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53 lines
1.7 KiB
CoffeeScript
53 lines
1.7 KiB
CoffeeScript
metrics = require('./Metrics')
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Settings = require('settings-sharelatex')
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redis = require("redis-sharelatex")
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rclient = redis.createClient(Settings.redis.web)
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keys = require('./RedisKeyBuilder')
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logger = require "logger-sharelatex"
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module.exports = LockManager =
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LOCK_TEST_INTERVAL: 50 # 50ms between each test of the lock
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MAX_LOCK_WAIT_TIME: 10000 # 10s maximum time to spend trying to get the lock
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REDIS_LOCK_EXPIRY: 30 # seconds. Time until lock auto expires in redis.
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tryLock : (doc_id, callback = (err, isFree)->)->
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rclient.set keys.blockingKey(doc_id: doc_id), "locked", "EX", LockManager.REDIS_LOCK_EXPIRY, "NX", (err, gotLock)->
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return callback(err) if err?
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if gotLock == "OK"
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metrics.inc "doc-not-blocking"
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callback err, true
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else
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metrics.inc "doc-blocking"
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logger.log doc_id: doc_id, redis_response: gotLock, "doc is locked"
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callback err, false
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getLock: (doc_id, callback = (error) ->) ->
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startTime = Date.now()
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do attempt = () ->
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if Date.now() - startTime > LockManager.MAX_LOCK_WAIT_TIME
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return callback(new Error("Timeout"))
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LockManager.tryLock doc_id, (error, gotLock) ->
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return callback(error) if error?
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if gotLock
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callback(null)
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else
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setTimeout attempt, LockManager.LOCK_TEST_INTERVAL
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checkLock: (doc_id, callback = (err, isFree)->)->
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multi = rclient.multi()
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multi.exists keys.blockingKey(doc_id:doc_id)
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multi.exec (err, replys)->
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return callback(err) if err?
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exists = parseInt replys[0]
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if exists == 1
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metrics.inc "doc-blocking"
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callback err, false
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else
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metrics.inc "doc-not-blocking"
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callback err, true
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releaseLock: (doc_id, callback)->
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rclient.del keys.blockingKey(doc_id:doc_id), callback
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