presto-client

presto-client-node

Distributed query engine "Presto" 's client library for node.js.

var presto = require('presto-client');
var client = new presto.Client();

client.execute({
  query:   'SELECT count(*) as cnt FROM tblname WHERE ...',
  catalog: 'hive',
  schema:  'default',
  columns: function(error, data){ console.log({resultColumns: data}); },
  data:    function(error, data, columns, stats){ console.log(data); },
  success: function(error, stats){},
  error:   function(error){}
});

Installation

npm install -g presto-client

Or add presto-client to your own packagen.json, and do npm install.

API

new Client(opts)

Instanciate client object and set default configurations.

• opts [object]
  • host [string]
    • presto coordinator hostname or address (default: localhost)
  • port [integer]
    • presto coordinator port (default: 8080)
  • user [string]
    • username of query (default: process user name)
  • catalog [string]
    • default catalog name
  • schema [string]
    • default schema name
  • checkInterval [integer]
    • interval milliseconds of each RPC to check query status (default: 800ms)

return value: client instance object

execute(opts)

Execute query on Presto cluster, and fetch results.

• opts [object]
• query [string]
  • presto query
• catalog [string]
  • catalog string (default: instance default catalog)
• schema [string]
  • schema string (default: intance default schema)
• info [boolean :optional]
  • fetch query info (execution statistics) for success callback, or not (default false)
• cancel [function() :optional]
  • client stops fetch of query results if this callback returns true
• columns [function(error, data) :optional]
  • called once when columns and its types are found in results
  • data
    • array of field info
    • [ { name: "username", type: "varchar" }, { name: "cnt", type: "bigint" } ]
• data [function(error, data, columns, stats) :optional]
  • called per fetch of query results (may be called 2 or more)
  • data
    • array of array of each column
    • [ [ "tagomoris", 1013 ], [ "dain", 2056 ], ... ]
  • columns (optional)
    • same as data of columns callback
  • stats (optional)
    • runtime statistics object of query
• success [function(error, stats, info) :optional]
  • called once when all results are fetched (default: value of callback)
• error [function(error) :optional]
  • callback for errors of query execution (default: value of callback)
• callback [function(error, stats) :optional]
  • callback for query completion (both of success and fail)
  • one of this option or success must be specified

Callbacks order (success query) is: columns -> data (-> data xN) -> success (or callback)

nodes(opts, callback)

Get node list of presto cluster and return it.

• opts [object :optional]
  • specify null, undefined or {} (currently)
• callback [function(error,data)]
  • error
  • data
    • array of node objects

Versions

• 0.0.2: maintenance release
  • add User-Agent header with version
• 0.0.1: initial release

Todo

• node: "failed" node list support
• patches welcome!

Author & License

• tagomoris
• License:
  • MIT (see LICENSE)