# Asynchronous Processing Patterns

**Last updated:** 2026-06-24 | Verified: MCP 2026-06
**Status:** GA
**Category:** Performance & Scalability
**Type:** reference
**Source:** https://learn.microsoft.com/azure/architecture/guide/architecture-styles/event-driven

---

## Innhold

- [Introduksjon](#introduksjon)
- [Kjernekomponenter](#kjernekomponenter)
- [Queue-based Architectures](#queue-based-architectures)
- [Event-Driven Design](#event-driven-design)
- [Request-Response Decoupling](#request-response-decoupling)
- [Status Polling and Webhooks](#status-polling-and-webhooks)
- [Event-Driven Architecture Styles (oppdatert 2026-04)](#event-driven-architecture-styles-oppdatert-2026-04)
- [Norsk offentlig sektor](#norsk-offentlig-sektor)
- [Beslutningsrammeverk](#beslutningsrammeverk)
- [Referanser](#referanser)
- [For Cosmo](#for-cosmo)

## Introduksjon

Asynkron prosessering er en arkitekturstrategi der AI-forespørsler behandles uavhengig av den opprinnelige klientforbindelsen. I stedet for at klienten venter synkront på et svar fra Azure OpenAI (som kan ta fra 500ms til flere minutter for reasoning-modeller), plasseres forespørselen i en kø, behandles i bakgrunnen, og resultatet leveres via polling, webhook eller push-notifikasjon.

For Azure OpenAI tilbyr Microsoft flere innebygde asynkrone mekanismer: Batch API for store volum, Background Tasks i Responses API for langvarige oppgaver, og Webhooks for hendelsesbasert leveranse. I tillegg kan organisasjoner bygge egne asynkrone arkitekturer med Azure Service Bus, Azure Queue Storage eller Azure Event Hubs som mellomlag.

I norsk offentlig sektor er asynkron prosessering spesielt relevant for dokumentanalyse, saksbehandlingsstøtte og rapportgenerering — oppgaver der brukeren ikke trenger umiddelbart svar, men der volumet kan være svært høyt i perioder (f.eks. ved frister for høringssvar eller klagebehandling).

## Kjernekomponenter

| Komponent | Formål | Teknologi |
|-----------|--------|-----------|
| Azure Service Bus | Enterprise message broker med køer og topics | Azure Service Bus |
| Azure Queue Storage | Enkel, kostnadseffektiv meldingskø | Azure Storage |
| Azure Event Hubs | Høy-throughput event streaming | Azure Event Hubs |
| Azure Functions | Serverless compute for kø-triggered prosessering | Azure Functions |
| Batch API | Innebygd asynkron batch-prosessering | Azure OpenAI |
| Background Tasks | Langvarige oppgaver i Responses API | Azure OpenAI |
| Webhooks | Hendelsesbasert notifikasjon | Azure OpenAI |

