Paco de la Cruz gave a presentation on Durable Functions 2.0 and stateful serverless functions. The presentation covered an overview of serverless computing on Azure, a recap of Azure Functions and an introduction to Durable Functions. It discussed new features in Durable Functions 2.0 including Durable Entities, additional function types and patterns. The presentation also provided demonstrations of common Durable Functions patterns and a stateful serverless request bin application. It concluded with a Q&A section.

1. @pacodelacruz
Paco de la Cruz
Durable Functions 2.0
Stateful Serverless Functions
IntegrationDownUnder
@pacodelacruz

2. @pacodelacruz
@pacodelacruz
linkedin.com/in/pacodelacruz
pacodelacruz.io
slideshare.net/pacodelac/presentations
github.com/pacodelacruz

3. @pacodelacruz
Serverless and Azure Functions Recap
What’s Coming in Durable Functions 2.0
Durable Functions Patterns
Function Types
Durable Entities
Demo
Q & A
Agenda

4. @pacodelacruz
Cloud Compute Spectrum

5. @pacodelacruz
Azure Compute Spectrum

6. @pacodelacruz
Serverless FaaS and its Benefits
Server abstraction
(Ops Productivity)
Scaling,
Load balancing &
High availability
built-in

7. @pacodelacruz
Serverless FaaS and its Benefits
Server abstraction
(Ops Productivity)
Event-driven scaling
not resource-driven
Scaling,
Load balancing &
High availability
built-in
Pay only for
what you use
Devs Productivity
(Programming
Models)

8. @pacodelacruz
Azure Functions in a Nutshell
Event Triggers Code Outputs
React and get inputs from
a growing list of services
(triggers and input
bindings)
C#, F#,
Node.js, Java,
Python, PowerShell
Send results to a
growing list of services
(output bindings)

9. @pacodelacruz
Durable Functions in a Nutshell
Based on
Durable Task Framework
Using Azure Storage
(Managed & Abstracted)
To Implement
stateful entities and
workflows-as-code
(C#, F# & Node.js)
Azure Functions
Extension

10. @pacodelacruz
Durable Entities (Actor-Like)
HTTP Calls from Orch. (with MI)
Pluggable State Providers
Testability Improvements
Orchestrator Roslyn Analyser
What’s Coming in Durable Functions 2.0

11. @pacodelacruz
Durable Functions Patterns (1.0)
Function Chaining Fan-out & Fan-in Async HTTP APIs
Human Interaction /
Wait for External Events
Monitoring
Start
Get Status

12. @pacodelacruz
Durable Functions Patterns (2.0)
Function Chaining Fan-out & Fan-in Async HTTP APIs
Human Interaction /
Wait for External Events
Monitoring Durable Entities *
Start
Get Status
Query
* New on 2.0

13. @pacodelacruz
Durable Functions Types (1.0)
Client ActivityOrchestrator
Start Orch.
Query Orch.
Terminate Orch.
Signal Orch.
Call Activity
Call Sub-orch.
Set Status
Perform Step,
IO
Stateless Stateful Stateless
Client Orchestrator Activity

14. @pacodelacruz
Durable Functions Types (2.0)
Entity*Client ActivityOrchestrator
Start Orch.
Query Orch.
Terminate Orch.
Signal Orch.
Signal Entity*
Query Entity*
Call Activity
Call Sub-orch.
Set Status
Call Entity*
Perform Step,
IO
Initialise*
Destruct*
Handle Event*
Set State*
Stateless Stateful Stateless Stateful
Client Orchestrator Activity Entity*
* New on 2.0

15. @pacodelacruz
Addressable via entity Id
Operations execute serially
Created when called or signalled
When not executing, unloaded from memory
One-way messaging from Clients and other Entities ^
Two-way requests from Orchestrations ^
Orchestrations provide distributed locking ^
Durability over latency ^
Durable Entities (Actor-Like)
^ Different from virtual-actors

