scuttleup

Scuttlebutt like eventual consistent log replication for levelup

npm install scuttleup

Usage

var scuttleup = require('scuttleup')

var log = scutlleup(db) // db is a levelup instance

var changes = log2.createReadStream({
  live: true
})

changes.on('data', function(data) {
  console.log(data) // print out the log - data.entry will be 'hello world'
})

log.append('hello world') // add something to the log

Replication

To replicate two logs pipe their replication stream together using the scuttlebutt protocol

var repl1 = log1.createReplicationStream()
var repl2 = log2.createReplicationStream()

// the two logs will now replicate to each other
repl1.pipe(repl2).pipe(repl1)

API

var log = scuttleup(db, [opts])

Create a log new instance. Options can include

{
  id: 'a-globally-unique-peer-id',
  valueEncoding: 'utf-8' // encoding of log entries
}

log.append(entry, [callback])

Add a new entry to the log

log.entry(peer, seq, [options], callback)

Retrieve a entry from the log from a given peer and seq

var ws = log.createAppendStream()

.append as a stream

var repl = log.createReplicationStream(opts)

Create a log replication stream. Pipe this to the replication stream of another log. Replication is eventual consistent and works using the scuttlebutt protocol

Options can include

{
  live: false, // disable live replication. defaults to true
  mode: 'sync' | 'push' | 'pull' // set replication mode. defaults to sync
}

var rs = log.createReadStream(opts)

Create a log read stream. Options can include

{
  live: false, // continiously read the changes,
  tail: false, // only read new changes
}

var ws = log.createWriteStream()

Create a log write stream

License

MIT