metrics = require('metrics-sharelatex') Settings = require('settings-sharelatex') RedisWrapper = require("./RedisWrapper") rclient = RedisWrapper.client("lock") logger = require "logger-sharelatex" module.exports = LockManager = LOCK_TEST_INTERVAL: 50 # 50ms between each test of the lock MAX_LOCK_WAIT_TIME: 10000 # 10s maximum time to spend trying to get the lock REDIS_LOCK_EXPIRY: 30 # seconds. Time until lock auto expires in redis. _blockingKey : (key)-> "lock:web:{#{key}}" tryLock : (key, callback = (err, isFree)->)-> rclient.set LockManager._blockingKey(key), "locked", "EX", LockManager.REDIS_LOCK_EXPIRY, "NX", (err, gotLock)-> return callback(err) if err? if gotLock == "OK" metrics.inc "lock-not-blocking" callback err, true else metrics.inc "lock-blocking" logger.log key: key, redis_response: gotLock, "lock is locked" callback err, false getLock: (key, callback = (error) ->) -> startTime = Date.now() do attempt = () -> if Date.now() - startTime > LockManager.MAX_LOCK_WAIT_TIME return callback(new Error("Timeout")) LockManager.tryLock key, (error, gotLock) -> return callback(error) if error? if gotLock callback(null) else setTimeout attempt, LockManager.LOCK_TEST_INTERVAL checkLock: (key, callback = (err, isFree)->)-> multi = rclient.multi() multi.exists LockManager._blockingKey(key) multi.exec (err, replys)-> return callback(err) if err? exists = parseInt replys[0] if exists == 1 metrics.inc "lock-blocking" callback err, false else metrics.inc "lock-not-blocking" callback err, true releaseLock: (key, callback)-> rclient.del LockManager._blockingKey(key), callback runWithLock: (key, runner = ( (releaseLock = (error) ->) -> ), callback = ( (error) -> )) -> LockManager.getLock key, (error) -> return callback(error) if error? runner (error1, values...) -> LockManager.releaseLock key, (error2) -> error = error1 or error2 return callback(error) if error? callback null, values...