97 lines
2.7 KiB
JavaScript
97 lines
2.7 KiB
JavaScript
'use strict';
|
|
|
|
var REDIS_DISTLOCK = {
|
|
DB: 5,
|
|
PREFIX: 'batch:locks:'
|
|
};
|
|
|
|
var Redlock = require('redlock');
|
|
var debug = require('../../util/debug')('redis-distlock');
|
|
|
|
function RedisDistlockLocker(redisPool) {
|
|
this.pool = redisPool;
|
|
this.redlock = null;
|
|
this.client = null;
|
|
this._locks = {};
|
|
}
|
|
|
|
module.exports = RedisDistlockLocker;
|
|
module.exports.type = 'redis-distlock';
|
|
|
|
function resourceId(host) {
|
|
return REDIS_DISTLOCK.PREFIX + host;
|
|
}
|
|
|
|
RedisDistlockLocker.prototype.lock = function(host, ttl, callback) {
|
|
var self = this;
|
|
debug('RedisDistlockLocker.lock(%s, %d)', host, ttl);
|
|
var resource = resourceId(host);
|
|
|
|
var lock = this._getLock(resource);
|
|
function acquireCallback(err, _lock) {
|
|
if (err) {
|
|
return callback(err);
|
|
}
|
|
self._setLock(resource, _lock);
|
|
return callback(null, _lock);
|
|
}
|
|
if (lock) {
|
|
return this._tryExtend(lock, ttl, function(err, _lock) {
|
|
if (err) {
|
|
return self._tryAcquire(resource, ttl, acquireCallback);
|
|
}
|
|
|
|
return callback(null, _lock);
|
|
});
|
|
} else {
|
|
return this._tryAcquire(resource, ttl, acquireCallback);
|
|
}
|
|
};
|
|
|
|
RedisDistlockLocker.prototype.unlock = function(host, callback) {
|
|
var lock = this._getLock(resourceId(host));
|
|
if (lock && this.redlock) {
|
|
return this.redlock.unlock(lock, callback);
|
|
}
|
|
};
|
|
|
|
RedisDistlockLocker.prototype._getLock = function(resource) {
|
|
if (this._locks.hasOwnProperty(resource)) {
|
|
return this._locks[resource];
|
|
}
|
|
return null;
|
|
};
|
|
|
|
RedisDistlockLocker.prototype._setLock = function(resource, lock) {
|
|
this._locks[resource] = lock;
|
|
};
|
|
|
|
RedisDistlockLocker.prototype._tryExtend = function(lock, ttl, callback) {
|
|
return lock.extend(ttl, function(err, _lock) {
|
|
return callback(err, _lock);
|
|
});
|
|
};
|
|
|
|
RedisDistlockLocker.prototype._tryAcquire = function(resource, ttl, callback) {
|
|
if (this.redlock & this.client && this.client.connected) {
|
|
return this.redlock.lock(resource, ttl, callback);
|
|
}
|
|
if (this.client && !this.client.connected) {
|
|
this.pool.release(REDIS_DISTLOCK.DB, this.client);
|
|
}
|
|
var self = this;
|
|
this.pool.acquire(REDIS_DISTLOCK.DB, function (err, client) {
|
|
self.client = client;
|
|
self.redlock = new Redlock([client], {
|
|
// see http://redis.io/topics/distlock
|
|
driftFactor: 0.01, // time in ms
|
|
// the max number of times Redlock will attempt to lock a resource before failing
|
|
retryCount: 3,
|
|
// the time in ms between attempts
|
|
retryDelay: 100
|
|
});
|
|
|
|
self.redlock.lock(resource, ttl, callback);
|
|
});
|
|
};
|