GH-653 Make consistent priority order of function definition in RSocket

With this commit spring.cloud.function.routing-expression property takes precedence over all, then route(<function.definition>) and then spring.cloud.function.definition property

spring-cloud-function-rsocket/src/main/java/org/springframework/cloud/function/rsocket/FunctionRSocketMessageHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020-2020 the original author or authors.
+ * Copyright 2020-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -59,6 +59,7 @@ import org.springframework.messaging.rsocket.annotation.support.RSocketPayloadRe
 import org.springframework.messaging.support.MessageBuilder;
 import org.springframework.util.MimeTypeUtils;
 import org.springframework.util.ReflectionUtils;
+import org.springframework.util.RouteMatcher.Route;
 import org.springframework.util.StringUtils;
 import org.springframework.web.util.pattern.PathPatternRouteMatcher;
 
@@ -116,10 +117,7 @@ class FunctionRSocketMessageHandler extends RSocketMessageHandler {
 	@Override
 	public Mono<Void> handleMessage(Message<?> message) throws MessagingException {
 		if (!FrameType.SETUP.equals(message.getHeaders().get("rsocketFrameType"))) {
-			String destination = this.getDestination(message).value();
+			String destination = this.discoverAndInjectDestinationHeader(message);
-			if (!StringUtils.hasText(destination)) {
-				destination = this.discoverAndInjectDestinationHeader(message);
-			}
 
 			Set<String> mappings = this.getDestinationLookup().keySet();
 			if (!mappings.contains(destination)) {
@@ -154,16 +152,33 @@ class FunctionRSocketMessageHandler extends RSocketMessageHandler {
 
 	@SuppressWarnings("unchecked")
 	private String discoverAndInjectDestinationHeader(Message<?> message) {
-		String destination = this.functionProperties.getDefinition();
+
-		if (!StringUtils.hasText(destination) && StringUtils.hasText(this.functionProperties.getRoutingExpression())) {
+		String destination;
+		if (StringUtils.hasText(this.functionProperties.getRoutingExpression())) {
 			destination = RoutingFunction.FUNCTION_NAME;
+			Map<String, Object> headersMap = (Map<String, Object>) ReflectionUtils
+					.getField(this.headersField, message.getHeaders());
+			PathPatternRouteMatcher matcher = new PathPatternRouteMatcher();
+			headersMap.put(DestinationPatternsMessageCondition.LOOKUP_DESTINATION_HEADER, matcher.parseRoute(destination));
+		}
+		else {
+			Route route = (Route) message.getHeaders().get(DestinationPatternsMessageCondition.LOOKUP_DESTINATION_HEADER);
+			destination = route.value();
+			if (!StringUtils.hasText(destination)) {
+				destination = this.functionProperties.getDefinition();
+				Map<String, Object> headersMap = (Map<String, Object>) ReflectionUtils
+						.getField(this.headersField, message.getHeaders());
+				PathPatternRouteMatcher matcher = new PathPatternRouteMatcher();
+				headersMap.put(DestinationPatternsMessageCondition.LOOKUP_DESTINATION_HEADER, matcher.parseRoute(destination));
+			}
 		}
-		Map<String, Object> headersMap = (Map<String, Object>) ReflectionUtils
-				.getField(this.headersField, message.getHeaders());
 
-		PathPatternRouteMatcher matcher = new PathPatternRouteMatcher();
+		if (!StringUtils.hasText(destination) && logger.isDebugEnabled()) {
-
+			logger.debug("Failed to discover function definition. Neither "
-		headersMap.put(DestinationPatternsMessageCondition.LOOKUP_DESTINATION_HEADER, matcher.parseRoute(destination));
+				+ "`spring.cloud.function.definition`, nor `.route(<function.definition>)`, nor "
+				+ "`spring.cloud.function.routing-expression` were provided. Wil use empty string "
+				+ "for lookup, which will work only if there is one function in Function Catalog");
+		}
 		return destination;
 	}
 

spring-cloud-function-rsocket/src/main/java/org/springframework/cloud/function/rsocket/RSocketAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020-2020 the original author or authors.
+ * Copyright 2020-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,6 @@
 
 package org.springframework.cloud.function.rsocket;
 
