GH-766 Initial support to expose FunctionCatalog as actuator endpoint

spring-cloud-function-context/pom.xml

@@ -43,9 +43,9 @@
 			<optional>true</optional>
 		</dependency>
 		<dependency>
-		    <groupId>com.fasterxml.jackson.module</groupId>
+			<groupId>com.fasterxml.jackson.module</groupId>
-		    <artifactId>jackson-module-kotlin</artifactId>
+			<artifactId>jackson-module-kotlin</artifactId>
-		    <optional>true</optional>
+			<optional>true</optional>
 		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
@@ -69,7 +69,7 @@
 			<exclusions>
 				<exclusion>
 					<groupId>com.vaadin.external.google</groupId>
-    				<artifactId>android-json</artifactId>
+					<artifactId>android-json</artifactId>
 				</exclusion>
 			</exclusions>
 		</dependency>
@@ -83,7 +83,7 @@
 			<groupId>com.fasterxml.jackson.core</groupId>
 			<artifactId>jackson-databind</artifactId>
 		</dependency>
-		
+
 		<!-- KOTLIN -->
 		<dependency>
 			<groupId>org.jetbrains.kotlin</groupId>
@@ -109,10 +109,17 @@
 			<optional>true</optional>
 		</dependency>
 		<dependency>
-		    <groupId>io.cloudevents</groupId>
+			<groupId>io.cloudevents</groupId>
-		    <artifactId>cloudevents-spring</artifactId>
+			<artifactId>cloudevents-spring</artifactId>
-		    <version>2.2.0</version>
+			<version>2.2.0</version>
-		    <optional>true</optional>
+			<optional>true</optional>
+		</dependency>
+
+		<!-- Actuator -->
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-actuator</artifactId>
+			<optional>true</optional>
 		</dependency>
 	</dependencies>
 	<build>

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java

@@ -440,7 +440,7 @@ public class SimpleFunctionRegistry implements FunctionRegistry, FunctionInspect
 
 
 		public boolean isPrototype() {
-			return this.isPrototype();
+			return !this.isSingleton;
 		}
 
 		public void setSkipInputConversion(boolean skipInputConversion) {

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

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2021-2021 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.function.context.config;
+
+import org.springframework.boot.actuate.autoconfigure.endpoint.EndpointAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.endpoint.condition.ConditionalOnAvailableEndpoint;
+import org.springframework.boot.autoconfigure.AutoConfigureAfter;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.cloud.function.context.FunctionCatalog;
+import org.springframework.cloud.function.endpoint.FunctionsEndpoint;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * @author Oleg Zhurakousky
+ * @since 3.2
+ */
+@Configuration(proxyBeanMethods = false)
+@ConditionalOnClass(name = {
+		"org.springframework.boot.actuate.endpoint.annotation.Endpoint" })
+@ConditionalOnBean(FunctionCatalog.class)
+@AutoConfigureAfter(EndpointAutoConfiguration.class)
+public class FunctionsEndpointAutoConfiguration {
+
+	@Bean
+	@ConditionalOnAvailableEndpoint
+	public FunctionsEndpoint bindingsEndpoint(FunctionCatalog functionCatalog) {
+		return new FunctionsEndpoint(functionCatalog);
+	}
+
+}

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/endpoint/FunctionsEndpoint.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2021-2021 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.function.endpoint;
+
+import java.util.LinkedHashMap;
+
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+
+import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
+import org.springframework.boot.actuate.endpoint.annotation.ReadOperation;
+import org.springframework.cloud.function.context.FunctionCatalog;
+import org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry.FunctionInvocationWrapper;
+import org.springframework.cloud.function.json.JsonMapper;
+
+/**
+ *
+ * Actuator endpoint to access {@link FunctionCatalog}
+ *
+ * @author Oleg Zhurakousky
+ * @since 3.2
+ */
+@Endpoint(id = "functions")
+public class FunctionsEndpoint {
+
+	private final FunctionCatalog functionCatalog;
+
+	public FunctionsEndpoint(FunctionCatalog functionCatalog) {
+		this.functionCatalog = functionCatalog;
+	}
+
+	@ReadOperation
+	public Map<String, Map<String, Object>> listAll() {
+		Map<String, Map<String, Object>> allFunctions = new TreeMap<>();
+		Set<String> names = functionCatalog.getNames(null);
+		for (String name : names) {
+			FunctionInvocationWrapper function = functionCatalog.lookup(name);
+			Map<String, Object> functionMap = new LinkedHashMap<>();
+			if (function.isFunction()) {
+				functionMap.put("type", "FUNCTION");
+				functionMap.put("input-type", function.getInputType().toString());
+				functionMap.put("output-type", function.getOutputType().toString());
+			}
+			else if (function.isConsumer()) {
+				functionMap.put("type", "CONSUMER");
+				functionMap.put("input-type", function.getInputType().toString());
+			}
+			else {
+				functionMap.put("type", "SUPPLIER");
+				functionMap.put("output-type", function.getOutputType().toString());
+			}
+			allFunctions.put(name, functionMap);
+		}
+		return allFunctions;
+	}
+
+}

spring-cloud-function-context/src/main/resources/META-INF/spring.factories

@@ -1,7 +1,8 @@
 org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
 org.springframework.cloud.function.context.config.ContextFunctionCatalogAutoConfiguration,\
 org.springframework.cloud.function.cloudevent.CloudEventsFunctionExtensionConfiguration,\
-org.springframework.cloud.function.context.config.KotlinLambdaToFunctionAutoConfiguration
+org.springframework.cloud.function.context.config.KotlinLambdaToFunctionAutoConfiguration,\
+org.springframework.cloud.function.context.config.FunctionsEndpointAutoConfiguration
 org.springframework.cloud.function.context.WrapperDetector=\
 org.springframework.cloud.function.context.config.FluxWrapperDetector
 org.springframework.context.ApplicationContextInitializer=\

spring-cloud-function-samples/function-sample/pom.xml

@@ -26,6 +26,10 @@
 
 	<dependencies>
 		<dependency>
+    <groupId>org.springframework.boot</groupId>
+    <artifactId>spring-boot-starter-actuator</artifactId>
+</dependency>
+		<dependency>
 			<groupId>org.springframework.cloud</groupId>
 			<artifactId>spring-cloud-starter-function-webflux</artifactId>
 		</dependency>

spring-cloud-function-samples/function-sample/src/main/java/com/example/SampleApplication.java

@@ -24,13 +24,14 @@ import reactor.core.publisher.Flux;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.annotation.Bean;
+import org.springframework.messaging.Message;
 
 // @checkstyle:off
 @SpringBootApplication
 public class SampleApplication {
 
 	public static void main(String[] args) throws Exception {
-		SpringApplication.run(SampleApplication.class, args);
+		SpringApplication.run(SampleApplication.class, "--management.endpoints.web.exposure.include=functions");
 	}
 
 	@Bean
@@ -38,6 +39,11 @@ public class SampleApplication {
 		return value -> value.toUpperCase();
 	}
 
+	@Bean
+	public Function<Message<String>, String> uppercaseMessage() {
+		return value -> value.getPayload().toUpperCase();
+	}
+
 	@Bean
 	public Function<Flux<String>, Flux<String>> lowercase() {
 		return flux -> flux.map(value -> value.toLowerCase());