GH-766 Initial support to expose FunctionCatalog as actuator endpoint

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=\