mongo shell启动配置文件.mongorc.js（三）

mongo shell启动配置文件.mongorc.js（三）

自定义MongoDB操作函数

可以把自己写的js代码保存在某个地方，让MongoDB加载它，然后就可以在MongoDB的命令行里操作它们。

mongodb shell默认会加载~/.mongorc.js文件

例如以下修改了启动提示文字、左侧提示文字，增加了my_show_shards shell函数用于显示当前sharded collection的chunks在各分片的负载情况：

//~/.mongorc.js  //show at begin    var compliment = ["attractive", "intelligent", "like batman"];    var index = Math.floor(Math.random()*3);    print("Hello, you're looking particularly " + compliment[index] + " today!");//change the prompt    prompt = function(){        if (typeof db == "undefined") {            return "(nodb)> ";        }        // Check the last db operation        try {            db.runCommand({getLastError: 1});        }        catch (e) {            print(e);        }        return db + "> ";    }//show all shard's chunks    function my_show_shards() {        var config_db = db.getSiblingDB("config");        var collections = {};        var shards = {};        var shard_it = config_db.chunks.find().snapshot();    while (shard_it.hasNext()) {          next_item = shard_it.next();            collections[JSON.stringify(next_item["ns"]).replace(/\"/g, "")] = 1;            shards[JSON.stringify(next_item["shard"]).replace(/\"/g, "")] = 1;        }        var list_collections = [];        var list_shards = [];        for (item in collections) {            list_collections.push(item);        }        for (item in shards) {            list_shards.push(item);        }    list_collections.forEach(function(collec) {              list_shards.forEach(function(item) {                    obj = {};                    obj["shard"] = item;                    obj["ns"] = collec;                    it = config_db.chunks.find(obj);                    print(collec, item, it.count());                    })                })    }