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local_manager.go
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local_manager.go
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// Copyright 2015 flannel 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 etcdv2
import (
"errors"
"fmt"
"strconv"
"time"
etcd "github.com/coreos/etcd/client"
"github.com/coreos/flannel/pkg/ip"
. "github.com/coreos/flannel/subnet"
log "github.com/golang/glog"
"golang.org/x/net/context"
)
const (
raceRetries = 10
subnetTTL = 24 * time.Hour
)
type LocalManager struct {
registry Registry
previousSubnet ip.IP4Net
}
type watchCursor struct {
index uint64
}
func isErrEtcdTestFailed(e error) bool {
if e == nil {
return false
}
etcdErr, ok := e.(etcd.Error)
return ok && etcdErr.Code == etcd.ErrorCodeTestFailed
}
func isErrEtcdNodeExist(e error) bool {
if e == nil {
return false
}
etcdErr, ok := e.(etcd.Error)
return ok || etcdErr.Code == etcd.ErrorCodeNodeExist
}
func isErrEtcdKeyNotFound(e error) bool {
if e == nil {
return false
}
etcdErr, ok := e.(etcd.Error)
return ok || etcdErr.Code == etcd.ErrorCodeKeyNotFound
}
func (c watchCursor) String() string {
return strconv.FormatUint(c.index, 10)
}
func NewLocalManager(config *EtcdConfig, prevSubnet ip.IP4Net) (Manager, error) {
r, err := newEtcdSubnetRegistry(config, nil)
if err != nil {
return nil, err
}
return newLocalManager(r, prevSubnet), nil
}
func newLocalManager(r Registry, prevSubnet ip.IP4Net) Manager {
return &LocalManager{
registry: r,
previousSubnet: prevSubnet,
}
}
func (m *LocalManager) GetNetworkConfig(ctx context.Context) (*Config, error) {
cfg, err := m.registry.getNetworkConfig(ctx)
if err != nil {
return nil, err
}
return ParseConfig(cfg)
}
func (m *LocalManager) AcquireLease(ctx context.Context, attrs *LeaseAttrs) (*Lease, error) {
config, err := m.GetNetworkConfig(ctx)
if err != nil {
return nil, err
}
for i := 0; i < raceRetries; i++ {
l, err := m.tryAcquireLease(ctx, config, attrs.PublicIP, attrs)
switch err {
case nil:
return l, nil
case errTryAgain:
continue
default:
return nil, err
}
}
return nil, errors.New("Max retries reached trying to acquire a subnet")
}
func findLeaseByIP(leases []Lease, pubIP ip.IP4) *Lease {
for _, l := range leases {
if pubIP == l.Attrs.PublicIP {
return &l
}
}
return nil
}
func findLeaseBySubnet(leases []Lease, subnet ip.IP4Net) *Lease {
for _, l := range leases {
if subnet.Equal(l.Subnet) {
return &l
}
}
return nil
}
func (m *LocalManager) tryAcquireLease(ctx context.Context, config *Config, extIaddr ip.IP4, attrs *LeaseAttrs) (*Lease, error) {
leases, _, err := m.registry.getSubnets(ctx)
if err != nil {
return nil, err
}
// Try to reuse a subnet if there's one that matches our IP
if l := findLeaseByIP(leases, extIaddr); l != nil {
// Make sure the existing subnet is still within the configured network
if isSubnetConfigCompat(config, l.Subnet) {
log.Infof("Found lease (%v) for current IP (%v), reusing", l.Subnet, extIaddr)
ttl := time.Duration(0)
if !l.Expiration.IsZero() {
// Not a reservation
ttl = subnetTTL
}
exp, err := m.registry.updateSubnet(ctx, l.Subnet, attrs, ttl, 0)
if err != nil {
return nil, err
}
l.Attrs = *attrs
l.Expiration = exp
return l, nil
} else {
log.Infof("Found lease (%v) for current IP (%v) but not compatible with current config, deleting", l.Subnet, extIaddr)
if err := m.registry.deleteSubnet(ctx, l.Subnet); err != nil {
return nil, err
}
}
}
// no existing match, check if there was a previous subnet to use
var sn ip.IP4Net
if !m.previousSubnet.Empty() {
// use previous subnet
if l := findLeaseBySubnet(leases, m.previousSubnet); l != nil {
// Make sure the existing subnet is still within the configured network
if isSubnetConfigCompat(config, l.Subnet) {
log.Infof("Found lease (%v) matching previously leased subnet, reusing", l.Subnet)
ttl := time.Duration(0)
if !l.Expiration.IsZero() {
// Not a reservation
ttl = subnetTTL
}
exp, err := m.registry.updateSubnet(ctx, l.Subnet, attrs, ttl, 0)
if err != nil {
return nil, err
}
l.Attrs = *attrs
l.Expiration = exp
return l, nil
} else {
log.Infof("Found lease (%v) matching previously leased subnet but not compatible with current config, deleting", l.Subnet)
if err := m.registry.deleteSubnet(ctx, l.Subnet); err != nil {
return nil, err
}
}
} else {
// Check if the previous subnet is a part of the network and of the right subnet length
if isSubnetConfigCompat(config, m.previousSubnet) {
