api: add server web api for statistics

utils/metric/counter.go

@@ -0,0 +1,60 @@
+// Copyright 2017 fatedier, fatedier@gmail.com
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric
+
+import (
+	"sync/atomic"
+)
+
+type Counter interface {
+	Count() int64
+	Inc(int64)
+	Dec(int64)
+	Snapshot() Counter
+	Clear()
+}
+
+func NewCounter() Counter {
+	return &StandardCounter{
+		count: 0,
+	}
+}
+
+type StandardCounter struct {
+	count int64
+}
+
+func (c *StandardCounter) Count() int64 {
+	return atomic.LoadInt64(&c.count)
+}
+
+func (c *StandardCounter) Inc(count int64) {
+	atomic.AddInt64(&c.count, count)
+}
+
+func (c *StandardCounter) Dec(count int64) {
+	atomic.AddInt64(&c.count, -count)
+}
+
+func (c *StandardCounter) Snapshot() Counter {
+	tmp := &StandardCounter{
+		count: atomic.LoadInt64(&c.count),
+	}
+	return tmp
+}
+
+func (c *StandardCounter) Clear() {
+	atomic.StoreInt64(&c.count, 0)
+}