Azure Functions Cheatsheets

By Saeed Salehi

4 min read

Authors

Part of series

Developing Solutions for Microsoft Azure (AZ-204) certification exam Cheatsheets

  1. Part 1:

    Introduction to (AZ-204) certification exam Cheatsheets

  2. Part 2:

    Implement IaaS in Azure Cheatsheets

  3. Part 3:

    Azure Functions Cheatsheets

  4. Part 4:

    Azure App Service Cheatsheets

  5. Part 5:

    Develop solutions that use Blob storage Cheatsheets

  6. Part 6:

    Develop solutions that use Azure Cosmos DB Cheatsheets

  7. Part 7:

    Implement Azure Security Cheatsheet

  8. Part 8:

    Microsoft Identity platform Cheatsheet

  9. Part 9:

    Monitoring And logging in Azure Cheatsheets

  10. Part 10:

    Azure Cache for Redis Cheatsheets

  11. Part 11:

    Develop message-based solutions Cheatsheets

  12. Part 12:

    Develop event-based solutions Cheatsheets

  13. Part 13:

    API Management in Azure Cheatsheets

Azure Functions lets you develop serverless applications on Microsoft Azure requires general Azure Storage Account

  • Azure Blob
  • Queue
  • Files and Table storage.

Difference with Azure Logic Apps

For Azure Functions, you develop orchestrations by writing code and using the Durable Functions extension. For Logic Apps, you create orchestrations by using a GUI or editing configuration files (workflow).

Logic Apps

  • Logic App code View: extend definitions you use Logic App code View
  • Integrate the workflow: Enterprise Integration Pack (EIP)

Hosting Plans

  • Consumption plan: Default, only pay for compute resources when your functions are running (1.5 GB or memory / 1 CPU )
  • Premium plan: pre-warmed workers
  • Dedicated plan: run your function within a AppService - price can be predictive, Best for long-running (Always on should be enabled!)

Deployment

  • AppService Environment (ASE)
  • Kubernetes (KEDA)

Scaling

scale controller to monitor the rate of events (scale out / in) latency of scaling from zero to one - cold start

Scaling behaviors

  • Maximum instances: 200
  • New instance rate: new instances allocated HTTP: once per second / Non-Http: once on every 30 seconds

limit scale out by setting functionAppScaleLimit parameter to 0 / null or a valid number

Each function contains:

  • Code
  • Config (function.json)

Code should be placed in Root and root folder should contains a host.json file contains runtime-specific configuration

triggers and bindings

  • Trigger: what cause a function to run. must have exactly 1 trigger!

  • Binding: way of connecting another resource (input bindings, output bindings, or both)

    Sample

{
  "bindings": [
    {
      "type": "queueTrigger",
      "direction": "in",
      "name": "order",
      "queueName": "myqueue-items",
      "connection": "MY_STORAGE_ACCT_APP_SETTING"
    },
    {
      "type": "table",
      "direction": "out",
      "name": "$return",
      "tableName": "outTable",
      "connection": "MY_TABLE_STORAGE_ACCT_APP_SETTING"
    }
  ]
}

Types of binding expressions (path parameter in function.json)

  • app settings (% sign)
    • The connection property of triggers and bindings is a special case and automatically resolves values as app settings, without percent signs.
  • filename {filename}
  • Trigger metadata
  • JSON payloads
  • Dot notation
  • Create GUIDs {rand-guid}
  • Current time {DateTime}

Return Value using $return in function.json

Connect functions to Azure services

Environment variables default configuration provider

  • Application Settings in azure function service
  • local setting file

Identity-based connections are not supported with Durable Functions.

