Add KV datastore

Signed-off-by: Emile Vauge <emile@vauge.com>

acme/acme.go

@@ -173,6 +173,7 @@ type ACME struct {
 	storageLock sync.RWMutex
 	client      *acme.Client
 	account     *Account
+	defaultCertificate *tls.Certificate
 }
 
 //Domains parse []Domain
@@ -216,28 +217,50 @@ type Domain struct {
 	SANs []string
 }
 
-// CreateConfig creates a tls.config from using ACME configuration
-func (a *ACME) CreateConfig(tlsConfig *tls.Config, CheckOnDemandDomain func(domain string) bool) error {
-	acme.Logger = fmtlog.New(ioutil.Discard, "", 0)
-
-	if len(a.StorageFile) == 0 {
-		return errors.New("Empty StorageFile, please provide a filename for certs storage")
+func (a *ACME) init() error {
+	if len(a.Store) == 0 {
+		a.Store = a.StorageFile
 	}
-
+	acme.Logger = fmtlog.New(ioutil.Discard, "", 0)
 	log.Debugf("Generating default certificate...")
-	if len(tlsConfig.Certificates) == 0 {
 	// no certificates in TLS config, so we add a default one
 	cert, err := generateDefaultCertificate()
 	if err != nil {
 		return err
 	}
-		tlsConfig.Certificates = append(tlsConfig.Certificates, *cert)
+	a.defaultCertificate = cert
+	return nil
+}
+
+// CreateClusterConfig creates a tls.config from using ACME configuration
+func (a *ACME) CreateClusterConfig(tlsConfig *tls.Config, CheckOnDemandDomain func(domain string) bool) error {
+	err := a.init()
+	if err != nil {
+		return err
 	}
+	if len(a.Store) == 0 {
+		return errors.New("Empty Store, please provide a filename/key for certs storage")
+	}
+	tlsConfig.Certificates = append(tlsConfig.Certificates, *a.defaultCertificate)
+	return nil
+}
+
+// CreateLocalConfig creates a tls.config from using ACME configuration
+func (a *ACME) CreateLocalConfig(tlsConfig *tls.Config, CheckOnDemandDomain func(domain string) bool) error {
+	err := a.init()
+	if err != nil {
+		return err
+	}
+	if len(a.Store) == 0 {
+		return errors.New("Empty Store, please provide a filename/key for certs storage")
+	}
+	tlsConfig.Certificates = append(tlsConfig.Certificates, *a.defaultCertificate)
+
 	var needRegister bool
 	var err error
 
 	// if certificates in storage, load them
-	if fileInfo, err := os.Stat(a.StorageFile); err == nil && fileInfo.Size() != 0 {
+	if fileInfo, fileErr := os.Stat(a.Store); fileErr == nil && fileInfo.Size() != 0 {
 		log.Infof("Loading ACME certificates...")
 		// load account
 		a.account, err = a.loadAccount(a)
@@ -265,7 +288,10 @@ func (a *ACME) CreateConfig(tlsConfig *tls.Config, CheckOnDemandDomain func(doma
 	}
 	a.client.ExcludeChallenges([]acme.Challenge{acme.HTTP01, acme.DNS01})
 	wrapperChallengeProvider := newWrapperChallengeProvider()
-	a.client.SetChallengeProvider(acme.TLSSNI01, wrapperChallengeProvider)
+	err = client.SetChallengeProvider(acme.TLSSNI01, wrapperChallengeProvider)
+	if err != nil {
+		return err
+	}
 
 	if needRegister {
 		// New users will need to register; be sure to save it
@@ -322,12 +348,9 @@ func (a *ACME) CreateConfig(tlsConfig *tls.Config, CheckOnDemandDomain func(doma
 
 	ticker := time.NewTicker(24 * time.Hour)
 	safe.Go(func() {
-		for {
-			select {
-			case <-ticker.C:
-				if err := a.renewCertificates(a.client); err != nil {
-					log.Errorf("Error renewing ACME certificate %+v: %s", a.account, err.Error())
-				}
+		for range ticker.C {
+			if err := a.renewCertificates(client, account); err != nil {
+				log.Errorf("Error renewing ACME certificate %+v: %s", account, err.Error())
 			}
 		}
 
