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redis-sync

A node.js redis replication slave toolkit.

redis-sync implements the replication slave side of the SYNC command, streaming in all commands that modify the dataset. It can also use rdb-parser to parse the dataset dump that precedes the commands. If it can't connect, gets disconnected or if redis is still loading the dataset, redis-sync will keep trying to reconnect - with exponential backoff.

Installation

npm install redis-sync

Usage

var redisSync = require('redis-sync');
var sync = new redisSync.Sync();

sync.on('command', function(command, args) {
  console.log('command', command, args);
});

sync.on('inlineCommand', function(buffers) {
  // the server sends regular PING commands
  console.log('inline command', buffers);
});

sync.on('error', function(err) {
  // listen to 'error' and rely on reconnection logic - otherwise it will get thrown
  console.error(err);
});

sync.connect();

Upon connection, the master will transfer the entire database in RDB format, before sending any commands. redis-sync can use rdb-parser to parse it as it streams in.

You can listen to entity events on the sync object:

sync.on('entity', function(e) {
  console.log(e);
});

or obtain the entity stream as it starts coming in

sync.on('rdb', function(rdb) {
  rdb.on('entity', function(e) {
    console.log(e);
  });
  rdb.on('error', function(err) {
    // listen to 'error' and rely on reconnection logic - otherwise it will get thrown
    console.error(err);
  });
  rdb.on('end', function() {
    console.log('end of rdb');
  });

Note that in case of reconnection redis will send the database again, emitting 'rdb' and 'entity' events again on the same sync object.

License

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.