001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.camel.impl.cloud;
018
019import java.util.Map;
020
021import org.apache.camel.AsyncCallback;
022import org.apache.camel.AsyncProcessor;
023import org.apache.camel.CamelContext;
024import org.apache.camel.Exchange;
025import org.apache.camel.ExchangePattern;
026import org.apache.camel.Expression;
027import org.apache.camel.Message;
028import org.apache.camel.cloud.ServiceDefinition;
029import org.apache.camel.cloud.ServiceLoadBalancer;
030import org.apache.camel.language.simple.SimpleLanguage;
031import org.apache.camel.processor.SendDynamicProcessor;
032import org.apache.camel.support.ServiceSupport;
033import org.apache.camel.util.AsyncProcessorHelper;
034import org.apache.camel.util.ObjectHelper;
035import org.apache.camel.util.ServiceHelper;
036import org.apache.camel.util.StringHelper;
037import org.slf4j.Logger;
038import org.slf4j.LoggerFactory;
039
040public class DefaultServiceCallProcessor extends ServiceSupport implements AsyncProcessor {
041    private static final Logger LOGGER = LoggerFactory.getLogger(DefaultServiceCallProcessor.class);
042
043    private final ExchangePattern exchangePattern;
044    private final String name;
045    private final String scheme;
046    private final String uri;
047    private final String contextPath;
048    private final CamelContext camelContext;
049    private final ServiceLoadBalancer loadBalancer;
050    private final Expression expression;
051    private SendDynamicProcessor processor;
052
053    public DefaultServiceCallProcessor(
054        CamelContext camelContext, String name, String scheme, String uri, ExchangePattern exchangePattern,
055        ServiceLoadBalancer loadBalancer, Expression expression) {
056
057        this.uri = uri;
058        this.exchangePattern = exchangePattern;
059        this.camelContext = camelContext;
060        this.loadBalancer = loadBalancer;
061
062        // setup from the provided name which can contain scheme and context-path information as well
063        String serviceName;
064        if (name.contains("/")) {
065            serviceName = StringHelper.before(name, "/");
066            this.contextPath = StringHelper.after(name, "/");
067        } else if (name.contains("?")) {
068            serviceName = StringHelper.before(name, "?");
069            this.contextPath = StringHelper.after(name, "?");
070        } else {
071            serviceName = name;
072            this.contextPath = null;
073        }
074        if (serviceName.contains(":")) {
075            this.scheme = StringHelper.before(serviceName, ":");
076            this.name = StringHelper.after(serviceName, ":");
077        } else {
078            this.scheme = scheme;
079            this.name = serviceName;
080        }
081
082        this.expression = expression;
083    }
084
085    // *************************************
086    // Properties
087    // *************************************
088
089
090    public ExchangePattern getExchangePattern() {
091        return exchangePattern;
092    }
093
094    public String getName() {
095        return name;
096    }
097
098    public String getScheme() {
099        return scheme;
100    }
101
102    public String getUri() {
103        return uri;
104    }
105
106    public String getContextPath() {
107        return contextPath;
108    }
109
110    public ServiceLoadBalancer getLoadBalancer() {
111        return loadBalancer;
112    }
113
114    public Expression getExpression() {
115        return expression;
116    }
117
118    // *************************************
119    // Lifecycle
120    // *************************************
121
122    @Override
123    protected void doStart() throws Exception {
124        StringHelper.notEmpty(name, "name", "service name");
125        ObjectHelper.notNull(camelContext, "camel context");
126        ObjectHelper.notNull(expression, "expression");
127        ObjectHelper.notNull(loadBalancer, "load balancer");
128
129        processor = new SendDynamicProcessor(uri, expression);
130        processor.setCamelContext(camelContext);
131        if (exchangePattern != null) {
132            processor.setPattern(exchangePattern);
133        }
134
135        // Start services if needed
136        ServiceHelper.startService(processor);
137        ServiceHelper.startService(loadBalancer);
138    }
139
140    @Override
141    protected void doStop() throws Exception {
142        // Stop services if needed
143        ServiceHelper.stopService(loadBalancer);
144        ServiceHelper.stopService(processor);
145    }
146
147    // *************************************
148    // Processor
149    // *************************************
150
151
152    @Override
153    public void process(Exchange exchange) throws Exception {
154        AsyncProcessorHelper.process(this, exchange);
155    }
156
157    @Override
158    public boolean process(final Exchange exchange, final AsyncCallback callback) {
159        final Message message = exchange.getIn();
160
161        // the values can be dynamic using simple language so compute those
162        final String serviceName = applySimpleLanguage(name, exchange);
163        final String serviceUri = applySimpleLanguage(uri, exchange);
164        final String servicePath = applySimpleLanguage(contextPath, exchange);
165        final String serviceScheme = applySimpleLanguage(scheme, exchange);
166
167        message.setHeader(ServiceCallConstants.SERVICE_CALL_URI, serviceUri);
168        message.setHeader(ServiceCallConstants.SERVICE_CALL_CONTEXT_PATH, servicePath);
169        message.setHeader(ServiceCallConstants.SERVICE_CALL_SCHEME, serviceScheme);
170        message.setHeader(ServiceCallConstants.SERVICE_NAME, serviceName);
171
172        try {
173            return loadBalancer.process(serviceName, server -> execute(server, exchange, callback));
174        } catch (Exception e) {
175            exchange.setException(e);
176            return true;
177        }
178    }
179
180    private boolean execute(ServiceDefinition service, Exchange exchange, AsyncCallback callback) throws Exception {
181        final Message message = exchange.getIn();
182        final String host = service.getHost();
183        final int port = service.getPort();
184        final Map<String, String> meta = service.getMetadata();
185
186        LOGGER.debug("Service {} active at server: {}:{}", name, host, port);
187
188        // set selected server as header
189        message.setHeader(ServiceCallConstants.SERVICE_HOST, host);
190        message.setHeader(ServiceCallConstants.SERVICE_PORT, port > 0 ? port : null);
191        message.setHeader(ServiceCallConstants.SERVICE_NAME, service.getName());
192        message.setHeader(ServiceCallConstants.SERVICE_META, meta);
193
194        // If context path is not set on service call definition, reuse the one from
195        // ServiceDefinition, if any
196        message.getHeaders().compute(ServiceCallConstants.SERVICE_CALL_CONTEXT_PATH, (k, v) ->
197            v == null ? meta.get(ServiceDefinition.SERVICE_META_PATH) : v
198        );
199
200        // If port is not set on service call definition, reuse the one from
201        // ServiceDefinition, if any
202        message.getHeaders().compute(ServiceCallConstants.SERVICE_PORT, (k, v) ->
203            v == null ? meta.get(ServiceDefinition.SERVICE_META_PORT) : v
204        );
205
206        // use the dynamic send processor to call the service
207        return processor.process(exchange, callback);
208    }
209
210    /**
211     * This function applies the simple language to the given expression.
212     *
213     * @param expression the expression
214     * @param exchange the exchange
215     * @return the computed expression
216     */
217    private String applySimpleLanguage(String expression, Exchange exchange) {
218        return SimpleLanguage.hasSimpleFunction(expression)
219            ? SimpleLanguage.simple(expression).evaluate(exchange, String.class)
220            : expression;
221    }
222}