@@ -470,22 +493,22 @@ func (a *ACME) LoadCertificateForDomains(domains []string) {
 func (a *ACME) loadAccount(acmeConfig *ACME) (*Account, error) {
 	a.storageLock.RLock()
 	defer a.storageLock.RUnlock()
-	Account := Account{
+	account := Account{
 		DomainsCertificate: DomainsCertificates{},
 	}
-	file, err := ioutil.ReadFile(acmeConfig.StorageFile)
+	file, err := ioutil.ReadFile(acmeConfig.Store)
 	if err != nil {
 		return nil, err
 	}
-	if err := json.Unmarshal(file, &Account); err != nil {
+	if err := json.Unmarshal(file, &account); err != nil {
 		return nil, err
 	}
-	err = Account.DomainsCertificate.init()
+	err = account.DomainsCertificate.init()
 	if err != nil {
 		return nil, err
 	}
-	log.Infof("Loaded ACME config from storage %s", acmeConfig.StorageFile)
-	return &Account, nil
+	log.Infof("Loaded ACME config from store %s", acmeConfig.Store)
+	return &account, nil
 }
 
 func (a *ACME) saveAccount() error {
@@ -496,7 +519,7 @@ func (a *ACME) saveAccount() error {
 	if err != nil {
 		return err
 	}
-	return ioutil.WriteFile(a.StorageFile, data, 0600)
+	return ioutil.WriteFile(a.Store, data, 0600)
 }
 
 func (a *ACME) getDomainsCertificates(client *acme.Client, domains []string) (*Certificate, error) {

acme/challengeProvider.go

@@ -8,18 +8,20 @@ import (
 	"github.com/xenolf/lego/acme"
 )
 
-type wrapperChallengeProvider struct {
+var _ acme.ChallengeProvider = (*inMemoryChallengeProvider)(nil)
+
+type inMemoryChallengeProvider struct {
 	challengeCerts map[string]*tls.Certificate
 	lock           sync.RWMutex
 }
 
-func newWrapperChallengeProvider() *wrapperChallengeProvider {
-	return &wrapperChallengeProvider{
+func newWrapperChallengeProvider() *inMemoryChallengeProvider {
+	return &inMemoryChallengeProvider{
 		challengeCerts: map[string]*tls.Certificate{},
 	}
 }
 
-func (c *wrapperChallengeProvider) getCertificate(domain string) (cert *tls.Certificate, exists bool) {
+func (c *inMemoryChallengeProvider) getCertificate(domain string) (cert *tls.Certificate, exists bool) {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
 	if cert, ok := c.challengeCerts[domain]; ok {
@@ -28,7 +30,7 @@ func (c *wrapperChallengeProvider) getCertificate(domain string) (cert *tls.Cert
 	return nil, false
 }
 
-func (c *wrapperChallengeProvider) Present(domain, token, keyAuth string) error {
+func (c *inMemoryChallengeProvider) Present(domain, token, keyAuth string) error {
 	cert, _, err := acme.TLSSNI01ChallengeCert(keyAuth)
 	if err != nil {
 		return err
@@ -45,10 +47,9 @@ func (c *wrapperChallengeProvider) Present(domain, token, keyAuth string) error
 	}
 
 	return nil
-
 }
 
-func (c *wrapperChallengeProvider) CleanUp(domain, token, keyAuth string) error {
+func (c *inMemoryChallengeProvider) CleanUp(domain, token, keyAuth string) error {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 	delete(c.challengeCerts, domain)

