Monitoring Azure Functions

Monitoring your Azure Functions is crucial for understanding their performance, identifying issues, and ensuring they are running reliably. Azure provides several tools and services to help you monitor your functions.

Key Monitoring Tools

Azure Monitor

Azure Monitor is the foundational monitoring service for Azure. It collects, analyzes, and acts on telemetry from your Azure and on-premises environments. For Azure Functions, Azure Monitor provides:

  • Metrics: Track performance indicators like function execution count, execution time, and memory usage.
  • Logs: Store and query detailed execution logs for deeper debugging.
  • Alerts: Configure alerts based on metrics or log queries to be notified of potential issues.

Application Insights

Application Insights, a feature of Azure Monitor, is specifically designed for application performance management (APM). It offers richer insights into your functions:

  • Live Metrics: View real-time metrics and traces as your functions execute.
  • End-to-end transaction monitoring: Trace requests across different services.
  • Performance analysis: Identify bottlenecks and optimize function performance.
  • Dependency tracking: Understand how your functions interact with other services.

Azure Portal Function App Overview

The Azure portal provides a quick overview of your function app's health and activity directly on the Function App blade.

Monitoring Logs

Functions automatically log information about their executions. You can access these logs in several ways:

Application Insights Logs

After enabling Application Insights for your function app, you can query logs using Kusto Query Language (KQL) in the "Logs" section of Application Insights:


// Get the last 100 function invocations
requests
| take 100
| order by timestamp desc

Or, to view exceptions:


exceptions
| order by timestamp desc
| take 50

Diagnostic Logs

You can also configure diagnostic settings to send logs to various destinations like Log Analytics, Storage Accounts, or Event Hubs.

Tip: Ensure you have proper logging statements within your function code to capture relevant information for debugging.

Monitoring Metrics

Key metrics to watch for your Azure Functions include:

Metric Description
Function Execution Count The number of times a specific function has been executed.
Function Execution Units A measure of CPU time consumed by function executions.
Memory Working Set The amount of physical memory used by the function app.
HTTP 5xx The count of server-side errors (5xx) returned by HTTP-triggered functions.
HTTP 4xx The count of client-side errors (4xx) returned by HTTP-triggered functions.

Setting Up Alerts

Alerts are essential for proactively notifying you of issues. You can configure alerts in Azure Monitor based on metrics or log queries. For example, you might set up an alert for:

  • A high number of HTTP 5xx errors.
  • A significant increase in function execution duration.
  • A sudden drop in the number of successful executions.
Note: Configure alerts to have appropriate thresholds and notification settings to avoid alert fatigue.

Best Practices for Monitoring

  • Enable Application Insights: It's the most comprehensive tool for APM.
  • Use Structured Logging: Log data in a structured format (e.g., JSON) to make querying easier.
  • Set Meaningful Alerts: Define critical thresholds for key metrics.
  • Monitor Dependencies: Understand the performance of services your functions interact with.
  • Regularly Review Logs and Metrics: Don't just wait for alerts; proactive analysis helps prevent issues.
  • Implement Health Checks: For HTTP-triggered functions, consider adding a health check endpoint.