diff --git a/vendor/github.com/bsm/sarama-cluster/.gitignore b/vendor/github.com/bsm/sarama-cluster/.gitignore
new file mode 100644
index 0000000..88113c5
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/.gitignore
@@ -0,0 +1,4 @@
+*.log
+*.pid
+kafka*/
+vendor/
diff --git a/vendor/github.com/bsm/sarama-cluster/.travis.yml b/vendor/github.com/bsm/sarama-cluster/.travis.yml
new file mode 100644
index 0000000..07c7c10
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/.travis.yml
@@ -0,0 +1,18 @@
+sudo: false
+language: go
+go:
+  - 1.10.x
+  - 1.9.x
+install:
+  - go get -u github.com/golang/dep/cmd/dep
+  - dep ensure
+env:
+  - SCALA_VERSION=2.12 KAFKA_VERSION=0.11.0.1
+  - SCALA_VERSION=2.12 KAFKA_VERSION=1.0.1
+  - SCALA_VERSION=2.12 KAFKA_VERSION=1.1.0
+script:
+  - make default test-race
+addons:
+  apt:
+    packages:
+      - oracle-java8-set-default
diff --git a/vendor/github.com/bsm/sarama-cluster/Gopkg.lock b/vendor/github.com/bsm/sarama-cluster/Gopkg.lock
new file mode 100644
index 0000000..e1bc110
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/Gopkg.lock
@@ -0,0 +1,151 @@
+# This file is autogenerated, do not edit; changes may be undone by the next 'dep ensure'.
+
+
+[[projects]]
+  name = "github.com/Shopify/sarama"
+  packages = ["."]
+  revision = "35324cf48e33d8260e1c7c18854465a904ade249"
+  version = "v1.17.0"
+
+[[projects]]
+  name = "github.com/davecgh/go-spew"
+  packages = ["spew"]
+  revision = "346938d642f2ec3594ed81d874461961cd0faa76"
+  version = "v1.1.0"
+
+[[projects]]
+  name = "github.com/eapache/go-resiliency"
+  packages = ["breaker"]
+  revision = "ea41b0fad31007accc7f806884dcdf3da98b79ce"
+  version = "v1.1.0"
+
+[[projects]]
+  branch = "master"
+  name = "github.com/eapache/go-xerial-snappy"
+  packages = ["."]
+  revision = "bb955e01b9346ac19dc29eb16586c90ded99a98c"
+
+[[projects]]
+  name = "github.com/eapache/queue"
+  packages = ["."]
+  revision = "44cc805cf13205b55f69e14bcb69867d1ae92f98"
+  version = "v1.1.0"
+
+[[projects]]
+  branch = "master"
+  name = "github.com/golang/snappy"
+  packages = ["."]
+  revision = "2e65f85255dbc3072edf28d6b5b8efc472979f5a"
+
+[[projects]]
+  name = "github.com/onsi/ginkgo"
+  packages = [
+    ".",
+    "config",
+    "extensions/table",
+    "internal/codelocation",
+    "internal/containernode",
+    "internal/failer",
+    "internal/leafnodes",
+    "internal/remote",
+    "internal/spec",
+    "internal/spec_iterator",
+    "internal/specrunner",
+    "internal/suite",
+    "internal/testingtproxy",
+    "internal/writer",
+    "reporters",
+    "reporters/stenographer",
+    "reporters/stenographer/support/go-colorable",
+    "reporters/stenographer/support/go-isatty",
+    "types"
+  ]
+  revision = "fa5fabab2a1bfbd924faf4c067d07ae414e2aedf"
+  version = "v1.5.0"
+
+[[projects]]
+  name = "github.com/onsi/gomega"
+  packages = [
+    ".",
+    "format",
+    "internal/assertion",
+    "internal/asyncassertion",
+    "internal/oraclematcher",
+    "internal/testingtsupport",
+    "matchers",
+    "matchers/support/goraph/bipartitegraph",
+    "matchers/support/goraph/edge",
+    "matchers/support/goraph/node",
+    "matchers/support/goraph/util",
+    "types"
+  ]
+  revision = "62bff4df71bdbc266561a0caee19f0594b17c240"
+  version = "v1.4.0"
+
+[[projects]]
+  name = "github.com/pierrec/lz4"
+  packages = [
+    ".",
+    "internal/xxh32"
+  ]
+  revision = "6b9367c9ff401dbc54fabce3fb8d972e799b702d"
+  version = "v2.0.2"
+
+[[projects]]
+  branch = "master"
+  name = "github.com/rcrowley/go-metrics"
+  packages = ["."]
+  revision = "e2704e165165ec55d062f5919b4b29494e9fa790"
+
+[[projects]]
+  branch = "master"
+  name = "golang.org/x/net"
+  packages = [
+    "html",
+    "html/atom",
+    "html/charset"
+  ]
+  revision = "afe8f62b1d6bbd81f31868121a50b06d8188e1f9"
+
+[[projects]]
+  branch = "master"
+  name = "golang.org/x/sys"
+  packages = ["unix"]
+  revision = "63fc586f45fe72d95d5240a5d5eb95e6503907d3"
+
+[[projects]]
+  name = "golang.org/x/text"
+  packages = [
+    "encoding",
+    "encoding/charmap",
+    "encoding/htmlindex",
+    "encoding/internal",
+    "encoding/internal/identifier",
+    "encoding/japanese",
+    "encoding/korean",
+    "encoding/simplifiedchinese",
+    "encoding/traditionalchinese",
+    "encoding/unicode",
+    "internal/gen",
+    "internal/tag",
+    "internal/utf8internal",
+    "language",
+    "runes",
+    "transform",
+    "unicode/cldr"
+  ]
+  revision = "f21a4dfb5e38f5895301dc265a8def02365cc3d0"
+  version = "v0.3.0"
+
+[[projects]]
+  name = "gopkg.in/yaml.v2"
+  packages = ["."]
