git ssb

1
var nonPrivate = require('non-private-ip')
2
var ip = require('ip')
3
var onWakeup = require('on-wakeup')
4
var onNetwork = require('on-change-network')
5
6
var Stats = require('statistics')
7
var os = require('os')
8
var pull = require('pull-stream')
9
var u = require('scuttlebot/lib/util')
10
11
function rand(array) {
12
  return array[~~(Math.random()*array.length)]
13
}
14
15
function not (fn) {
16
  return function (e) { return !fn(e) }
17
}
18
19
function and () {
20
  var args = [].slice.call(arguments)
21
  return function (value) {
22
    return args.every(function (fn) { return fn.call(null, value) })
23
  }
24
}
25
26
//min delay (delay since last disconnect of most recent peer in unconnected set)
27
//unconnected filter delay peer < min delay
28
function delay (failures, factor, max) {
29
  return Math.min(Math.pow(2, failures)*factor, max || Infinity)
30
}
31
32
function maxStateChange (M, e) {
33
  return Math.max(M, e.stateChange || 0)
34
}
35
36
function peerNext(peer, opts) {
37
  return (peer.stateChange|0) + delay(peer.failure|0, opts.factor, opts.max)
38
}
39
40
41
//detect if not connected to wifi or other network
42
//(i.e. if there is only localhost)
43
44
function isOffline (e) {
45
  if(ip.isLoopback(e.host)) return false
46
  var lo = Object.keys(os.networkInterfaces())
47
  return lo.length === 1 && lo[0] === 'lo'
48
}
49
50
var isOnline = not(isOffline)
51
52
function isLocal (e) {
53
  // don't rely on private ip address, because
54
  // cjdns creates fake private ip addresses.
55
  return ip.isPrivate(e.host) && e.type === 'local'
56
}
57
58
function isFollowing (e) {
59
  return e.source === 'self'
60
}
61
62
function isUnattempted (e) {
63
  return !e.stateChange
64
}
65
66
//select peers which have never been successfully connected to yet,
67
//but have been tried.
68
function isInactive (e) {
69
  return e.stateChange && e.duration.mean == 0
70
}
71
72
function isLongterm (e) {
73
  return e.ping && e.ping.rtt.mean > 0
74
}
75
76
//peers which we can connect to, but are not upgraded.
77
//select peers which we can connect to, but are not upgraded to LT.
78
//assume any peer is legacy, until we know otherwise...
79
function isLegacy (peer) {
80
  return peer.duration.mean > 0 && !exports.isLongterm(peer)
81
}
82
83
function isConnect (e) {
84
  return 'connected' === e.state || 'connecting' === e.state
85
}
86
87
//sort oldest to newest then take first n
88
function earliest(peers, n) {
89
  return peers.sort(function (a, b) {
90
    return a.stateChange - b.stateChange
91
  }).slice(0, Math.max(n, 0))
92
}
93
94
function select(peers, ts, filter, opts) {
95
  if(opts.disable) return []
96
  //opts: { quota, groupMin, min, factor, max }
97
  var type = peers.filter(filter)
98
  var unconnect = type.filter(not(isConnect))
99
  var count = Math.max(opts.quota - type.filter(isConnect).length, 0)
100
  var min = unconnect.reduce(maxStateChange, 0) + opts.groupMin
101
  if(ts < min) return []
102
103
  return earliest(unconnect.filter(function (peer) {
104
    return peerNext(peer, opts) < ts
105
  }), count)
106
}
107
108
var schedule = exports = module.exports =
109
function (gossip, config, server) {
110
111
  var min = 60e3, hour = 60*60e3
112
113
  //trigger hard reconnect after suspend or local network changes
114
  onWakeup(gossip.reconnect)
115
  onNetwork(gossip.reconnect)
116
117
  function conf(name, def) {
118
    if(!config.gossip) return def
119
    var value = config.gossip[name]
120
    return (value === undefined || value === '') ? def : value
121
  }
122
123
  function connect (peers, ts, name, filter, opts) {
124
    var connected = peers.filter(isConnect).filter(filter)
125
      .filter(function (peer) {
126
        // don't disconnect from followed pubs
127
        return !isFollowing(peer) && peer.stateChange + 10e3 < ts
128
      })
129
130
    if(connected.length > opts.quota) {
131
      return earliest(connected, connected.length - opts.quota)
132
        .forEach(function (peer) {
133
          gossip.disconnect(peer)
134
        })
135
    }
136
137
    select(peers, ts, and(filter, isOnline), opts)
138
      .forEach(function (peer) {
139
        gossip.connect(peer)
140
      })
141
  }
142
143
144
  var connecting = false
145
  function connections () {
146
    if(connecting) return
147
    connecting = true
148
    setTimeout(function () {
149
    connecting = false
150
    var ts = Date.now()
151
    var peers = gossip.peers()
152
153
//    if(Math.random() > 0.1) return
154
155
    connect(peers, ts, 'following', exports.isFollowing, {
156
        min: 0, quota: 5, factor: 0, max: 0, groupMin: 0,
157
        disable: !conf('global', true)
158
    })
159
160
    connect(peers, ts, 'attempt', exports.isUnattempted, {
161
        min: 0, quota: 1, factor: 2e3, max: 0, groupMin: 0,
162
        disable: !conf('global', true)
163
    })
164
165
    //quota, groupMin, min, factor, max
166
    connect(peers, ts, 'retry', exports.isInactive, {
167
        min: 0,
168
        quota: 3, factor: 5*60e3, max: 3*60*60e3, groupMin: 5*50e3
169
      })
170
171
    connect(peers, ts, 'legacy', exports.isLegacy, {
172
        quota: 3, factor: 5*min, max: 3*hour, groupMin: 5*min,
173
        disable: !conf('global', true)
174
      })
175
176
    connect(peers, ts, 'longterm', exports.isLongterm, {
177
      quota: 3, factor: 10e3, max: 10*min, groupMin: 5e3,
178
      disable: !conf('global', true)
179
    })
180
181
    connect(peers, ts, 'local', exports.isLocal, {
182
      quota: 3, factor: 2e3, max: 10*min, groupMin: 1e3,
183
      disable: !conf('local', true)
184
    })
185
186
    }, 100*Math.random())
187
188
  }
189
190
    pull(
191
      gossip.changes(),
192
      pull.drain(function (ev) {
193
        if(ev.type == 'disconnect')
194
          connections()
195
      })
196
    )
197
198
    var int = setInterval(connections, 2e3)
199
    if(int.unref) int.unref()
200
201
    connections()
202
203
}
204
205
exports.isUnattempted = isUnattempted
206
exports.isInactive = isInactive
207
exports.isLongterm = isLongterm
208
exports.isFollowing = isFollowing
209
exports.isLegacy = isLegacy
210
exports.isLocal = isLocal
211
exports.isConnectedOrConnecting = isConnect
212
exports.select = select
213