## Queue-based Architectures

### Service Bus-basert AI-prosessering

```python
# Producer: Legg forespørsler i kø
from azure.servicebus import ServiceBusClient, ServiceBusMessage
import json

class AIRequestProducer:
    """Queue AI requests via Azure Service Bus."""

    def __init__(self, connection_string: str, queue_name: str = "ai-requests"):
        self.client = ServiceBusClient.from_connection_string(connection_string)
        self.sender = self.client.get_queue_sender(queue_name)

    async def submit_request(
        self,
        request_id: str,
        messages: list[dict],
        priority: str = "normal",
        callback_url: str = None
    ) -> str:
        """Submit AI request to queue. Returns request ID for polling."""
        payload = {
            "request_id": request_id,
            "messages": messages,
            "priority": priority,
            "callback_url": callback_url,
            "submitted_at": datetime.utcnow().isoformat()
        }

        message = ServiceBusMessage(
            body=json.dumps(payload),
            message_id=request_id,
            subject=priority,
            session_id=request_id if priority == "urgent" else None,
            time_to_live=timedelta(hours=24)
        )

        await self.sender.send_messages(message)
        return request_id


# Consumer: Prosesser forespørsler fra kø
from azure.servicebus.aio import ServiceBusClient as AsyncServiceBusClient
from openai import AsyncAzureOpenAI

class AIRequestConsumer:
    """Process AI requests from Service Bus queue."""

    def __init__(
        self,
        sb_connection: str,
        queue_name: str,
        openai_client: AsyncAzureOpenAI,
        max_concurrent: int = 10
    ):
        self.sb_client = AsyncServiceBusClient.from_connection_string(
            sb_connection)
        self.queue_name = queue_name
        self.openai = openai_client
        self.semaphore = asyncio.Semaphore(max_concurrent)

    async def process_messages(self):
        """Continuously process messages from queue."""
        async with self.sb_client.get_queue_receiver(
            self.queue_name,
            max_wait_time=30
        ) as receiver:
            async for message in receiver:
                asyncio.create_task(
                    self._handle_message(receiver, message))

    async def _handle_message(self, receiver, message):
        async with self.semaphore:
            try:
                payload = json.loads(str(message))

                # Prosesser med Azure OpenAI
                response = await self.openai.chat.completions.create(
                    model="gpt-4o",
                    messages=payload["messages"],
                    max_tokens=2000
                )

                # Lagre resultat
                await self._store_result(
                    payload["request_id"],
                    response.choices[0].message.content
                )

                # Callback hvis konfigurert
                if payload.get("callback_url"):
                    await self._send_callback(
                        payload["callback_url"],
                        payload["request_id"],
                        response.choices[0].message.content
                    )

                await receiver.complete_message(message)

            except Exception as e:
                if message.delivery_count < 3:
                    await receiver.abandon_message(message)
                else:
                    await receiver.dead_letter_message(
                        message,
                        reason=str(e))
```

### Azure Functions Queue Trigger

```csharp
// Azure Function: Prosesser AI-forespørsler fra Storage Queue
using Azure.AI.OpenAI;
using Azure.Messaging.ServiceBus;
using Microsoft.Azure.Functions.Worker;

public class AIRequestProcessor
{
    private readonly AzureOpenAIClient _openAIClient;

    public AIRequestProcessor(AzureOpenAIClient openAIClient)
    {
        _openAIClient = openAIClient;
    }

    [Function("ProcessAIRequest")]
    [ServiceBusOutput("ai-results", Connection = "ServiceBusConnection")]
    public async Task<ServiceBusMessage> Run(
        [ServiceBusTrigger("ai-requests",
         Connection = "ServiceBusConnection")]
        ServiceBusReceivedMessage message,
        FunctionContext context)
    {
        var logger = context.GetLogger("ProcessAIRequest");
        var request = JsonSerializer.Deserialize<AIRequest>(
            message.Body.ToString());

        logger.LogInformation(
            "Processing request {RequestId}", request!.RequestId);

        var chatClient = _openAIClient.GetChatClient("gpt-4o");
        var response = await chatClient.CompleteChatAsync(
            request.Messages.Select(m =>
                new UserChatMessage(m.Content)).ToList());

        var result = new AIResult
        {
            RequestId = request.RequestId,
            Output = response.Value.Content[0].Text,
            CompletedAt = DateTime.UtcNow,
            TokensUsed = response.Value.Usage.TotalTokenCount
        };

        return new ServiceBusMessage(
            JsonSerializer.Serialize(result))
        {
            MessageId = request.RequestId,
            Subject = "completed"
        };
    }
}
```