16. @pacodelacruz
Function Chaining Pattern
public static async Task<object> Run(
[OrchestrationTrigger] DurableOrchestrationContext ctx)
{
try
{
var x = await ctx.CallActivityAsync<object>("F1");
var y = await ctx.CallActivityAsync<object>("F2", x);
return await ctx.CallActivityAsync<object>("F3", y);
}
catch (Exception ex)
{
// error handling / compensation
}
}

17. @pacodelacruz
Function Chaining Pattern
public static async Task<object> Run(
[OrchestrationTrigger] DurableOrchestrationContext ctx)
{
try
{
var x = await ctx.CallActivityAsync<object>("F1");
var y = await ctx.CallActivityAsync<object>("F2", x);
return await ctx.CallActivityAsync<object>("F3", y);
}
catch (Exception ex)
{
// error handling / compensation
}
}

18. @pacodelacruz
Function Chaining Pattern
public static async Task<object> Run(
[OrchestrationTrigger] DurableOrchestrationContext ctx)
{
try
{
var x = await ctx.CallActivityAsync<object>("F1");
var y = await ctx.CallActivityAsync<object>("F2", x);
return await ctx.CallActivityAsync<object>("F3", y);
}
catch (Exception ex)
{
// error handling / compensation
}
}

19. @pacodelacruz
Fan-out & Fan-In Pattern
public static async Task<int> Run(
[OrchestrationTrigger] DurableOrchestrationContext ctx)
{
object[] workBatch = await ctx.CallActivityAsync<object[]>("F1");
var tasks = new Task<long>[workBatch.Length];
for (int i = 0; i < workBatch.Length; i++)
{
tasks[i] = ctx.CallActivityAsync<int>("F2", workBatch[i]);
}
await Task.WhenAll(tasks);
long sum = tasks.Sum(t => t.Result);
return sum;
}

20. @pacodelacruz
Fan-out & Fan-In Pattern
public static async Task<int> Run(
[OrchestrationTrigger] DurableOrchestrationContext ctx)
{
object[] workBatch = await ctx.CallActivityAsync<object[]>("F1");
var tasks = new Task<long>[workBatch.Length];
for (int i = 0; i < workBatch.Length; i++)
{
tasks[i] = ctx.CallActivityAsync<int>("F2", workBatch[i]);
}
await Task.WhenAll(tasks);
long sum = tasks.Sum(t => t.Result);
return sum;
}
CallActivityWithRetryAsync

21. @pacodelacruz
Orchestration Client
public static async Task<HttpResponseMessage> Run(
[HttpTrigger(AuthorizationLevel.Function, methods: "post",
Route = "orchestrators/{functionName}")] HttpRequestMessage req,
[OrchestrationClient] DurableOrchestrationClientBase starter, ILogger log)
{
// Function input comes from the request content.
dynamic eventData = await req.Content.ReadAsAsync<object>();
string instanceId = await starter.StartNewAsync("myOrchestrator", eventData);
log.LogInformation($"Started orchestration with ID = '{instanceId}'.");
var res = starter.CreateCheckStatusResponse(req, instanceId);
return res;
}

22. @pacodelacruz
Orchestration Client
public static async Task<HttpResponseMessage> Run(
[HttpTrigger(AuthorizationLevel.Function, methods: "post",
Route = "orchestrators/{functionName}")] HttpRequestMessage req,
[OrchestrationClient] DurableOrchestrationClientBase starter, ILogger log)
{
// Function input comes from the request content.
dynamic eventData = await req.Content.ReadAsAsync<object>();
string instanceId = await starter.StartNewAsync("myOrchestrator", eventData);
log.LogInformation($"Started orchestration with ID = '{instanceId}'.");
var res = starter.CreateCheckStatusResponse(req, instanceId);
return res;
}

