_file() if config_settings is not None: try: api_client.delete_usage_plan_key(usagePlanId=config_settings['usagePlanId'], keyId=config_settings['apiKeyId']) api_client.delete_usage_plan(usagePlanId=config_settings['usagePlanId']) api_client.delete_api_key(apiKey=config_settings['apiKeyId']) except ClientError as e: logging.error(e) # Delete the configuration file delete_config_file() def translate_text(text): """Translate text The translation is performed by making an HTTPS call. No need for AWS credentials or an AWS SDK. Uses the Python requests package (pip install requests) :param text: Text to translate :return: String of translated text. If error, returns None. """ # Load the API URL and API key value from the config file config_settings = load_config_file() if config_settings is None: logging.error('The Translate configuration settings do not exist') return None payload = {f'{API_QUERY_PARAM}': text} headers = {'X-API-Key': config_settings['apiKeyValue']} try: response = requests.get(config_settings['url'], params=payload, headers=headers, timeout=30) except requests.exceptions.RequestException as e: logging.error(e) return None # Process the response if response.status_code == 403: logging.error('Access to the Translate API is forbidden') return None if response.status_code == 200: # Decode the bytes content to a UTF-8 string and load into a dict text_decoded = response.content.decode('utf-8') translated_text = json.loads(text_decoded) logging.debug(f'Translation Response: {text_decoded}') # Return the translated text if 'TranslatedText' in translated_text: return translated_text['TranslatedText'] # Error occurred during translation if '__type' in translated_text: logging.error(translated_text['__type']) else: logging.error('Unknown error occurred during translation') return None def save_config_file(api_url, api_key_id, api_key_value, usage_plan_id): """Save the API's settings in a disk file :param api_url: API URL :param api_key_id: API key ID :param api_key_value: Value of API key :param usage_plan_id: Usage plan ID """ # Store the API's configuration settings in a disk file with open(CONFIG_FILENAME, 'w') as fp: fp.write(api_url + '\n') fp.write(api_key_id + '\n') fp.write(api_key_value + '\n') fp.write(usage_plan_id + '\n') def load_config_file(): """Read the Translate API's configuration settings from a disk file :return: Dict of configuration settings. If error, return None. """ # Does the URL file exist? if not os.path.isfile(CONFIG_FILENAME): logging.error(f'The {CONFIG_FILENAME} file does not exist') return None # Read the URL file with open(CONFIG_FILENAME) as fp: url = fp.readline().rstrip() api_key_id = fp.readline().rstrip() api_key_value = fp.readline().rstrip() usage_plan_id = fp.readline().rstrip() # Return config settings in a dict config_settings = { 'url': url, 'apiKeyId': api_key_id, 'apiKeyValue': api_key_value, 'usagePlanId': usage_plan_id, } return config_settings def delete_config_file(): """Delete the saved-URL disk file""" if os.path.isfile(CONFIG_FILENAME): os.remove(CONFIG_FILENAME) def load_src_text_file(src_text_file): """Read a file containing text to translate :param src_text_file: File with text to translate :return: String of text to translate. If error, return None. """ # Does the file exist? if not os.path.isfile(src_text_file): logging.error(f'The {src_text_file} file does not exist') return None # Read the file with open(src_text_file) as fp: text = fp.read() return text def main(): """Exercise the module's API Gateway functions""" # Set up logging logging.basicConfig(level=logging.DEBUG, format='%(levelname)s: %(asctime)s: %(message)s') # Process command-line arguments arg_parser = argparse.ArgumentParser(description='WebSocket Example') arg_parser.add_argument('-d', '--delete', action='store_true', help='delete allocated resources') arg_parser.add_argument('-f', '--file', help='file with text to translate') arg_parser.add_argument('-t', '--text', help='text to translate') args = arg_parser.parse_args() delete_resources = args.delete src_text_file = args.file src_text = args.text # Delete the allocated API Gateway resources? if delete_resources: delete_rest_api(API_NAME, REGION) logging.info(f'Deleted API: {API_NAME}') exit(0) # File with text to translate? if src_text_file is not None: src_text = load_src_text_file(src_text_file) if src_text is None: exit(1) # Else fall through to the next code block to translate the text # Text to translate? if src_text is not None: # Pass the text to the API service translated_text = translate_text(src_text) if translated_text is not None: logging.info(f'Translated Text: {translated_text}') # If src_text was read from a file, write the translated text # to a file if src_text_file is not None: filename = f'{src_text_file}.{TARGET_LANGUAGE_CODE}' with open(filename, 'w') as fp: fp.write(translated_text) logging.info(f'Saved translated text to {filename}') exit(0) # Create an API Gateway REST interface for the Amazon Translate service api_url = create_rest_api_for_aws_service(API_NAME, REGION) if api_url is None: exit(1) logging.info(f'Translate service TranslateText URL: {api_url}') logging.info('To translate text with the API, run the program with the option -t "Text to translate"') if __name__ == '__main__': main()

Sample Details

Service: apigateway

Last tested: 2019-08-14

Author: AWS

Type: snippet

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