2020-02-19 06:14:14 -05:00
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/*
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* decaffeinate suggestions:
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* DS101: Remove unnecessary use of Array.from
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* DS102: Remove unnecessary code created because of implicit returns
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* DS207: Consider shorter variations of null checks
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* Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
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*/
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let LockManager;
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const logger = require("logger-sharelatex");
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2018-03-05 06:02:31 -05:00
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2020-02-19 06:14:14 -05:00
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const LockState = {}; // locks for docker container operations, by container name
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2018-03-05 06:02:31 -05:00
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2020-02-19 06:14:14 -05:00
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module.exports = (LockManager = {
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2018-03-05 06:02:31 -05:00
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2020-02-19 06:14:14 -05:00
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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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2018-03-05 06:02:31 -05:00
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2020-02-19 06:14:14 -05:00
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tryLock(key, callback) {
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let lockValue;
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if (callback == null) { callback = function(err, gotLock) {}; }
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const existingLock = LockState[key];
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if (existingLock != null) { // the lock is already taken, check how old it is
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const 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, lock: existingLock, age:lockAge}, "taking old lock by force");
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}
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}
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// take the lock
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LockState[key] = (lockValue = {created: Date.now()});
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return callback(null, true, lockValue);
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},
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2018-03-05 06:02:31 -05:00
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2020-02-19 06:14:14 -05:00
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getLock(key, callback) {
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let attempt;
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if (callback == null) { callback = function(error, lockValue) {}; }
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const startTime = Date.now();
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return (attempt = () =>
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LockManager.tryLock(key, function(error, gotLock, lockValue) {
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if (error != null) { return callback(error); }
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if (gotLock) {
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return callback(null, lockValue);
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} else if ((Date.now() - startTime) > LockManager.MAX_LOCK_WAIT_TIME) {
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const 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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return setTimeout(attempt, LockManager.LOCK_TEST_INTERVAL);
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}
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})
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)();
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},
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2018-03-05 06:02:31 -05:00
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2020-02-19 06:14:14 -05:00
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releaseLock(key, lockValue, callback) {
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if (callback == null) { callback = function(error) {}; }
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const existingLock = LockState[key];
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if (existingLock === 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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return callback();
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} else if (existingLock != null) { // lock exists but doesn't match ours
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logger.error({key, lock: existingLock}, "tried to release lock taken by force");
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return callback();
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} else {
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logger.error({key, lock: existingLock}, "tried to release lock that has gone");
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return callback();
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}
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},
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2018-03-05 06:02:31 -05:00
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2020-02-19 06:14:14 -05:00
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runWithLock(key, runner, callback) {
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if (callback == null) { callback = function(error) {}; }
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return LockManager.getLock(key, function(error, lockValue) {
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if (error != null) { return callback(error); }
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return runner((error1, ...args) =>
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LockManager.releaseLock(key, lockValue, function(error2) {
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error = error1 || error2;
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if (error != null) { return callback(error); }
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return callback(null, ...Array.from(args));
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})
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);
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});
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}
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});
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