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Merge pull request #39 from sharelatex/bg-lock-exponential-backoff

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exponential backoff for lock up to maximum time
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Brian Gough 2017-05-16 17:01:43 +01:00 committed by GitHub
commit 4622362e42
1 changed files with 5 additions and 1 deletions
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6
services/document-updater/app/coffee/LockManager.coffee
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@ -14,6 +14,7 @@ COUNT = 0
module.exports = LockManager =
LOCK_TEST_INTERVAL: 50 # 50ms between each test of the lock
MAX_TEST_INTERVAL: 1000 # back off to 1s between each test of the lock
MAX_LOCK_WAIT_TIME: 10000 # 10s maximum time to spend trying to get the lock
LOCK_TTL: 30 # seconds. Time until lock auto expires in redis.
@ -41,6 +42,7 @@ module.exports = LockManager =
getLock: (doc_id, callback = (error, lockValue) ->) ->
startTime = Date.now()
testInterval = LockManager.LOCK_TEST_INTERVAL
do attempt = () ->
if Date.now() - startTime > LockManager.MAX_LOCK_WAIT_TIME
e = new Error("Timeout")
@ -52,7 +54,9 @@ module.exports = LockManager =
if gotLock
callback(null, lockValue)
else
setTimeout attempt, LockManager.LOCK_TEST_INTERVAL
setTimeout attempt, testInterval
# back off when the lock is taken to avoid overloading
testInterval = Math.min(testInterval * 2, LockManager.MAX_TEST_INTERVAL)
checkLock: (doc_id, callback = (err, isFree)->)->
key = keys.blockingKey(doc_id:doc_id)