/
exports.go
83 lines (70 loc) · 2.01 KB
/
exports.go
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// Copyright 2016 The Serviced Authors.
// 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 web
import (
"math/rand"
"sync"
"time"
"github.com/control-center/serviced/zzk/registry"
)
func init() {
rand.Seed(time.Now().Unix())
}
// Exports manage a list of available exports
type Exports interface {
Set(data []registry.ExportDetails)
Next() *registry.ExportDetails
}
// RoundRobinExports returns the next export in a round-robin manner
type RoundRobinExports struct {
mu *sync.Mutex
xid int
data []registry.ExportDetails
}
// NewRoundRobinExports creates a new round robin list of exports
func NewRoundRobinExports(data []registry.ExportDetails) *RoundRobinExports {
e := &RoundRobinExports{
mu: &sync.Mutex{},
}
e.set(data)
return e
}
// Set updates the list of exports.
func (e *RoundRobinExports) Set(data []registry.ExportDetails) {
e.mu.Lock()
defer e.mu.Unlock()
e.set(data)
}
// set updates the export list, but first randomizes the order and resets the
// counter.
func (e *RoundRobinExports) set(data []registry.ExportDetails) {
// reset the counter
e.xid = 0
// randomize the exports
e.data = make([]registry.ExportDetails, len(data))
for i, j := range rand.Perm(len(data)) {
e.data[i] = data[j]
}
}
// Next returns the next available export
func (e *RoundRobinExports) Next() *registry.ExportDetails {
e.mu.Lock()
defer e.mu.Unlock()
// make sure there is data to submit
if size := len(e.data); size > 0 {
dat := e.data[e.xid]
e.xid = (e.xid + 1) % size
return &dat
}
return nil
}