23. @pacodelacruz
Orchestration Client
public static async Task<HttpResponseMessage> Run(
[HttpTrigger(AuthorizationLevel.Function, methods: "post",
Route = "orchestrators/{functionName}")] HttpRequestMessage req,
[OrchestrationClient] DurableOrchestrationClientBase starter, ILogger log)
{
// Function input comes from the request content.
dynamic eventData = await req.Content.ReadAsAsync<object>();
string instanceId = await starter.StartNewAsync("myOrchestrator", eventData);
log.LogInformation($"Started orchestration with ID = '{instanceId}'.");
var res = starter.CreateCheckStatusResponse(req, instanceId);
return res;
}

24. @pacodelacruz
Durable Entity Functions
public class Counter
{
[JsonProperty("value")]
public int CurrentValue { get; set; }
public void Add(int amount) => this.CurrentValue += amount;
public void Reset() => this.CurrentValue = 0;
public int Get() => this.CurrentValue;
[FunctionName(nameof(Counter))]
public static Task Run([EntityTrigger] IDurableEntityContext ctx)
=> ctx.DispatchAsync<Counter>();
}

25. @pacodelacruz
Durable Entity Functions
public class Counter
{
[JsonProperty("value")]
public int CurrentValue { get; set; }
public void Add(int amount) => this.CurrentValue += amount;
public void Reset() => this.CurrentValue = 0;
public int Get() => this.CurrentValue;
[FunctionName(nameof(Counter))]
public static Task Run([EntityTrigger] IDurableEntityContext ctx)
=> ctx.DispatchAsync<Counter>();
}

26. @pacodelacruz
Durable Entity Functions
public class Counter
{
[JsonProperty("value")]
public int CurrentValue { get; set; }
public void Add(int amount) => this.CurrentValue += amount;
public void Reset() => this.CurrentValue = 0;
public int Get() => this.CurrentValue;
[FunctionName(nameof(Counter))]
public static Task Run([EntityTrigger] IDurableEntityContext ctx)
=> ctx.DispatchAsync<Counter>();
}

27. @pacodelacruz
Durable Entity Functions
public class Counter
{
[JsonProperty("value")]
public int CurrentValue { get; set; }
public void Add(int amount) => this.CurrentValue += amount;
public void Reset() => this.CurrentValue = 0;
public int Get() => this.CurrentValue;
[FunctionName(nameof(Counter))]
public static Task Run([EntityTrigger] IDurableEntityContext ctx)
=> ctx.DispatchAsync<Counter>();
}

28. @pacodelacruz
Durable Functions vs Logic Apps?
Durable Functions Logic Apps
Stateful workflows and entities Stateful workflows
C#, F# and JavaScript Visual designer and WDL
Bindings (~ 20 supported) 250+ connectors
Portable Runtime Run only on Azure
Monitoring based on App Insights & APIs Rich monitoring & management tools
Serverless, dedicated and isolated Serverless & dedicated (ISE)
platform.deloitte.com.au/articles/azure-durable-functions-vs-logic-apps

29. @pacodelacruz
Questions so far?

30. @pacodelacruz
Stateful Serverless Request Bin
Why Having Your Own Serverless Request Bin?
Deploy to Azure
Understand the Solution
Test It!
Demo
github.com/pacodelacruz/
serverless-request-bin-durable-functions

31. @pacodelacruz
Q & A
IntegrationDownUnder

32. @pacodelacruz
Additional Resources
Twitter @azurefunctions
Documentation aka.ms/durablefunctions &
aka.ms/durable/2docs
Live Web Cast aka.ms/azurefunctionslive
Repos github.com/Azure/azure-functions-durable-extension
github.com/Azure/azure-functions-durable-js
Samples aka.ms/durable/entitysamples

33. @pacodelacruz
@pacodelacruz
linkedin.com/in/pacodelacruz
pacodelacruz.io
slideshare.net/pacodelac/presentations
github.com/pacodelacruz

34. @pacodelacruz
:)
IntegrationDownUnder