+  revision = "5420a8b6744d3b0345ab293f6fcba19c978f1183"
+  version = "v2.2.1"
+
+[solve-meta]
+  analyzer-name = "dep"
+  analyzer-version = 1
+  inputs-digest = "2fa33a2d1ae87e0905ef09332bb4b3fda29179f6bcd48fd3b94070774b9e458b"
+  solver-name = "gps-cdcl"
+  solver-version = 1
diff --git a/vendor/github.com/bsm/sarama-cluster/Gopkg.toml b/vendor/github.com/bsm/sarama-cluster/Gopkg.toml
new file mode 100644
index 0000000..1eecfef
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/Gopkg.toml
@@ -0,0 +1,26 @@
+
+# Gopkg.toml example
+#
+# Refer to https://github.com/golang/dep/blob/master/docs/Gopkg.toml.md
+# for detailed Gopkg.toml documentation.
+#
+# required = ["github.com/user/thing/cmd/thing"]
+# ignored = ["github.com/user/project/pkgX", "bitbucket.org/user/project/pkgA/pkgY"]
+#
+# [[constraint]]
+#   name = "github.com/user/project"
+#   version = "1.0.0"
+#
+# [[constraint]]
+#   name = "github.com/user/project2"
+#   branch = "dev"
+#   source = "github.com/myfork/project2"
+#
+# [[override]]
+#  name = "github.com/x/y"
+#  version = "2.4.0"
+
+
+[[constraint]]
+  name = "github.com/Shopify/sarama"
+  version = "^1.14.0"
diff --git a/vendor/github.com/bsm/sarama-cluster/LICENSE b/vendor/github.com/bsm/sarama-cluster/LICENSE
new file mode 100644
index 0000000..127751c
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2017 Black Square Media Ltd
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/vendor/github.com/bsm/sarama-cluster/Makefile b/vendor/github.com/bsm/sarama-cluster/Makefile
new file mode 100644
index 0000000..25c5bc2
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/Makefile
@@ -0,0 +1,35 @@
+SCALA_VERSION?= 2.12
+KAFKA_VERSION?= 1.1.0
+KAFKA_DIR= kafka_$(SCALA_VERSION)-$(KAFKA_VERSION)
+KAFKA_SRC= https://archive.apache.org/dist/kafka/$(KAFKA_VERSION)/$(KAFKA_DIR).tgz
+KAFKA_ROOT= testdata/$(KAFKA_DIR)
+PKG=$(shell go list ./... | grep -v vendor)
+
+default: vet test
+
+vet:
+	go vet $(PKG)
+
+test: testdeps
+	KAFKA_DIR=$(KAFKA_DIR) go test $(PKG) -ginkgo.slowSpecThreshold=60
+
+test-verbose: testdeps
+	KAFKA_DIR=$(KAFKA_DIR) go test $(PKG) -ginkgo.slowSpecThreshold=60 -v
+
+test-race: testdeps
+	KAFKA_DIR=$(KAFKA_DIR) go test $(PKG) -ginkgo.slowSpecThreshold=60 -v -race
+
+testdeps: $(KAFKA_ROOT)
+
+doc: README.md
+
+.PHONY: test testdeps vet doc
+
+# ---------------------------------------------------------------------
+
+$(KAFKA_ROOT):
+	@mkdir -p $(dir $@)
+	cd $(dir $@) && curl -sSL $(KAFKA_SRC) | tar xz
+
+README.md: README.md.tpl $(wildcard *.go)
+	becca -package $(subst $(GOPATH)/src/,,$(PWD))
diff --git a/vendor/github.com/bsm/sarama-cluster/README.md b/vendor/github.com/bsm/sarama-cluster/README.md
new file mode 100644
index 0000000..ebcd755
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/README.md
@@ -0,0 +1,151 @@
+# Sarama Cluster
+
+[![GoDoc](https://godoc.org/github.com/bsm/sarama-cluster?status.svg)](https://godoc.org/github.com/bsm/sarama-cluster)
+[![Build Status](https://travis-ci.org/bsm/sarama-cluster.svg?branch=master)](https://travis-ci.org/bsm/sarama-cluster)
+[![Go Report Card](https://goreportcard.com/badge/github.com/bsm/sarama-cluster)](https://goreportcard.com/report/github.com/bsm/sarama-cluster)
+[![License](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
+
+Cluster extensions for [Sarama](https://github.com/Shopify/sarama), the Go client library for Apache Kafka 0.9 (and later).
+
+## Documentation
+
+Documentation and example are available via godoc at http://godoc.org/github.com/bsm/sarama-cluster
+
+## Examples
+
+Consumers have two modes of operation. In the default multiplexed mode messages (and errors) of multiple
+topics and partitions are all passed to the single channel:
+
+```go
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+
+	cluster "github.com/bsm/sarama-cluster"
+)
+
+func main() {
+
+	// init (custom) config, enable errors and notifications
+	config := cluster.NewConfig()
+	config.Consumer.Return.Errors = true
+	config.Group.Return.Notifications = true
+
+	// init consumer
+	brokers := []string{"127.0.0.1:9092"}
+	topics := []string{"my_topic", "other_topic"}
+	consumer, err := cluster.NewConsumer(brokers, "my-consumer-group", topics, config)
+	if err != nil {
+		panic(err)
+	}
+	defer consumer.Close()
+
+	// trap SIGINT to trigger a shutdown.
