Azure Functions:

Serverless development concepts

Lansing DevOps Meetup
June 5th, 2018

Brendon Thiede

• DevOps Engineer at the Michigan Supreme Court
• Focused on Automation
• Linux and Java for the last decade

Now I am assimilated...

Topics

• Azure ARM Template
• Runtime/Framework version compatibility
• Build definition/Deployment
• Function annotations
• Bindings
• Dependency Injection
• Demo

Function Infrastructure

• App Service Plan (Consumption or Dedicated)
• App Service (Function type)
  • Application Settings (Environment Variables)
• Storage Account
• Application Insights (Optional)

Function Runtime

• 1.x - Fully Supported
• 2.x - Beta

Language

• C# (Precompiled class library or script)
  • .NET Framework 4.6
  • .NET Standard
• JavaScript
• F#

More at: https://docs.microsoft.com/en-us/azure/azure-functions/supported-languages

My Secret Sauce

• .NET Standard 2.0
• Precompiled
• 2.x (Beta) Function Runtime
• Consumption Plan

Build Process

• Validate ARM template
• Publish ARM template
• dotnet test
• dotnet publish
• Publish artifact

Deployment Process

• New-AzureRmResourceGroupDeployment ...
• az functionapp deployment source config-zip ...

Function Annotations

Specify function name:

[FunctionName("DevHealthCheckScheduler")]
                

Disable function:

[Disable("DISABLE_SCHEDULERS")]
                

Pro

Con

Bindings

[FunctionName("DevHealthCheckScheduler")]
[Disable("DISABLE_SCHEDULERS")]
public static void Run(
    [TimerTrigger("%DevHealthCheckSchedulerCronExpression%")] TimerInfo myTimer,
    [OrchestrationClient] DurableOrchestrationClient starter)
{
    starter.StartNewAsync("Orchestrators_HealthCheckMasterOrchestrator", "dev");
}
                

Binding Types

• Timer
• HTTP
• Storage account
  • Queue
  • Table
  • Blob
• ServiceBus
• Cosmos DB
• ...
https://docs.microsoft.com/en-us/azure/azure-functions/functions-triggers-bindings

Dependency Injection

[FunctionName("Activities_HealthChecker")]
public static AppEnvStatus GetHealthCheckStatus(
    [ActivityTrigger] HealthCheckEndpoint healthCheckEndpoint,
    [Table("AppEnvStatuses")] CloudTable appEnvStatuses)
{
    using (HttpClient httpClient = new HttpClient())
    {
        AppEnvStatus appEnvStatus = SlackBotUtils.RetrieveAppEnvStatus(healthCheckEndpoint, appEnvStatuses);
        appEnvStatus.LatestStatus = AppEnvStatus.FAILURE;
        appEnvStatus.LatestStatusTimeStamp = DateTime.Now;

        RequestHealthCheckEndpoint(healthCheckEndpoint, appEnvStatuses, httpClient, appEnvStatus);

        return appEnvStatus;
    }
}

Function Chaining

• Output binding -> Function trigger
• Durable Functions

Cost Comparison

• Manual queue based chaining: $0.06/day, $1.90/month
• Durable Function orchestration: $0.18/day, $5.47/month
• Storage I/O ~ 90% of cost

Demo