Authorization Levels

  • Anonymous - No Api Key required.
  • function - a function-specific API key is required (default)
  • Admin - the master key is required

Durable Functions

a.k.a stateful functions

Application patterns

  • Function chaining:

    a sequence of functions executes in a specific orde

    the output of one function is applied to the input of another function

  • Fan-out/fan-in:

    execute multiple functions in parallel and then wait for all functions to finish

  • Async HTTP APIs:

    HTTP endpoint trigger the long-running action. Then, redirect the client to a status endpoint that the client polls to learn when the operation is finished

    Function must include DurableClient input binding

  • Monitor:

    recurring process in a workflow. An example is polling until specific conditions are met

  • Human interaction:

    Involving humans in an automated process

    timeouts and compensation logic

Durable Functions types and features

  • Orchestrator functions describe how actions are executed and the order in which actions are executed

    • different types of actions, including activity functions, sub-orchestrations, waiting for external events, HTTP, and timers.

  • Activity Function: basic unit of work in a durable function. DurableActivityContext as a parameter Activity functions can only have a single value passed to them (Array / Tuple supported!). activity functions only guarantee at least once execution. You can trigger an activity function only from an orchestrator function.

  • Entity functions: reading and updating state . Entities are accessed via a unique identifier Operations on entities require that you specify the Entity ID of the target entity, and the Operation name,

  • Client functions: The primary way to deliver these messages is by using an orchestrator client binding, or an entity client binding. Any non-orchestrator function can be a client function. What makes a function a client function is its use of the durable client output binding Orchestrator and entity functions cannot be triggered directly using the buttons in Azure Portal

Task hubs

logical container for durable storage resources

Task Hub in Azure Storage resources:

  • 1 or more control queue
  • 1 work-item queue
  • 1 history table
  • 1 instance table
  • 1 storage container (1 or more lease BLOB)

Durable orchestrations

  • define function workflows using procedural code
  • call other durable functions synchronously and asynchronously
  • Execution progress is automatically checkpointed

Features and patterns

  • Sub-orchestrations
  • Durable timers
  • External events
  • Error handling
  • Critical sections (LockAsync)
  • Calling HTTP endpoints
  • Passing multiple parameters (Array / Tuple)

Durable Timers

implement delays or to set up timeouts with context.CreateTimer

Send and wait for events

wait and listen for external events.

handling human interaction or other external triggers

context.WaitForExternalEvent

RaiseEventAsync method takes eventName and eventData as parameters. The event data must be JSON-serializable.

Upcoming events

  • The Test Automation Meetup

    PLEASE RSVP SO THAT WE KNOW HOW MUCH FOOD WE WILL NEED Test automation is a cornerstone of effective software development. It's about creating robust, predictable test suites that enhance quality and reliability. By diving into automation, you're architecting systems that ensure consistency and catch issues early. This expertise not only improves the development process but also broadens your skillset, making you a more versatile team member. Whether you're a developer looking to enhance your testing skills or a QA professional aiming to dive deeper into automation, RSVP for an evening of learning, delicious food, and the fusion of coding and quality assurance! 🚀🚀 18:00 – 🚪 Doors open to the public 18:15 – 🍕 Let’s eat 19:00 – 📢 First round of Talks 19:45 – 🍹 Small break 20:00 – 📢 Second round of Talks 20:45 – 🍻 Drinks 21:00 – 🙋‍♀️ See you next time? First Round of Talks: The Power of Cross-browser Component Testing - Clarke Verdel, SR. Front-end Developer at iO How can you use Component Testing to ensure consistency cross-browser? Second Round of Talks: Omg who wrote this **** code!? - Erwin Heitzman, SR. Test Automation Engineer at Rabobank How can tests help you and your team? Beyond the Unit Test - Christian Würthner, SR. Android Developer at iO How can you do advanced automated testing for, for instance, biometrics? RSVP now to secure your spot, and let's explore the fascinating world of test automation together!

