mirror of
https://github.com/overleaf/overleaf.git
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57 lines
2.1 KiB
CoffeeScript
57 lines
2.1 KiB
CoffeeScript
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logger = require "logger-sharelatex"
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LockState = {} # locks for docker container operations, by container name
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module.exports = LockManager =
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MAX_LOCK_HOLD_TIME: 15000 # how long we can keep a lock
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MAX_LOCK_WAIT_TIME: 10000 # how long we wait for a lock
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LOCK_TEST_INTERVAL: 1000 # retry time
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tryLock: (key, callback = (err, gotLock) ->) ->
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existingLock = LockState[key]
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if existingLock? # the lock is already taken, check how old it is
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lockAge = Date.now() - existingLock.created
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if lockAge < LockManager.MAX_LOCK_HOLD_TIME
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return callback(null, false) # we didn't get the lock, bail out
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else
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logger.error {key: key, lock: existingLock, age:lockAge}, "taking old lock by force"
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# take the lock
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LockState[key] = lockValue = {created: Date.now()}
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callback(null, true, lockValue)
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getLock: (key, callback = (error, lockValue) ->) ->
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startTime = Date.now()
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do attempt = () ->
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LockManager.tryLock key, (error, gotLock, lockValue) ->
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return callback(error) if error?
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if gotLock
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callback(null, lockValue)
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else if Date.now() - startTime > LockManager.MAX_LOCK_WAIT_TIME
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e = new Error("Lock timeout")
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e.key = key
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return callback(e)
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else
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setTimeout attempt, LockManager.LOCK_TEST_INTERVAL
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releaseLock: (key, lockValue, callback = (error) ->) ->
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existingLock = LockState[key]
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if existingLock is lockValue # lockValue is an object, so we can test by reference
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delete LockState[key] # our lock, so we can free it
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callback()
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else if existingLock? # lock exists but doesn't match ours
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logger.error {key:key, lock: existingLock}, "tried to release lock taken by force"
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callback()
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else
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logger.error {key:key, lock: existingLock}, "tried to release lock that has gone"
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callback()
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runWithLock: (key, runner = ( (releaseLock = (error) ->) -> ), callback = ( (error) -> )) ->
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LockManager.getLock key, (error, lockValue) ->
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return callback(error) if error?
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runner (error1, args...) ->
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LockManager.releaseLock key, lockValue, (error2) ->
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error = error1 or error2
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return callback(error) if error?
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callback(null, args...)
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