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    How to Receive Emails by Subscribing to a Cloud Pub/Sub Topic
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      How to Receive Emails by Subscribing to a Cloud Pub/Sub Topic

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        Article Summary

        This article is specific to the following platforms - BigQuery.

        Overview

        This article is a step by step guide to setting up Cloud Pub/Sub to receive emails.

        Important Information

        Users will need:

        • Access to the Google Cloud Platform (GCP) Console.
        • Users will need the following required GCP permissions:
          • pubsub.topics.list
          • serviceusage.services.list

        Create a Topic

        Follow the five steps below to first create a topic within the GCP Console.

        1. Navigate to the GCP Console and log in.

        2. Click the menu button to open the navigation menu.

        3. Scroll down until you reach the heading "BIG DATA" and then first click on Pub/Sub and second click Topics.

        4. Click CREATE TOPIC.

        5. Specify a topic ID. In this example we have named our topic "docs-notification-topic".

        Create a Cloud Function

        Follow the steps below to next create a cloud function within the GCP Console.

        6. In the GCP Console, click the menu button to open the navigation menu.

        7. Scroll down to the heading "COMPUTE" and click Cloud Functions.

        8. Click CREATE FUNCTION.

        9. The Create function page requires users to configure the function.

        PropertyDescription
        NameSpecify a name for your new Cloud Function.
        Memory allocatedSelect the computing memory option to allocate.
        TriggerSelect Cloud Pub/Sub from this dropdown menu.
        Select a Cloud Pub/Sub topicSelect the topic you created earlier in step 5.
        Source codeSelect Inline editor.
        RuntimeSelect Python 3.7.
        CodeTry the following:
        import smtplib, ssl, os, base64, json
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart

        # Supply these via Environment Variables in the Cloud Function
        
SMTP_SERVER = os.environ.get('SMTP_SERVER')
        
SMTP_PORT = os.environ.get('SMTP_PORT')
        
SENDER_EMAIL = os.environ.get('SENDER_EMAIL')
        
SENDER_PASSWORD = os.environ.get('SENDER_PASSWORD')

        def build_message(request):

        receiver_email = request.get('receiver_email')
subject = request.get('subject')
text = MIMEText(request.get('message'), "plain")
# html = MIMEText(html, 'html')

        message = MIMEMultipart("alternative")
        
message["Subject"] = subject
        
message["From"] = SENDER_EMAIL
        
message["To"] = receiver_email
        
message.attach(text)
        

        return message
        

        except Exception as e:
        
# Print any error messages to stdout
        
print(e)
        

        def send_tls(event, context):
        

        # print(event)
request = json.loads(base64.b64decode(event['data']).decode('utf-8'))
# print(request)
ssl_context = ssl.create_default_context()
ssl_context.check_hostname = False

        message = build_message(request=request)
        

        with smtplib.SMTP(host=SMTP_SERVER, port=SMTP_PORT) as server:
        
server.connect(host=SMTP_SERVER, port=SMTP_PORT) # seems redundant, but accommodates a bug in smtplib
        
server.starttls(context=ssl_context)
        
server.login(user=message.get('To'),password=SENDER_PASSWORD)
        
server.sendmail(from_addr=message.get('From'), to_addrs=message.get('To'), msg=message.as_string())
        

        except Exception as e:
        
# Print any error messages to stdout
        
print(e)
        Function to executesend_tls

        The next two images provide further context to the above table.

        Add Environment Variables

        Click the ENVIRONMENT VARIABLES, NETWORKING, TIMEOUTS, AND MORE header.

        Users will need to add four variables, detailed below. To add a variable, click + ADD VARIABLE.

        NameValue
        SMTP_SERVERSpecify your simple mail transfer protocol (SMTP) server address.
        SMTP_PORTSpecify your simple mail transfer protocl (SMTP) port number.
        SENDER_EMAILInput the corresponding email address.
        SENDER_PASSWORDInput the corresponding password.




        Publishing Messages in Matillion ETL

        In Matillion ETL, use the Cloud Pub/Sub component to publish messages to the Pub/Sub topic that you created previously.

        Note

        To successfully send email notifications, the message in the Cloud Pub/Sub component must be a JSON object that provides parameters that the Cloud Function expects. These parameters, which come as key-value dictionaries are:

        • receiver_email
        • subject
        • message

        An example is provided below:

        {
"receiver_email":"alerts@matillion.com",
"subject":"Test GCP Subject",
"message":"This is a test message"
}

        Contact Support

        If you need help setting up Cloud Pub/Sub to receive emails, please contact support.

        What's Next