AWS SNS (AWS Simple Notification Service)

Django Action Triggers supports sending messages to an AWS SNS (Simple Notification Service) message broker. This section guides you through configuring AWS SNS and creating triggers that send messages to an AWS SNS broker.

Configuration

Before messages can be sent to an AWS SNS message broker, the broker needs to be configured in the Django settings.

Note

See the message brokers configuration guide for information on configuring message brokers.

Example Configuration in settings.py using topic_arn

Here is an example configuration for AWS SNS:

ACTION_BROKERS = {
  "aws_sns_1": {
    "broker_type": "aws_sns",
    "conn_details": {
      "endpoint_url": None
    },
    "params": {
      "topic_arn": "arn:aws:sns:us-east-1:123456789012:my_topic"
    }
  }
}

Example Configuration in settings.py using endpoint_url

Here is an example configuration for AWS SNS using the endpoint URL. This can be useful when using a local instance of the AWS SNS service:

ACTION_BROKERS = {
  "aws_sns_3": {
    "broker_type": "aws_sns",
    "conn_details": {
      "endpoint_url": "http://localhost:4566"
    },
    "params": {
      "topic_arn": "arn:aws:sns:us-east-1:123456789012:my_topic"
    }
  }
}

Creating an AWS SNS Action

Once AWS SNS is configured, you can create a trigger that sends messages to the AWS SNS broker whenever the trigger is activated.

Scenario

Suppose you have the following Django models:

from django.db import models

class Customer(models.Model):
  name = models.CharField(max_length=255)
  email = models.EmailField()

class Product(models.Model):
    name = models.CharField(max_length=255)
    description = models.TextField()


class Sale(models.Model):
    customer = models.ForeignKey(Customer, on_delete=models.CASCADE)
    product = models.ForeignKey(Product, on_delete=models.CASCADE)
    quantity = models.IntegerField()

Let’s say you want to send a message to AWS SNS when a new sale is created. You can achieve this by following these steps:

Step 1: Create a Config Model Instance (Base Action)

The Config model defines the base action, including the payload that will be sent when the trigger is activated.

from django.contrib.contenttypes.models import ContentType
from action_triggers.models import Config

config = Config.objects.create(
  payload={
    "customer_name": "{{ customer.name }}",
    "product_name": "{{ product.name }}",
    "quantity": "{{ quantity }}"
  },
  active=True,
  content_types=[
    ContentType.objects.get_for_model(Sale)
  ]
)

The payload is designed to behave like a Django template. If the resulting value is JSON-serializable, the payload will be returned as JSON; otherwise, it will be returned as plain text.

Step 3: Create a ConfigSignal Model Instance (Trigger)

Finally, link the action to a trigger event, such as saving a model instance.

from action_triggers.models import ConfigSignal
from action_triggers.enums import SignalChoices

config_signal = ConfigSignal.objects.create(
  config=config,
  signal=SignalChoices.POST_SAVE,
)

Now, whenever a new sale is created, the Redis action will be triggered.

Dynamically Setting conn_details and parameters

In the previous example, hardcoding connection details and parameters is insecure. Instead, you can dynamically set these values at runtime.

To do this, we can use the dynamic loading feature. This feature allows you to specify a path to a callable or variable that will be evaluated at runtime to retrieve the value.

Replacing Hardcoded Values

Suppose you have the following variable:

myproject.settings.AWS_ACCESS_KEY_ID: Stores the AWS access key ID.
myproject.settings.AWS_SECRET_ACCESS_KEY: Stores the AWS secret access key.
myproject.settings.AWS_REGION_NAME: Stores the AWS region name.
myproject.settings.AWS_SNS_TOPIC_ARN: Stores the AWS SNS topic ARN.

You can use these in the conn_details field as follows:

from action_triggers.models import MessageBrokerQueue

aws_sns_action = MessageBrokerQueue.objects.create(
    config=config,
    name="aws_sns_1",
    conn_details={
      "endpoint_url": None,
      "aws_access_key_id": "{{ myproject.settings.AWS_ACCESS_KEY_ID }}",
      "aws_secret_access_key": "{{ myproject.settings.AWS_SECRET_ACCESS_KEY }}",
      "region_name": "{{ myproject.settings.AWS_REGION_NAME }}"
    },
    parameters={
      "topic_arn": "{{ myproject.settings.AWS_SNS_TOPIC_ARN }}"
    }
)

Adding Dynamic Import Paths to Settings

To enable dynamic loading, ensure that the callables or variables you are specifying are defined in your Django settings.

Any callable or variable that you wish to be evaluated at runtime must be defined in ACTION_TRIGGER_SETTINGS.ALLOWED_DYNAMIC_IMPORT_PATHS.

In settings.py, add the following:

ACTION_TRIGGER_SETTINGS = {
    ...
    'ALLOWED_DYNAMIC_IMPORT_PATHS': (
        'myproject.settings.AWS_ACCESS_KEY_ID',
        'myproject.settings.AWS_SECRET_ACCESS_KEY',
        'myproject.settings.AWS_REGION_NAME',
        'myproject.settings.AWS_SNS_TOPIC_ARN',
    ),
}

This configuration ensures that the specified paths can be evaluated at runtime.

—

By following these steps, you can securely and effectively set up AWS SNS as a message broker in Django Action Triggers. For more advanced configurations, refer to the related documentation sections.