org.apache.samza.webapp.ApplicationMasterRestClient.java Source code

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Here is the source code for org.apache.samza.webapp.ApplicationMasterRestClient.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.samza.webapp;

import java.io.Closeable;
import java.io.IOException;
import java.util.Map;
import org.apache.http.HttpHost;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.StatusLine;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.util.EntityUtils;
import org.apache.samza.SamzaException;
import org.apache.samza.serializers.model.SamzaObjectMapper;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.type.TypeReference;

/**
 * Client for the {@link ApplicationMasterRestServlet}.
 */
public class ApplicationMasterRestClient implements Closeable {
    private final CloseableHttpClient httpClient;
    private final HttpHost appMasterHost;
    private final ObjectMapper jsonMapper = SamzaObjectMapper.getObjectMapper();

    public ApplicationMasterRestClient(CloseableHttpClient client, String amHostName, int amRpcPort) {
        httpClient = client;
        appMasterHost = new HttpHost(amHostName, amRpcPort);
    }

    /**
     * @return  the metrics as a map of groupName to metricName to metricValue.
     * @throws IOException if there was an error fetching the metrics from the servlet.
     */
    public Map<String, Map<String, Object>> getMetrics() throws IOException {
        String jsonString = getEntityAsJson("/metrics", "metrics");
        return jsonMapper.readValue(jsonString, new TypeReference<Map<String, Map<String, Object>>>() {
        });
    }

    /**
     * @return  the task context as a map of key to value
     * @throws IOException if there was an error fetching the task context from the servlet.
     */
    public Map<String, Object> getTaskContext() throws IOException {
        String jsonString = getEntityAsJson("/task-context", "task context");
        return jsonMapper.readValue(jsonString, new TypeReference<Map<String, Object>>() {
        });
    }

    /**
     * @return  the AM state as a map of key to value
     * @throws IOException if there was an error fetching the AM state from the servlet.
     */
    public Map<String, Object> getAmState() throws IOException {
        String jsonString = getEntityAsJson("/am", "AM state");
        return jsonMapper.readValue(jsonString, new TypeReference<Map<String, Object>>() {
        });
    }

    /**
     * @return  the config as a map of key to value
     * @throws IOException if there was an error fetching the config from the servlet.
     */
    public Map<String, Object> getConfig() throws IOException {
        String jsonString = getEntityAsJson("/config", "config");
        return jsonMapper.readValue(jsonString, new TypeReference<Map<String, Object>>() {
        });
    }

    @Override
    public void close() throws IOException {
        httpClient.close();
    }

    private String getEntityAsJson(String path, String entityName) throws IOException {
        HttpGet getRequest = new HttpGet(path);
        HttpResponse httpResponse = httpClient.execute(appMasterHost, getRequest);

        StatusLine status = httpResponse.getStatusLine();
        if (status.getStatusCode() != HttpStatus.SC_OK) {
            throw new SamzaException(String.format("Error retrieving %s from host %s. Response: %s", entityName,
                    appMasterHost.toURI(), status.getReasonPhrase()));
        }

        return EntityUtils.toString(httpResponse.getEntity());
    }

    @Override
    public String toString() {
        return "AppMasterClient for uri: " + appMasterHost.toURI().toString();
    }
}