RequestResponseSizeMetricsGenerator.java

/**
 * Copyright (c) 2009-2011 VMware, Inc. All Rights Reserved.
 *
 * 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
 *
 *         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 com.springsource.insight.plugin.servlet;

import java.util.Collection;
import java.util.Collections;
import java.util.List;

import com.springsource.insight.intercept.metrics.AbstractMetricsGenerator;
import com.springsource.insight.intercept.metrics.MetricsBag;
import com.springsource.insight.intercept.metrics.MetricsBag.PointType;
import com.springsource.insight.intercept.operation.Operation;
import com.springsource.insight.intercept.operation.OperationMap;
import com.springsource.insight.intercept.operation.OperationType;
import com.springsource.insight.intercept.resource.ResourceKey;
import com.springsource.insight.intercept.trace.Frame;
import com.springsource.insight.intercept.trace.Trace;
import com.springsource.insight.util.DataPoint;
import com.springsource.insight.util.ListUtil;
import com.springsource.insight.util.time.TimeRange;
import com.springsource.insight.util.time.TimeUtil;

/**
 * Generates an {@link MetricsBag} for the request and response size of the
 * endpoint within a {@link Trace}
 */
public class RequestResponseSizeMetricsGenerator extends AbstractMetricsGenerator {
    // TODO the "type" value should be using the same MetricDataType(s) literals (which should be exposed)
    public static final String ENDPOINT_RESPONSE_SIZE = "endPointResponseSize:type=bytes";
    public static final String ENDPOINT_REQUEST_SIZE = "endPointRequestSize:type=bytes";
    private static final RequestResponseSizeMetricsGenerator INSTANCE = new RequestResponseSizeMetricsGenerator();

    private RequestResponseSizeMetricsGenerator() {
        super(OperationType.HTTP);
    }

    public static final RequestResponseSizeMetricsGenerator getInstance() {
        return INSTANCE;
    }

    @Override
    public Collection<Frame> locateFrames(Trace trace) {
        Frame frame = trace.getFirstFrameOfType(getOperationType());
        if (frame == null) {
            return Collections.emptyList();
        } else {
            return Collections.singletonList(frame);
        }
    }

    @Override
    public List<MetricsBag> generateMetrics(Trace trace, ResourceKey endpointResourceKey, Collection<Frame> frames) {
        if (ListUtil.size(frames) != 1) {
            return Collections.emptyList();
        }

        Frame frame = ListUtil.getFirstMember(frames);
        Operation op = frame.getOperation();
        ResourceKey resourceKey = getResourceKey(op, endpointResourceKey);
        TimeRange range = trace.getRange();
        int time = TimeUtil.nanosToSeconds(range.getStart());
        MetricsBag mb = MetricsBag.create(resourceKey, range);

        // Add the response size data point
        OperationMap response = op.get("response", OperationMap.class);
        Number contentSize = (response == null) ? null : response.get("contentSize", Number.class);
        if (contentSize != null) {    // OK if missing since collected only if extra information
            DataPoint responseSizePoint = new DataPoint(time, contentSize.doubleValue());
            mb.add(ENDPOINT_RESPONSE_SIZE, PointType.GAUGE);
            mb.add(responseSizePoint, ENDPOINT_RESPONSE_SIZE);
        }

        // Add the request size data point
        OperationMap request = op.get("request", OperationMap.class);
        Number contentLength = (request == null) ? null : request.get("contentLength", Number.class);
        if (contentLength != null) {    // OK if missing since collected only if extra information
            DataPoint requestSizePoint = new DataPoint(time, contentLength.doubleValue());
            mb.add(ENDPOINT_REQUEST_SIZE, PointType.GAUGE);
            mb.add(requestSizePoint, ENDPOINT_REQUEST_SIZE);
        }

        if (mb.isEmpty()) {
            return Collections.emptyList();
        } else {
            return Collections.singletonList(mb);
        }
    }
}