## Event-Driven Design

### Azure OpenAI med Event Grid

```python
# Event-driven pattern: Trigger AI-prosessering fra dokumenter
# Ny blob → Event Grid → Function → OpenAI → Result store

from azure.functions import Blueprint, EventGridEvent
from openai import AzureOpenAI
import json

bp = Blueprint()

@bp.event_grid_trigger(arg_name="event")
@bp.cosmos_db_output(
    arg_name="resultDoc",
    database_name="ai-results",
    container_name="completions",
    connection="CosmosConnection"
)
async def process_document_event(
    event: EventGridEvent,
    resultDoc: func.Out[str]
):
    """Process document when uploaded to Blob Storage."""
    data = event.get_json()
    blob_url = data["url"]

    # Hent dokumentinnhold
    document_text = await download_and_extract(blob_url)

    # Prosesser med Azure OpenAI
    client = AzureOpenAI(
        azure_endpoint=os.environ["AZURE_OPENAI_ENDPOINT"],
        api_key=os.environ["AZURE_OPENAI_KEY"],
        api_version="2024-10-21"
    )

    response = client.chat.completions.create(
        model="gpt-4o",
        messages=[
            {"role": "system", "content": "Analyser dette dokumentet..."},
            {"role": "user", "content": document_text[:128000]}
        ],
        max_tokens=2000
    )

    result = {
        "id": event.id,
        "source_blob": blob_url,
        "analysis": response.choices[0].message.content,
        "tokens_used": response.usage.total_tokens,
        "processed_at": datetime.utcnow().isoformat()
    }

    resultDoc.set(json.dumps(result))
```

## Request-Response Decoupling

### Background Tasks med Azure OpenAI Responses API

```python
from openai import AzureOpenAI
import time

def submit_background_task(client: AzureOpenAI, prompt: str) -> str:
    """Submit long-running task using background mode."""
    response = client.responses.create(
        model="o3",  # Reasoning modell — kan ta minutter
        input=prompt,
        background=True  # Kjør asynkront
    )
    return response.id

def poll_for_result(
    client: AzureOpenAI,
    response_id: str,
    max_wait_seconds: int = 600,
    poll_interval: int = 5
) -> dict:
    """Poll for background task completion."""
    start = time.time()

    while time.time() - start < max_wait_seconds:
        result = client.responses.retrieve(response_id)

        if result.status == "completed":
            return {
                "status": "completed",
                "output": result.output,
                "duration_seconds": round(time.time() - start, 1)
            }
        elif result.status == "failed":
            return {"status": "failed", "error": result.error}

        time.sleep(poll_interval)

    return {"status": "timeout"}

# Bruk: Kompleks analyse som kan ta flere minutter
response_id = submit_background_task(
    client,
    "Analyser dette reguleringsverket og identifiser alle krav..."
)

# Klienten kan gjøre andre ting mens vi venter
result = poll_for_result(client, response_id)
```

## Status Polling and Webhooks

### Webhook-basert notifikasjon

```python
# Webhook handler for Azure OpenAI events
from flask import Flask, request, Response
import hmac
import hashlib

app = Flask(__name__)

WEBHOOK_SECRET = os.environ["OPENAI_WEBHOOK_SECRET"]

@app.route("/webhooks/openai", methods=["POST"])
def handle_openai_webhook():
    """Handle Azure OpenAI webhook events."""
    # Verifiser signatur
    signature = request.headers.get("Webhook-Signature")
    webhook_id = request.headers.get("Webhook-ID")

    if not verify_signature(request.data, signature):
        return Response("Invalid signature", status=400)

    # Idempotency check
    if is_already_processed(webhook_id):
        return Response(status=200)

    event = request.get_json()

    # Prosesser event
    if event.get("type") == "batch.completed":
        handle_batch_complete(event["data"])
    elif event.get("type") == "fine_tuning.job.succeeded":
        handle_finetuning_complete(event["data"])

    mark_as_processed(webhook_id)
    return Response(status=200)

def verify_signature(payload: bytes, signature: str) -> bool:
    """Verify webhook signature."""
    expected = hmac.new(
        WEBHOOK_SECRET.encode(),
        payload,
        hashlib.sha256
    ).hexdigest()
    return hmac.compare_digest(expected, signature)


# Polling-basert status-sjekk med exponential backoff
import asyncio

async def poll_with_backoff(
    check_fn,
    initial_interval: float = 2.0,
    max_interval: float = 60.0,
    backoff_factor: float = 1.5,
    timeout: float = 3600.0
) -> dict:
    """Poll with exponential backoff until completion or timeout."""
    interval = initial_interval
    elapsed = 0.0

    while elapsed < timeout:
        result = await check_fn()

        if result.get("status") in ("completed", "failed"):
            return result

        await asyncio.sleep(interval)
        elapsed += interval
        interval = min(interval * backoff_factor, max_interval)

    return {"status": "timeout", "elapsed": elapsed}
```

