Serverless Anomaly Detection with Azure Functions

Question

Pulumi · Accepted Answer

In Azure, you can create a serverless anomaly detection system using Azure Functions. Azure Functions is an event-driven, compute-on-demand experience that extends the existing Azure application platform with capabilities to implement code triggered by events occurring in Azure or third party services.

To accomplish this, you'll need to set up a few things:
1. **Azure Function App**: A function app provides the environment for executing your function logic. It is the unit of deployment and management for your functions.
2. **Azure Functions**: Within the function app, you'll write functions to process data, which can be triggered by various events, such as HTTP requests or new messages on an Azure Queue.
3. **Application Insights**: This is an extensible Application Performance Management (APM) service for developers and DevOps professionals. You would use this service for monitoring your live applications, and it integrates with Azure Functions.
4. **Storage Account**: Azure Functions require a storage account because functions use Azure Storage for operations such as managing triggers and logging function executions.

Below is a program written in Python for Pulumi, which sets up a basic Azure Functions App for anomaly detection. The code includes comments explaining each section and the purpose of the resources being defined.

```python
import pulumi
import pulumi_azure as azure

# Define an Azure resource group, which is a container for related resources.
resource_group = azure.core.ResourceGroup("resource_group", location="West Europe")

# Define an Azure storage account to be associated with the Function App.
storage_account = azure.storage.Account("storageaccount",
                                        resource_group_name=resource_group.name,
                                        location=resource_group.location,
                                        account_tier="Standard",
                                        account_replication_type="LRS")

# Define an Azure app service plan which dictates how the function app will be scaled and billed.
app_service_plan = azure.appservice.Plan("appserviceplan",
                                         resource_group_name=resource_group.name,
                                         location=resource_group.location,
                                         kind="FunctionApp",
                                         reserved=True,  # Required for Linux plan
                                         sku=azure.appservice.PlanSkuArgs(
                                             tier="Dynamic",
                                             size="Y1"
                                         ))

# Define the Function App itself.
function_app = azure.appservice.FunctionApp("functionapp",
                                            resource_group_name=resource_group.name,
                                            location=resource_group.location,
                                            app_service_plan_id=app_service_plan.id,
                                            storage_account_name=storage_account.name,
                                            storage_account_access_key=storage_account.primary_access_key)

# Link the Function App to Application Insights for monitoring.
app_insights = azure.appinsights.Insights("appinsights",
                                          resource_group_name=resource_group.name,
                                          location=resource_group.location,
                                          application_type="web")

# Export the Function App URL so it can be accessed easily.
pulumi.export("endpoint", function_app.default_hostname.apply(
    lambda hostname: f"https://{hostname}/api"))
```

This program starts by defining a resource group in Azure, which acts as a logical container for all other resources. Next, it sets up a storage account that the function app will use to manage state and other functionalities like logging. Then, it defines an app service plan, which in this case is set to the consumption plan, an ideal choice for serverless computing as you only pay per execution.

The function app is then defined and associated with the previously created storage account and service plan. At this point, you'd typically deploy your actual function code to the function app, which contains the logic for detecting anomalies. This code is usually packaged as a ZIP file and can be deployed using Pulumi as well, but the details of this process depend on your specific application's code.

Lastly, Application Insights is set up for monitoring the Function App. The monitoring can give you insights into your application's performance and help you detect and diagnose complex application problems.

To deploy the anomaly detection system's code, you can use tools like `func azure functionapp publish` from the Azure Functions Core Tools or integrate with a CI/CD pipeline to push code updates automatically to the Function App.

Remember, for this Pulumi program to run, you should have the Azure Pulumi provider configured with credentials to deploy and manage Azure resources. Once you've written your functions for anomaly detection, you would modify the `function_app` resource in this program to include configurations and settings specific to those functions.