+	signals := make(chan os.Signal, 1)
+	signal.Notify(signals, os.Interrupt)
+
+	// consume errors
+	go func() {
+		for err := range consumer.Errors() {
+			log.Printf("Error: %s\n", err.Error())
+		}
+	}()
+
+	// consume notifications
+	go func() {
+		for ntf := range consumer.Notifications() {
+			log.Printf("Rebalanced: %+v\n", ntf)
+		}
+	}()
+
+	// consume messages, watch signals
+	for {
+		select {
+		case msg, ok := <-consumer.Messages():
+			if ok {
+				fmt.Fprintf(os.Stdout, "%s/%d/%d\t%s\t%s\n", msg.Topic, msg.Partition, msg.Offset, msg.Key, msg.Value)
+				consumer.MarkOffset(msg, "")	// mark message as processed
+			}
+		case <-signals:
+			return
+		}
+	}
+}
+```
+
+Users who require access to individual partitions can use the partitioned mode which exposes access to partition-level
+consumers:
+
+```go
+package main
+
+import (
+  "fmt"
+  "log"
+  "os"
+  "os/signal"
+
+  cluster "github.com/bsm/sarama-cluster"
+)
+
+func main() {
+
+	// init (custom) config, set mode to ConsumerModePartitions
+	config := cluster.NewConfig()
+	config.Group.Mode = cluster.ConsumerModePartitions
+
+	// init consumer
+	brokers := []string{"127.0.0.1:9092"}
+	topics := []string{"my_topic", "other_topic"}
+	consumer, err := cluster.NewConsumer(brokers, "my-consumer-group", topics, config)
+	if err != nil {
+		panic(err)
+	}
+	defer consumer.Close()
+
+	// trap SIGINT to trigger a shutdown.
+	signals := make(chan os.Signal, 1)
+	signal.Notify(signals, os.Interrupt)
+
+	// consume partitions
+	for {
+		select {
+		case part, ok := <-consumer.Partitions():
+			if !ok {
+				return
+			}
+
+			// start a separate goroutine to consume messages
+			go func(pc cluster.PartitionConsumer) {
+				for msg := range pc.Messages() {
+					fmt.Fprintf(os.Stdout, "%s/%d/%d\t%s\t%s\n", msg.Topic, msg.Partition, msg.Offset, msg.Key, msg.Value)
+					consumer.MarkOffset(msg, "")	// mark message as processed
+				}
+			}(part)
+		case <-signals:
+			return
+		}
+	}
+}
+```
+
+## Running tests
+
+You need to install Ginkgo & Gomega to run tests. Please see
+http://onsi.github.io/ginkgo for more details.
+
+To run tests, call:
+
+	$ make test
+
+## Troubleshooting
+
+### Consumer not receiving any messages?
+
+By default, sarama's `Config.Consumer.Offsets.Initial` is set to `sarama.OffsetNewest`. This means that in the event that a brand new consumer is created, and it has never committed any offsets to kafka, it will only receive messages starting from the message after the current one that was written.
+
+If you wish to receive all messages (from the start of all messages in the topic) in the event that a consumer does not have any offsets committed to kafka, you need to set `Config.Consumer.Offsets.Initial` to `sarama.OffsetOldest`.
diff --git a/vendor/github.com/bsm/sarama-cluster/README.md.tpl b/vendor/github.com/bsm/sarama-cluster/README.md.tpl
new file mode 100644
index 0000000..5f63a69
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/README.md.tpl
@@ -0,0 +1,67 @@
+# Sarama Cluster
+
+[![GoDoc](https://godoc.org/github.com/bsm/sarama-cluster?status.svg)](https://godoc.org/github.com/bsm/sarama-cluster)
+[![Build Status](https://travis-ci.org/bsm/sarama-cluster.svg?branch=master)](https://travis-ci.org/bsm/sarama-cluster)
+[![Go Report Card](https://goreportcard.com/badge/github.com/bsm/sarama-cluster)](https://goreportcard.com/report/github.com/bsm/sarama-cluster)
+[![License](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
+
+Cluster extensions for [Sarama](https://github.com/Shopify/sarama), the Go client library for Apache Kafka 0.9 (and later).
+
+## Documentation
+
+Documentation and example are available via godoc at http://godoc.org/github.com/bsm/sarama-cluster
+
+## Examples
+
+Consumers have two modes of operation. In the default multiplexed mode messages (and errors) of multiple
+topics and partitions are all passed to the single channel:
+
+```go
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+
+	cluster "github.com/bsm/sarama-cluster"
+)
+
+func main() {{ "ExampleConsumer" | code }}
+```
+
+Users who require access to individual partitions can use the partitioned mode which exposes access to partition-level
+consumers:
+
+```go
+package main
+
+import (
+  "fmt"
+  "log"
+  "os"
+  "os/signal"
+
+  cluster "github.com/bsm/sarama-cluster"
+)
+
+func main() {{ "ExampleConsumer_Partitions" | code }}
+```
+
+## Running tests
+
+You need to install Ginkgo & Gomega to run tests. Please see
+http://onsi.github.io/ginkgo for more details.
+
+To run tests, call:
+
+	$ make test
+
+## Troubleshooting
+
+### Consumer not receiving any messages?
+
+By default, sarama's `Config.Consumer.Offsets.Initial` is set to `sarama.OffsetNewest`. This means that in the event that a brand new consumer is created, and it has never committed any offsets to kafka, it will only receive messages starting from the message after the current one that was written.
+
+If you wish to receive all messages (from the start of all messages in the topic) in the event that a consumer does not have any offsets committed to kafka, you need to set `Config.Consumer.Offsets.Initial` to `sarama.OffsetOldest`.
