Getting Started with Azure Functions: Serverless Made Simple

Introduction

Azure Functions accelerates event-driven development by abstracting infrastructure so you can focus on code. This guide moves from a minimal HTTP trigger to an enterprise-ready architecture with durable orchestrations, secure secret management, observability, automation pipelines, and cost/performance tuning.

You will learn:

• Core concepts: triggers, bindings, function app lifecycle
• Choosing hosting plans (Consumption, Premium, Dedicated, Container Apps)
• Implementing HTTP, Timer, Queue, Service Bus, Event Grid, Blob triggers
• Durable Functions orchestration & state management patterns
• Integration with Key Vault, Storage, Cosmos DB, Event Grid
• Security (Managed Identity, Entra ID auth, network isolation)
• Monitoring (Application Insights + OpenTelemetry)
• Scaling & cost optimization strategies
• CI/CD with GitHub Actions
• Troubleshooting and resiliency patterns

Time to Read: 60–90 minutes
Skill Level: Beginner → Intermediate

Architecture Overview

Prerequisites

Install tooling:

winget install Microsoft.AzureCLI
winget install Microsoft.VisualStudioCode
winget install Git.Git

Step-by-Step Implementation

1. Resource Group & Core Services

az group create --name rg-func-intro --location eastus
az storage account create --name funcintrostore --resource-group rg-func-intro --sku Standard_LRS
az monitor app-insights component create --app func-intro-ai --location eastus --resource-group rg-func-intro --application-type web

2. Create Function App (Consumption)

az functionapp create --resource-group rg-func-intro --consumption-plan-location eastus --runtime dotnet --functions-version 4 --name func-intro-app --storage-account funcintrostore --app-insights func-intro-ai

3. Add Managed Identity & Key Vault

az keyvault create --name kv-func-intro --resource-group rg-func-intro --location eastus
az functionapp identity assign --name func-intro-app --resource-group rg-func-intro
$principalId = az functionapp identity show -g rg-func-intro -n func-intro-app --query principalId -o tsv
az keyvault set-policy -n kv-func-intro --object-id $principalId --secret-permissions get list

4. Sample HTTP Trigger (C#)

public static class HttpHello
{
    [FunctionName("HttpHello")]
    public static IActionResult Run(
        [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = "hello")] HttpRequest req,
        ILogger log)
    {
        log.LogInformation("Processing HttpHello request");
        var name = req.Query["name"];
        return new OkObjectResult(new { message = $"Hello {name}" });
    }
}

5. Timer Trigger (Maintenance)

public static class NightlyMaintenance
{
    [FunctionName("NightlyMaintenance")]
    public static async Task Run([TimerTrigger("0 0 2 * * *")]TimerInfo timer, ILogger log)
    {
        log.LogInformation("Nightly maintenance started");
        // purge temp blobs / archive logs
        await Task.Delay(250);
        log.LogInformation("Nightly maintenance complete");
    }
}

6. Durable Orchestration Pattern

public static class OrderOrchestrator
{
    [FunctionName("OrderOrchestrator")]
    public static async Task<object> Run([OrchestrationTrigger] IDurableOrchestrationContext ctx)
    {
        var order = ctx.GetInput<Order>();
        var valid = await ctx.CallActivityAsync<bool>("ValidateOrder", order);
        if(!valid) return new { status = "Rejected" };
        var enriched = await ctx.CallActivityAsync<Order>("EnrichOrder", order);
        await ctx.CallActivityAsync("PersistOrder", enriched);
        await ctx.CallActivityAsync("NotifyQueue", enriched.Id);
        return new { status = "Completed", id = enriched.Id };
    }
}

7. Local Development & Debugging

func init src --dotnet
cd src
func new --name HttpHello --template "HTTP trigger" --authlevel Function
func start

Browse http://localhost:7071/api/hello?name=Azure.

Security & Identity

Key Vault retrieval example (C#):

var client = new SecretClient(new Uri(Environment.GetEnvironmentVariable("KEY_VAULT_URI")), new DefaultAzureCredential());
var secret = client.GetSecret("ApiKey").Value.Value;

Monitoring & Telemetry

Enable logging & traces:

builder.Services.AddLogging();
// For isolated process, configure host.json + app insights connection string

Kusto query (failed functions):

requests
| where cloud_RoleName == "func-intro-app"
| where success == false
| summarize count() by operation_Name, bin(timestamp, 1h)

Performance & Cost Optimization

CI/CD Pipeline

name: deploy-azure-functions
on:
  push:
    paths: [ 'src/**' ]
    branches: [ main ]
jobs:
  build-deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Setup .NET
        uses: actions/setup-dotnet@v4
        with:
          dotnet-version: '8.0.x'
      - name: Build
        run: dotnet build src/FunctionApp.csproj -c Release
      - name: Publish
        run: dotnet publish src/FunctionApp.csproj -c Release -o publish
      - name: Azure Login
        uses: azure/login@v2
        with:
          creds: ${{ secrets.AZURE_CREDENTIALS }}
      - name: Deploy
        uses: azure/functions-action@v1
        with:
          app-name: func-intro-app
          package: publish

Troubleshooting Matrix

Resiliency Patterns

• Retries with exponential backoff for transient external calls.
• Circuit breaker around enrichment APIs.
• Poison queue handling: move failed messages to dead-letter queue and alert.

Image References

References

• Azure Functions Triggers & Bindings
• Durable Functions Overview
• Azure Functions Monitoring
• Key Vault Integration
• Hosting Plans