log.Infof("Found previously leased subnet (%v), reusing", m.previousSubnet)
sn = m.previousSubnet
} else {
log.Errorf("Found previously leased subnet (%v) that is not compatible with the Etcd network config, ignoring", m.previousSubnet)
}
}
}
if sn.Empty() {
// no existing match, grab a new one
sn, err = m.allocateSubnet(config, leases)
if err != nil {
return nil, err
}
}
exp, err := m.registry.createSubnet(ctx, sn, attrs, subnetTTL)
switch {
case err == nil:
log.Infof("Allocated lease (%v) to current node (%v) ", sn, extIaddr)
return &Lease{
Subnet: sn,
Attrs: *attrs,
Expiration: exp,
}, nil
case isErrEtcdNodeExist(err):
return nil, errTryAgain
default:
return nil, err
}
}
func (m *LocalManager) allocateSubnet(config *Config, leases []Lease) (ip.IP4Net, error) {
log.Infof("Picking subnet in range %s ... %s", config.SubnetMin, config.SubnetMax)
var bag []ip.IP4
sn := ip.IP4Net{IP: config.SubnetMin, PrefixLen: config.SubnetLen}
OuterLoop:
for ; sn.IP <= config.SubnetMax && len(bag) < 100; sn = sn.Next() {
for _, l := range leases {
if sn.Overlaps(l.Subnet) {
continue OuterLoop
}
}
bag = append(bag, sn.IP)
}
if len(bag) == 0 {
return ip.IP4Net{}, errors.New("out of subnets")
} else {
i := randInt(0, len(bag))
return ip.IP4Net{IP: bag[i], PrefixLen: config.SubnetLen}, nil
}
}
func (m *LocalManager) RenewLease(ctx context.Context, lease *Lease) error {
exp, err := m.registry.updateSubnet(ctx, lease.Subnet, &lease.Attrs, subnetTTL, 0)
if err != nil {
return err
}
lease.Expiration = exp
return nil
}
func getNextIndex(cursor interface{}) (uint64, error) {
nextIndex := uint64(0)
if wc, ok := cursor.(watchCursor); ok {
nextIndex = wc.index
} else if s, ok := cursor.(string); ok {
var err error
nextIndex, err = strconv.ParseUint(s, 10, 64)
if err != nil {
return 0, fmt.Errorf("failed to parse cursor: %v", err)
}
} else {
return 0, fmt.Errorf("internal error: watch cursor is of unknown type")
}
return nextIndex, nil
}
func (m *LocalManager) leaseWatchReset(ctx context.Context, sn ip.IP4Net) (LeaseWatchResult, error) {
l, index, err := m.registry.getSubnet(ctx, sn)
if err != nil {
return LeaseWatchResult{}, err
}
return LeaseWatchResult{
Snapshot: []Lease{*l},
Cursor: watchCursor{index},
}, nil
}
func (m *LocalManager) WatchLease(ctx context.Context, sn ip.IP4Net, cursor interface{}) (LeaseWatchResult, error) {
if cursor == nil {
return m.leaseWatchReset(ctx, sn)
}
nextIndex, err := getNextIndex(cursor)
if err != nil {
return LeaseWatchResult{}, err
}
evt, index, err := m.registry.watchSubnet(ctx, nextIndex, sn)
switch {
case err == nil:
return LeaseWatchResult{
Events: []Event{evt},
Cursor: watchCursor{index},
}, nil
case isIndexTooSmall(err):
log.Warning("Watch of subnet leases failed because etcd index outside history window")
return m.leaseWatchReset(ctx, sn)
default:
return LeaseWatchResult{}, err
}
}
func (m *LocalManager) WatchLeases(ctx context.Context, cursor interface{}) (LeaseWatchResult, error) {
if cursor == nil {
return m.leasesWatchReset(ctx)
}
nextIndex, err := getNextIndex(cursor)
if err != nil {
return LeaseWatchResult{}, err
}
evt, index, err := m.registry.watchSubnets(ctx, nextIndex)
switch {
case err == nil:
return LeaseWatchResult{
Events: []Event{evt},
Cursor: watchCursor{index},
}, nil
case isIndexTooSmall(err):
log.Warning("Watch of subnet leases failed because etcd index outside history window")
return m.leasesWatchReset(ctx)
default:
return LeaseWatchResult{}, err
}
}
func isIndexTooSmall(err error) bool {
etcdErr, ok := err.(etcd.Error)
return ok && etcdErr.Code == etcd.ErrorCodeEventIndexCleared
}
// leasesWatchReset is called when incremental lease watch failed and we need to grab a snapshot
func (m *LocalManager) leasesWatchReset(ctx context.Context) (LeaseWatchResult, error) {
wr := LeaseWatchResult{}
leases, index, err := m.registry.getSubnets(ctx)
if err != nil {
return wr, fmt.Errorf("failed to retrieve subnet leases: %v", err)
}
wr.Cursor = watchCursor{index}
wr.Snapshot = leases
return wr, nil
}
func isSubnetConfigCompat(config *Config, sn ip.IP4Net) bool {
if sn.IP < config.SubnetMin || sn.IP > config.SubnetMax {
return false
}
return sn.PrefixLen == config.SubnetLen
}
func (m *LocalManager) Name() string {
previousSubnet := m.previousSubnet.String()
if m.previousSubnet.Empty() {
previousSubnet = "None"
}
return fmt.Sprintf("Etcd Local Manager with Previous Subnet: %s", previousSubnet)
}