AWS Lambda

Django Action Triggers supports invoking AWS Lambda functions. This section guides you through configuring AWS Lambda into the project and creating triggers that invoke AWS Lambda functions.

Installation

To the AWS Lambda integration, you will need to install an additional package. This can be done by running the following command:

pip install django-action-triggers[aws]

Configuration

Before AWS Lambda functions can be invoked, the AWS Lambda action needs to be configured in the Django settings.

AWS Lambda Configuration

The following configuration options must be set in the Django settings to configure the AWS Lambda action:

conn_details.endpoint_url: The endpoint URL of the AWS Lambda service. If you are using AWS’ Lambda service, you can set this to None. Otherwise, you can set this to the endpoint URL of the AWS Lambda service/emulator you are using.
params.FunctionName: The name of the Lambda function to invoke.

Example Configuration in settings.py

Here is an example configuration for AWS Lambda:

ACTION_TRIGGERS = {
  "actions": {
    "my_lambda_action": {
      "action_type": "aws_lambda",
      "conn_details": {
        "endpoint_url": None
      },
      "params": {
        "FunctionName": "my_lambda_function"
      }
    }
  }
}

Example Configuration in settings.py using endpoint_url

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

ACTION_TRIGGERS = {
  "actions": {
    "my_lambda_action": {
      "action_type": "aws_lambda",
      "conn_details": {
        "endpoint_url": "localhost:4566",
        "region_name": "us-east-1",
      },
      "params": {
        "FunctionName": "my_lambda_function"
      }
    }
  }
}

Creating an AWS Lambda Action

Once AWS Lambda is configured, you can create a trigger that invokes the AWS Lambda function 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()

Suppose you have an AWS Lambda function that sends an email to a user when a trigger is activated. We’ll call this function send_email_to_user.

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 2: Create an Action Model Instance (AWS Lambda Action)

Warning

Hardcoding sensitive information such as connection details is not recommended. In the next section, we will explore how to dynamically set these values using callables or variables at runtime.

from action_triggers.models import Action

aws_lambda_action = Action.objects.create(
    config=config,
    name="my_lambda_action",  # This needs to correspond to a key in the `ACTION_TRIGGERS.actions` dictionary
    action_type="aws_lambda",
    conn_details={
      "endpoint_url": None,
      "aws_access_key_id": "my_access_key_id",
      "aws_secret_access_key": "my_secret_access_key",
      "region_name": "us-east-1"
    },
    params={
        "FunctionName": "send_email_to_user"
    }
)

In this example, the conn_details dictionary contains the connection details required to connect to the AWS Lambda service. The params dictionary contains the name of the Lambda function to invoke.

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 AWS Lambda function will be invoked.

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_FUNCTION_NAME: Stores the AWS Lambda function name.

You can use these in the conn_details field as follows:

from action_triggers.models import Action

aws_lambda_action = Action.objects.create(
    config=config,
    name="my_lambda_action",
    action_type="aws_lambda",
    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 }}"
    },
    params={
        "FunctionName": "{{ myproject.settings.AWS_FUNCTION_NAME }}"
    }
)

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_FUNCTION_NAME',
    ),

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

—

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