1d3e660248
This change includes minor refactoring and cleanup of the proxy package including the following items: * Rename source files with misspelling of round robin * Remove unnecessary and redundant comments * Update comments for clarity * Add locking when updating the round-robin index * Improve method receiver names * Rename the LoadBalance method to NextEndpoint to add clarity No changes in behaviour have been introduced.
119 lines
3.3 KiB
Go
119 lines
3.3 KiB
Go
/*
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Copyright 2014 Google Inc. All rights reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package proxy
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import (
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"errors"
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"net"
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"reflect"
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"strconv"
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"sync"
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"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
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"github.com/golang/glog"
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)
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var (
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ErrMissingServiceEntry = errors.New("missing service entry")
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ErrMissingEndpoints = errors.New("missing endpoints")
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)
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// LoadBalancerRR is a round-robin load balancer.
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type LoadBalancerRR struct {
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lock sync.RWMutex
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endpointsMap map[string][]string
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rrIndex map[string]int
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}
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// NewLoadBalancerRR returns a new LoadBalancerRR.
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func NewLoadBalancerRR() *LoadBalancerRR {
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return &LoadBalancerRR{
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endpointsMap: make(map[string][]string),
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rrIndex: make(map[string]int),
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}
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}
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// NextEndpoint returns a service endpoint.
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// The service endpoint is chosen using the round-robin algorithm.
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func (lb LoadBalancerRR) NextEndpoint(service string, srcAddr net.Addr) (string, error) {
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lb.lock.RLock()
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endpoints, exists := lb.endpointsMap[service]
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index := lb.rrIndex[service]
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lb.lock.RUnlock()
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if !exists {
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return "", ErrMissingServiceEntry
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}
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if len(endpoints) == 0 {
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return "", ErrMissingEndpoints
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}
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endpoint := endpoints[index]
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lb.lock.Lock()
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lb.rrIndex[service] = (index + 1) % len(endpoints)
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lb.lock.Unlock()
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return endpoint, nil
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}
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func (lb LoadBalancerRR) isValid(spec string) bool {
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_, port, err := net.SplitHostPort(spec)
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if err != nil {
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return false
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}
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value, err := strconv.Atoi(port)
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if err != nil {
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return false
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}
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return value > 0
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}
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func (lb LoadBalancerRR) filterValidEndpoints(endpoints []string) []string {
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var result []string
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for _, spec := range endpoints {
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if lb.isValid(spec) {
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result = append(result, spec)
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}
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}
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return result
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}
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// OnUpdate manages the registered service endpoints.
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// Registered endpoints are updated if found in the update set or
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// unregistered if missing from the update set.
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func (lb LoadBalancerRR) OnUpdate(endpoints []api.Endpoints) {
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registeredEndpoints := make(map[string]bool)
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lb.lock.Lock()
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defer lb.lock.Unlock()
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// Update endpoints for services.
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for _, endpoint := range endpoints {
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existingEndpoints, exists := lb.endpointsMap[endpoint.ID]
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validEndpoints := lb.filterValidEndpoints(endpoint.Endpoints)
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if !exists || !reflect.DeepEqual(existingEndpoints, validEndpoints) {
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glog.Infof("LoadBalancerRR: Setting endpoints for %s to %+v", endpoint.ID, endpoint.Endpoints)
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lb.endpointsMap[endpoint.ID] = validEndpoints
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// Reset the round-robin index.
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lb.rrIndex[endpoint.ID] = 0
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}
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registeredEndpoints[endpoint.ID] = true
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}
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// Remove endpoints missing from the update.
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for k, v := range lb.endpointsMap {
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if _, exists := registeredEndpoints[k]; !exists {
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glog.Infof("LoadBalancerRR: Removing endpoints for %s -> %+v", k, v)
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delete(lb.endpointsMap, k)
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}
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}
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}
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