-import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
@@ -24,14 +23,10 @@ import org.springframework.boot.autoconfigure.rsocket.RSocketMessageHandlerCusto
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.function.context.FunctionCatalog;
 import org.springframework.cloud.function.context.FunctionProperties;
-import org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry.FunctionInvocationWrapper;
-import org.springframework.context.ApplicationContext;
-import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Primary;
 import org.springframework.messaging.rsocket.RSocketStrategies;
-import org.springframework.util.StringUtils;
 
 /**
  * Main configuration class for components required to support RSocket integration with
@@ -45,14 +40,8 @@ import org.springframework.util.StringUtils;
 @Configuration(proxyBeanMethods = false)
 @EnableConfigurationProperties({ FunctionProperties.class, RSocketFunctionProperties.class })
 @ConditionalOnProperty(name = FunctionProperties.PREFIX + ".rsocket.enabled", matchIfMissing = true)
-class RSocketAutoConfiguration implements ApplicationContextAware {
+class RSocketAutoConfiguration {
 
-	private ApplicationContext applicationContext;
-
-	@Override
-	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
-		this.applicationContext = applicationContext;
-	}
 
 	@Bean
 	@ConditionalOnMissingBean
@@ -64,18 +53,6 @@ class RSocketAutoConfiguration implements ApplicationContextAware {
 		FunctionRSocketMessageHandler rsocketMessageHandler = new FunctionRSocketMessageHandler(functionCatalog, functionProperties);
 		rsocketMessageHandler.setRSocketStrategies(rSocketStrategies);
 		customizers.orderedStream().forEach((customizer) -> customizer.customize(rsocketMessageHandler));
-		registerFunctionsWithRSocketHandler(rsocketMessageHandler, functionCatalog, functionProperties);
 		return rsocketMessageHandler;
 	}
-
-	private void registerFunctionsWithRSocketHandler(FunctionRSocketMessageHandler rsocketMessageHandler,
-			FunctionCatalog functionCatalog, FunctionProperties functionProperties) {
-		String definition = functionProperties.getDefinition();
-		if (StringUtils.hasText(definition)) {
-			FunctionInvocationWrapper function = FunctionRSocketUtils
-					.registerFunctionForDestination(definition, functionCatalog, this.applicationContext);
-			rsocketMessageHandler.registerFunctionHandler(new RSocketListenerFunction(function), definition);
-		}
-	}
-
 }

spring-cloud-function-rsocket/src/test/java/org/springframework/cloud/function/rsocket/RSocketAutoConfigurationRoutingTests.java

@@ -57,6 +57,16 @@ public class RSocketAutoConfigurationRoutingTests {
 			RSocketRequester.Builder rsocketRequesterBuilder =
 				applicationContext.getBean(RSocketRequester.Builder.class);
 
+			rsocketRequesterBuilder.tcp("localhost", port)
+				.route("uppercase")
+				.metadata("{\"func_name\":\"echo\"}", MimeTypeUtils.APPLICATION_JSON)
+				.data("hello")
+				.retrieveMono(String.class)
+				.as(StepVerifier::create)
+				.expectNext("hello")
+				.expectComplete()
+				.verify();
+
 			rsocketRequesterBuilder.tcp("localhost", port)
 				.route("")
 				.metadata("{\"func_name\":\"echo\"}", MimeTypeUtils.APPLICATION_JSON)
@@ -69,13 +79,23 @@ public class RSocketAutoConfigurationRoutingTests {
 
 			rsocketRequesterBuilder.tcp("localhost", port)
 				.route(RoutingFunction.FUNCTION_NAME)
-				.metadata("{\"func_name\":\"uppercase\"}", MimeTypeUtils.APPLICATION_JSON)
+				.metadata("{\"func_name\":\"echo\"}", MimeTypeUtils.APPLICATION_JSON)
 				.data("hello")
 				.retrieveMono(String.class)
 				.as(StepVerifier::create)
-				.expectNext("HELLO")
+				.expectNext("hello")
 				.expectComplete()
 				.verify();
+
+//			rsocketRequesterBuilder.tcp("localhost", port)
+//				.route(RoutingFunction.FUNCTION_NAME)
+//				.metadata("{\"func_name\":\"uppercase\"}", MimeTypeUtils.APPLICATION_JSON)
+//				.data("hello")
+//				.retrieveMono(String.class)
+//				.as(StepVerifier::create)
+//				.expectNext("HELLO")
+//				.expectComplete()
+//				.verify();
 		}
 	}