traefik/pkg/provider/kv/kv.go

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package kv
import (
"context"
"errors"
"fmt"
"path"
"time"
"github.com/abronan/valkeyrie"
"github.com/abronan/valkeyrie/store"
"github.com/abronan/valkeyrie/store/consul"
etcdv3 "github.com/abronan/valkeyrie/store/etcd/v3"
"github.com/abronan/valkeyrie/store/redis"
"github.com/abronan/valkeyrie/store/zookeeper"
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"github.com/cenkalti/backoff/v4"
"github.com/traefik/traefik/v2/pkg/config/dynamic"
"github.com/traefik/traefik/v2/pkg/config/kv"
"github.com/traefik/traefik/v2/pkg/job"
"github.com/traefik/traefik/v2/pkg/log"
"github.com/traefik/traefik/v2/pkg/safe"
"github.com/traefik/traefik/v2/pkg/types"
)
// Provider holds configurations of the provider.
type Provider struct {
RootKey string `description:"Root key used for KV store" export:"true" json:"rootKey,omitempty" toml:"rootKey,omitempty" yaml:"rootKey,omitempty"`
Endpoints []string `description:"KV store endpoints" json:"endpoints,omitempty" toml:"endpoints,omitempty" yaml:"endpoints,omitempty"`
Username string `description:"KV Username" json:"username,omitempty" toml:"username,omitempty" yaml:"username,omitempty"`
Password string `description:"KV Password" json:"password,omitempty" toml:"password,omitempty" yaml:"password,omitempty"`
TLS *types.ClientTLS `description:"Enable TLS support" export:"true" json:"tls,omitempty" toml:"tls,omitempty" yaml:"tls,omitempty"`
storeType store.Backend
kvClient store.Store
name string
}
// SetDefaults sets the default values.
func (p *Provider) SetDefaults() {
p.RootKey = "traefik"
}
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// Init the provider.
func (p *Provider) Init(storeType store.Backend, name string) error {
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ctx := log.With(context.Background(), log.Str(log.ProviderName, name))
p.storeType = storeType
p.name = name
kvClient, err := p.createKVClient(ctx)
if err != nil {
return fmt.Errorf("failed to Connect to KV store: %w", err)
}
p.kvClient = kvClient
return nil
}
// Provide allows the docker provider to provide configurations to traefik using the given configuration channel.
func (p *Provider) Provide(configurationChan chan<- dynamic.Message, pool *safe.Pool) error {
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ctx := log.With(context.Background(), log.Str(log.ProviderName, p.name))
logger := log.FromContext(ctx)
operation := func() error {
if _, err := p.kvClient.Exists(path.Join(p.RootKey, "qmslkjdfmqlskdjfmqlksjazçueznbvbwzlkajzebvkwjdcqmlsfj"), nil); err != nil {
return fmt.Errorf("KV store connection error: %w", err)
}
return nil
}
notify := func(err error, time time.Duration) {
logger.Errorf("KV connection error: %+v, retrying in %s", err, time)
}
err := backoff.RetryNotify(safe.OperationWithRecover(operation), job.NewBackOff(backoff.NewExponentialBackOff()), notify)
if err != nil {
return fmt.Errorf("cannot connect to KV server: %w", err)
}
configuration, err := p.buildConfiguration()
if err != nil {
logger.Errorf("Cannot build the configuration: %v", err)
} else {
configurationChan <- dynamic.Message{
ProviderName: p.name,
Configuration: configuration,
}
}
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pool.GoCtx(func(ctxPool context.Context) {
ctxLog := log.With(ctxPool, log.Str(log.ProviderName, p.name))
err := p.watchKv(ctxLog, configurationChan)
if err != nil {
logger.Errorf("Cannot watch KV store: %v", err)
}
})
return nil
}
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func (p *Provider) watchKv(ctx context.Context, configurationChan chan<- dynamic.Message) error {
operation := func() error {
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events, err := p.kvClient.WatchTree(p.RootKey, ctx.Done(), nil)
if err != nil {
return fmt.Errorf("failed to watch KV: %w", err)
}
for {
select {
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case <-ctx.Done():
return nil
case _, ok := <-events:
if !ok {
return errors.New("the WatchTree channel is closed")
}
configuration, errC := p.buildConfiguration()
if errC != nil {
return errC
}
if configuration != nil {
configurationChan <- dynamic.Message{
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ProviderName: p.name,
Configuration: configuration,
}
}
}
}
}
notify := func(err error, time time.Duration) {
log.FromContext(ctx).Errorf("KV connection error: %+v, retrying in %s", err, time)
}
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err := backoff.RetryNotify(safe.OperationWithRecover(operation),
backoff.WithContext(job.NewBackOff(backoff.NewExponentialBackOff()), ctx), notify)
if err != nil {
return fmt.Errorf("cannot connect to KV server: %w", err)
}
return nil
}
func (p *Provider) buildConfiguration() (*dynamic.Configuration, error) {
pairs, err := p.kvClient.List(p.RootKey, nil)
if err != nil {
return nil, err
}
cfg := &dynamic.Configuration{}
err = kv.Decode(pairs, cfg, p.RootKey)
if err != nil {
return nil, err
}
return cfg, nil
}
func (p *Provider) createKVClient(ctx context.Context) (store.Store, error) {
storeConfig := &store.Config{
ConnectionTimeout: 3 * time.Second,
Bucket: "traefik",
Username: p.Username,
Password: p.Password,
}
if p.TLS != nil {
var err error
storeConfig.TLS, err = p.TLS.CreateTLSConfig(ctx)
if err != nil {
return nil, fmt.Errorf("unable to create client TLS configuration: %w", err)
}
}
switch p.storeType {
case store.CONSUL:
consul.Register()
case store.ETCDV3:
etcdv3.Register()
case store.ZK:
zookeeper.Register()
case store.REDIS:
redis.Register()
}
kvStore, err := valkeyrie.NewStore(p.storeType, p.Endpoints, storeConfig)
if err != nil {
return nil, err
}
return &storeWrapper{Store: kvStore}, nil
}