Merge pull request #434 from CodeNow/redis-locks-ttl

Redis locks ttl

Author: tjmehta

configs/.env

@@ -1,6 +1,7 @@
 LOG_ERRORS=true
 TOKEN_EXPIRES="1 year"
 REDIS_KEY_EXPIRES="5 minutes"
+REDIS_LOCK_EXPIRES="6 minutes"
 DOCK_PROJECT_LIMIT=100000000
 DEPLOY_COMMAND="echo DEPLOY"
 COOKIE_SECRET="\$up3r,$3<r3t"

lib/models/redis/mutex.js

@@ -9,11 +9,15 @@ function RedisMutex (key) {
 }
 
 RedisMutex.prototype.lock = function (cb) {
-  this.redis.setnx(this.key, 'lock', function (err, success) {
-    cb(err, success === '1');
+  // SET resource-name anystring NX EX max-lock-time
+  // Is a simple way to implement a locking system with Redis.
+  // See http://redis.io/commands/set
+  var expires = process.env.REDIS_LOCK_EXPIRES;
+  this.redis.set(this.key, 'lock', 'NX', 'PX', expires, function (err, success) {
+    cb(err, success === 'OK');
   });
 };
 
 RedisMutex.prototype.unlock = function (cb) {
   this.redis.del(this.key, cb);
-};
+};

unit/redis-mutex.js

@@ -0,0 +1,93 @@
+var Lab = require('lab');
+var describe = Lab.experiment;
+var it = Lab.test;
+var expect = Lab.expect;
+var before = Lab.before;
+var after = Lab.after;
+var createCount = require('callback-count');
+var redisCleaner = require('../test/fixtures/redis-cleaner');
+var RedisMutex = require('models/redis/mutex');
+
+
+describe('RedisMutex', function () {
+  before(redisCleaner.clean('*'));
+  after(redisCleaner.clean('*'));
+
+  var ctx = {};
+
+  describe('lock', function () {
+
+    it('should lock', function (done) {
+      var mutex = new RedisMutex('key-1');
+      mutex.lock(function (err, success) {
+        if (err) { return done(err); }
+        expect(success).to.equal(true);
+        done();
+      });
+    });
+
+    it('should fail to lock with the same key', function (done) {
+      var mutex = new RedisMutex('key-1');
+      mutex.lock(function (err, success) {
+        if (err) { return done(err); }
+        expect(success).to.equal(false);
+        done();
+      });
+    });
+
+    describe('unlock', function () {
+
+      it('should be able to lock after unlock', function (done) {
+        var mutex = new RedisMutex('key-1');
+        mutex.unlock(function (err, success) {
+          if (err) { return done(err); }
+          expect(success).to.equal('1');
+          mutex.lock(function (err, success) {
+            if (err) { return done(err); }
+            expect(success).to.equal(true);
+            done();
+          });
+        });
+      });
+
+    });
+
+
+    describe('ttl', function () {
+      before(function (done) {
+        ctx.originREDIS_LOCK_EXPIRES = process.env.REDIS_LOCK_EXPIRES;
+        done();
+      });
+      after(function (done) {
+        process.env.REDIS_LOCK_EXPIRES = ctx.originREDIS_LOCK_EXPIRES;
+        done();
+      });
+
+      it('should release lock after expiration time', function (done) {
+        var count = createCount(2, done);
+        process.env.REDIS_LOCK_EXPIRES = 50;
+        var mutex1 = new RedisMutex('new-key-1');
+        var mutex2 = new RedisMutex('new-key-1');
+        setTimeout(function () {
+          mutex2.lock(function (err, success) {
+            if (err) { return done(err); }
+            expect(success).to.equal(true);
+            count.next();
+          });
+        }, 100);
+        mutex1.lock(function (err, success) {
+          if (err) { return done(err); }
+          expect(success).to.equal(true);
+          mutex2.lock(function (err, success) {
+            if (err) { return done(err); }
+            expect(success).to.equal(false);
+            count.next();
+          });
+        });
+      });
+    });
+
+  });
+
+
+});