### REST API for Status Polling

```csharp
// ASP.NET Core: Status polling endpoint for async AI requests
[ApiController]
[Route("api/ai")]
public class AIRequestController : ControllerBase
{
    private readonly ICosmosDbService _cosmosDb;
    private readonly IServiceBusSender _sender;

    [HttpPost("requests")]
    public async Task<IActionResult> SubmitRequest(
        [FromBody] AIRequestDto request)
    {
        var requestId = Guid.NewGuid().ToString();

        // Legg i kø for asynkron prosessering
        await _sender.SendAsync(new ServiceBusMessage(
            JsonSerializer.Serialize(request))
        {
            MessageId = requestId
        });

        // Returner 202 Accepted med Location header
        return AcceptedAtAction(
            nameof(GetStatus),
            new { requestId },
            new { requestId, status = "queued" });
    }

    [HttpGet("requests/{requestId}/status")]
    public async Task<IActionResult> GetStatus(string requestId)
    {
        var result = await _cosmosDb.GetRequestStatus(requestId);

        if (result == null)
            return NotFound();

        if (result.Status == "completed")
            return Ok(result);

        // Returnér 200 med status og Retry-After header
        Response.Headers.Append("Retry-After", "5");
        return Ok(new { requestId, status = result.Status });
    }
}
```


## Event-Driven Architecture Styles (oppdatert 2026-04)

Microsoft dokumenterer to primære topologier for event-drevet AI-prosessering:

### Broker-topologi vs. Mediator-topologi

| Aspekt | Broker-topologi | Mediator-topologi |
|--------|----------------|-------------------|
| Koordinering | Events publiseres direkte til broker | Central mediator koordinerer workflow |
| Eksempel | Azure Event Hubs + Service Bus | Azure Durable Functions |
| Kobling | Løs kobling mellom produsenter/konsumenter | Sterkere kobling via mediator |
| Bruksscenario | Høyvolum streaming, uavhengige konsumenter | Komplekse AI-arbeidsflyter med avhengigheter |

### Azure Event Hubs vs. Azure Event Grid

| Service | Type | Bruksscenario |
|---------|------|---------------|
| **Azure Event Hubs** | Durable event stream (log) | AI-inferensresultater som skal prosesseres av mange konsumenter |
| **Azure Event Grid** | Publish-subscribe, reaktiv | Trigger AI-jobb ved filnedlasting, blob-endring |
| **Azure Service Bus** | Message queue, garantert levering | Jobb-kø for AI-prosessering med retry og dead-letter |

### Utfordringer i event-drevne AI-arkitekturer

```python
# Utfordring 1: Garantert levering
# Bruk Service Bus med peek-lock for å garantere at AI-jobb fullføres

from azure.servicebus import ServiceBusClient, ServiceBusMessage
import json

def process_ai_job_safely(
    servicebus_conn: str,
    queue_name: str,
    ai_processor
) -> None:
    """Garantert levering via peek-lock mønster."""
    with ServiceBusClient.from_connection_string(servicebus_conn) as sb:
        with sb.get_queue_receiver(queue_name, max_wait_time=5) as receiver:
            for message in receiver:
                # Peek-lock: meldingen er reservert, ikke slettet
                try:
                    payload = json.loads(str(message))
                    result = ai_processor(payload)
                    # Fullfør melding (slett fra kø) kun ved suksess
                    receiver.complete_message(message)
                    publish_result(result)
                except Exception as e:
                    # Abandon: meldingen returneres til kø for ny levering
                    receiver.abandon_message(message)

# Utfordring 2: Eventual consistency
# AI-resultater publiseres asynkront — bruk correlation ID for sporing

def create_ai_job(correlation_id: str, payload: dict) -> dict:
    """Returner job receipt umiddelbart, resultat kommer asynkront."""
    return {
        "correlation_id": correlation_id,
        "status": "accepted",
        "result_url": f"/api/results/{correlation_id}",
        "estimated_completion_seconds": 30
    }

# Utfordring 3: Ordregaranti
# Event Hubs garanterer ordre innen én partisjon
# Bruk samme partisjonsnøkkel for relaterte AI-forespørsler

def publish_ordered_event(
    producer,
    partition_key: str,  # f.eks. dokument-ID
    event_data: dict
) -> None:
    from azure.eventhub import EventData
    event = EventData(json.dumps(event_data))
    event.properties = {"partition_key": partition_key}
    producer.send_batch([event], partition_key=partition_key)
```