cluster/datastore.go

@@ -0,0 +1,184 @@
+package cluster
+
+import (
+	"fmt"
+	log "github.com/Sirupsen/logrus"
+	"github.com/cenkalti/backoff"
+	"github.com/containous/staert"
+	"github.com/docker/libkv/store"
+	"github.com/satori/go.uuid"
+	"golang.org/x/net/context"
+	"sync"
+	"time"
+)
+
+// Object is the struct to store
+type Object interface{}
+
+// Metadata stores Object plus metadata
+type Metadata struct {
+	Lock string
+}
+
+// Datastore holds a struct synced in a KV store
+type Datastore struct {
+	kv        *staert.KvSource
+	ctx       context.Context
+	localLock *sync.RWMutex
+	object    Object
+	meta      *Metadata
+	lockKey   string
+}
+
+// NewDataStore creates a Datastore
+func NewDataStore(kvSource *staert.KvSource, ctx context.Context, object Object) (*Datastore, error) {
+	datastore := Datastore{
+		kv:        kvSource,
+		ctx:       ctx,
+		meta:      &Metadata{},
+		object:    object,
+		lockKey:   kvSource.Prefix + "/lock",
+		localLock: &sync.RWMutex{},
+	}
+	err := datastore.watchChanges()
+	if err != nil {
+		return nil, err
+	}
+	return &datastore, nil
+}
+
+func (d *Datastore) watchChanges() error {
+	stopCh := make(chan struct{})
+	kvCh, err := d.kv.Watch(d.lockKey, stopCh)
+	if err != nil {
+		return err
+	}
+	go func() {
+		ctx, cancel := context.WithCancel(d.ctx)
+		operation := func() error {
+			for {
+				select {
+				case <-ctx.Done():
+					stopCh <- struct{}{}
+					return nil
+				case _, ok := <-kvCh:
+					if !ok {
+						cancel()
+						return err
+					}
+					d.localLock.Lock()
+					err := d.kv.LoadConfig(d.object)
+					if err != nil {
+						d.localLock.Unlock()
+						return err
+					}
+					err = d.kv.LoadConfig(d.meta)
+					if err != nil {
+						d.localLock.Unlock()
+						return err
+					}
+					d.localLock.Unlock()
+				}
+			}
+		}
+		notify := func(err error, time time.Duration) {
+			log.Errorf("Error in watch datastore: %+v, retrying in %s", err, time)
+		}
+		err := backoff.RetryNotify(operation, backoff.NewExponentialBackOff(), notify)
+		if err != nil {
+			log.Errorf("Error in watch datastore: %v", err)
+		}
+	}()
+	return nil
+}
+
+// Begin creates a transaction with the KV store.
+func (d *Datastore) Begin() (*Transaction, error) {
+	value := uuid.NewV4().String()
+	remoteLock, err := d.kv.NewLock(d.lockKey, &store.LockOptions{TTL: 20 * time.Second, Value: []byte(value)})
+	if err != nil {
+		return nil, err
+	}
+	stopCh := make(chan struct{})
+	ctx, cancel := context.WithCancel(d.ctx)
+	var errLock error
+	go func() {
+		_, errLock = remoteLock.Lock(stopCh)
+		cancel()
+	}()
+	select {
+	case <-ctx.Done():
+		if errLock != nil {
+			return nil, errLock
+		}
+	case <-d.ctx.Done():
+		stopCh <- struct{}{}
+		return nil, d.ctx.Err()
+	}
+
+	// we got the lock! Now make sure we are synced with KV store
+	operation := func() error {
+		meta := d.get()
+		if meta.Lock != value {
+			return fmt.Errorf("Object lock value: expected %s, got %s", value, meta.Lock)
+		}
+		return nil
+	}
+	notify := func(err error, time time.Duration) {
+		log.Errorf("Datastore sync error: %v, retrying in %s", err, time)
+	}
+	ebo := backoff.NewExponentialBackOff()
+	ebo.MaxElapsedTime = 60 * time.Second
+	err = backoff.RetryNotify(operation, ebo, notify)
+	if err != nil {
+		return nil, fmt.Errorf("Datastore cannot sync: %v", err)
+	}
+
+	// we synced with KV store, we can now return Setter
+	return &Transaction{
+		Datastore:  d,
+		remoteLock: remoteLock,
+	}, nil
+}
+
+func (d *Datastore) get() *Metadata {
+	d.localLock.RLock()
+	defer d.localLock.RUnlock()
+	return d.meta
+}
+
+// Get atomically a struct from the KV store
+func (d *Datastore) Get() Object {
+	d.localLock.RLock()
+	defer d.localLock.RUnlock()
+	return d.object
+}
+
+// Transaction allows to set a struct in the KV store
+type Transaction struct {
+	*Datastore
+	remoteLock store.Locker
+	dirty      bool
+}
+
+// Commit allows to set an object in the KV store
+func (s *Transaction) Commit(object Object) error {
+	s.localLock.Lock()
+	defer s.localLock.Unlock()
+	if s.dirty {
+		return fmt.Errorf("Transaction already used. Please begin a new one.")
+	}
+	err := s.kv.StoreConfig(object)
+	if err != nil {
+		return err
+	}
+
+	err = s.remoteLock.Unlock()
+	if err != nil {
+		return err
+	}
+
+	s.Datastore.object = object
+	s.dirty = true
+	return nil
+}

