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consul_catalog.go
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/
consul_catalog.go
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package provider
import (
"errors"
"strings"
"text/template"
"time"
log "github.com/Sirupsen/logrus"
"github.com/cenkalti/backoff"
"github.com/containous/traefik/safe"
"github.com/containous/traefik/types"
"github.com/hashicorp/consul/api"
)
const (
// DefaultWatchWaitTime is the duration to wait when polling consul
DefaultWatchWaitTime = 15 * time.Second
)
// ConsulCatalog holds configurations of the Consul catalog provider.
type ConsulCatalog struct {
BaseProvider `mapstructure:",squash"`
Endpoint string
Domain string
client *api.Client
}
type catalogUpdate struct {
Service string
Nodes []*api.ServiceEntry
}
func (provider *ConsulCatalog) watchServices(stopCh <-chan struct{}) <-chan map[string][]string {
watchCh := make(chan map[string][]string)
catalog := provider.client.Catalog()
safe.Go(func() {
defer close(watchCh)
opts := &api.QueryOptions{WaitTime: DefaultWatchWaitTime}
for {
select {
case <-stopCh:
return
default:
}
data, meta, err := catalog.Services(opts)
if err != nil {
log.WithError(err).Errorf("Failed to list services")
return
}
// If LastIndex didn't change then it means `Get` returned
// because of the WaitTime and the key didn't changed.
if opts.WaitIndex == meta.LastIndex {
continue
}
opts.WaitIndex = meta.LastIndex
if data != nil {
watchCh <- data
}
}
})
return watchCh
}
func (provider *ConsulCatalog) healthyNodes(service string) (catalogUpdate, error) {
health := provider.client.Health()
opts := &api.QueryOptions{}
data, _, err := health.Service(service, "", true, opts)
if err != nil {
log.WithError(err).Errorf("Failed to fetch details of " + service)
return catalogUpdate{}, err
}
return catalogUpdate{
Service: service,
Nodes: data,
}, nil
}
func (provider *ConsulCatalog) getBackend(node *api.ServiceEntry) string {
return strings.ToLower(node.Service.Service)
}
func (provider *ConsulCatalog) getFrontendValue(service string) string {
return "Host:" + service + "." + provider.Domain
}
func (provider *ConsulCatalog) buildConfig(catalog []catalogUpdate) *types.Configuration {
var FuncMap = template.FuncMap{
"getBackend": provider.getBackend,
"getFrontendValue": provider.getFrontendValue,
"replace": replace,
}
allNodes := []*api.ServiceEntry{}
serviceNames := []string{}
for _, info := range catalog {
if len(info.Nodes) > 0 {
serviceNames = append(serviceNames, info.Service)
allNodes = append(allNodes, info.Nodes...)
}
}
templateObjects := struct {
Services []string
Nodes []*api.ServiceEntry
}{
Services: serviceNames,
Nodes: allNodes,
}
configuration, err := provider.getConfiguration("templates/consul_catalog.tmpl", FuncMap, templateObjects)
if err != nil {
log.WithError(err).Error("Failed to create config")
}
return configuration
}
func (provider *ConsulCatalog) getNodes(index map[string][]string) ([]catalogUpdate, error) {
visited := make(map[string]bool)
nodes := []catalogUpdate{}
for service := range index {
name := strings.ToLower(service)
if !strings.Contains(name, " ") && !visited[name] {
visited[name] = true
log.WithFields(log.Fields{
"service": name,
}).Debug("Fetching service")
healthy, err := provider.healthyNodes(name)
if err != nil {
return nil, err
}
nodes = append(nodes, healthy)
}
}
return nodes, nil
}
func (provider *ConsulCatalog) watch(configurationChan chan<- types.ConfigMessage) error {
stopCh := make(chan struct{})
serviceCatalog := provider.watchServices(stopCh)
defer close(stopCh)
for {
select {
case index, ok := <-serviceCatalog:
if !ok {
return errors.New("Consul service list nil")
}
log.Debug("List of services changed")
nodes, err := provider.getNodes(index)
if err != nil {
return err
}
configuration := provider.buildConfig(nodes)
configurationChan <- types.ConfigMessage{
ProviderName: "consul_catalog",
Configuration: configuration,
}
}
}
}
// Provide allows the provider to provide configurations to traefik
// using the given configuration channel.
func (provider *ConsulCatalog) Provide(configurationChan chan<- types.ConfigMessage) error {
config := api.DefaultConfig()
config.Address = provider.Endpoint
client, err := api.NewClient(config)
if err != nil {
return err
}
provider.client = client
safe.Go(func() {
notify := func(err error, time time.Duration) {
log.Errorf("Consul connection error %+v, retrying in %s", err, time)
}
worker := func() error {
return provider.watch(configurationChan)
}
err := backoff.RetryNotify(worker, backoff.NewExponentialBackOff(), notify)
if err != nil {
log.Fatalf("Cannot connect to consul server %+v", err)
}
})
return err
}