Add incrby to zcache

Author: Nathan Lawrence

lib/CacheCluster.js

@@ -149,6 +149,12 @@ CacheCluster.prototype.get = function (key) {
   return this._wrapPromiseWithProfiling(cacheInstance.get(key), 'get')
 }
 
+/** @override */
+CacheCluster.prototype.incr = function (key, increment) {
+  var cacheInstance = this._servers[this._hashRing.get(key)]
+  return this._wrapPromiseWithProfiling(cacheInstance.incr(key, increment), 'set')
+}
+
 /** @override */
 CacheCluster.prototype.set = function (key, val, maxAgeMs) {
   var cacheInstance = this._servers[this._hashRing.get(key)]

lib/CacheInstance.js

@@ -96,6 +96,17 @@ CacheInstance.prototype.get = function (key) {
   throw new Error("get() must be implemented by any class extending CacheInstance")
 }
 
+/**
+ * Increment a key.
+ *
+ * @param {string} key The key to set
+ * @param {number=} increment The value to increment by.  1 if unspecified.
+ * @return {Q.Promise}
+ */
+CacheInstance.prototype.incr = function (key, increment) {
+  throw new Error("incr() must be implemented by any class extending CacheInstance")
+}
+
 /**
  * Set a key.
  *

lib/CachePair.js

@@ -138,6 +138,13 @@ CachePair.prototype.get = function (key) {
     })
 }
 
+/** @override */
+CachePair.prototype.incr = function (key, increment) {
+  var promises = [this._primary.incr(key, increment)]
+  if (this._maybeOnSecondary(key)) promises.push(this._secondary.incr(key, increment))
+  return Q.all(promises)
+}
+
 /** @override */
 CachePair.prototype.set = function (key, val, maxAgeMs, setWhenNotExist) {
   var promises = [this._primary.set(key, val, maxAgeMs, setWhenNotExist)]

lib/FakeCache.js

@@ -75,6 +75,28 @@ FakeCache.prototype.del = function (key) {
     })
 }
 
+/** @override */
+FakeCache.prototype.incr = function (key, increment) {
+  if (this._failureCount > 0) return this._fakeFail('set')
+  this._logger.fine('FakeCache - incr', key, increment)
+
+  if (increment === undefined) {
+    increment = 1
+  }
+
+  var self = this
+  // Add an artificial delay to mimic real world cache latency.
+  return Q.delay(this._latencyMs)
+    .then(function actualIncr() {
+      self._requestCounts.incr += 1
+      if (key in self._data) {
+        self._data[key] += increment
+      } else {
+        self._data[key] = increment
+      }
+    })
+}
+
 /** @override */
 FakeCache.prototype.set = function (key, value, maxAgeMs, setWhenNotExist) {
   if (this._failureCount > 0) return this._fakeFail('set')

lib/InMemoryCache.js

@@ -121,6 +121,20 @@ InMemoryCache.prototype.mget = function (keys) {
   return Q.resolve(ret)
 }
 
+/** @override */
+InMemoryCache.prototype.incr = function (key, increment) {
+  if (increment === undefined) {
+    increment = 1
+  }
+
+  if (key in this._data) {
+    this._data[key] += increment
+  } else {
+    this._data[key] = increment
+  }
+  return Q.resolve(null)
+}
+
 /** @override */
 InMemoryCache.prototype.set = function (key, val, maxAgeMs, setWhenNotExist) {
   if ((maxAgeMs === undefined || maxAgeMs <= 0) && !this._maxAgeOverride) {

lib/MultiplexingCache.js

@@ -152,6 +152,13 @@ MultiplexingCache.prototype.mset = function (items, maxAgeMs, setWhenNotExist) {
 }
 
 
+/** @override */
+MultiplexingCache.prototype.incr = function (key, increment) {
+  this._invalidateKeys([key])
+  return this._delegate.incr(key, increment)
+}
+
+
 /** @override */
 MultiplexingCache.prototype.set = function (key, val, maxAgeMs, setWhenNotExist) {
   this._invalidateKeys([key])

lib/RedisConnection.js

@@ -45,6 +45,18 @@ RedisConnection.prototype.isAvailable = function () {
   return this._isAvailable
 }
 