cluster/leadership.go

@@ -0,0 +1,56 @@
+package cluster
+
+import (
+	log "github.com/Sirupsen/logrus"
+	"github.com/cenkalti/backoff"
+	"github.com/containous/traefik/safe"
+	"github.com/containous/traefik/types"
+	"github.com/docker/leadership"
+	"time"
+)
+
+// Leadership allows leadership election using a KV store
+type Leadership struct {
+	types.Cluster
+	candidate *leadership.Candidate
+}
+
+// Participate tries to be a leader
+func (l *Leadership) Participate(pool *safe.Pool, isElected func(bool)) {
+	pool.Go(func(stop chan bool) {
+		l.candidate = leadership.NewCandidate(l.Store, l.Store.Prefix+"/leader", l.Node, 30*time.Second)
+		backOff := backoff.NewExponentialBackOff()
+		operation := func() error {
+			return l.run(l.candidate, stop, isElected)
+		}
+
+		notify := func(err error, time time.Duration) {
+			log.Errorf("Leadership election error %+v, retrying in %s", err, time)
+		}
+		err := backoff.RetryNotify(operation, backOff, notify)
+		if err != nil {
+			log.Errorf("Cannot elect leadership %+v", err)
+		}
+	})
+}
+
+// Resign resigns from being a leader
+func (l *Leadership) Resign() {
+	if l.candidate != nil {
+		l.candidate.Resign()
+	}
+}
+
+func (l *Leadership) run(candidate *leadership.Candidate, stop chan bool, isElected func(bool)) error {
+	electedCh, errCh := candidate.RunForElection()
+	for {
+		select {
+		case elected := <-electedCh:
+			isElected(elected)
+		case err := <-errCh:
+			return err
+		case <-stop:
+			return nil
+		}
+	}
+}

configuration.go

@@ -29,6 +29,7 @@ type GlobalConfiguration struct {
 	TraefikLogsFile           string      `description:"Traefik logs file"`
 	LogLevel                  string      `short:"l" description:"Log level"`
 	EntryPoints               EntryPoints `description:"Entrypoints definition using format: --entryPoints='Name:http Address::8000 Redirect.EntryPoint:https' --entryPoints='Name:https Address::4442 TLS:tests/traefik.crt,tests/traefik.key'"`
+	Cluster                   *types.Cluster
 	Constraints               types.Constraints       `description:"Filter services by constraint, matching with service tags."`
 	ACME                      *acme.ACME              `description:"Enable ACME (Let's Encrypt): automatic SSL"`
 	DefaultEntryPoints        DefaultEntryPoints      `description:"Entrypoints to be used by frontends that do not specify any entrypoint"`
@@ -73,7 +74,9 @@ func (dep *DefaultEntryPoints) Set(value string) error {
 }
 