diff --git a/vendor/github.com/bsm/sarama-cluster/balancer.go b/vendor/github.com/bsm/sarama-cluster/balancer.go
new file mode 100644
index 0000000..3aeaece
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/balancer.go
@@ -0,0 +1,170 @@
+package cluster
+
+import (
+	"math"
+	"sort"
+
+	"github.com/Shopify/sarama"
+)
+
+// NotificationType defines the type of notification
+type NotificationType uint8
+
+// String describes the notification type
+func (t NotificationType) String() string {
+	switch t {
+	case RebalanceStart:
+		return "rebalance start"
+	case RebalanceOK:
+		return "rebalance OK"
+	case RebalanceError:
+		return "rebalance error"
+	}
+	return "unknown"
+}
+
+const (
+	UnknownNotification NotificationType = iota
+	RebalanceStart
+	RebalanceOK
+	RebalanceError
+)
+
+// Notification are state events emitted by the consumers on rebalance
+type Notification struct {
+	// Type exposes the notification type
+	Type NotificationType
+
+	// Claimed contains topic/partitions that were claimed by this rebalance cycle
+	Claimed map[string][]int32
+
+	// Released contains topic/partitions that were released as part of this rebalance cycle
+	Released map[string][]int32
+
+	// Current are topic/partitions that are currently claimed to the consumer
+	Current map[string][]int32
+}
+
+func newNotification(current map[string][]int32) *Notification {
+	return &Notification{
+		Type:    RebalanceStart,
+		Current: current,
+	}
+}
+
+func (n *Notification) success(current map[string][]int32) *Notification {
+	o := &Notification{
+		Type:     RebalanceOK,
+		Claimed:  make(map[string][]int32),
+		Released: make(map[string][]int32),
+		Current:  current,
+	}
+	for topic, partitions := range current {
+		o.Claimed[topic] = int32Slice(partitions).Diff(int32Slice(n.Current[topic]))
+	}
+	for topic, partitions := range n.Current {
+		o.Released[topic] = int32Slice(partitions).Diff(int32Slice(current[topic]))
+	}
+	return o
+}
+
+// --------------------------------------------------------------------
+
+type topicInfo struct {
+	Partitions []int32
+	MemberIDs  []string
+}
+
+func (info topicInfo) Perform(s Strategy) map[string][]int32 {
+	if s == StrategyRoundRobin {
+		return info.RoundRobin()
+	}
+	return info.Ranges()
+}
+
+func (info topicInfo) Ranges() map[string][]int32 {
+	sort.Strings(info.MemberIDs)
+
+	mlen := len(info.MemberIDs)
+	plen := len(info.Partitions)
+	res := make(map[string][]int32, mlen)
+
+	for pos, memberID := range info.MemberIDs {
+		n, i := float64(plen)/float64(mlen), float64(pos)
+		min := int(math.Floor(i*n + 0.5))
+		max := int(math.Floor((i+1)*n + 0.5))
+		sub := info.Partitions[min:max]
+		if len(sub) > 0 {
+			res[memberID] = sub
+		}
+	}
+	return res
+}
+
+func (info topicInfo) RoundRobin() map[string][]int32 {
+	sort.Strings(info.MemberIDs)
+
+	mlen := len(info.MemberIDs)
+	res := make(map[string][]int32, mlen)
+	for i, pnum := range info.Partitions {
+		memberID := info.MemberIDs[i%mlen]
+		res[memberID] = append(res[memberID], pnum)
+	}
+	return res
+}
+
+// --------------------------------------------------------------------
+
+type balancer struct {
+	client sarama.Client
+	topics map[string]topicInfo
+}
+
+func newBalancerFromMeta(client sarama.Client, members map[string]sarama.ConsumerGroupMemberMetadata) (*balancer, error) {
+	balancer := newBalancer(client)
+	for memberID, meta := range members {
+		for _, topic := range meta.Topics {
+			if err := balancer.Topic(topic, memberID); err != nil {
+				return nil, err
+			}
+		}
+	}
+	return balancer, nil
+}
+
+func newBalancer(client sarama.Client) *balancer {
+	return &balancer{
+		client: client,
+		topics: make(map[string]topicInfo),
+	}
+}
+
+func (r *balancer) Topic(name string, memberID string) error {
+	topic, ok := r.topics[name]
+	if !ok {
+		nums, err := r.client.Partitions(name)
+		if err != nil {
+			return err
+		}
+		topic = topicInfo{
+			Partitions: nums,
+			MemberIDs:  make([]string, 0, 1),
+		}
+	}
+	topic.MemberIDs = append(topic.MemberIDs, memberID)
+	r.topics[name] = topic
+	return nil
+}
+
+func (r *balancer) Perform(s Strategy) map[string]map[string][]int32 {
+	res := make(map[string]map[string][]int32, 1)
+	for topic, info := range r.topics {
+		for memberID, partitions := range info.Perform(s) {
+			if _, ok := res[memberID]; !ok {
+				res[memberID] = make(map[string][]int32, 1)
+			}
+			res[memberID][topic] = partitions
+		}
+	}
+	return res
+}
diff --git a/vendor/github.com/bsm/sarama-cluster/client.go b/vendor/github.com/bsm/sarama-cluster/client.go
new file mode 100644
index 0000000..42ffb30
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/client.go
@@ -0,0 +1,50 @@
+package cluster
+
+import (
+	"errors"
+	"sync/atomic"
+
+	"github.com/Shopify/sarama"
+)
+
+var errClientInUse = errors.New("cluster: client is already used by another consumer")
+
+// Client is a group client
+type Client struct {
+	sarama.Client
+	config Config
+
+	inUse uint32
+}
+
+// NewClient creates a new client instance
+func NewClient(addrs []string, config *Config) (*Client, error) {
+	if config == nil {
+		config = NewConfig()
+	}
+
+	if err := config.Validate(); err != nil {
+		return nil, err
+	}
+
+	client, err := sarama.NewClient(addrs, &config.Config)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Client{Client: client, config: *config}, nil
+}
+
+// ClusterConfig returns the cluster configuration.
+func (c *Client) ClusterConfig() *Config {
+	cfg := c.config
+	return &cfg
+}
+
+func (c *Client) claim() bool {
+	return atomic.CompareAndSwapUint32(&c.inUse, 0, 1)
+}
+
+func (c *Client) release() {
+	atomic.CompareAndSwapUint32(&c.inUse, 1, 0)
+}
diff --git a/vendor/github.com/bsm/sarama-cluster/cluster.go b/vendor/github.com/bsm/sarama-cluster/cluster.go
new file mode 100644
index 0000000..adcf0e9
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/cluster.go
@@ -0,0 +1,25 @@
+package cluster
+
+// Strategy for partition to consumer assignement
+type Strategy string
+
+const (
+	// StrategyRange is the default and assigns partition ranges to consumers.