+/** @override */
+RedisConnection.prototype.incr = function (key, increment) {
+  if (increment === undefined) {
+    increment = 1
+  }
+
+  var deferred = Q.defer()
+  var params = [key, increment]
+  this._client.incrby(params, this._makeNodeResolverWithTimeout(deferred, 'incrby', 'Redis [incr] key: ' + key))
+  return deferred.promise
+}
+
 /** @override */
 RedisConnection.prototype.set = function (key, val, maxAgeMs, setWhenNotExist) {
   return this._compress(val)

lib/RedundantCacheGroup.js

@@ -179,6 +179,19 @@ RedundantCacheGroup.prototype.mset = function (items, maxAgeMs, setWhenNotExist)
     .then(returnTrue)
 }
 
+/** @override */
+RedundantCacheGroup.prototype.incr = function (key, increment) {
+  var instances = this._getAllInstances()
+  var promises = []
+
+  for (var i = 0; i < instances.length; i++) {
+    promises.push(instances[i].incr(key, increment))
+  }
+
+  return Q.all(promises)
+    .then(returnTrue)
+}
+
 /** @override */
 RedundantCacheGroup.prototype.set = function (key, val, maxAgeMs, setWhenNotExist) {
   var instances = this._getAllInstances()

package.json

@@ -1,7 +1,7 @@
 {
   "name": "zcache",
   "description": "AWS zone-aware multi-layer cache",
-  "version": "0.5.0",
+  "version": "0.5.1",
   "homepage": "https://github.com/Medium/zcache",
   "authors": [
     "Jeremy Stanley <[email protected]> (https://github.com/azulus)",

test/test_InMemoryCache.js

@@ -25,6 +25,21 @@ exports.testInMemoryCache = function (test) {
   test.done()
 }
 
+exports.testCacheIncr = function (test) {
+  var self = this
+  test.equal(0, this.cI.getKeyCount(), 'There is no key in cache')
+  this.cI.incr('counter', 15)
+    .then(function() {
+      test.equal(self.cI._data['counter'], 15, '15 should be returned')
+      test.equal(1, self.cI.getKeyCount(), 'There is 1 key in cache')
+      return self.cI.incr('counter')
+    }).then(function() {
+      test.equal(self.cI._data['counter'], 16, '16 should be returned')
+      test.equal(1, self.cI.getKeyCount(), 'There is 1 key in cache')
+      test.done()
+    })
+}
+
 exports.testCacheSet = function (test) {
   var self = this
   test.equal(0, this.cI.getKeyCount(), 'There is no key in cache')

test/test_RedisConnection.js

@@ -108,6 +108,38 @@ builder.add(function testRedisConnection(test) {
   cacheInstance.connect()
 })
 
+builder.add(function testIncr(test) {
+  var cacheInstance = new zcache.RedisConnection('localhost', 6379)
+
+  cacheInstance.on('connect', function () {
+    cacheInstance.removeAllListeners('connect')
+    test.equal(cacheInstance.isAvailable(), true, 'Connection should be available')
+
+    cacheInstance.incr('counter', 15)
+      .then(function () {
+        return cacheInstance.incr('counter')
+      })
+      .then(function (val) {
+        return cacheInstance.get('counter')
+      })
+      .then(function (val) {
+        test.equal(val, '16')
+        cacheInstance.destroy()
+      })
+      .fail(function (e) {
+        console.error(e)
+        test.fail(e.message)
+        test.done()
+      })
+  })
+
+  cacheInstance.on('destroy', function () {
+    test.done()
+  })
+
+  cacheInstance.connect()
+})
+
 builder.add(function testSetNotExist(test) {
   var cacheInstance = new zcache.RedisConnection('localhost', 6379)