 // Get return the EntryPoints map
-func (dep *DefaultEntryPoints) Get() interface{} { return DefaultEntryPoints(*dep) }
+func (dep *DefaultEntryPoints) Get() interface{} {
+	return DefaultEntryPoints(*dep)
+}
 
 // SetValue sets the EntryPoints map with val
 func (dep *DefaultEntryPoints) SetValue(val interface{}) {
@@ -153,7 +156,9 @@ func (ep *EntryPoints) Set(value string) error {
 }
 
 // Get return the EntryPoints map
-func (ep *EntryPoints) Get() interface{} { return EntryPoints(*ep) }
+func (ep *EntryPoints) Get() interface{} {
+	return EntryPoints(*ep)
+}
 
 // SetValue sets the EntryPoints map with val
 func (ep *EntryPoints) SetValue(val interface{}) {

glide.lock

@@ -1,5 +1,14 @@
+<<<<<<< a13549cc28273ba5c15a739fa4aaeb3e0f7216a4
 hash: c0ac205a859d78847e21d3cd63f427ffba985755c6ae84373e4a20364ba39b05
+<<<<<<< 38b62d4ae311e2d5247065cbc2c09421a2bb81ab
 updated: 2016-09-30T10:57:42.336729457+02:00
+=======
+updated: 2016-09-28T16:50:04.352639437+01:00
+=======
+hash: 809b3fa812ca88940fdc15530804a4bcd881708e4819fed5aa45c42c871ba5cf
+updated: 2016-09-20T14:50:04.029710103+02:00
+>>>>>>> Add KV datastore
+>>>>>>> Add KV datastore
 imports:
 - name: github.com/abbot/go-http-auth
   version: cb4372376e1e00e9f6ab9ec142e029302c9e7140
@@ -36,7 +45,15 @@ imports:
   subpackages:
   - spew
 - name: github.com/docker/distribution
+<<<<<<< 38b62d4ae311e2d5247065cbc2c09421a2bb81ab
   version: 87917f30529e6a7fca8eaff2932424915fb11225
+=======
+<<<<<<< a13549cc28273ba5c15a739fa4aaeb3e0f7216a4
+  version: 99cb7c0946d2f5a38015443e515dc916295064d7
+=======
+  version: 857d0f15c0a4d8037175642e0ca3660829551cb5
+>>>>>>> Add KV datastore
+>>>>>>> Add KV datastore
   subpackages:
   - context
   - digest
@@ -122,7 +139,13 @@ imports:
   - sockets
   - tlsconfig
 - name: github.com/docker/go-units
+<<<<<<< 38b62d4ae311e2d5247065cbc2c09421a2bb81ab
   version: f2d77a61e3c169b43402a0a1e84f06daf29b8190
+=======
+  version: f2145db703495b2e525c59662db69a7344b00bb8
+- name: github.com/docker/leadership
+  version: bfc7753dd48af19513b29deec23c364bf0f274eb
+>>>>>>> Add KV datastore
 - name: github.com/docker/libcompose
   version: d1876c1d68527a49c0aac22a0b161acc7296b740
   subpackages:
