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43 lines
1.6 KiB
CoffeeScript
43 lines
1.6 KiB
CoffeeScript
config = require '../../server_config'
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redis = require 'redis'
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log = require 'winston'
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class LockManager
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constructor: ->
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unless config.isProduction
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throw "You shouldn't be instantiating distributed locks unless in production."
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@redisNotAvailable = true
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@redisClient = redis.createClient config.redis.port, config.redis.host
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@redisClient.on "ready", =>
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log.info "Redis ready!"
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@redisNotAvailable = false
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@redisClient.on "error", (err) =>
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@redisNotAvailable = true
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log.error "Redis connection error! Err: #{err}"
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@redisClient.on "end", =>
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@redisNotAvailable = true
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log.error "Redis connection ended!"
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@lockValues = {}
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@unlockScript = "if redis.call(\"get\",KEYS[1]) == ARGV[1] then return redis.call(\"del\",KEYS[1]) else return 0 end"
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setLock: (lockName, timeoutMs, cb) =>
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if @redisNotAvailable is true then return cb "Redis not available!"
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randomNumber = Math.floor(Math.random() * 1000000000)
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@redisClient.set [lockName,randomNumber, "NX", "PX", timeoutMs], (err, res) =>
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if err? then return cb err, null
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if res is "OK"
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@lockValues[lockName] = randomNumber
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return cb null, "Lock set!"
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unless res
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return cb "Lock already set!", null
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releaseLock: (lockName, cb) =>
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if @redisNotAvailable is true then return cb "Redis not available!"
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@redisClient.eval [@unlockScript, 1, lockName, @lockValues[lockName]], (err, res) ->
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if err? then return cb err, null
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if res
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cb null, "The lock was released!"
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else
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cb "The lock was not released.", null
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module.exports = new LockManager()
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