How to receive emails by subscribing to a cloud Pub/Sub topic
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.listserviceusage.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.
| Property | Description |
|---|---|
| Name | Specify a name for your new Cloud Function. |
| Memory allocated | Select the computing memory option to allocate. |
| Trigger | Select Cloud Pub/Sub from this dropdown menu. |
| Select a Cloud Pub/Sub topic | Select the topic you created earlier in step 5. |
| Source code | Select Inline editor. |
| Runtime | Select Python 3.7. |
| Code | Try the following:
import smtplib, ssl, os, base64, json from email.mime.text import MIMEText from email.mime.multipart import MIMEMultipart 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 execute | send_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.
| Name | Value |
|---|---|
| SMTP_SERVER | Specify your simple mail transfer protocol (SMTP) server address. |
| SMTP_PORT | Specify your simple mail transfer protocl (SMTP) port number. |
| SENDER_EMAIL | Input the corresponding email address. |
| SENDER_PASSWORD | Input 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.