@@ -141,7 +164,11 @@ imports:
   - version
   - yaml
 - name: github.com/docker/libkv
+<<<<<<< 38b62d4ae311e2d5247065cbc2c09421a2bb81ab
   version: 35d3e2084c650109e7bcc7282655b1bc8ba924ff
+=======
+  version: aabc039ad04deb721e234f99cd1b4aa28ac71a40
+>>>>>>> Add KV datastore
   subpackages:
   - store
   - store/boltdb
@@ -157,7 +184,15 @@ imports:
 - name: github.com/go-check/check
   version: 4f90aeace3a26ad7021961c297b22c42160c7b25
 - name: github.com/gogo/protobuf
+<<<<<<< 38b62d4ae311e2d5247065cbc2c09421a2bb81ab
   version: e33835a643a970c11ac74f6333f5f6866387a101
+=======
+<<<<<<< a13549cc28273ba5c15a739fa4aaeb3e0f7216a4
+  version: 89f1976ff373a3e549675d2f212c10f98b6c6316
+=======
+  version: e57a569e1882958f6b188cb42231d6db87701f2a
+>>>>>>> Add KV datastore
+>>>>>>> Add KV datastore
   subpackages:
   - proto
 - name: github.com/golang/glog
@@ -220,7 +255,11 @@ imports:
 - name: github.com/miekg/dns
   version: 5d001d020961ae1c184f9f8152fdc73810481677
 - name: github.com/mitchellh/mapstructure
+<<<<<<< 38b62d4ae311e2d5247065cbc2c09421a2bb81ab
   version: d2dd0262208475919e1a362f675cfc0e7c10e905
+=======
+  version: 21a35fb16463dfb7c8eee579c65d995d95e64d1e
+>>>>>>> Add KV datastore
 - name: github.com/moul/http2curl
   version: b1479103caacaa39319f75e7f57fc545287fca0d
 - name: github.com/NYTimes/gziphandler
@@ -228,7 +267,15 @@ imports:
 - name: github.com/ogier/pflag
   version: 45c278ab3607870051a2ea9040bb85fcb8557481
 - name: github.com/opencontainers/runc
+<<<<<<< 38b62d4ae311e2d5247065cbc2c09421a2bb81ab
   version: 1a81e9ab1f138c091fe5c86d0883f87716088527
+=======
+<<<<<<< a13549cc28273ba5c15a739fa4aaeb3e0f7216a4
+  version: d9fec4c63b089ddfc267194ecb6cda58a13f072c
+=======
+  version: ff88baa42fa5b2a1568a3a14665142fb4bdb3a2a
+>>>>>>> Add KV datastore
+>>>>>>> Add KV datastore
   subpackages:
   - libcontainer/user
 - name: github.com/parnurzeal/gorequest
@@ -243,6 +290,8 @@ imports:
   version: e64db453f3512cade908163702045e0f31137843
   subpackages:
   - zk
+- name: github.com/satori/go.uuid
+  version: 879c5887cd475cd7864858769793b2ceb0d44feb
 - name: github.com/Sirupsen/logrus
   version: a283a10442df8dc09befd873fab202bf8a253d6a
 - name: github.com/streamrail/concurrent-map