+	// Example with six partitions and two consumers:
+	//   C1: [0, 1, 2]
+	//   C2: [3, 4, 5]
+	StrategyRange Strategy = "range"
+
+	// StrategyRoundRobin assigns partitions by alternating over consumers.
+	// Example with six partitions and two consumers:
+	//   C1: [0, 2, 4]
+	//   C2: [1, 3, 5]
+	StrategyRoundRobin Strategy = "roundrobin"
+)
+
+// Error instances are wrappers for internal errors with a context and
+// may be returned through the consumer's Errors() channel
+type Error struct {
+	Ctx string
+	error
+}
diff --git a/vendor/github.com/bsm/sarama-cluster/config.go b/vendor/github.com/bsm/sarama-cluster/config.go
new file mode 100644
index 0000000..084b835
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/config.go
@@ -0,0 +1,146 @@
+package cluster
+
+import (
+	"regexp"
+	"time"
+
+	"github.com/Shopify/sarama"
+)
+
+var minVersion = sarama.V0_9_0_0
+
+type ConsumerMode uint8
+
+const (
+	ConsumerModeMultiplex ConsumerMode = iota
+	ConsumerModePartitions
+)
+
+// Config extends sarama.Config with Group specific namespace
+type Config struct {
+	sarama.Config
+
+	// Group is the namespace for group management properties
+	Group struct {
+
+		// The strategy to use for the allocation of partitions to consumers (defaults to StrategyRange)
+		PartitionStrategy Strategy
+
+		// By default, messages and errors from the subscribed topics and partitions are all multiplexed and
+		// made available through the consumer's Messages() and Errors() channels.
+		//
+		// Users who require low-level access can enable ConsumerModePartitions where individual partitions
+		// are exposed on the Partitions() channel. Messages and errors must then be consumed on the partitions
+		// themselves.
+		Mode ConsumerMode
+
+		Offsets struct {
+			Retry struct {
+				// The numer retries when committing offsets (defaults to 3).
+				Max int
+			}
+			Synchronization struct {
+				// The duration allowed for other clients to commit their offsets before resumption in this client, e.g. during a rebalance
+				// NewConfig sets this to the Consumer.MaxProcessingTime duration of the Sarama configuration
+				DwellTime time.Duration
+			}
+		}
+
+		Session struct {
+			// The allowed session timeout for registered consumers (defaults to 30s).
+			// Must be within the allowed server range.
+			Timeout time.Duration
+		}
+
+		Heartbeat struct {
+			// Interval between each heartbeat (defaults to 3s). It should be no more
+			// than 1/3rd of the Group.Session.Timout setting
+			Interval time.Duration
+		}
+
+		// Return specifies which group channels will be populated. If they are set to true,
+		// you must read from the respective channels to prevent deadlock.
+		Return struct {
+			// If enabled, rebalance notification will be returned on the
+			// Notifications channel (default disabled).
+			Notifications bool
+		}
+
+		Topics struct {
+			// An additional whitelist of topics to subscribe to.
+			Whitelist *regexp.Regexp
+			// An additional blacklist of topics to avoid. If set, this will precede over
+			// the Whitelist setting.
+			Blacklist *regexp.Regexp
+		}
+
+		Member struct {
+			// Custom metadata to include when joining the group. The user data for all joined members
+			// can be retrieved by sending a DescribeGroupRequest to the broker that is the
+			// coordinator for the group.
+			UserData []byte
+		}
+	}
+}
+
+// NewConfig returns a new configuration instance with sane defaults.
+func NewConfig() *Config {
+	c := &Config{
+		Config: *sarama.NewConfig(),
+	}
+	c.Group.PartitionStrategy = StrategyRange
+	c.Group.Offsets.Retry.Max = 3
+	c.Group.Offsets.Synchronization.DwellTime = c.Consumer.MaxProcessingTime
+	c.Group.Session.Timeout = 30 * time.Second
+	c.Group.Heartbeat.Interval = 3 * time.Second
+	c.Config.Version = minVersion
+	return c
+}
+
+// Validate checks a Config instance. It will return a
+// sarama.ConfigurationError if the specified values don't make sense.
+func (c *Config) Validate() error {
+	if c.Group.Heartbeat.Interval%time.Millisecond != 0 {
+		sarama.Logger.Println("Group.Heartbeat.Interval only supports millisecond precision; nanoseconds will be truncated.")
+	}
+	if c.Group.Session.Timeout%time.Millisecond != 0 {
+		sarama.Logger.Println("Group.Session.Timeout only supports millisecond precision; nanoseconds will be truncated.")
+	}
+	if c.Group.PartitionStrategy != StrategyRange && c.Group.PartitionStrategy != StrategyRoundRobin {
+		sarama.Logger.Println("Group.PartitionStrategy is not supported; range will be assumed.")
+	}
+	if !c.Version.IsAtLeast(minVersion) {
+		sarama.Logger.Println("Version is not supported; 0.9. will be assumed.")