    | Coven of Wisdom - Amsterdam

    Go to page for The Test Automation Meetup

  • Coven of Wisdom - Herentals - Winter `24 edition

    Worstelen jij en je team met automated testing en performance? Kom naar onze meetup waar ervaren sprekers hun inzichten en ervaringen delen over het bouwen van robuuste en efficiënte applicaties. Schrijf je in voor een avond vol kennis, heerlijk eten en een mix van creativiteit en technologie! 🚀 18:00 – 🚪 Deuren open 18:15 – 🍕 Food & drinks 19:00 – 📢 Talk 1 20:00 – 🍹 Kleine pauze 20:15 – 📢 Talk 2 21:00 – 🙋‍♀️ Drinks 22:00 – 🍻 Tot de volgende keer? Tijdens deze meetup gaan we dieper in op automated testing en performance. Onze sprekers delen heel wat praktische inzichten en ervaringen. Ze vertellen je hoe je effectieve geautomatiseerde tests kunt schrijven en onderhouden, en hoe je de prestaties van je applicatie kunt optimaliseren. Houd onze updates in de gaten voor meer informatie over de sprekers en hun specifieke onderwerpen. Over iO Wij zijn iO: een groeiend team van experts die end-to-end-diensten aanbieden voor communicatie en digitale transformatie. We denken groot en werken lokaal. Aan strategie, creatie, content, marketing en technologie. In nauwe samenwerking met onze klanten om hun merken te versterken, hun digitale systemen te verbeteren en hun toekomstbestendige groei veilig te stellen. We helpen klanten niet alleen hun zakelijke doelen te bereiken. Samen verkennen en benutten we de eindeloze mogelijkheden die markten in constante verandering bieden. De springplank voor die visie is talent. Onze campus is onze broedplaats voor innovatie, die een omgeving creëert die talent de ruimte en stimulans geeft die het nodig heeft om te ontkiemen, te ontwikkelen en te floreren. Want werken aan de infinite opportunities van morgen, dat doen we vandaag.

    | Coven of Wisdom Herentals

    Go to page for Coven of Wisdom - Herentals - Winter `24 edition

  • Mastering Event-Driven Design

    PLEASE RSVP SO THAT WE KNOW HOW MUCH FOOD WE WILL NEED Are you and your team struggling with event-driven microservices? Join us for a meetup with Mehmet Akif Tütüncü, a senior software engineer, who has given multiple great talks so far and Allard Buijze founder of CTO and founder of AxonIQ, who built the fundaments of the Axon Framework. RSVP for an evening of learning, delicious food, and the fusion of creativity and tech! 🚀 18:00 – 🚪 Doors open to the public 18:15 – 🍕 Let’s eat 19:00 – 📢 Getting Your Axe On Event Sourcing with Axon Framework 20:00 – 🍹 Small break 20:15 – 📢 Event-Driven Microservices - Beyond the Fairy Tale 21:00 – 🙋‍♀️ drinks 22:00 – 🍻 See you next time? Details: Getting Your Axe On - Event Sourcing with Axon Framework In this presentation, we will explore the basics of event-driven architecture using Axon Framework. We'll start by explaining key concepts such as Event Sourcing and Command Query Responsibility Segregation (CQRS), and how they can improve the scalability and maintainability of modern applications. You will learn what Axon Framework is, how it simplifies implementing these patterns, and see hands-on examples of setting up a project with Axon Framework and Spring Boot. Whether you are new to these concepts or looking to understand them more, this session will provide practical insights and tools to help you build resilient and efficient applications. Event-Driven Microservices - Beyond the Fairy Tale Our applications need to be faster, better, bigger, smarter, and more enjoyable to meet our demanding end-users needs. In recent years, the way we build, run, and operate our software has changed significantly. We use scalable platforms to deploy and manage our applications. Instead of big monolithic deployment applications, we now deploy small, functionally consistent components as microservices. Problem. Solved. Right? Unfortunately, for most of us, microservices, and especially their event-driven variants, do not deliver on the beautiful, fairy-tale-like promises that surround them.In this session, Allard will share a different take on microservices. We will see that not much has changed in how we build software, which is why so many “microservices projects” fail nowadays. What lessons can we learn from concepts like DDD, CQRS, and Event Sourcing to help manage the complexity of our systems? He will also show how message-driven communication allows us to focus on finding the boundaries of functionally cohesive components, which we can evolve into microservices should the need arise.

    | Coven of Wisdom - Utrecht

    Go to page for Mastering Event-Driven Design

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