Durable Functions 2.0

Transcript

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6. Andrea Ceroni andrea.ceroni@elfo.net @andrekiba http://www.linkedin.com/in/andreaceroni elfo.net klabcommunity.org
7. Durable Functions 2.0
8. Durable Functions stateful patterns Function chaining F1 F2 F3 Async HTTP APIs Start DoWork GetStatus Long-running monitor Event aggregator Human interaction RequestApproval ProcessApproval Escalate Fan-out / fan-in F1 F2 F3
9. Durable Functions Types Client stateless Orchestrator stateful Activity stateless Entity stateful
10. Durable Functions Actions [DurableClient] IDurableOrchestrationClient Client Function • Start orchestration • Query orchestration • Terminate orchestration • Signal orchestration • Signal entity • Query entity [OrchestrationTrigger] IDurableOrchestrationContext Orchestrator Function • Call an activity • Call sub-orchestrator • Set status • Call entity [EntityTrigger] IDurableEntityContext Entity Function • Initialize • Destroy • Handle event • Set state • Get state
11. Durable Entities Serverless virtual actors very similar to actors (Akka.Net, Orleans...) but with some substantial differences Explicit state express the state " in an explicit way " and not in the form of a workflow as happens with orchestrators, but they can be used together with orchestrators Reliability for messages (call and signal) "exactly-once" delivery is guaranteed communication takes place through persistent queues (Azure Storage Queue) which guarantee sorting and de-duplication Messages are processed one at a time
12. EntityId EntityId an entity is uniquely defined by its id in the form @EntityType@EntityKey, for example @Light@Hue1 SingnalEntityAsync vs CallEntitiyAsync "signaling" means the enqueue of an operation (asynchronous command, ane-way) "call" instead is usable only inside an orchestrator and returns an answer directly Proxy defining an interface, which the entity will implement, we can perform operations on the entity in a type-safe way avoiding the " magic strings " in code
14. Demo
15. Comparison with virtual actors Commons: • addressable via ID • serial execution of operations • automatically created during the first opeartion • unloaded from memory when not in use • messages are delivered in order and reliably • support for distributed lock via orchestrator • pattern request / response possible only from the orchestrator (entity-to-entity signaling only, as in the actors) Differences:
16. public class Question { public string Answer { get; set; } public void AskAQuestion(string question) => Answer = ThinkAboutTheAnswer( J ); public string GetAnswer() => this.Answer; [FunctionName(nameof(Question))] public static Task Run( [EntityTrigger] IDurableEntityContext ctx, => ctx.DisptachAsync<Question>(); }
17. Links https://docs.microsoft.com/en-us/azure/azure-functions/durable/durable-functions-overview https://docs.microsoft.com/en-us/azure/azure-functions/durable/durable-functions-preview https://docs.microsoft.com/en-us/azure/azure-functions/durable/durable-functions-entities https://github.com/Azure/azure-functions-durable-extension/tree/v2 https://www.youtube.com/watch?v=aHue7XuN
18. Thanks! andrea.ceroni@elfo.net andrea.ceroni@gmail.com @andrekiba http://github.com/andrekiba http://www.linkedin.com/in/andreaceroni https://creativecommons.org/licenses/by-nc-sa/3.0/