overleaf/services/real-time/app/coffee/EventLogger.coffee

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2 KiB
CoffeeScript

logger = require 'logger-sharelatex'
metrics = require 'metrics-sharelatex'
settings = require 'settings-sharelatex'
# keep track of message counters to detect duplicate and out of order events
# messsage ids have the format "UNIQUEHOSTKEY-COUNTER"
EVENT_LOG_COUNTER = {}
EVENT_LOG_TIMESTAMP = {}
EVENT_LAST_CLEAN_TIMESTAMP = 0
# counter for debug logs
COUNTER = 0
module.exports = EventLogger =
MAX_STALE_TIME_IN_MS: 3600 * 1000
debugEvent: (channel, message) ->
if settings.debugEvents > 0
logger.log {channel:channel, message:message, counter: COUNTER++}, "logging event"
settings.debugEvents--
checkEventOrder: (channel, message_id, message) ->
return if typeof(message_id) isnt 'string'
return if !(result = message_id.match(/^(.*)-(\d+)$/))
key = result[1]
count = parseInt(result[2], 0)
if !(count >= 0)# ignore checks if counter is not present
return
# store the last count in a hash for each host
previous = EventLogger._storeEventCount(key, count)
if !previous? || count == (previous + 1)
metrics.inc "event.#{channel}.valid", 0.001 # downsample high rate docupdater events
return # order is ok
if (count == previous)
metrics.inc "event.#{channel}.duplicate"
logger.warn {channel:channel, message_id:message_id}, "duplicate event"
return "duplicate"
else
metrics.inc "event.#{channel}.out-of-order"
logger.warn {channel:channel, message_id:message_id, key:key, previous: previous, count:count}, "out of order event"
return "out-of-order"
_storeEventCount: (key, count) ->
previous = EVENT_LOG_COUNTER[key]
now = Date.now()
EVENT_LOG_COUNTER[key] = count
EVENT_LOG_TIMESTAMP[key] = now
# periodically remove old counts
if (now - EVENT_LAST_CLEAN_TIMESTAMP) > EventLogger.MAX_STALE_TIME_IN_MS
EventLogger._cleanEventStream(now)
EVENT_LAST_CLEAN_TIMESTAMP = now
return previous
_cleanEventStream: (now) ->
for key, timestamp of EVENT_LOG_TIMESTAMP
if (now - timestamp) > EventLogger.MAX_STALE_TIME_IN_MS
delete EVENT_LOG_COUNTER[key]
delete EVENT_LOG_TIMESTAMP[key]