+		c.Version = minVersion
+	}
+	if err := c.Config.Validate(); err != nil {
+		return err
+	}
+
+	// validate the Group values
+	switch {
+	case c.Group.Offsets.Retry.Max < 0:
+		return sarama.ConfigurationError("Group.Offsets.Retry.Max must be >= 0")
+	case c.Group.Offsets.Synchronization.DwellTime <= 0:
+		return sarama.ConfigurationError("Group.Offsets.Synchronization.DwellTime must be > 0")
+	case c.Group.Offsets.Synchronization.DwellTime > 10*time.Minute:
+		return sarama.ConfigurationError("Group.Offsets.Synchronization.DwellTime must be <= 10m")
+	case c.Group.Heartbeat.Interval <= 0:
+		return sarama.ConfigurationError("Group.Heartbeat.Interval must be > 0")
+	case c.Group.Session.Timeout <= 0:
+		return sarama.ConfigurationError("Group.Session.Timeout must be > 0")
+	case !c.Metadata.Full && c.Group.Topics.Whitelist != nil:
+		return sarama.ConfigurationError("Metadata.Full must be enabled when Group.Topics.Whitelist is used")
+	case !c.Metadata.Full && c.Group.Topics.Blacklist != nil:
+		return sarama.ConfigurationError("Metadata.Full must be enabled when Group.Topics.Blacklist is used")
+	}
+
+	// ensure offset is correct
+	switch c.Consumer.Offsets.Initial {
+	case sarama.OffsetOldest, sarama.OffsetNewest:
+	default:
+		return sarama.ConfigurationError("Consumer.Offsets.Initial must be either OffsetOldest or OffsetNewest")
+	}
+
+	return nil
+}
diff --git a/vendor/github.com/bsm/sarama-cluster/consumer.go b/vendor/github.com/bsm/sarama-cluster/consumer.go
new file mode 100644
index 0000000..e7a67da
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/consumer.go
@@ -0,0 +1,919 @@
+package cluster
+
+import (
+	"sort"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/Shopify/sarama"
+)
+
+// Consumer is a cluster group consumer
+type Consumer struct {
+	client    *Client
+	ownClient bool
+
+	consumer sarama.Consumer
+	subs     *partitionMap
+
+	consumerID string
+	groupID    string
+
+	memberID     string
+	generationID int32
+	membershipMu sync.RWMutex
+
+	coreTopics  []string
+	extraTopics []string
+
+	dying, dead chan none
+	closeOnce   sync.Once
+
+	consuming     int32
+	messages      chan *sarama.ConsumerMessage
+	errors        chan error
+	partitions    chan PartitionConsumer
+	notifications chan *Notification
+
+	commitMu sync.Mutex
+}
+
+// NewConsumer initializes a new consumer
+func NewConsumer(addrs []string, groupID string, topics []string, config *Config) (*Consumer, error) {
+	client, err := NewClient(addrs, config)
+	if err != nil {
+		return nil, err
+	}
+
+	consumer, err := NewConsumerFromClient(client, groupID, topics)
+	if err != nil {
+		return nil, err
+	}
+	consumer.ownClient = true
+	return consumer, nil
+}
+
+// NewConsumerFromClient initializes a new consumer from an existing client.
+//
+// Please note that clients cannot be shared between consumers (due to Kafka internals),
+// they can only be re-used which requires the user to call Close() on the first consumer
+// before using this method again to initialize another one. Attempts to use a client with
+// more than one consumer at a time will return errors.
+func NewConsumerFromClient(client *Client, groupID string, topics []string) (*Consumer, error) {
+	if !client.claim() {
+		return nil, errClientInUse
+	}
+
+	consumer, err := sarama.NewConsumerFromClient(client.Client)
+	if err != nil {
+		client.release()
+		return nil, err
+	}
+
+	sort.Strings(topics)
+	c := &Consumer{
+		client:   client,
+		consumer: consumer,
+		subs:     newPartitionMap(),
+		groupID:  groupID,
+
+		coreTopics: topics,
+
+		dying: make(chan none),
+		dead:  make(chan none),
+
+		messages:      make(chan *sarama.ConsumerMessage),
+		errors:        make(chan error, client.config.ChannelBufferSize),
+		partitions:    make(chan PartitionConsumer, 1),
+		notifications: make(chan *Notification),
+	}
+	if err := c.client.RefreshCoordinator(groupID); err != nil {
+		client.release()
+		return nil, err
+	}
+
+	go c.mainLoop()
+	return c, nil
+}
+
+// Messages returns the read channel for the messages that are returned by
+// the broker.
+//
+// This channel will only return if Config.Group.Mode option is set to
+// ConsumerModeMultiplex (default).
+func (c *Consumer) Messages() <-chan *sarama.ConsumerMessage { return c.messages }
+
+// Partitions returns the read channels for individual partitions of this broker.
+//
+// This will channel will only return if Config.Group.Mode option is set to
+// ConsumerModePartitions.
+//
+// The Partitions() channel must be listened to for the life of this consumer;
+// when a rebalance happens old partitions will be closed (naturally come to
+// completion) and new ones will be emitted. The returned channel will only close
+// when the consumer is completely shut down.
+func (c *Consumer) Partitions() <-chan PartitionConsumer { return c.partitions }
+
+// Errors returns a read channel of errors that occur during offset management, if
+// enabled. By default, errors are logged and not returned over this channel. If
+// you want to implement any custom error handling, set your config's
+// Consumer.Return.Errors setting to true, and read from this channel.
+func (c *Consumer) Errors() <-chan error { return c.errors }
+
+// Notifications returns a channel of Notifications that occur during consumer
+// rebalancing. Notifications will only be emitted over this channel, if your config's
+// Group.Return.Notifications setting to true.
+func (c *Consumer) Notifications() <-chan *Notification { return c.notifications }
+
+// HighWaterMarks returns the current high water marks for each topic and partition
+// Consistency between partitions is not guaranteed since high water marks are updated separately.
+func (c *Consumer) HighWaterMarks() map[string]map[int32]int64 { return c.consumer.HighWaterMarks() }
+
+// MarkOffset marks the provided message as processed, alongside a metadata string
+// that represents the state of the partition consumer at that point in time. The
+// metadata string can be used by another consumer to restore that state, so it
+// can resume consumption.
+//
+// Note: calling MarkOffset does not necessarily commit the offset to the backend
+// store immediately for efficiency reasons, and it may never be committed if
+// your application crashes. This means that you may end up processing the same
+// message twice, and your processing should ideally be idempotent.
+func (c *Consumer) MarkOffset(msg *sarama.ConsumerMessage, metadata string) {
+	if sub := c.subs.Fetch(msg.Topic, msg.Partition); sub != nil {
+		sub.MarkOffset(msg.Offset, metadata)
+	}
+}
+
+// MarkPartitionOffset marks an offset of the provided topic/partition as processed.
+// See MarkOffset for additional explanation.
