hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/balancer/balancer.js

/**
 * 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.
 */
(function () {
    "use strict";

    var data = {};

    dust.loadSource(dust.compile($('#tmpl-balancer').html(), 'balancer'));

    var BEANS = [
        {"name": "mBeanServerInfo", "url": "/jmx?qry=JMImplementation:type=MBeanServerDelegate"},
        {"name": "balancer", "url": "/jmx?qry=Hadoop:service=Balancer,name=BalancerInfo"},
        {"name": "balancers", "url": "/jmx?qry=Hadoop:service=Balancer,name=Balancer-*"}
    ];

    load_json(BEANS, guard_with_startup_progress(function (d) {
        for (var k in d) {
            data[k] = k === 'balancers' ? workaround(d[k].beans) : d[k].beans[0];
        }

        extractMetrics();

        render();
    }), function (url, jqxhr, text, err) {
        show_err_msg('<p>Failed to retrieve data from ' + url + ', cause: ' + err + '</p>');
    });

    function guard_with_startup_progress(fn) {
        return function () {
            try {
                fn.apply(this, arguments);
            } catch (err) {
                if (err instanceof TypeError) {
                    show_err_msg('Balancer error: ' + err);
                }
            }
        };
    }

    function workaround(balancers) {
        for (var balancer of balancers) {
            var str = balancer['modelerType'];
            var index = str.indexOf("-");
            balancer['BlockPoolID'] = str.substring(index + 1);
        }
        return balancers;
    }

    function extractMetrics() {
        var str = data['mBeanServerInfo']['MBeanServerId'];
        var index = str.indexOf("_");
        if (index !== -1) {
            data['balancer']['HostName'] = str.substring(0, index);
            data['balancer']['BalancerStartedTimeInMillis'] = str.substring(index + 1);
        } else {
            data['balancer']['HostName'] = "invalid data";
            data['balancer']['BalancerStartedTimeInMillis'] = "invalid data";
        }
    }

    var HELPERS = {
        'helper_date_tostring': function (chunk, ctx, bodies, params) {
            var value = dust.helpers.tap(params.value, chunk, ctx);
            return chunk.write('' + moment(Number(value)).format('ddd MMM DD HH:mm:ss ZZ YYYY'));
        }
    };

    function render() {
        var base = dust.makeBase(HELPERS);
        dust.render('balancer', base.push(data), function (err, out) {
            $('#tab-overview').html(out);
            $('#tab-overview').addClass('active');
        });
    }

    function show_err_msg() {
        $('#alert-panel-body').html("Failed to load balancer information");
        $('#alert-panel').show();
    }
})();