co.cask.cdap.metrics.query.BaseMetricsHandler.java Source code

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Here is the source code for co.cask.cdap.metrics.query.BaseMetricsHandler.java

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/*
 * Copyright  2014 Cask Data, Inc.
 *
 * 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 co.cask.cdap.metrics.query;

import co.cask.cdap.common.conf.Constants;
import co.cask.cdap.common.service.ServerException;
import co.cask.cdap.common.utils.ImmutablePair;
import co.cask.cdap.gateway.auth.Authenticator;
import co.cask.cdap.gateway.handlers.AuthenticatedHttpHandler;
import com.google.common.collect.ImmutableSet;
import org.jboss.netty.handler.codec.http.HttpRequest;

import java.net.URI;
import java.util.Set;

/**
 * Base metrics handler that can validate metrics path for existence of elements like streams, datasets, and programs.
 */
public abstract class BaseMetricsHandler extends AuthenticatedHttpHandler {

    private final Set<String> existingServices;

    protected BaseMetricsHandler(Authenticator authenticator) {
        super(authenticator);

        this.existingServices = ImmutableSet.of(Constants.Service.METRICS, Constants.Service.APP_FABRIC_HTTP,
                Constants.Service.DATASET_EXECUTOR, Constants.Service.DATASET_MANAGER, Constants.Service.STREAMS,
                Constants.Service.GATEWAY);
    }

    protected MetricsRequest parseAndValidate(HttpRequest request, URI requestURI)
            throws MetricsPathException, ServerException {
        ImmutablePair<MetricsRequest, MetricsRequestContext> pair = MetricsRequestParser
                .parseRequestAndContext(requestURI);
        validatePathElements(request, pair.getSecond());
        return pair.getFirst();
    }

    /**
     * Checks whether the elements (datasets, streams, and programs) in the context exist, throwing
     * a {@link MetricsPathException} with relevant error message if there is an element that does not exist.
     *
     * @param metricsRequestContext context containing elements whose existence we need to check.
     * @throws ServerException
     * @throws MetricsPathException
     */
    protected void validatePathElements(HttpRequest request, MetricsRequestContext metricsRequestContext)
            throws ServerException, MetricsPathException {

        // TODO: we want to check for existence of elements in the path, but be aware of overhead; for now we do only for
        //       services. CDAP-16

        if (metricsRequestContext.getPathType() != null) {
            if (metricsRequestContext.getPathType().equals(MetricsRequestParser.PathType.SERVICES)) {
                if (!serviceExists(metricsRequestContext.getTypeId())) {
                    throw new MetricsPathException(
                            String.format("Service %s does not exist", metricsRequestContext.getTypeId()));
                }
                return;
            }
        }
    }

    private boolean serviceExists(String serviceName) {
        return existingServices.contains(serviceName);
    }

}