camel-k-loader-js/src/main/java/org/apache/camel/k/loader/js/JavaScriptSourceLoader.java

/*
 * 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.camel.k.loader.js;

import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.util.Collections;
import java.util.List;

import org.apache.camel.CamelContext;
import org.apache.camel.RoutesBuilder;
import org.apache.camel.builder.endpoint.EndpointRouteBuilder;
import org.apache.camel.k.Runtime;
import org.apache.camel.k.Source;
import org.apache.camel.k.SourceLoader;
import org.apache.camel.k.annotation.Loader;
import org.apache.camel.k.loader.js.dsl.IntegrationConfiguration;
import org.apache.camel.support.LifecycleStrategySupport;
import org.apache.commons.io.IOUtils;
import org.graalvm.polyglot.Context;
import org.graalvm.polyglot.Value;

@Loader("js")
public class JavaScriptSourceLoader implements SourceLoader {
    private static final String LANGUAGE_ID = "js";

    @Override
    public List<String> getSupportedLanguages() {
        return Collections.singletonList(LANGUAGE_ID);
    }

    @Override
    public void load(Runtime runtime, Source source) throws Exception {
        RoutesBuilder builder = new EndpointRouteBuilder() {
            @Override
            public void configure() throws Exception {
                final Context context = Context.newBuilder("js").allowAllAccess(true).build();

                try (InputStream is = source.resolveAsInputStream(getContext())) {
                    Value bindings = context.getBindings(LANGUAGE_ID);

                    // configure bindings
                    bindings.putMember("__dsl", new IntegrationConfiguration(this));

                    final String script = IOUtils.toString(is, StandardCharsets.UTF_8);
                    final String wrappedScript = "with (__dsl) { " + script + " }";

                    context.eval(LANGUAGE_ID, wrappedScript);

                    //
                    // Close the polyglot context when the camel context stops
                    //
                    getContext().addLifecycleStrategy(new LifecycleStrategySupport() {
                        @Override
                        public void onContextStop(CamelContext camelContext) {
                            context.close(true);
                        }
                    });
                }
            }
        };

        runtime.addRoutes(builder);
    }
}