platypush/platypush/plugins/google/pubsub.py
2019-12-30 09:33:26 +01:00

89 lines
3.6 KiB
Python

import json
import os
from platypush.plugins import Plugin, action
class GooglePubsubPlugin(Plugin):
"""
Send messages over a Google pub/sub instance.
You'll need a Google Cloud active project and a set of credentials to use this plugin:
1. Create a project on the `Google Cloud console <https://console.cloud.google.com/projectcreate>`_ if
you don't have one already.
2. In the `Google Cloud API console <https://console.cloud.google.com/apis/credentials/serviceaccountkey>`_
create a new service account key. Select "New Service Account", choose the role "Pub/Sub Editor" and leave
the key type as JSON.
3. Download the JSON service credentials file. By default platypush will look for the credentials file under
~/.credentials/platypush/google/pubsub.json.
Requires:
* **google-cloud-pubsub** (``pip install google-cloud-pubsub``)
"""
publisher_audience = 'https://pubsub.googleapis.com/google.pubsub.v1.Publisher'
subscriber_audience = 'https://pubsub.googleapis.com/google.pubsub.v1.Subscriber'
default_credentials_file = os.path.join(os.path.expanduser('~'),
'.credentials', 'platypush', 'google', 'pubsub.json')
def __init__(self, credentials_file: str = default_credentials_file, **kwargs):
"""
:param credentials_file: Path to the JSON credentials file for Google pub/sub (default:
~/.credentials/platypush/google/pubsub.json)
"""
super().__init__(**kwargs)
self.credentials_file = credentials_file
self.project_id = self.get_project_id()
def get_project_id(self):
credentials = json.load(open(self.credentials_file))
return credentials.get('project_id')
def get_credentials(self, audience: str):
# noinspection PyPackageRequirements
from google.auth import jwt
return jwt.Credentials.from_service_account_file(self.credentials_file, audience=audience)
@action
def send_message(self, topic: str, msg, **kwargs):
"""
Sends a message to a topic
:param topic: Topic/channel where the message will be delivered. You can either specify the full topic name in
the format ``projects/<project_id>/topics/<topic_name>``, where ``<project_id>`` must be the ID of your
Google Pub/Sub project, or just ``<topic_name>`` - in such case it's implied that you refer to the
``topic_name`` under the ``project_id`` of your service credentials.
:param msg: Message to be sent. It can be a list, a dict, or a Message object
:param kwargs: Extra arguments to be passed to .publish()
"""
# noinspection PyPackageRequirements
from google.cloud import pubsub_v1
# noinspection PyPackageRequirements
from google.api_core.exceptions import AlreadyExists
credentials = self.get_credentials(self.publisher_audience)
publisher = pubsub_v1.PublisherClient(credentials=credentials)
if not topic.startswith('projects/{}/topics/'.format(self.project_id)):
topic = 'projects/{}/topics/{}'.format(self.project_id, topic)
try:
publisher.create_topic(topic)
except AlreadyExists:
pass
if isinstance(msg, int) or isinstance(msg, float):
msg = str(msg)
if isinstance(msg, dict) or isinstance(msg, list):
msg = json.dumps(msg)
if isinstance(msg, str):
msg = msg.encode()
publisher.publish(topic, msg, **kwargs)
# vim:sw=4:ts=4:et: