| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 |
| * |
| * http://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.apache.flink.statefun.flink.core.jsonmodule; |
| |
| import java.io.IOException; |
| import java.net.URL; |
| import java.util.stream.Collectors; |
| import java.util.stream.StreamSupport; |
| import org.apache.flink.annotation.VisibleForTesting; |
| import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.JsonNode; |
| import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.ObjectMapper; |
| import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.dataformat.yaml.YAMLFactory; |
| import org.apache.flink.statefun.flink.common.ResourceLocator; |
| import org.apache.flink.statefun.flink.core.spi.Constants; |
| import org.apache.flink.statefun.sdk.spi.StatefulFunctionModule; |
| |
| public final class JsonServiceLoader { |
| |
| public static Iterable<StatefulFunctionModule> load() { |
| ObjectMapper mapper = mapper(); |
| |
| Iterable<URL> namedResources = |
| ResourceLocator.findNamedResources("classpath:" + Constants.STATEFUL_FUNCTIONS_MODULE_NAME); |
| |
| return StreamSupport.stream(namedResources.spliterator(), false) |
| .map(moduleUrl -> fromUrl(mapper, moduleUrl)) |
| .collect(Collectors.toList()); |
| } |
| |
| @VisibleForTesting |
| static StatefulFunctionModule fromUrl(ObjectMapper mapper, URL moduleUrl) { |
| try { |
| JsonNode root = readAndValidateModuleTree(mapper, moduleUrl); |
| return JsonModuleFactory.create(root, moduleUrl); |
| } catch (Throwable t) { |
| throw new RuntimeException("Failed loading a module at " + moduleUrl, t); |
| } |
| } |
| |
| /** |
| * Read a {@code StatefulFunction} module definition. |
| * |
| * <p>A valid resource module definition has to contain the following sections: |
| * |
| * <ul> |
| * <li>meta - contains the metadata associated with this module, such as its type. |
| * <li>spec - a specification of the module. i.e. the definied functions, routers etc'. |
| * </ul> |
| * |
| * <p>If any of these sections are missing, this would be considered an invalid module definition, |
| * in addition a type is a mandatory field of a module spec. |
| */ |
| private static JsonNode readAndValidateModuleTree(ObjectMapper mapper, URL moduleYamlFile) |
| throws IOException { |
| JsonNode root = mapper.readTree(moduleYamlFile); |
| validateMeta(moduleYamlFile, root); |
| validateSpec(moduleYamlFile, root); |
| return root; |
| } |
| |
| private static void validateMeta(URL moduleYamlFile, JsonNode root) { |
| JsonNode typeNode = root.at(Pointers.MODULE_META_TYPE); |
| if (typeNode.isMissingNode()) { |
| throw new IllegalStateException("Unable to find a module type in " + moduleYamlFile); |
| } |
| if (!typeNode.asText().equalsIgnoreCase(ModuleType.REMOTE.name())) { |
| throw new IllegalStateException( |
| "Unknown module type " |
| + typeNode.asText() |
| + ", currently supported: " |
| + ModuleType.REMOTE); |
| } |
| } |
| |
| private static void validateSpec(URL moduleYamlFile, JsonNode root) { |
| if (root.at(Pointers.MODULE_SPEC).isMissingNode()) { |
| throw new IllegalStateException("A module without a spec at " + moduleYamlFile); |
| } |
| } |
| |
| @VisibleForTesting |
| static ObjectMapper mapper() { |
| return new ObjectMapper(new YAMLFactory()); |
| } |
| } |