ssb-replicate

ssb-replicate

ssb legacy replication. this was previously built into ssb-server (formerly known as scuttlebot)

protocol

peers replicate by calling createHistoryStream({id, seq}) for every feed to be replicate. (if replicate.request({id: <id>, replicate: true}) has been called - this is usually handled by ssb-friends). (id is the replicated feed id, and seq is the latest sequence number a peer has)

see the protocol guide

Since an ssb peer may replicate thousands of feeds, just making all these calls to createHistoryStream can use quite a bit of bandwidth (and cpu on the receiving end) thus this module has been superceded by ssb-ebt. but this is still included so for interop with other old instances.

Also note, when a peer connects, at first only a single createHistoryStream is requested for the peer's own feed - then it waits to see if the remote peer makes any createHistoryStream requests before making more, this avoids hammering a peer not supporting legacy replication with thousands of requests.

usage

var createSSB = require('ssb-server')
  .use(require('ssb-replicate'))

var sbot = createSSB({config...})

config

{
  replicate: {
    legacy: boolean, // whether to support legacy replication.
                     // if set to false, another plugin must provide replication.
                     // (such as ssb-ebt)
    fallback: boolean, //if enabled, wait for another plugin to try to replicate first.
                       //if set will not start to replicate until replicate:fallback event is emitted on the rpc connection.
  }
}

api

replicate.request({id:feedId, replicate:replicate}) : sync

request that feedId be replicated (or not if replicate is false. will begin or end replication on any currently open connections.

replicate.changes : source

get a feed of replication progress.

replicate.block : sync

call when from blocks to: block(from, to, isBlocking).

replicate.upto : source

returns {} of feeds to replicate, with sequences.

License

MIT