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port_allocator.go
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/
port_allocator.go
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/*
* Copyright (C) 2016 Red Hat, Inc.
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 common
import (
"errors"
)
var (
// ErrInvalidPortRange invalid port range
ErrInvalidPortRange = errors.New("Invalid port range")
// ErrNoPortLeft no port left in the range
ErrNoPortLeft = errors.New("No free port left")
)
// PortAllocator describes a threads safe port list that can be allocated
type PortAllocator struct {
RWMutex
MinPort int
MaxPort int
PortMap map[int]bool
}
// Allocate returns a new port between min and max ports.
func (p *PortAllocator) Allocate() (int, error) {
p.Lock()
defer p.Unlock()
for i := p.MinPort; i <= p.MaxPort; i++ {
if _, ok := p.PortMap[i]; !ok {
p.PortMap[i] = true
return i, nil
}
}
return 0, ErrNoPortLeft
}
// Release a port
func (p *PortAllocator) Release(i int) error {
p.Lock()
defer p.Unlock()
if i < p.MinPort || i > p.MaxPort {
return ErrInvalidPortRange
}
delete(p.PortMap, i)
return nil
}
// ReleaseAll ports
func (p *PortAllocator) ReleaseAll() {
p.Lock()
defer p.Unlock()
p.PortMap = make(map[int]bool)
}
// NewPortAllocator creates a new port allocator range
func NewPortAllocator(min, max int) (*PortAllocator, error) {
if min <= 0 || max < min {
return nil, ErrInvalidPortRange
}
return &PortAllocator{
MinPort: min,
MaxPort: max,
PortMap: make(map[int]bool),
}, nil
}