## Norsk offentlig sektor

- **Saksbehandlingssystemer**: Asynkron prosessering er ideelt for AI-assistert saksbehandling der analyse kan ta tid. Saksbehandler sender inn dokument, fortsetter med annet arbeid, og mottar notifikasjon når analysen er ferdig.
- **Arkivloven**: Sørg for at alle mellomliggende meldinger i køer (Service Bus, Queue Storage) krypteres og at sensitive data ikke lagres utover nødvendig prosesseringstid.
- **Personvern**: Dead letter queues kan inneholde personopplysninger — konfigurer automatisk sletting og monitorering av DLQ-dybde.
- **Tilgjengelighet**: Asynkrone mønstre forbedrer brukeropplevelsen for tjenester med krav om universell utforming — brukere slipper å vente på skjermen.
- **Batch-prosessering**: Bruk Azure OpenAI Batch API for periodiske oppgaver (nattlige rapporter, ukentlige analyser) med 50% kostnadsreduksjon.

## Beslutningsrammeverk

| Scenario | Anbefaling | Begrunnelse |
|----------|------------|-------------|
| Bruker venter på svar (<3s) | Synkron + streaming | Best brukeropplevelse for korte svar |
| Dokumentanalyse (minutter) | Service Bus kø + polling | Bruker kan gjøre annet arbeid |
| Reasoning-modell (o3/o1) | Background Tasks API | Innebygd asynkron prosessering |
| Stort batch-volum (1000+) | Azure OpenAI Batch API | 50% kostnadsreduksjon |
| Event-drevet pipeline | Event Grid + Functions | Automatisk trigger ved nye data |
| Kritisk pålitelighet | Service Bus + DLQ | Garantert leveranse og feilhåndtering |

## Referanser

- [Azure OpenAI Batch API](https://learn.microsoft.com/azure/foundry/openai/how-to/batch) — Batch processing
- [Azure OpenAI Responses API — Background tasks](https://learn.microsoft.com/azure/foundry/openai/how-to/responses) — Background mode
- [Azure OpenAI Webhooks](https://learn.microsoft.com/azure/foundry/openai/how-to/webhooks) — Event notifications
- [Event-driven architecture style](https://learn.microsoft.com/azure/architecture/guide/architecture-styles/event-driven) — Architecture patterns
- [Azure Functions on Container Apps](https://learn.microsoft.com/azure/container-apps/functions-unified-platform) — Event-driven compute

## For Cosmo

- **Bruk denne referansen** når kunden har AI-workloads som ikke krever umiddelbart svar, eller når de opplever timeout-problemer med langvarige AI-forespørsler.
- Azure OpenAI Background Tasks er den enkleste løsningen for reasoning-modeller (o3, o1) som kan ta minutter — sett `background: true`.
- For enterprise-arkitekturer, anbefal Service Bus fremfor Queue Storage — gir sessions, dead letter queues og transaksjonsstøtte.
- Implementer alltid idempotency i webhook-handlere og consumers — meldinger kan leveres mer enn én gang.
- Batch API bør være standard for alle ikke-sanntids workloads — 50% kostnadsreduksjon er en enkel gevinst.