Node-LevelDB

The leveldb library provides a persistent key value store. Keys and values are arbitrary byte arrays. The keys are ordered within the key value store according to a user-specified comparator function.

This project is node bindings to this excellent library so that node programs can either implement their own custom databases or simply use it directly as a fast, simple key/value store.

While implementing nStore, I realized there are a couple things that V8 and node are not very good at. They are heavy disk I/O and massive objects with either millions of keys or millions of sub objects.

Since LevelDB provides good primitives like MVCC and binary support (It was designed to back IndexDB in the Chrome browser), then it can be used as a base to implement things like CouchDB.

Usage

leveldb.open("path/to/my/db", { create_if_missing: true }, onOpen);

function onOpen(err, db) {
  var key = "mykey";
  db.put(key, "My Value!", function(err) {
    db.getSync(key, function(err, value) {
      console.dir(value); // prints: My Value!
      db.del(key);
    });
  });
}

Installing

To compile native code and CoffeeScript do:

npm install

Testing

To run tests do:

npm test

You can also view the current build status on Travis-CI.

Stripping the library

The leveldb library is bundled in the deps folder and is compiled in staticly. The resulting node addon is about 4mb unstripped. If you want to make it smaller, I've had success using the strip command on it which shrinks it down to about 300kb.

strip build/default/leveldb.node

Contributing

Since I am not experienced in the world of C++ and am still learning, I welcome contributions. Mainly what I need right now is someone with experience to review my code and tell me things I'm doing stupid. Maybe add a C++ best pratices note to this document.

Currently Randall Leeds (@tilgovi and one of the CouchDB commiters) has expressed interest in helping and already has commit rights to the project.

Contributors

   176  Michael Phan-Ba
    55  Nathan Landis
    39  Tim Caswell
    19  gabor@google.com
    15  jorlow@chromium.org
    12  dgrogan@chromium.org
    12  Stefan Thomas
     9  Randall Leeds
     9  Carter Thaxton
     6  Damon Oehlman
     5  Hans Wennborg
     4  shinuza
     3  hans@chromium.org
     2  Sanjay Ghemawat
     1  (no author)
     1  Paul Vorbach
     1  justmoon
     1  Gabor Cselle