NOTE: To run locally on top of Azure Functions, and to deploy to your live Azure environment, you will need Azure Functions Core Tools installed along with the Azure CLI (see here for details) as well as the Use Azurite emulator for local Azure Storage development. For the emulator you can run a docker container (see below) or use the Visual-Studio-Code extension.

docker run --name azurite --rm -p 10000:10000 -p 10001:10001 -p 10002:10002 mcr.microsoft.com/azure-storage/azurite

./mvnw clean package
./mvnw azure-functions:run

The timer triggers the function every minute. In result the the uppercase Spring Cloud Function is called and uppercase the timeInfo and logs it into the context.

[2022-10-11T08:53:00.011Z] Timer is triggered: {"Schedule":{"AdjustForDST":true},"ScheduleStatus":{"Last":"2022-10-11T10:52:00.003967+02:00","Next":"2022-10-11T10:53:00+02:00","LastUpdated":"2022-10-11T10:52:00.003967+02:00"},"IsPastDue":false}

Running on Azure

Make sure you are logged in your Azure account.

az login

Build and deploy

./mvnw clean package
./mvnw azure-functions:deploy

Implementation details

The uppercase function signature is Function<Message<String>, Void> uppercase(). The implementation of UppercaseHandler (which extends FunctionInvoker) provides access to the Azure Function context via the MessageHeaders.

NOTE: Implementation of FunctionInvoker (your handler), should contain the least amount of code. It is really a type-safe way to define and configure function to be recognized as Azure Function. Everything else should be delegated to the base FunctionInvoker via handleRequest(..) callback which will invoke your function, taking care of necessary type conversion, transformation etc. One exception to this rule is when custom result handling is required. In that case, the proper post-process method can be overridden as well in order to take control of the results processing.

UppercaseHandler.java:

public class UppercaseHandler extends FunctionInvoker<Message<String>, Void> {

    @FunctionName("uppercase")
    public void execute(@TimerTrigger(name = "keepAliveTrigger", schedule = "0 */1 * * * *") String timerInfo,
            ExecutionContext context) {

        Message<String> message = MessageBuilder.withPayload(timerInfo).build();
        
        handleRequest(message, context);
    }
}

Note that this function does not return value (e.g. Void output type) and is backed by java.util.Consumer SCF implementation:

	@Bean
	public Consumer<Message<String>> uppercase() {
		return message -> {
			// /timeInfo is a JSON string, you can deserialize it to an object using your favorite JSON library
			String timeInfo = message.getPayload();

			// Business logic -> convert the timeInfo to uppercase.
			String value = timeInfo.toUpperCase();
			
			// (Optionally) access and use the Azure function context.
			ExecutionContext context = (ExecutionContext) message.getHeaders().get("executionContext");
			context.getLogger().info("Timer is triggered with TimeInfo: " + value);

			// No response.
		};
	}

Notes

Disable the spring-boot-maven-plugin in favor of the azure-functions-maven-plugin.
Exclude the org.springframework.boot:spring-boot-starter-logging dependency from the org.springframework.cloud:spring-cloud-function-adapter-azure.
Add "AzureWebJobsStorage": "UseDevelopmentStorage=true" to the local.settings.json.