glide.yaml

@@ -99,3 +99,6 @@ import:
 - package: github.com/miekg/dns
   version: 5d001d020961ae1c184f9f8152fdc73810481677
 - package: github.com/NYTimes/gziphandler
+- package: github.com/docker/leadership
+- package: github.com/satori/go.uuid
+  version: ^1.1.0

integration/consul_test.go

@@ -5,18 +5,22 @@ import (
 	"os/exec"
 	"time"
 
+	"github.com/containous/staert"
 	"github.com/docker/libkv"
 	"github.com/docker/libkv/store"
 	"github.com/docker/libkv/store/consul"
 	"github.com/go-check/check"
+	"golang.org/x/net/context"
 
 	"errors"
+	"github.com/containous/traefik/cluster"
 	"github.com/containous/traefik/integration/utils"
 	"github.com/containous/traefik/provider"
 	checker "github.com/vdemeester/shakers"
 	"io/ioutil"
 	"os"
 	"strings"
+	"sync"
 )
 
 // Consul test suites (using libcompose)
@@ -427,3 +431,93 @@ func (s *ConsulSuite) TestCommandStoreConfig(c *check.C) {
 
 	}
 }
+
+type TestStruct struct {
+	String string
+	Int    int
+}
+
+func (s *ConsulSuite) TestDatastore(c *check.C) {
+	s.setupConsul(c)
+	consulHost := s.composeProject.Container(c, "consul").NetworkSettings.IPAddress
+	kvSource, err := staert.NewKvSource(store.CONSUL, []string{consulHost + ":8500"}, &store.Config{
+		ConnectionTimeout: 10 * time.Second,
+	}, "traefik")
+	c.Assert(err, checker.IsNil)
+
+	ctx := context.Background()
+	datastore1, err := cluster.NewDataStore(kvSource, ctx, &TestStruct{})
+	c.Assert(err, checker.IsNil)
+	datastore2, err := cluster.NewDataStore(kvSource, ctx, &TestStruct{})
+	c.Assert(err, checker.IsNil)
+
+	setter1, err := datastore1.Begin()
+	c.Assert(err, checker.IsNil)
+	err = setter1.Commit(&TestStruct{
+		String: "foo",
+		Int:    1,
+	})
+	c.Assert(err, checker.IsNil)
+	time.Sleep(2 * time.Second)
+	test1 := datastore1.Get().(*TestStruct)
+	c.Assert(test1.String, checker.Equals, "foo")
+
+	test2 := datastore2.Get().(*TestStruct)
+	c.Assert(test2.String, checker.Equals, "foo")
+
+	setter2, err := datastore2.Begin()
+	c.Assert(err, checker.IsNil)
+	err = setter2.Commit(&TestStruct{
+		String: "bar",
+		Int:    2,
+	})
+	c.Assert(err, checker.IsNil)
+	time.Sleep(2 * time.Second)
+	test1 = datastore1.Get().(*TestStruct)
+	c.Assert(test1.String, checker.Equals, "bar")
+
+	test2 = datastore2.Get().(*TestStruct)
+	c.Assert(test2.String, checker.Equals, "bar")
+
+	wg := &sync.WaitGroup{}
+	wg.Add(4)
+	go func() {
+		for i := 0; i < 100; i++ {
+			setter1, err := datastore1.Begin()
+			c.Assert(err, checker.IsNil)
+			err = setter1.Commit(&TestStruct{
+				String: "datastore1",
+				Int:    i,
+			})
+			c.Assert(err, checker.IsNil)
+		}
+		wg.Done()
+	}()
+	go func() {
+		for i := 0; i < 100; i++ {
+			setter2, err := datastore2.Begin()
+			c.Assert(err, checker.IsNil)
+			err = setter2.Commit(&TestStruct{
+				String: "datastore2",
+				Int:    i,
+			})
+			c.Assert(err, checker.IsNil)
+		}
+		wg.Done()
+	}()
+	go func() {
+		for i := 0; i < 100; i++ {
+			test1 := datastore1.Get().(*TestStruct)
+			c.Assert(test1, checker.NotNil)
+		}
+		wg.Done()
+	}()
+	go func() {
+		for i := 0; i < 100; i++ {
+			test2 := datastore2.Get().(*TestStruct)
+			c.Assert(test2, checker.NotNil)
+		}
+		wg.Done()
+	}()
+	wg.Wait()
+}

provider/boltdb.go

@@ -8,6 +8,8 @@ import (
 	"github.com/docker/libkv/store/boltdb"
 )
 
+var _ Provider = (*BoltDb)(nil)
+
 // BoltDb holds configurations of the BoltDb provider.
 type BoltDb struct {
 	Kv `mapstructure:",squash"`

provider/consul.go

@@ -8,6 +8,8 @@ import (
 	"github.com/docker/libkv/store/consul"
 )
 
+var _ Provider = (*Consul)(nil)
+
 // Consul holds configurations of the Consul provider.
 type Consul struct {
 	Kv `mapstructure:",squash"`

provider/consul_catalog.go

@@ -24,6 +24,8 @@ const (
 	DefaultConsulCatalogTagPrefix = "traefik"
 )
 
+var _ Provider = (*ConsulCatalog)(nil)
+
 // ConsulCatalog holds configurations of the Consul catalog provider.
 type ConsulCatalog struct {
 	BaseProvider `mapstructure:",squash"`

provider/docker.go

@@ -40,6 +40,8 @@ const (
 	SwarmDefaultWatchTime = 15 * time.Second
 )
 
+var _ Provider = (*Docker)(nil)
+
 // Docker holds configurations of the Docker provider.
 type Docker struct {
 	BaseProvider     `mapstructure:",squash"`

provider/etcd.go

@@ -8,6 +8,8 @@ import (
 	"github.com/docker/libkv/store/etcd"
 )
 
