Folders

This node.js package implements the folders.io synthetic file system.

This Folders Module is based on 'Presto' open source distributed SQL query engine, Module can be installed via "npm install folders-presto".

Example:

Installation (use --save to save to package.json)

npm install folders-presto

##Presto

Basic Usage

Configuration

In order to Presto access, specify the following args.

{
  "user" : "your_username",
  "host" : "your_host",
  "port" : "your_port",
  "catalog" : "hive",
  "schema" : "default"
}

Constructor

Provider constructor, could pass the special option/param in the config param.

var prefix = 'folders.io_0:presto_hive';

var config = {
  "user" : "your_username",
  "host" : "your_host",
  "port" : "your_port",
  "catalog" : "hive",
  "schema" : "default"
};

var foldersPresto = new FoldersPresto(prefix, config);

ls

ls the database, tables as folders.

/**
 * list db metadata in folders.io format
 * 
 * @param uri,
 *   the uri for db. /${database}/${table}/ eg:
 *     '/' , show the root path, show the databases/schemas
 *     '/test-db', show all the tables in database 'test-db' 
 *     '/test-db/test-table', show the metadata of table we support 'test-table' in database 'test-db';
 *   all the path could also start with {prefix}, '/folders.io_0:presto/test-db'
 * @param cb,
 *   callback function(err, result) function. result will be a file info array. [{}, ... {}] 
 *   a example file information 
 *   { 
 *     name: 'default',
 *     fullPath: 'default',
 *     meta: {},
 *     uri: 'folders.io_0:presto_hive/default',
 *     size: 0,
 *     extension: '+folder',
 *     modificationTime: 0
 *   }
 */
FoldersPresto.prototype.ls = function(path, cb);

foldersPresto.ls('/', function cb(error, databases) {
  if (error) {
    console.log("error in ls /");
    console.log(error);
  }

  console.log("ls databases success, ", databases);
 }

cat

cat columns metadata of table ( maybe support cat records '/{database}/{table}/records' in the future)

/**
 * @param uri, the file uri to cat 
 * @param cb, callback  function(err, result) function.
 *    example for result.
 *    {
 *      stream: .., // a readable 'request' stream
 *      size : .. , // file size
 *      name: path
 *    }
 *
 * cat(uri,cb) 
 */
 
foldersPresto.cat('/folders/test/columns', function cb(error,columns) {
    if (error) {
       console.log('error in cat table columns');
       console.log(error);
    }

    console.log('cat table columns success, \n', columns);
 });