+func (c *Consumer) MarkPartitionOffset(topic string, partition int32, offset int64, metadata string) {
+	if sub := c.subs.Fetch(topic, partition); sub != nil {
+		sub.MarkOffset(offset, metadata)
+	}
+}
+
+// MarkOffsets marks stashed offsets as processed.
+// See MarkOffset for additional explanation.
+func (c *Consumer) MarkOffsets(s *OffsetStash) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	for tp, info := range s.offsets {
+		if sub := c.subs.Fetch(tp.Topic, tp.Partition); sub != nil {
+			sub.MarkOffset(info.Offset, info.Metadata)
+		}
+		delete(s.offsets, tp)
+	}
+}
+
+// ResetOffsets marks the provided message as processed, alongside a metadata string
+// that represents the state of the partition consumer at that point in time. The
+// metadata string can be used by another consumer to restore that state, so it
+// can resume consumption.
+//
+// Difference between ResetOffset and MarkOffset is that it allows to rewind to an earlier offset
+func (c *Consumer) ResetOffset(msg *sarama.ConsumerMessage, metadata string) {
+	if sub := c.subs.Fetch(msg.Topic, msg.Partition); sub != nil {
+		sub.ResetOffset(msg.Offset, metadata)
+	}
+}
+
+// ResetPartitionOffset marks an offset of the provided topic/partition as processed.
+// See ResetOffset for additional explanation.
+func (c *Consumer) ResetPartitionOffset(topic string, partition int32, offset int64, metadata string) {
+	sub := c.subs.Fetch(topic, partition)
+	if sub != nil {
+		sub.ResetOffset(offset, metadata)
+	}
+}
+
+// ResetOffsets marks stashed offsets as processed.
+// See ResetOffset for additional explanation.
+func (c *Consumer) ResetOffsets(s *OffsetStash) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	for tp, info := range s.offsets {
+		if sub := c.subs.Fetch(tp.Topic, tp.Partition); sub != nil {
+			sub.ResetOffset(info.Offset, info.Metadata)
+		}
+		delete(s.offsets, tp)
+	}
+}
+
+// Subscriptions returns the consumed topics and partitions
+func (c *Consumer) Subscriptions() map[string][]int32 {
+	return c.subs.Info()
+}
+
+// CommitOffsets allows to manually commit previously marked offsets. By default there is no
+// need to call this function as the consumer will commit offsets automatically
+// using the Config.Consumer.Offsets.CommitInterval setting.
+//
+// Please be aware that calling this function during an internal rebalance cycle may return
+// broker errors (e.g. sarama.ErrUnknownMemberId or sarama.ErrIllegalGeneration).
+func (c *Consumer) CommitOffsets() error {
+	c.commitMu.Lock()
+	defer c.commitMu.Unlock()
+
+	memberID, generationID := c.membership()
+	req := &sarama.OffsetCommitRequest{
+		Version:                 2,
+		ConsumerGroup:           c.groupID,
+		ConsumerGroupGeneration: generationID,
+		ConsumerID:              memberID,
+		RetentionTime:           -1,
+	}
+
+	if ns := c.client.config.Consumer.Offsets.Retention; ns != 0 {
+		req.RetentionTime = int64(ns / time.Millisecond)
+	}
+
+	snap := c.subs.Snapshot()
+	dirty := false
+	for tp, state := range snap {
+		if state.Dirty {
+			dirty = true
+			req.AddBlock(tp.Topic, tp.Partition, state.Info.Offset, 0, state.Info.Metadata)
+		}
+	}
+	if !dirty {
+		return nil
+	}
+
+	broker, err := c.client.Coordinator(c.groupID)
+	if err != nil {
+		c.closeCoordinator(broker, err)
+		return err
+	}
+
+	resp, err := broker.CommitOffset(req)
+	if err != nil {
+		c.closeCoordinator(broker, err)
+		return err
+	}
+
+	for topic, errs := range resp.Errors {
+		for partition, kerr := range errs {
+			if kerr != sarama.ErrNoError {
+				err = kerr
+			} else if state, ok := snap[topicPartition{topic, partition}]; ok {
+				if sub := c.subs.Fetch(topic, partition); sub != nil {
+					sub.markCommitted(state.Info.Offset)
+				}
+			}
+		}
+	}
+	return err
+}
+
+// Close safely closes the consumer and releases all resources
+func (c *Consumer) Close() (err error) {
+	c.closeOnce.Do(func() {
+		close(c.dying)
+		<-c.dead
+
+		if e := c.release(); e != nil {
+			err = e
+		}
+		if e := c.consumer.Close(); e != nil {
+			err = e
+		}
+		close(c.messages)
+		close(c.errors)
+
+		if e := c.leaveGroup(); e != nil {
+			err = e
+		}
+		close(c.partitions)
+		close(c.notifications)
+
+		// drain
+		for range c.messages {
+		}
+		for range c.errors {
+		}
+		for p := range c.partitions {
+			_ = p.Close()
+		}
+		for range c.notifications {
+		}
+
+		c.client.release()
+		if c.ownClient {
+			if e := c.client.Close(); e != nil {
+				err = e
+			}
+		}
+	})
+	return
+}
+
+func (c *Consumer) mainLoop() {
+	defer close(c.dead)
+	defer atomic.StoreInt32(&c.consuming, 0)
+
+	for {
+		atomic.StoreInt32(&c.consuming, 0)
+
+		// Check if close was requested
+		select {
+		case <-c.dying:
+			return
+		default:
+		}
+
+		// Start next consume cycle
+		c.nextTick()
+	}
+}
+
+func (c *Consumer) nextTick() {
+	// Remember previous subscriptions
+	var notification *Notification
+	if c.client.config.Group.Return.Notifications {
+		notification = newNotification(c.subs.Info())
+	}
+
+	// Refresh coordinator
+	if err := c.refreshCoordinator(); err != nil {
