# Roslyn analyzers for Azure Functions


> [!WARNING]
> **NServiceBus.AzureFunctions.InProcess.ServiceBus component has been sunset**
>
> Microsoft announced that .NET 8 will be [the last release supporting the in-process hosting model](https://techcommunity.microsoft.com/t5/apps-on-azure-blog/net-on-azure-functions-august-2023-roadmap-update/ba-p/3910098).
> We will continue to provide support and address critical fixes during the sunset period, but no new features will be added.
> New projects should use the [isolated worker model](/nservicebus/hosting/azure-functions-service-bus/index.md) instead. Follow [these instructions](/nservicebus/upgrades/azure-functions-service-bus-in-process-isolated-worker.md) to migrate.
> For information on the date when this component will stop receiving any update check our [support policy page](/nservicebus/upgrades/all-versions.md#host-packages-nservicebus-azurefunctions-inprocess-servicebus).


Starting in version 4.3, [Roslyn analyzers](https://learn.microsoft.com/en-us/visualstudio/code-quality/roslyn-analyzers-overview) are packaged with the Azure Functions host package that analyze the NServiceBus code to prevent the use of API calls that are not applicable in a serverless environment.

## Endpoint configuration API

### PurgeOnStartup is not supported

* **Rule ID**: NSBFUNC003
* **Severity**:Error
* **Example message**: Azure Functions endpoints do not support PurgeOnStartup.

### LimitMessageProcessingTo is not supported

* **Rule ID**: NSBFUNC004
* **Severity**:Error
* **Example message**: Concurrency-related settings are controlled via the Azure Function host.json configuration file.

### DefineCriticalErrorAction is not supported

* **Rule ID**: NSBFUNC005
* **Severity**:Error
* **Example message**: Azure Functions endpoints do not control the application lifecycle and should not define behavior in the case of critical errors.

### SetDiagnosticsPath is not supported

* **Rule ID**: NSBFUNC006
* **Severity**:Error
* **Example message**: Azure Functions endpoints should not write diagnostics to the local file system. Use CustomDiagnosticsWriter to write diagnostics to another location.

### MakeInstanceUniquelyAddressable is not supported

* **Rule ID**: NSBFUNC007
* **Severity**:Error
* **Example message**: Azure Functions endpoints have unpredictable lifecycles and should not be uniquely addressable.

### UseTransport is not supported

* **Rule ID**: NSBFUNC008
* **Severity**:Warning
* **Example message**: The package configures Azure Service Bus transport by default. Use ServiceBusTriggeredEndpointConfiguration.Transport to access the transport configuration.

### OverrideLocalAddress is not supported

* **Rule ID**: NSBFUNC009
* **Severity**:Error
* **Example message**: The NServiceBus endpoint address in Azure Functions is determined by the ServiceBusTrigger attribute.

## Options API

### RouteReplyToThisInstance is not supported

* **Rule ID**: NSBFUNC010
* **Severity**:Error
* **Example message**: Azure Functions instances cannot be directly addressed as they have a highly volatile lifetime. Use 'RouteToThisEndpoint' instead.

### RouteToThisInstance is not supported

* **Rule ID**: NSBFUNC011
* **Severity**:Error
* **Example message**: Azure Functions instances cannot be directly addressed as they have a highly volatile lifetime. Use 'RouteToThisEndpoint' instead.

## Transport Settings API

### TransportTransactionMode is not supported

* **Rule ID**: NSBFUNC012
* **Severity**:Error
* **Example message**: Transport TransactionMode is controlled by the Azure Service Bus trigger and cannot be configured via the NServiceBus transport configuration API when using Azure Functions.

### MaxAutoLockRenewalDuration is not supported

* **Rule ID**: NSBFUNC013
* **Severity**:Error
* **Example message**: Azure Functions endpoints do not control the message receiver and cannot decide the lock renewal duration.

### PrefetchCount is not supported

* **Rule ID**: NSBFUNC014
* **Severity**:Error
* **Example message**: Message prefetching is controlled by the Azure Service Bus trigger and cannot be configured via the NServiceBus transport configuration API when using Azure Functions.

### PrefetchMultiplier is not supported

* **Rule ID**: NSBFUNC015
* **Severity**:Error
* **Example message**: Message prefetching is controlled by the Azure Service Bus trigger and cannot be configured via the NServiceBus transport configuration API when using Azure Functions

### TimeToWaitBeforeTriggeringCircuitBreaker is not supported

* **Rule ID**: NSBFUNC016
* **Severity**:Error
* **Example message**: Azure Functions endpoints do not control the message receiver and cannot access circuit breaker settings.

### EntityMaximumSize is not supported

* **Rule ID**: NSBFUNC017
* **Severity**:Error
* **Example message**: Azure Functions endpoints do not support automatic queue creation.

### EnablePartitioning is not supported

* **Rule ID**: NSBFUNC018
* **Severity**:Error
* **Example message**: Azure Functions endpoints do not support automatic queue creation.