Utility JS function for Mongo when used with Jackrabbit Oak

oak-mongo.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.
 */


var oak = (function(global){
    "use strict";

    var api,
        version = "1.0";

    api = function(){
        return api.version();
    };

    /*
     * Print the current version
     */
    api.version = function () {
        return print('Oak Mongo helpers : ' + version);
    };

    api.indexStats = function () {
        var result = [];
        var totalCount = 0;
        var totalSize = 0;
        db.nodes.find({'_id': /^2\:\/oak\:index\//}, {_id: 1}).forEach(function (doc) {
            var stats = api.getChildStats(api.pathFromId(doc._id));
            stats.id = doc._id;
            result.push(stats);

            totalCount += stats.count;
            totalSize += stats.size;
        });

        result.push({id: "summary", count: totalCount, size: totalSize, "simple": this.humanFileSize(totalSize)});
        return result;
    };

    /**
     * Determines the number of child node (including all sub tree)
     * for a given parent node path. This would be faster compared to
     * {@link getChildStats} as it does not load the doc and works on
     * index only.
     *
     * Note that there might be some difference between db.nodes.count()
     * and countChildren('/') as split docs, intermediate docs are not
     * accounted for
     *
     * @param path
     * @returns {number}
     */
    api.countChildren = function(path){
        var depth = this.pathDepth(path);
        var totalCount = 0;
        while (true) {
            var count = db.nodes.count({_id: this.pathFilter(depth++, path)});
            if( count == 0){
                break;
            }
            totalCount += count;
        }
        return totalCount
    }

    /**
     * Provides stats related to number of child nodes
     * below given path or total size taken by such nodes
     *
     * @param path
     * @returns {{count: number, size: number}}
     */
    api.getChildStats = function(path){
        var count = 0;
        var size = 0;
        this.forEachChild(path, function(doc){
            count++;
            size +=  Object.bsonsize(doc);
        });
        return {"count" : count, "size" : size, "simple" : this.humanFileSize(size)};
    };

    api.forEachChild = function(path, callable) {
        var depth = this.pathDepth(path);
        while (true) {
            var cur = db.nodes.find({_id: this.pathFilter(depth++, path)});
            if(!cur.hasNext()){
                break;
            }
            cur.forEach(callable);
        }
    };

    api.pathFilter = function (depth, prefix){
        return new RegExp("^"+ depth + ":" + prefix)
    };

    api.pathDepth = function(path){
        if(path == '/'){
            return 0;
        }
        var depth = 0;
        for(var i = 0; i < path.length; i++){
            if(path.charAt(i) == '/'){
                depth++;
            }
        }
        return depth;
    };

    api.pathFromId = function(id) {
        var index = id.indexOf(':');
        return id.substring(index + 1);
    };

    //http://stackoverflow.com/a/20732091/1035417
    api.humanFileSize = function (size) {
        var i = Math.floor( Math.log(size) / Math.log(1024) );
        return ( size / Math.pow(1024, i) ).toFixed(2) * 1 + ' ' + ['B', 'kB', 'MB', 'GB', 'TB'][i];
    };

    return api;
}(this));

Oak-mongo.js.md

Following js file can be load at start of mongo shell and then the functions can be accessed

$ wget https://gist.githubusercontent.com/chetanmeh/836ca8fffc4c410daed2/raw/oak-mongo.js
$ mongo localhost/oak --shell oak-mongo.js
MongoDB shell version: 2.6.3
connecting to: localhost/oak
type "help" for help
> oak.countChildren('/oak:index/')
356787
> oak.getChildStats('/oak:index')
{ "count" : 356788, "size" : 127743372, "simple" : "121.83 MB" }
> oak.getChildStats('/')
{ "count" : 593191, "size" : 302005011, "simple" : "288.01 MB" }
>