CAS API go-couchbase

client.go

@@ -433,6 +433,48 @@ func (b *Bucket) Write(k string, flags, exp int, v interface{},
 	return err
 }
 
+func (b *Bucket) WriteCas(k string, flags, exp int, cas uint64, v interface{},
+	opt WriteOptions) (err error) {
+
+	if ClientOpCallback != nil {
+		defer func(t time.Time) {
+			ClientOpCallback(fmt.Sprintf("Write(%v)", opt), k, t, err)
+		}(time.Now())
+	}
+
+	var data []byte
+	if opt&Raw == 0 {
+		data, err = json.Marshal(v)
+		if err != nil {
+			return err
+		}
+	} else if v != nil {
+		data = v.([]byte)
+	}
+
+	var res *gomemcached.MCResponse
+	err = b.Do(k, func(mc *memcached.Client, vb uint16) error {
+		res, err = mc.SetCas(vb, k, flags, exp, cas, data)
+		return err
+	})
+
+	if err == nil && (opt&(Persist|Indexable) != 0) {
+		err = b.WaitForPersistence(k, res.Cas, data == nil)
+	}
+
+	return err
+}
+
+// Set a value in this bucket with Cas
+func (b *Bucket) Cas(k string, exp int, cas uint64, v interface{}) error {
+	return b.WriteCas(k, 0, exp, cas, v, 0)
+}
+
+// Set a value in this bucket with Cas without json encoding it
+func (b *Bucket) CasRaw(k string, exp int, cas uint64, v interface{}) error {
+	return b.WriteCas(k, 0, exp, cas, v, Raw)
+}
+
 // Set a value in this bucket.
 // The value will be serialized into a JSON document.
 func (b *Bucket) Set(k string, exp int, v interface{}) error {

examples/hello/hello.go

@@ -34,6 +34,38 @@ func doOps(b *couchbase.Bucket) {
 		total*3, time.Now().Sub(start).String())
 }
 
+func doMoreOps(b *couchbase.Bucket) {
+	fmt.Printf("Doing some Cas ops on %s\n", b.Name)
+	start := time.Now()
+	total := 2048
+	for i := 0; i < total; i++ {
+		k := fmt.Sprintf("k2%d", i)
+		maybeFatal(b.Set(k, 0, []string{"a", "b", "c"}))
+		rv := make([]string, 0, 10)
+		var cas uint64
+		maybeFatal(b.Gets(k, &rv, &cas))
+		if fmt.Sprintf("%#v", rv) != `[]string{"a", "b", "c"}` {
+			log.Fatalf("Expected %#v, got %#v",
+				[]string{"a", "b", "c"}, rv)
+		}
+		maybeFatal(b.Cas(k, 0, cas, []string{"a", "b", "d"}))
+		maybeFatal(b.Get(k, &rv))
+		if fmt.Sprintf("%#v", rv) != `[]string{"a", "b", "d"}` {
+			log.Fatalf("Expected %#v, got %#v",
+				[]string{"a", "b", "c"}, rv)
+		}
+		// this should fail since we don't know the latest cas value
+		err := b.Cas(k, 0, cas, []string{"a", "b", "x"})
+		if err == nil {
+			log.Fatalf("Expected \"Data exists for key\"")
+		}
+
+		maybeFatal(b.Delete(k))
+	}
+	fmt.Printf("Did %d ops in %s\n",
+		total*6, time.Now().Sub(start).String())
+}
+
 func exploreBucket(bucket *couchbase.Bucket) {
 	vbm := bucket.VBServerMap()
 	fmt.Printf("     %v uses %s\n", bucket.Name, vbm.HashAlgorithm)
@@ -48,6 +80,7 @@ func exploreBucket(bucket *couchbase.Bucket) {
 	}
 
 	doOps(bucket)
+	doMoreOps(bucket)
 
 }