If the trigger function must be customized, disable generation of the trigger function by removing the NServiceBusTriggerFunction attribute. A custom trigger function can then be added manually to the project:
class CustomTriggerDefinition
{
IFunctionEndpoint functionEndpoint;
public CustomTriggerDefinition(IFunctionEndpoint functionEndpoint)
{
this.functionEndpoint = functionEndpoint;
}
[FunctionName("MyCustomTrigger")]
public Task Run(
[ServiceBusTrigger("MyFunctionsEndpoint")]
ServiceBusReceivedMessage message,
ServiceBusClient client,
ServiceBusMessageActions messageActions,
ILogger logger,
ExecutionContext executionContext)
{
return functionEndpoint.ProcessAtomic(message, executionContext, client, messageActions, logger);
}
}
Configuring transaction mode
If the NServiceBusTriggerFunction attribute is not used, IFunctionEndpoint. will determine the transaction mode based on the ServiceBusTrigger's auto-complete property:
If auto-complete is enabled, which is the default, NServiceBus can't control the receive transaction and the message is processed in TransportTransactionMode. mode.
[FunctionName("ProcessMessage")]
public async Task Run(
// Setting AutoComplete to true (the default) processes the message non-transactionally
[ServiceBusTrigger("ProcessMessage", AutoCompleteMessages = true)]
ServiceBusReceivedMessage message,
ILogger logger,
ExecutionContext executionContext)
{
await endpoint.ProcessNonAtomic(message, executionContext, logger);
}
If auto-complete is disabled, NServiceBus can fully control incoming and outgoing messages and the message is processed in TransportTransactionMode. mode.
[FunctionName("ProcessMessageTx")]
public Task RunTx(
// Setting AutoComplete to false processes the message transactionally
[ServiceBusTrigger("ProcessMessageTx", AutoCompleteMessages = false)]
ServiceBusReceivedMessage message,
ServiceBusClient client,
ServiceBusMessageActions messageActions,
ILogger logger,
ExecutionContext executionContext)
{
return endpoint.ProcessAtomic(message, executionContext, client, messageActions, logger);
}
Incorrectly configuring the service bus trigger auto-complete setting can lead to message loss. Use the auto-detection mechanism on the function endpoint interface, or use the trigger function attribute to specify message consistency.