mirror of
https://github.com/prometheus/prometheus.git
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261 lines
7.4 KiB
Go
261 lines
7.4 KiB
Go
// Copyright 2015 The Prometheus Authors
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package consul
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import (
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"fmt"
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"strconv"
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"strings"
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"time"
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consul "github.com/hashicorp/consul/api"
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"github.com/prometheus/common/log"
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"github.com/prometheus/common/model"
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"golang.org/x/net/context"
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"github.com/prometheus/prometheus/config"
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)
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const (
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watchTimeout = 30 * time.Second
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retryInterval = 15 * time.Second
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// addressLabel is the name for the label containing a target's address.
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addressLabel = model.MetaLabelPrefix + "consul_address"
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// nodeLabel is the name for the label containing a target's node name.
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nodeLabel = model.MetaLabelPrefix + "consul_node"
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// tagsLabel is the name of the label containing the tags assigned to the target.
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tagsLabel = model.MetaLabelPrefix + "consul_tags"
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// serviceLabel is the name of the label containing the service name.
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serviceLabel = model.MetaLabelPrefix + "consul_service"
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// serviceAddressLabel is the name of the label containing the (optional) service address.
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serviceAddressLabel = model.MetaLabelPrefix + "consul_service_address"
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//servicePortLabel is the name of the label containing the service port.
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servicePortLabel = model.MetaLabelPrefix + "consul_service_port"
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// datacenterLabel is the name of the label containing the datacenter ID.
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datacenterLabel = model.MetaLabelPrefix + "consul_dc"
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// serviceIDLabel is the name of the label containing the service ID.
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serviceIDLabel = model.MetaLabelPrefix + "consul_service_id"
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)
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// Discovery retrieves target information from a Consul server
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// and updates them via watches.
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type Discovery struct {
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client *consul.Client
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clientConf *consul.Config
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clientDatacenter string
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tagSeparator string
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watchedServices []string // Set of services which will be discovered.
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}
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// NewDiscovery returns a new Discovery for the given config.
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func NewDiscovery(conf *config.ConsulSDConfig) (*Discovery, error) {
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clientConf := &consul.Config{
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Address: conf.Server,
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Scheme: conf.Scheme,
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Datacenter: conf.Datacenter,
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Token: conf.Token,
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HttpAuth: &consul.HttpBasicAuth{
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Username: conf.Username,
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Password: conf.Password,
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},
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}
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client, err := consul.NewClient(clientConf)
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if err != nil {
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return nil, err
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}
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cd := &Discovery{
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client: client,
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clientConf: clientConf,
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tagSeparator: conf.TagSeparator,
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watchedServices: conf.Services,
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}
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// If the datacenter isn't set in the clientConf, let's get it from the local Consul agent
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// (Consul default is to use local node's datacenter if one isn't given for a query).
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if clientConf.Datacenter == "" {
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info, err := client.Agent().Self()
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if err != nil {
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return nil, err
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}
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cd.clientDatacenter = info["Config"]["Datacenter"].(string)
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} else {
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cd.clientDatacenter = clientConf.Datacenter
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}
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return cd, nil
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}
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// shouldWatch returns whether the service of the given name should be watched.
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func (cd *Discovery) shouldWatch(name string) bool {
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// If there's no fixed set of watched services, we watch everything.
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if len(cd.watchedServices) == 0 {
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return true
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}
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for _, sn := range cd.watchedServices {
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if sn == name {
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return true
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}
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}
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return false
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}
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// Run implements the TargetProvider interface.
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func (cd *Discovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
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defer close(ch)
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// Watched services and their cancelation functions.
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services := map[string]func(){}
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var lastIndex uint64
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for {
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catalog := cd.client.Catalog()
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srvs, meta, err := catalog.Services(&consul.QueryOptions{
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WaitIndex: lastIndex,
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WaitTime: watchTimeout,
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})
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// We have to check the context at least once. The checks during channel sends
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// do not guarantee that.
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select {
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case <-ctx.Done():
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return
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default:
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}
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if err != nil {
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log.Errorf("Error refreshing service list: %s", err)
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time.Sleep(retryInterval)
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continue
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}
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// If the index equals the previous one, the watch timed out with no update.
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if meta.LastIndex == lastIndex {
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continue
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}
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lastIndex = meta.LastIndex
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// Check for new services.
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for name := range srvs {
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if !cd.shouldWatch(name) {
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continue
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}
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if _, ok := services[name]; ok {
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continue // We are already watching the service.
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}
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srv := &consulService{
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client: cd.client,
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name: name,
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labels: model.LabelSet{
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serviceLabel: model.LabelValue(name),
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datacenterLabel: model.LabelValue(cd.clientDatacenter),
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},
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tagSeparator: cd.tagSeparator,
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}
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wctx, cancel := context.WithCancel(ctx)
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go srv.watch(wctx, ch)
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services[name] = cancel
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}
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// Check for removed services.
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for name, cancel := range services {
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if _, ok := srvs[name]; !ok {
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// Call the watch cancelation function.
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cancel()
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delete(services, name)
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// Send clearing target group.
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select {
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case <-ctx.Done():
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return
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case ch <- []*config.TargetGroup{{Source: name}}:
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}
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}
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}
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}
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}
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// consulService contains data belonging to the same service.
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type consulService struct {
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name string
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labels model.LabelSet
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client *consul.Client
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tagSeparator string
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}
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func (srv *consulService) watch(ctx context.Context, ch chan<- []*config.TargetGroup) {
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catalog := srv.client.Catalog()
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lastIndex := uint64(0)
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for {
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nodes, meta, err := catalog.Service(srv.name, "", &consul.QueryOptions{
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WaitIndex: lastIndex,
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WaitTime: watchTimeout,
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})
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// Check the context before potentially falling in a continue-loop.
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select {
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case <-ctx.Done():
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return
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default:
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// Continue.
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}
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if err != nil {
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log.Errorf("Error refreshing service %s: %s", srv.name, err)
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time.Sleep(retryInterval)
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continue
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}
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// If the index equals the previous one, the watch timed out with no update.
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if meta.LastIndex == lastIndex {
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continue
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}
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lastIndex = meta.LastIndex
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tgroup := config.TargetGroup{
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Source: srv.name,
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Labels: srv.labels,
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Targets: make([]model.LabelSet, 0, len(nodes)),
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}
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for _, node := range nodes {
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var (
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addr = fmt.Sprintf("%s:%d", node.Address, node.ServicePort)
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// We surround the separated list with the separator as well. This way regular expressions
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// in relabeling rules don't have to consider tag positions.
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tags = srv.tagSeparator + strings.Join(node.ServiceTags, srv.tagSeparator) + srv.tagSeparator
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)
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tgroup.Targets = append(tgroup.Targets, model.LabelSet{
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model.AddressLabel: model.LabelValue(addr),
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addressLabel: model.LabelValue(node.Address),
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nodeLabel: model.LabelValue(node.Node),
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tagsLabel: model.LabelValue(tags),
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serviceAddressLabel: model.LabelValue(node.ServiceAddress),
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servicePortLabel: model.LabelValue(strconv.Itoa(node.ServicePort)),
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serviceIDLabel: model.LabelValue(node.ServiceID),
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})
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}
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// Check context twice to ensure we always catch cancelation.
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select {
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case <-ctx.Done():
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return
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default:
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}
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select {
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case <-ctx.Done():
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return
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case ch <- []*config.TargetGroup{&tgroup}:
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}
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}
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}
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