com.appdynamics.extensions.couchdb.CouchDBWrapper.java Source code

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Here is the source code for com.appdynamics.extensions.couchdb.CouchDBWrapper.java

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/** 
 * Copyright 2013 AppDynamics 
 * 
 * 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.appdynamics.extensions.couchdb;

import java.math.BigDecimal;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.log4j.Logger;

import com.appdynamics.extensions.couchdb.api.CouchDBMetric;
import com.appdynamics.extensions.couchdb.api.MetricAggregationType;
import com.appdynamics.extensions.http.Response;
import com.appdynamics.extensions.http.SimpleHttpClient;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.JsonParser;

public class CouchDBWrapper {

    private static final Logger logger = Logger.getLogger("com.singularity.extensions.CouchDBWrapper");
    private static final String STATS_URI = "/_stats?range=60";

    /**
     * Connects to the couchDB host and retrieves metrics using the CouchDB REST
     * API
     * 
     * @param httpClient
     * @return HashMap Map containing metrics retrieved from using the CouchDB
     *         REST API
     */
    public List<CouchDBMetric> gatherMetrics(SimpleHttpClient httpClient) throws Exception {
        JsonObject statsResponse = getResponse(httpClient, STATS_URI);
        List<CouchDBMetric> metricsList = constructMetricsList(statsResponse);
        return metricsList;

    }

    private JsonObject getResponse(SimpleHttpClient httpClient, String uri) {
        String response = getResponseString(httpClient, uri);
        JsonObject jsonObject = null;
        try {
            jsonObject = new JsonParser().parse(response).getAsJsonObject();
        } catch (JsonParseException e) {
            logger.error("Response from " + uri + "is not a json");
        }
        return jsonObject;
    }

    /**
     * Returns HttpResponse as string from given url
     * 
     * @param httpClient
     * @param path
     * @return
     */
    private String getResponseString(SimpleHttpClient httpClient, String path) {
        Response response = null;
        String responseString = "";
        try {
            response = httpClient.target().path(path).get();
            responseString = response.string();
        } catch (Exception e) {
            logger.error("Exception in getting response from " + path, e);
            throw new RuntimeException(e);
        } finally {
            try {
                if (response != null) {
                    response.close();
                }
            } catch (Exception ex) {
                // Ignore
            }
        }
        return responseString;
    }

    /**
     * Constructs a HashMap of metrics based on the JSON Response received upon
     * executing CouchDB's /_stats REST API request
     * 
     * @param metricsObject
     * @return
     */
    public List<CouchDBMetric> constructMetricsList(JsonObject metricsObject) {
        // 1st level: Metric Category
        // 2nd level: Metric Name
        // 3rd level: MetricAggregationType
        List<CouchDBMetric> metricsList = Lists.newArrayList();
        for (Entry<String, JsonElement> category : metricsObject.entrySet()) {
            JsonObject categoryMetrics = category.getValue().getAsJsonObject();
            for (Entry<String, JsonElement> metric : categoryMetrics.entrySet()) {
                CouchDBMetric couchDBMetric = new CouchDBMetric();
                couchDBMetric.setMetricCategory(category.getKey());
                couchDBMetric.setMetricName(metric.getKey());
                JsonObject jsonObject = metric.getValue().getAsJsonObject();
                Map<MetricAggregationType, BigDecimal> values = Maps.newHashMap();
                for (MetricAggregationType type : MetricAggregationType.values()) {
                    if (!jsonObject.get(type.getAggregationType()).isJsonNull()) {
                        BigDecimal metricValue = jsonObject.get(type.getAggregationType()).getAsBigDecimal();
                        logger.debug("Category:" + couchDBMetric.getMetricCategory() + " MetricName:"
                                + couchDBMetric.getMetricName() + " " + type + ":" + metricValue);
                        values.put(type, metricValue);
                    }
                }
                couchDBMetric.setValues(values);
                metricsList.add(couchDBMetric);
            }
        }
        return metricsList;
    }
}