#!/usr/bin/env python # Copyright 2017 Google Inc. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License 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. """Python sample for connecting to Google Cloud IoT Core via HTTP, using JWT. This example connects to Google Cloud IoT Core via HTTP, using a JWT for device authentication. After connecting, by default the device publishes 100 messages to the server at a rate of one per second, and then exits. Before you run the sample, you must register your device as described in the README in the parent folder. """ import argparse import base64 import datetime import json import time from google.api_core import retry import jwt import requests _BASE_URL = 'https://cloudiot-device.googleapis.com/v1beta1' _BACKOFF_DURATION = 60 def create_jwt(project_id, private_key_file, algorithm): token = { # The time the token was issued. 'iat': datetime.datetime.utcnow(), # Token expiration time. 'exp': datetime.datetime.utcnow() + datetime.timedelta(minutes=60), # The audience field should always be set to the GCP project id. 'aud': project_id } # Read the private key file. with open(private_key_file, 'r') as f: private_key = f.read() print('Creating JWT using {} from private key file {}'.format( algorithm, private_key_file)) return jwt.encode(token, private_key, algorithm=algorithm).decode('ascii') @retry.Retry( predicate=retry.if_exception_type(AssertionError), deadline=_BACKOFF_DURATION) def publish_message( message, message_type, base_url, project_id, cloud_region, registry_id, device_id, jwt_token): headers = { 'authorization': 'Bearer {}'.format(jwt_token), 'content-type': 'application/json', 'cache-control': 'no-cache' } # Publish to the events or state topic based on the flag. url_suffix = 'publishEvent' if message_type == 'event' else 'setState' publish_url = ( '{}/projects/{}/locations/{}/registries/{}/devices/{}:{}').format( base_url, project_id, cloud_region, registry_id, device_id, url_suffix) body = None msg_bytes = base64.urlsafe_b64encode(message.encode('utf-8')) if message_type == 'event': body = {'binary_data': msg_bytes.decode('ascii')} else: body = { 'state': {'binary_data': msg_bytes.decode('ascii')} } resp = requests.post( publish_url, data=json.dumps(body), headers=headers) if (resp.status_code != 200): print('Response came back {}, retrying'.format(resp.status_code)) raise AssertionError('Not OK response: {}'.format(resp.status_code)) return resp @retry.Retry( predicate=retry.if_exception_type(AssertionError), deadline=_BACKOFF_DURATION) # [START iot_http_getconfig] def get_config( version, message_type, base_url, project_id, cloud_region, registry_id, device_id, jwt_token): headers = { 'authorization': 'Bearer {}'.format(jwt_token), 'content-type': 'application/json', 'cache-control': 'no-cache' } basepath = '{}/projects/{}/locations/{}/registries/{}/devices/{}/' template = basepath + 'config?local_version={}' config_url = template.format( base_url, project_id, cloud_region, registry_id, device_id, version) resp = requests.get(config_url, headers=headers) if (resp.status_code != 200): print('Error getting config: {}, retrying'.format(resp.status_code)) raise AssertionError('Not OK response: {}'.format(resp.status_code)) return resp # [END iot_http_getconfig] def parse_command_line_args(): """Parse command line arguments.""" parser = argparse.ArgumentParser(description=( 'Example Google Cloud IoT Core HTTP device connection code.')) parser.add_argument( '--project_id', required=True, help='GCP cloud project name') parser.add_argument( '--registry_id', required=True, help='Cloud IoT Core registry id') parser.add_argument( '--device_id', required=True, help='Cloud IoT Core device id') parser.add_argument( '--private_key_file', required=True, help='Path to private key file.') parser.add_argument( '--algorithm', choices=('RS256', 'ES256'), required=True, help='The encryption algorithm to use to generate the JWT.') parser.add_argument( '--cloud_region', default='us-central1', help='GCP cloud region') parser.add_argument( '--ca_certs', default='roots.pem', help=('CA root from https://pki.google.com/roots.pem')) parser.add_argument( '--num_messages', type=int, default=100, help='Number of messages to publish.') parser.add_argument( '--message_type', choices=('event', 'state'), default='event', required=True, help=('Indicates whether the message to be published is a ' 'telemetry event or a device state message.')) parser.add_argument( '--base_url', default=_BASE_URL, help=('Base URL for the Cloud IoT Core Device Service API')) parser.add_argument( '--jwt_expires_minutes', default=20, type=int, help=('Expiration time, in minutes, for JWT tokens.')) return parser.parse_args() def main(): args = parse_command_line_args() jwt_token = create_jwt( args.project_id, args.private_key_file, args.algorithm) jwt_iat = datetime.datetime.utcnow() jwt_exp_mins = args.jwt_expires_minutes print('Latest configuration: {}'.format(get_config( '0', args.message_type, args.base_url, args.project_id, args.cloud_region, args.registry_id, args.device_id, jwt_token).text)) # Publish num_messages mesages to the HTTP bridge once per second. for i in range(1, args.num_messages + 1): seconds_since_issue = (datetime.datetime.utcnow() - jwt_iat).seconds if seconds_since_issue > 60 * jwt_exp_mins: print('Refreshing token after {}s').format(seconds_since_issue) jwt_token = create_jwt( args.project_id, args.private_key_file, args.algorithm) jwt_iat = datetime.datetime.utcnow() payload = '{}/{}-payload-{}'.format( args.registry_id, args.device_id, i) print('Publishing message {}/{}: \'{}\''.format( i, args.num_messages, payload)) resp = publish_message( payload, args.message_type, args.base_url, args.project_id, args.cloud_region, args.registry_id, args.device_id, jwt_token) print('HTTP response: ', resp) # Send events every second. State should not be updated as often time.sleep(1 if args.message_type == 'event' else 5) print('Finished.') if __name__ == '__main__': main()