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relay: improve the way we allocate channels

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Now the server allocates a channel randomly from set of available ids
with the shortest possible length. So concurrency=1 will always yield a
channel-id between 1 and 9 (inclusive). If we have 9 simultaneous
sessions, we'll start allocating channels from 10 to 99. 100
simultaneous connections kicks us into the 100-999 bucket, etc.
This commit is contained in:
Brian Warner 2015-04-09 22:44:04 -05:00
parent ecc04ff675
commit c8d2fc8750
1 changed files with 21 additions and 13 deletions
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34
src/wormhole/servers/relay.py
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@ -1,5 +1,5 @@
from __future__ import print_function
import re, json, time
import re, json, time, random
from twisted.python import log
from twisted.internet import protocol
from twisted.application import strports, service, internet
@ -56,13 +56,12 @@ WELCOME = {
}
# relay URLs are:
#
# POST /allocate -> {channel-id: INT}
# GET /list -> {channel-ids: [INT..]}
# POST /allocate -> {channel-id: INT}
# these return all messages for CHANNEL-ID= and MSGNUM= but SIDE!= :
# POST /CHANNEL-ID/SIDE/post/MSGNUM {message: STR} -> {messages: [STR..]}
# POST /CHANNEL-ID/SIDE/poll/MSGNUM -> {messages: [STR..]}
# GET /CHANNEL-ID/SIDE/poll/MSGNUM (eventsource) -> STR, STR, ..
#
# POST /CHANNEL-ID/SIDE/deallocate -> waiting | deleted
class Channel(resource.Resource):
@ -166,7 +165,6 @@ class Relay(resource.Resource):
def __init__(self):
resource.Resource.__init__(self)
self.channels = {}
self.next_channel = 1
def prune_old_channels(self):
now = time.time()
@ -176,14 +174,26 @@ class Relay(resource.Resource):
log.msg("expiring %d" % channel_id)
self.free_child(channel_id)
def allocate_channel_id(self):
for size in range(1,4): # stick to 1-999 for now
available = set()
for cid in range(10**(size-1), 10**size):
if cid not in self.channels:
available.add(cid)
if available:
return random.choice(list(available))
# ouch, 999 currently allocated. Try random ones for a while.
for tries in range(1000):
cid = random.randrange(1000, 1000*1000)
if cid not in self.channels:
return cid
raise ValueError("unable to find a free channel-id")
def getChild(self, path, request):
if path == "allocate":
# be more clever later. Rotate through 1-99 unless they're all
# full, then rotate through 1-999, etc.
channel_id = self.next_channel
self.next_channel += 1
channel_id = self.allocate_channel_id()
self.channels[channel_id] = Channel(channel_id, self)
log.msg("allocated %d, now have %d channels" %
log.msg("allocated #%d, now have %d channels" %
(channel_id, len(self.channels)))
return Allocated(channel_id)
if path == "list":
@ -202,10 +212,8 @@ class Relay(resource.Resource):
def free_child(self, channel_id):
self.channels.pop(channel_id)
log.msg("freed %d, now have %d channels" %
log.msg("freed #%d, now have %d channels" %
(channel_id, len(self.channels)))
if not self.channels:
self.next_channel = 1
class TransitConnection(protocol.Protocol):
def __init__(self):