overleaf/services/real-time/app/coffee/ChannelManager.js

71 lines
3.2 KiB
JavaScript

logger = require 'logger-sharelatex'
metrics = require "metrics-sharelatex"
settings = require "settings-sharelatex"
ClientMap = new Map() # for each redis client, store a Map of subscribed channels (channelname -> subscribe promise)
# Manage redis pubsub subscriptions for individual projects and docs, ensuring
# that we never subscribe to a channel multiple times. The socket.io side is
# handled by RoomManager.
module.exports = ChannelManager =
getClientMapEntry: (rclient) ->
# return the per-client channel map if it exists, otherwise create and
# return an empty map for the client.
ClientMap.get(rclient) || ClientMap.set(rclient, new Map()).get(rclient)
subscribe: (rclient, baseChannel, id) ->
clientChannelMap = @getClientMapEntry(rclient)
channel = "#{baseChannel}:#{id}"
actualSubscribe = () ->
# subscribe is happening in the foreground and it should reject
p = rclient.subscribe(channel)
p.finally () ->
if clientChannelMap.get(channel) is subscribePromise
clientChannelMap.delete(channel)
.then () ->
logger.log {channel}, "subscribed to channel"
metrics.inc "subscribe.#{baseChannel}"
.catch (err) ->
logger.error {channel, err}, "failed to subscribe to channel"
metrics.inc "subscribe.failed.#{baseChannel}"
return p
pendingActions = clientChannelMap.get(channel) || Promise.resolve()
subscribePromise = pendingActions.then(actualSubscribe, actualSubscribe)
clientChannelMap.set(channel, subscribePromise)
logger.log {channel}, "planned to subscribe to channel"
return subscribePromise
unsubscribe: (rclient, baseChannel, id) ->
clientChannelMap = @getClientMapEntry(rclient)
channel = "#{baseChannel}:#{id}"
actualUnsubscribe = () ->
# unsubscribe is happening in the background, it should not reject
p = rclient.unsubscribe(channel)
.finally () ->
if clientChannelMap.get(channel) is unsubscribePromise
clientChannelMap.delete(channel)
.then () ->
logger.log {channel}, "unsubscribed from channel"
metrics.inc "unsubscribe.#{baseChannel}"
.catch (err) ->
logger.error {channel, err}, "unsubscribed from channel"
metrics.inc "unsubscribe.failed.#{baseChannel}"
return p
pendingActions = clientChannelMap.get(channel) || Promise.resolve()
unsubscribePromise = pendingActions.then(actualUnsubscribe, actualUnsubscribe)
clientChannelMap.set(channel, unsubscribePromise)
logger.log {channel}, "planned to unsubscribe from channel"
return unsubscribePromise
publish: (rclient, baseChannel, id, data) ->
metrics.summary "redis.publish.#{baseChannel}", data.length
if id is 'all' or !settings.publishOnIndividualChannels
channel = baseChannel
else
channel = "#{baseChannel}:#{id}"
# we publish on a different client to the subscribe, so we can't
# check for the channel existing here
rclient.publish channel, data