+var _ Provider = (*Etcd)(nil)
+
 // Etcd holds configurations of the Etcd provider.
 type Etcd struct {
 	Kv `mapstructure:",squash"`

provider/file.go

@@ -12,6 +12,8 @@ import (
 	"gopkg.in/fsnotify.v1"
 )
 
+var _ Provider = (*File)(nil)
+
 // File holds configurations of the File provider.
 type File struct {
 	BaseProvider `mapstructure:",squash"`

provider/kubernetes.go

@@ -50,6 +50,8 @@ func (ns *Namespaces) SetValue(val interface{}) {
 	*ns = Namespaces(val.(Namespaces))
 }
 
+var _ Provider = (*Kubernetes)(nil)
+
 // Kubernetes holds configurations of the Kubernetes provider.
 type Kubernetes struct {
 	BaseProvider           `mapstructure:",squash"`

provider/marathon.go

@@ -21,6 +21,8 @@ import (
 	"github.com/gambol99/go-marathon"
 )
 
+var _ Provider = (*Marathon)(nil)
+
 // Marathon holds configuration of the Marathon provider.
 type Marathon struct {
 	BaseProvider

provider/mesos.go

@@ -24,6 +24,8 @@ import (
 	"time"
 )
 
+var _ Provider = (*Mesos)(nil)
+
 //Mesos holds configuration of the mesos provider.
 type Mesos struct {
 	BaseProvider

provider/zk.go

@@ -8,6 +8,8 @@ import (
 	"github.com/docker/libkv/store/zookeeper"
 )
 
+var _ Provider = (*Zookepper)(nil)
+
 // Zookepper holds configurations of the Zookepper provider.
 type Zookepper struct {
 	Kv `mapstructure:",squash"`

server.go

@@ -375,7 +375,7 @@ func (server *Server) createTLSConfig(entryPointName string, tlsOption *TLS, rou
 					}
 					return false
 				}
-				err := server.globalConfiguration.ACME.CreateConfig(config, checkOnDemandDomain)
+				err := server.globalConfiguration.ACME.CreateLocalConfig(config, checkOnDemandDomain)
 				if err != nil {
 					return nil, err
 				}

traefik.go

@@ -154,6 +154,10 @@ Complete documentation is available at https://traefik.io`,
 
 	// IF a KV Store is enable and no sub-command called in args
 	if kv != nil && usedCmd == traefikCmd {
+		if traefikConfiguration.Cluster == nil {
+			hostname, _ := os.Hostname()
+			traefikConfiguration.Cluster = &types.Cluster{Store: types.Store{Prefix: kv.Prefix, Store: kv.Store}, Node: hostname}
+		}
 		s.AddSource(kv)
 		if _, err := s.LoadConfig(); err != nil {
 			fmtlog.Println(err)
@@ -235,7 +239,7 @@ func run(traefikConfiguration *TraefikConfiguration) {
 }
 
 // CreateKvSource creates KvSource
-// TLS support is enable for Consul and ects backends
+// TLS support is enable for Consul and Etcd backends
 func CreateKvSource(traefikConfiguration *TraefikConfiguration) (*staert.KvSource, error) {
 	var kv *staert.KvSource
 	var store store.Store

types/types.go

@@ -3,6 +3,7 @@ package types
 import (
 	"errors"
 	"fmt"
+	"github.com/docker/libkv/store"
 	"github.com/ryanuber/go-glob"
 	"strings"
 )
@@ -192,6 +193,18 @@ func (cs *Constraints) Type() string {
 	return fmt.Sprint("constraint")
 }
 
+// Store holds KV store cluster config
+type Store struct {
+	store.Store
+	Prefix string // like this "prefix" (without the /)
+}
+
+// Cluster holds cluster config
+type Cluster struct {
+	Node  string
+	Store Store
+}
+
 // Auth holds authentication configuration (BASIC, DIGEST, users)
 type Auth struct {
 	Basic  *Basic