Serverless and especially Functions as a Service are en vogue these days and every cloud provider has their own offering. In this talk, Christian Lechner will show you what Microsoft brings to the table offering Azure Functions. In addition, we will take a look at an extension of these functions, namely Durable Functions. They make your life easier when dealing with real world workflow-like scenarios. As talk is cheap, you will see some live coding to get insights to Azure Functions as well as into the experience when working in the Azure environment.

1. Azure Functions

2. Agenda
• Why Serverless?
• Azure Functions 101
• FaaS vs. “Reality”
• Azure Durable Functions

3. About me
• Software Development since 2005
• Focus Topics: Extensibility, Cloud Native Development,
Serverless
• @lechnerc77
• www.linkedin.com/in/christian-lechner-963b7017

4. Why Serverless?StackAbstraction
Focus on Business Logic
Virtual Machines
Serverless
Containers
• Fully managed services
• Flexible scaling
• Only pay for what you use
• Seamless integration
• Enhanced productivity

5. What FaaS offerings do you know/use?
Go to www.menti.com
Code: 36 93 46

6. What does Microsoft bring
to the table?

7. Azure Functions

8. Azure Functions - Prerequisites
• Step 1: Install Node.JS (LTS) - https://nodejs.org/en/
• Step 2: Install Microsoft Visual Studio Code
https://code.visualstudio.com/
• Step 3: Install Azure Core Tools
npm install -g azure-functions-core-tools@3
• Step 4: Azure Functions extension - via Visual Studio Code Marketplace
https://marketplace.visualstudio.com/items?itemName=ms-
azuretools.vscode-azurefunctions

9. Azure Functions 101

10. How to deal with Business
Processes and FaaS?

11. FaaS - Principles
• Functions must be stateless
• Functions should not call other functions
• Functions should do only one thing
• BUT: Business Processes need state

12. Function Chaining to achieve State
• Queues are a necessary evil
• Context must be stored in a DB
• Unclear relation between functions
• Error handling becomes very complex
Function 1 Function 2 Function 3

13. Durable Functions for the Rescue
• Extension to the Azure Functions Framework
• Preserves local state via Event Sourcing
• Heavy work happens behind the curtain
• Supports you in front of the curtain with additional features

14. Tasks in orchestrator
1. let x = await ctx.CallActivityAsync(“F1”)
2. let y = await ctx.CallActivityAsync(“F2”, x)
3. return await ctx.CallActivityAsync(“F3”, y)

15. Tasks in orchestrator
1. let x = await ctx.CallActivityAsync(“F1”)
2. let y = await ctx.CallActivityAsync(“F2”, x)
3. return await ctx.CallActivityAsync(“F3”, y)
Trigger
Orchestrator
Activity

16. Tasks in orchestrator
1. let x = await ctx.CallActivityAsync(“F1”)
2. let y = await ctx.CallActivityAsync(“F2”, x)
3. return await ctx.CallActivityAsync(“F3”, y)
Trigger
Orchestrator
Activity

17. Tasks in orchestrator
1. let x = await ctx.CallActivityAsync(“F1”)
2. let y = await ctx.CallActivityAsync(“F2”, x)
3. return await ctx.CallActivityAsync(“F3”, y)
Trigger
Orchestrator
Activity

18. Tasks in orchestrator
1. let x = await ctx.CallActivityAsync(“F1”)
2. let y = await ctx.CallActivityAsync(“F2”, x)
3. return await ctx.CallActivityAsync(“F3”, y)
Trigger
Orchestrator
Activity

19. Tasks in orchestrator
1. let x = await ctx.CallActivityAsync(“F1”)
2. let y = await ctx.CallActivityAsync(“F2”, x)
3. return await ctx.CallActivityAsync(“F3”, y)
Trigger
Orchestrator
Activity

20. Tasks in orchestrator
1. let x = await ctx.CallActivityAsync(“F1”)
2. let y = await ctx.CallActivityAsync(“F2”, x)
3. return await ctx.CallActivityAsync(“F3”, y)
Trigger
Orchestrator
Activity

21. Tasks in orchestrator
1. let x = await ctx.CallActivityAsync(“F1”)
2. let y = await ctx.CallActivityAsync(“F2”, x)
3. return await ctx.CallActivityAsync(“F3”, y)
Trigger
Activity

22. In one Picture …

23. Azure Durable Functions - Prerequistes
• Step 1 – Install Azure Durable Functions Extension
(npm install durable-functions)
• Step 2 – Install Microsoft Azure Storage Emulator
(https://github.com/MicrosoftDocs/azure-
docs/blob/master/articles/storage/common/storage-use-
emulator.md)
• Optional: Microsoft Azure Storage Explorer
(https://azure.microsoft.com/en-us/features/storage-explorer/)

24. Azure Durable Functions 101

25. Challenge
Handle Errors in Activity Calls (Retry)
Orchestrator
Activity 1 Activity 2
SAP Cloud Applications

26. Challenge
Handle Timeouts in Activity Calls
Orchestrator
Activity 1 Activity 2
SAP Cloud Applications
Race Condition

27. Wrap Up – Azure Functions …
• … are cool ☺
• … have a low entry barrier due to local development options
• … allow modelling of complex scenarios without losing the benefits of FaaS
via Durable Functions
• … have even more (like Durable Entities)
• … just wait for you to try them

28. Thanks For Your Attention!

29. Q: Is there a lock-in to Microsoft Azure
A: No Azure Functions are Open Source as are Durable Functions
You can put them into a container and deploy them to docker
(supported by the func CLI)
If you deploy to Kubernetes – take a look at KEDA (https://keda.sh/)

30. Q: What about Cold Starts?
A: In general the Azure Team tries to reduce the cold start time
You can mitigate it via (more expensive consumption plans)

31. Q: What if my preferred language is not
supported?
A: You can implement Custom Handlers.
See also: https://github.com/Azure-Samples/functions-custom-
handlers

32. Q: I need a binding that is not supported
A: You can create your own bindings via so called custom bindings