Expire old data using TTL indexes

expireData.js

//run on mongodb server as
//mongo < expireData.js

var COUNTLY_DRILL = 'countly_drill',
    COUNTLY = 'countly',
    EXPIRE_AFTER = 31536000,
    INDEX_NAME = "cd_1";

var PROCESS = [
	/^drill_events\.*/,
	/^app_crashes\.*/,
];

var conn = new Mongo(),
    cly = conn.getDB(COUNTLY),
    drill = conn.getDB(COUNTLY_DRILL);

var clyCollections = cly.getCollectionNames(), collections = clyCollections.concat(drill.getCollectionNames()), check = [];

collections.forEach(function(c){
  var process = false;
	PROCESS.forEach(function(r){
		if (typeof r === 'string' && r === c) { process = true; }
		else if (typeof r === 'object' && r.test(c)) { process = true; }
	});
	if (process) {
        var db = clyCollections.indexOf(c) === -1 ? drill : cly;
        var indexes = db[c].getIndexes();
        var hasIndex = false;
        for(var i = 0; i < indexes.length; i++){
            if(indexes[i].name == INDEX_NAME){
                if(indexes[i].expireAfterSeconds == EXPIRE_AFTER){
                    print("skipping", c)
                    hasIndex = true;
                }
                //has index but incorrect expire time, need to be reindexed
                else{
                    print("Dropping index for", c)
                    db[c].dropIndex(INDEX_NAME);
                }
                break;
            }          
        }
        if(!hasIndex)
            check.push(c); 
    }
});

print('Indexing following collections:');
printjson(check);

check.forEach(function(c){
	var db = clyCollections.indexOf(c) === -1 ? drill : cly;
	db.getCollection(c).createIndex({"cd": 1}, { expireAfterSeconds: EXPIRE_AFTER, background: true } );
});