⚡ Python Functions Pub/Sub

• Google Cloud Functions used to send data using Python code to Google Cloud Pub/Sub where data can be published with a message
• Code from D-I-Ry with modifications - see 👏 Inspiration below
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• ⚡ Python Functions Pub/Sub
  • 📄 Table of contents
  • 📚 General info
  • 📷 Screenshots
  • 📶 Technologies
  • 💾 Setup
  • 💻 Code Examples
  • 🆒 Features
  • 📋 Status & To-do list
  • 👏 Inspiration
  • ✉️ Contact

📚 General info

• Pub/Sub used to pass messages between services and to trigger Cloud Functions to run workflow
• To subscribe to data in Cloud Pub/Sub, you create a subscription based on the topic, and subscribe to that, passing a callback function.
• Python code deployed from VS Code terminal
• Cloud Build API has to be enabled for deployment to work. Mine was already enabled from a similar previous project
• From Pub/Sub factor-sensors topic is triggered by message published to pubsub factory sensors topic

📷 Screenshots

📶 Technologies

• Python v3 programming language
• Python Cloud Client Libraries
• JavaScript Object Notation - JSON lightweight data-interchange format
• Google Cloud Functions functions as a service (FaaS) to run Python code
• Google Cloud Pub/Sub a fully-managed real-time messaging service that allows you to send and receive messages between independent applications.
• Google Cloud FireStore fully managed, scalable, and serverless document database.

💾 Setup

• Ref. tutorial
• When creating a Pub/Sub I found that the subscription was created automatically
• gcloud functions deploy automation_readings --runtime python39 --trigger-http --allow-unauthenticated to deploy to Cloud Functions. Python code can be viewed in Cloud Functions automation_readings SOURCE menu. Message logs can be viewed under the LOGS menu. Logs can also be viewed in Firebase Console Logs menu.
• python sendMessage.py to run sendMessage.py. This will trigger the Cloud Function using a http trigger URL and will supply sensor readings payload data in JSON format to the Cloud Functions Topic automation_readings. A response is returned with a status code. Clicking on 'PULL' in Cloud Pubsub Topic Messages will display message

💻 Code Examples

• main.py extract - to move data to Pubsub. Topic path copied from Cloud Pub/Sub Subscription Details/Topic name

    topic_path = 'projects/python-pubsub-firestore/topics/factory-automation'

    message_json = json.dumps({
        'data': {'message': 'automation sensor readings'},
        'readings': {
            'sensorName': sensor_name,
            'sensorReference': sensor_reference,
            'temperature': temperature,
            'humidity': humidity
        }
    })
    message_bytes = message_json.encode('utf-8')

    try:
        publish_future = publisher.publish(topic_path, data=message_bytes)
        publish_future.result() # verify that the publish succeeded
    except Exception as e:
        print(e)
        return (e, 500)

    return ('Message received and published to Pubsub', 200)

🆒 Features

• Cloud Pub/Sub decoupling senders and receivers, allowing secure and highly available communications between independently written applications.

📋 Status & To-do list

• Status: Working
• To-do: Nothing

👏 Inspiration

• D-I-Ry: Send data from Cloud Functions to PubSub in Python

✉️ Contact

• Repo created by ABateman, email: gomezbateman@yahoo.com