Programming Functions. Debugging and testing

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Ruby Wilkerson
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2 Serverless architectures Programming Functions Going to production Introducing Azure Functions Debugging and testing Wrapup 2

3 3 Server-less architectures and Azure Functions

4 There are no servers When you do not need them 4

5 Servers and compute Available when you need it 5

6 Event-driven Responds to external triggers Instant scaling Abstraction of server infrastructure Scales when needed Pay by consumption Charged by sub-second units of compute 6

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9 Stores in Blob storage Produces scaled images 9

10 Function apps Hosted as Azure App Service JSON based configuration Running (multiple) functions Bindings for input and output Zero or more possible Triggers and bindings can vary per function 10

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Azure tooling generates metadata files Integrates with source control

13 1 2 Scripts Azure Portal or Visual Studio Code.NET with C# Visual Studio 2017 Instant feedback and testing Less control Azure tooling generates metadata files Integrates with source control Achieve higher code quality Compilation and code analysis Unit testing Combine in CI/CD pipelines 13

14 14 Demo Creating and using Azure Functions

15 16 Developing Azure Functions with.net and Visual Studio

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19 [FunctionName("HelloWorldFunction")] public static HttpResponseMessage Run( [HttpTrigger] HttpRequestMessage req, TraceWriter log) { log.info("c# HTTP trigger function processed a request."); Defines what this function is triggered by } return req.createresponse(httpstatuscode.ok, "Hello, World!"); 20

[FunctionName("ImageAnalyzer")] [return: Queue("AnalysisResults", Connection=" ")] public static string Run( [QueueTrigger("ImagesToAnalyze", Connection=" ")] string imagename,

20 [FunctionName("ImageAnalyzer")] [return: Queue("AnalysisResults", Connection=" ")] public static string Run( [QueueTrigger("ImagesToAnalyze", Connection=" ")] string imagename, [Blob("images/{queueTrigger}", FileAccess.Read, } Connection = " ")] Stream blob, TraceWriter log) { return...; Attribute values can refer to trigger metadata with { } Connection property refers to value from settings 21

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22 23 Demo Programming Azure Functions with Visual Studio 2017

23 [FunctionName("ValidateBlobSize")] public static void Run( [QueueTrigger("ImagesInput", Connection = " ")] string blobnameinqueue, [Blob("images/{queueTrigger}", FileAccess.Read, Connection = " ")] Stream blob, } TraceWriter log) { // Your function code 24

24 25 [FunctionName("FunctionQueueTrigger")] public static void Run( [QueueTrigger("imagesinput", Connection = " ")]string blobnameinqueue, [Blob("images/{queueTrigger}", FileAccess.Read, Connection = " ")]Stream blob, [Queue("imagestoolarge", Connection = " ")]ICollector<string> imagestoolarge, TraceWriter log)

25 26 Debugging and testing Azure Functions

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27 28 Tools to trigger

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29 Blob and queue Simply supply message content Depends on input type (string, byte[] or POCO class) HttpRequestMessage Able to be constructed as dummy object Set properties for Body and Headers Similar for HttpResponse(Message) TraceWriter Inherit and override Write method for mock Alternatively use ILogger provided through DI 30

30 31 Demo Debugging and unit testing Azure Functions

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33 { "IsEncrypted": false, "Values": { "AzureWebJobsStorage": "", "key1": "value1" }, "ConnectionStrings": { "db": { "ConnectionString":...", "ProviderName": "System.Data.SqlClient" } } } local.settings.json file 34

34 35 Demo Deploying Azure Functions

Azure Consumption-based Scaling as needed Might require time to provide compute instances App Service plan Available scale Not so much server-less Easy to

35 Azure Consumption-based Scaling as needed Might require time to provide compute instances App Service plan Available scale Not so much server-less Easy to combine with PaaS On-premises Azure Functions Runtime Local installation of hosts Connected via SQL Server database Infrastructure operations Not so much server-less 36

36 37 { } "aggregator": { "batchsize": 1000, "flushtimeout": "00:00:30" }, "logger": { "categoryfilter": { "defaultlevel": "Information", "categorylevels": { "Host": "Error", "Function": "Error", "Host.Aggregator": "Information" } } }

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Single responsibility principle Do one thing focussed Finish as quickly as possible Avoid long running functions Stateless, idempotent and defensive Cross

38 Single responsibility principle Do one thing focussed Finish as quickly as possible Avoid long running functions Stateless, idempotent and defensive Cross function communication Messaging: Storage Queues (small <64 KB) or Service Bus (<256 KB) Service Bus topics for message filtering Event Hub for high volume messaging 39

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Resources https://aka.ms/tryfunctions https://functions.azure.com https://docs.

40 Resources Channel9 41

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WebJobs & Azure Functions in modern and Serverless applications. Paris Polyzos Software Engineer at ZuluTrade Inc Microsoft Azure MVP

WebJobs & Azure Functions in modern and Serverless applications Paris Polyzos Software Engineer at ZuluTrade Inc Microsoft Azure MVP ns 2016The ZuluTrade Group Paris Polyzos Senior Software Engineer Microsoft