multilevel implemented using leveldowns with seamless retry support
npm install multileveldown
Similar to multilevel you can use this to share a levelup across multiple processes over a stream. In addition multileveldown supports seamless retry so you can reconnect to a server without your read streams / puts failing etc.
First create a server
var multileveldown = require('multileveldown')
var level = require('level')
var net = require('net')
var db = level('db')
var server = net.createServer(function (sock) {
sock.on('error', function () {
sock.destroy()
})
sock.pipe(multileveldown.server(db)).pipe(sock)
})
server.listen(9000)Then create some clients
var multileveldown = require('multileveldown')
var net = require('net')
var db = multileveldown.client()
var sock = net.connect(9000)
sock.pipe(db.connect()).pipe(sock)
db.put('hello', 'world', function () {
db.get('hello', console.log)
})To setup reconnect in your client simply set retry: true and reconnect to your server when the connection fails
var multileveldown = require('multileveldown')
var net = require('net')
var db = multileveldown.client({
retry: true
})
var connect = function () {
var sock = net.connect(9000)
var remote = db.connect()
sock.on('error', function () {
sock.destroy()
})
sock.on('close', function () {
remote.destroy()
setTimeout(connect, 1000) // reconnect after 1s
})
sock.pipe(remote).pipe(sock)
}
connect()multileveldown will now make sure to retry your pending operations when you reconnect. If you create a read stream and your connection fails half way through reading that stream multileveldown makes sure to only retry the part of the stream you are missing. Please note that this might not guarantee leveldb snapshotting if you rely on that.
Returns a new duplex server stream that you should connect with a client. Options include
{
readonly: true, // make the database be accessible as read only
preput: function (key, val, cb) {}, // called before puts
predel: function (key, cb) {}, // called before dels
prebatch: function (batch, cb) {} // called before batches
}Creates a new client levelup that you can connect to a server. Options are forwarded to the levelup constructor.
Returns a new duplex client stream that you should connect with a server stream
Just an alias to .connect for multilevel API compatibility.
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