traefik/provider/kv.go

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// Package provider holds the different provider implementation.
package provider
import (
"fmt"
"strings"
"text/template"
"time"
"errors"
"github.com/BurntSushi/ty/fun"
"github.com/cenk/backoff"
"github.com/containous/traefik/job"
"github.com/containous/traefik/log"
"github.com/containous/traefik/safe"
"github.com/containous/traefik/types"
"github.com/docker/libkv"
"github.com/docker/libkv/store"
)
// Kv holds common configurations of key-value providers.
type Kv struct {
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BaseProvider `mapstructure:",squash"`
Endpoint string `description:"Comma sepparated server endpoints"`
Prefix string `description:"Prefix used for KV store"`
TLS *ClientTLS `description:"Enable TLS support"`
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storeType store.Backend
kvclient store.Store
}
func (provider *Kv) createStore() (store.Store, error) {
storeConfig := &store.Config{
ConnectionTimeout: 30 * time.Second,
Bucket: "traefik",
}
if provider.TLS != nil {
var err error
storeConfig.TLS, err = provider.TLS.CreateTLSConfig()
if err != nil {
return nil, err
}
}
return libkv.NewStore(
provider.storeType,
strings.Split(provider.Endpoint, ","),
storeConfig,
)
}
func (provider *Kv) watchKv(configurationChan chan<- types.ConfigMessage, prefix string, stop chan bool) error {
operation := func() error {
events, err := provider.kvclient.WatchTree(provider.Prefix, make(chan struct{}))
if err != nil {
return fmt.Errorf("Failed to KV WatchTree: %v", err)
}
for {
select {
case <-stop:
return nil
case _, ok := <-events:
if !ok {
return errors.New("watchtree channel closed")
}
configuration := provider.loadConfig()
if configuration != nil {
configurationChan <- types.ConfigMessage{
ProviderName: string(provider.storeType),
Configuration: configuration,
}
}
}
}
}
notify := func(err error, time time.Duration) {
log.Errorf("KV connection error: %+v, retrying in %s", err, time)
}
err := backoff.RetryNotify(operation, job.NewBackOff(backoff.NewExponentialBackOff()), notify)
if err != nil {
return fmt.Errorf("Cannot connect to KV server: %v", err)
}
return nil
}
func (provider *Kv) provide(configurationChan chan<- types.ConfigMessage, pool *safe.Pool, constraints types.Constraints) error {
provider.Constraints = append(provider.Constraints, constraints...)
operation := func() error {
if _, err := provider.kvclient.Exists("qmslkjdfmqlskdjfmqlksjazçueznbvbwzlkajzebvkwjdcqmlsfj"); err != nil {
return fmt.Errorf("Failed to test KV store connection: %v", err)
}
if provider.Watch {
pool.Go(func(stop chan bool) {
err := provider.watchKv(configurationChan, provider.Prefix, stop)
if err != nil {
log.Errorf("Cannot watch KV store: %v", err)
}
})
}
configuration := provider.loadConfig()
configurationChan <- types.ConfigMessage{
ProviderName: string(provider.storeType),
Configuration: configuration,
}
return nil
}
notify := func(err error, time time.Duration) {
log.Errorf("KV connection error: %+v, retrying in %s", err, time)
}
err := backoff.RetryNotify(operation, job.NewBackOff(backoff.NewExponentialBackOff()), notify)
if err != nil {
return fmt.Errorf("Cannot connect to KV server: %v", err)
}
return nil
}
func (provider *Kv) loadConfig() *types.Configuration {
templateObjects := struct {
Prefix string
}{
// Allow `/traefik/alias` to superesede `provider.Prefix`
strings.TrimSuffix(provider.get(provider.Prefix, provider.Prefix+"/alias"), "/"),
}
var KvFuncMap = template.FuncMap{
"List": provider.list,
"ListServers": provider.listServers,
"Get": provider.get,
"SplitGet": provider.splitGet,
"Last": provider.last,
}
configuration, err := provider.getConfiguration("templates/kv.tmpl", KvFuncMap, templateObjects)
if err != nil {
log.Error(err)
}
for key, frontend := range configuration.Frontends {
if _, ok := configuration.Backends[frontend.Backend]; ok == false {
delete(configuration.Frontends, key)
}
}
return configuration
}
func (provider *Kv) list(keys ...string) []string {
joinedKeys := strings.Join(keys, "")
keysPairs, err := provider.kvclient.List(joinedKeys)
if err != nil {
log.Debugf("Cannot get keys %s %s ", joinedKeys, err)
return nil
}
directoryKeys := make(map[string]string)
for _, key := range keysPairs {
directory := strings.Split(strings.TrimPrefix(key.Key, joinedKeys), "/")[0]
directoryKeys[directory] = joinedKeys + directory
}
return fun.Values(directoryKeys).([]string)
}
func (provider *Kv) listServers(backend string) []string {
serverNames := provider.list(backend, "/servers/")
return fun.Filter(func(serverName string) bool {
return provider.checkConstraints(serverName, "/tags")
}, serverNames).([]string)
}
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func (provider *Kv) get(defaultValue string, keys ...string) string {
joinedKeys := strings.Join(keys, "")
keyPair, err := provider.kvclient.Get(strings.TrimPrefix(joinedKeys, "/"))
if err != nil {
log.Debugf("Cannot get key %s %s, setting default %s", joinedKeys, err, defaultValue)
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return defaultValue
} else if keyPair == nil {
log.Debugf("Cannot get key %s, setting default %s", joinedKeys, defaultValue)
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return defaultValue
}
return string(keyPair.Value)
}
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func (provider *Kv) splitGet(keys ...string) []string {
joinedKeys := strings.Join(keys, "")
keyPair, err := provider.kvclient.Get(joinedKeys)
if err != nil {
log.Debugf("Cannot get key %s %s, setting default empty", joinedKeys, err)
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return []string{}
} else if keyPair == nil {
log.Debugf("Cannot get key %s, setting default %empty", joinedKeys)
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return []string{}
}
return strings.Split(string(keyPair.Value), ",")
}
func (provider *Kv) last(key string) string {
splittedKey := strings.Split(key, "/")
return splittedKey[len(splittedKey)-1]
}
func (provider *Kv) checkConstraints(keys ...string) bool {
joinedKeys := strings.Join(keys, "")
keyPair, err := provider.kvclient.Get(joinedKeys)
value := ""
if err == nil && keyPair != nil && keyPair.Value != nil {
value = string(keyPair.Value)
}
constraintTags := strings.Split(value, ",")
ok, failingConstraint := provider.MatchConstraints(constraintTags)
if ok == false {
if failingConstraint != nil {
log.Debugf("Constraint %v not matching with following tags: %v", failingConstraint.String(), value)
}
return false
}
return true
}