package com.tinkerpop.gremlin.server.handler;
import com.codahale.metrics.Meter;
import com.tinkerpop.gremlin.driver.message.RequestMessage;
import com.tinkerpop.gremlin.driver.message.ResponseMessage;
import com.tinkerpop.gremlin.driver.message.ResponseStatusCode;
import com.tinkerpop.gremlin.groovy.engine.GremlinExecutor;
import com.tinkerpop.gremlin.server.Context;
import com.tinkerpop.gremlin.server.Graphs;
import com.tinkerpop.gremlin.server.GremlinServer;
import com.tinkerpop.gremlin.server.OpProcessor;
import com.tinkerpop.gremlin.server.Settings;
import com.tinkerpop.gremlin.server.op.OpLoader;
import com.tinkerpop.gremlin.server.op.OpProcessorException;
import com.tinkerpop.gremlin.server.util.MetricManager;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToMessageDecoder;
import org.javatuples.Pair;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.List;
import java.util.Optional;
import java.util.concurrent.ScheduledExecutorService;
import static com.codahale.metrics.MetricRegistry.name;
/**
* @author Stephen Mallette (http://stephen.genoprime.com)
*/
public class OpSelectorHandler extends MessageToMessageDecoder<RequestMessage> {
private static final Logger logger = LoggerFactory.getLogger(OpSelectorHandler.class);
static final Meter errorMeter = MetricManager.INSTANCE.getMeter(name(GremlinServer.class, "errors"));
private final Settings settings;
private final Graphs graphs;
private final GremlinExecutor gremlinExecutor;
private final ScheduledExecutorService scheduledExecutorService;
public OpSelectorHandler(final Settings settings, final Graphs graphs, final GremlinExecutor gremlinExecutor,
final ScheduledExecutorService scheduledExecutorService) {
this.settings = settings;
this.graphs = graphs;
this.gremlinExecutor = gremlinExecutor;
this.scheduledExecutorService = scheduledExecutorService;
}
@Override
protected void decode(final ChannelHandlerContext channelHandlerContext, final RequestMessage msg,
final List<Object> objects) throws Exception {
final Context gremlinServerContext = new Context(msg, channelHandlerContext, settings,
graphs, gremlinExecutor, this.scheduledExecutorService);
try {
// choose a processor to do the work based on the request message.
final Optional<OpProcessor> processor = OpLoader.getProcessor(msg.getProcessor());
if (processor.isPresent())
// the processor is known so use it to evaluate the message
objects.add(Pair.with(msg, processor.get().select(gremlinServerContext)));
else {
// invalid op processor selected so write back an error by way of OpProcessorException.
final String errorMessage = String.format("Invalid OpProcessor requested [%s]", msg.getProcessor());
throw new OpProcessorException(errorMessage, ResponseMessage.build(msg).code(ResponseStatusCode.REQUEST_ERROR_INVALID_REQUEST_ARGUMENTS).result(errorMessage).create());
}
} catch (OpProcessorException ope) {
errorMeter.mark();
logger.warn(ope.getMessage(), ope);
channelHandlerContext.writeAndFlush(ope.getResponseMessage());
}
}
}