GH-620 Add BeanResolver support for RoutingFunction

Resolves #620

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/config/ContextFunctionCatalogAutoConfiguration.java

@@ -1,5 +1,9 @@
 /*
+<<<<<<< HEAD
  * Copyright 2016-2019 the original author or authors.
+=======
+ * Copyright 2016-2021 the original author or authors.
+>>>>>>> 3a3fd4a6... GH-620 Add BeanResolver support for RoutingFunction
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,6 +31,7 @@ import java.util.stream.Collectors;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.google.gson.Gson;
 
+import org.springframework.beans.factory.BeanFactory;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
@@ -45,6 +50,7 @@ import org.springframework.context.annotation.ComponentScan;
 import org.springframework.context.annotation.ComponentScan.Filter;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.FilterType;
+import org.springframework.context.expression.BeanFactoryResolver;
 import org.springframework.core.convert.converter.GenericConverter;
 import org.springframework.core.convert.support.ConfigurableConversionService;
 import org.springframework.messaging.converter.ByteArrayMessageConverter;
@@ -119,8 +125,10 @@ public class ContextFunctionCatalogAutoConfiguration {
 	}
 
 	@Bean(RoutingFunction.FUNCTION_NAME)
-	RoutingFunction functionRouter(FunctionCatalog functionCatalog, FunctionInspector functionInspector, FunctionProperties functionProperties) {
-		return new RoutingFunction(functionCatalog, functionInspector, functionProperties);
+	RoutingFunction functionRouter(FunctionCatalog functionCatalog, FunctionInspector functionInspector,
+			FunctionProperties functionProperties, BeanFactory beanFactory) {
+
+		return new RoutingFunction(functionCatalog, functionProperties, functionInspector, new BeanFactoryResolver(beanFactory));
 	}
 
 	private boolean isConverterEligible(Object messageConverter) {

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/config/RoutingFunction.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2019 the original author or authors.
+ * Copyright 2019-2021 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.
@@ -30,6 +30,7 @@ import org.springframework.cloud.function.context.FunctionProperties;
 import org.springframework.cloud.function.context.catalog.FunctionInspector;
 import org.springframework.cloud.function.context.catalog.FunctionTypeUtils;
 import org.springframework.context.expression.MapAccessor;
+import org.springframework.expression.BeanResolver;
 import org.springframework.expression.Expression;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.expression.spel.support.StandardEvaluationContext;
@@ -65,11 +66,20 @@ public class RoutingFunction implements Function<Object, Object> {
 
 	private final FunctionInspector functionInspector;
 
-	public RoutingFunction(FunctionCatalog functionCatalog, FunctionInspector functionInspector, FunctionProperties functionProperties) {
+	public RoutingFunction(FunctionCatalog functionCatalog, FunctionInspector functionInspector,
+			FunctionProperties functionProperties) {
+
+		this(functionCatalog, functionProperties, functionInspector, null);
+	}
+
+	public RoutingFunction(FunctionCatalog functionCatalog, FunctionProperties functionProperties,
+			FunctionInspector functionInspector, BeanResolver beanResolver) {
 		this.functionCatalog = functionCatalog;
 		this.functionProperties = functionProperties;
 		this.functionInspector = functionInspector;
 		this.evalContext.addPropertyAccessor(new MapAccessor());
+		this.evalContext.setBeanResolver(beanResolver);
+		evalContext.setBeanResolver(beanResolver);
 	}
 
 	@Override
@@ -170,6 +180,7 @@ public class RoutingFunction implements Function<Object, Object> {
 	@SuppressWarnings("rawtypes")
 	private Function functionFromExpression(String routingExpression, Object input) {
 		Expression expression = spelParser.parseExpression(routingExpression);
+
 		String functionName = expression.getValue(this.evalContext, input, String.class);
 		Assert.hasText(functionName, "Failed to resolve function name based on routing expression '" + functionProperties.getRoutingExpression() + "'");
 		Function function = functionCatalog.lookup(functionName);

spring-cloud-function-context/src/test/java/org/springframework/cloud/function/context/config/RoutingFunctionTests.java

@@ -127,6 +127,17 @@ public class RoutingFunctionTests {
 		assertThat(function.apply(message)).isEqualTo("olleh");
 	}
 
+	@SuppressWarnings({ "rawtypes", "unchecked" })
+	@Test
+	public void testInvocationWithRoutingBeanExpression() {
+		System.setProperty(FunctionProperties.PREFIX + ".routing-expression", "@reverse.apply(#root.getHeaders().get('func'))");
+		FunctionCatalog functionCatalog = this.configureCatalog();
+		Function function = functionCatalog.lookup(RoutingFunction.FUNCTION_NAME);
+		assertThat(function).isNotNull();
+		Message<String> message = MessageBuilder.withPayload("hello").setHeader("func", "esacreppu").build();
+		assertThat(function.apply(message)).isEqualTo("HELLO");
+	}
+
 	@SuppressWarnings({ "rawtypes", "unchecked" })
 	@Test
 	public void testOtherExpectedFailures() {
@@ -169,6 +180,11 @@ public class RoutingFunctionTests {
 	@Configuration
 	protected static class RoutingFunctionConfiguration {
 
+		@Bean
+		public String functionName() {
+			return "reverse";
+		}
+
 		@Bean
 		public Function<String, String> reverse() {
 			return v -> new StringBuilder(v).reverse().toString();