+		c.rebalanceError(err, nil)
+		return
+	}
+
+	// Release subscriptions
+	if err := c.release(); err != nil {
+		c.rebalanceError(err, nil)
+		return
+	}
+
+	// Issue rebalance start notification
+	if c.client.config.Group.Return.Notifications {
+		c.handleNotification(notification)
+	}
+
+	// Rebalance, fetch new subscriptions
+	subs, err := c.rebalance()
+	if err != nil {
+		c.rebalanceError(err, notification)
+		return
+	}
+
+	// Coordinate loops, make sure everything is
+	// stopped on exit
+	tomb := newLoopTomb()
+	defer tomb.Close()
+
+	// Start the heartbeat
+	tomb.Go(c.hbLoop)
+
+	// Subscribe to topic/partitions
+	if err := c.subscribe(tomb, subs); err != nil {
+		c.rebalanceError(err, notification)
+		return
+	}
+
+	// Update/issue notification with new claims
+	if c.client.config.Group.Return.Notifications {
+		notification = notification.success(subs)
+		c.handleNotification(notification)
+	}
+
+	// Start topic watcher loop
+	tomb.Go(c.twLoop)
+
+	// Start consuming and committing offsets
+	tomb.Go(c.cmLoop)
+	atomic.StoreInt32(&c.consuming, 1)
+
+	// Wait for signals
+	select {
+	case <-tomb.Dying():
+	case <-c.dying:
+	}
+}
+
+// heartbeat loop, triggered by the mainLoop
+func (c *Consumer) hbLoop(stopped <-chan none) {
+	ticker := time.NewTicker(c.client.config.Group.Heartbeat.Interval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ticker.C:
+			switch err := c.heartbeat(); err {
+			case nil, sarama.ErrNoError:
+			case sarama.ErrNotCoordinatorForConsumer, sarama.ErrRebalanceInProgress:
+				return
+			default:
+				c.handleError(&Error{Ctx: "heartbeat", error: err})
+				return
+			}
+		case <-stopped:
+			return
+		case <-c.dying:
+			return
+		}
+	}
+}
+
+// topic watcher loop, triggered by the mainLoop
+func (c *Consumer) twLoop(stopped <-chan none) {
+	ticker := time.NewTicker(c.client.config.Metadata.RefreshFrequency / 2)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ticker.C:
+			topics, err := c.client.Topics()
+			if err != nil {
+				c.handleError(&Error{Ctx: "topics", error: err})
+				return
+			}
+
+			for _, topic := range topics {
+				if !c.isKnownCoreTopic(topic) &&
+					!c.isKnownExtraTopic(topic) &&
+					c.isPotentialExtraTopic(topic) {
+					return
+				}
+			}
+		case <-stopped:
+			return
+		case <-c.dying:
+			return
+		}
+	}
+}
+
+// commit loop, triggered by the mainLoop
+func (c *Consumer) cmLoop(stopped <-chan none) {
+	ticker := time.NewTicker(c.client.config.Consumer.Offsets.CommitInterval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ticker.C:
+			if err := c.commitOffsetsWithRetry(c.client.config.Group.Offsets.Retry.Max); err != nil {
+				c.handleError(&Error{Ctx: "commit", error: err})
+				return
+			}
+		case <-stopped:
+			return
+		case <-c.dying:
+			return
+		}
+	}
+}
+
+func (c *Consumer) rebalanceError(err error, n *Notification) {
+	if n != nil {
+		n.Type = RebalanceError
+		c.handleNotification(n)
+	}
+
+	switch err {
+	case sarama.ErrRebalanceInProgress:
+	default:
+		c.handleError(&Error{Ctx: "rebalance", error: err})
+	}
+
+	select {
+	case <-c.dying:
+	case <-time.After(c.client.config.Metadata.Retry.Backoff):
+	}
+}
+
+func (c *Consumer) handleNotification(n *Notification) {
+	if c.client.config.Group.Return.Notifications {
+		select {
+		case c.notifications <- n:
+		case <-c.dying:
+			return
+		}
+	}
+}
+
+func (c *Consumer) handleError(e *Error) {
+	if c.client.config.Consumer.Return.Errors {
+		select {
+		case c.errors <- e:
+		case <-c.dying:
+			return
+		}
+	} else {
+		sarama.Logger.Printf("%s error: %s\n", e.Ctx, e.Error())
+	}
+}
+
+// Releases the consumer and commits offsets, called from rebalance() and Close()
+func (c *Consumer) release() (err error) {
+	// Stop all consumers
+	c.subs.Stop()
+
+	// Clear subscriptions on exit
+	defer c.subs.Clear()
+
+	// Wait for messages to be processed
+	timeout := time.NewTimer(c.client.config.Group.Offsets.Synchronization.DwellTime)
+	defer timeout.Stop()
+
+	select {
+	case <-c.dying:
+	case <-timeout.C:
+	}
+
+	// Commit offsets, continue on errors
+	if e := c.commitOffsetsWithRetry(c.client.config.Group.Offsets.Retry.Max); e != nil {
+		err = e
+	}
+
+	return
+}
+
+// --------------------------------------------------------------------
+
+// Performs a heartbeat, part of the mainLoop()
+func (c *Consumer) heartbeat() error {
+	broker, err := c.client.Coordinator(c.groupID)
+	if err != nil {
+		c.closeCoordinator(broker, err)
+		return err
+	}
+
+	memberID, generationID := c.membership()
+	resp, err := broker.Heartbeat(&sarama.HeartbeatRequest{
+		GroupId:      c.groupID,
+		MemberId:     memberID,
+		GenerationId: generationID,
+	})
+	if err != nil {
+		c.closeCoordinator(broker, err)
+		return err
+	}
+	return resp.Err
+}
+
+// Performs a rebalance, part of the mainLoop()
+func (c *Consumer) rebalance() (map[string][]int32, error) {
+	memberID, _ := c.membership()
+	sarama.Logger.Printf("cluster/consumer %s rebalance\n", memberID)
+
+	allTopics, err := c.client.Topics()
+	if err != nil {
+		return nil, err
+	}
+	c.extraTopics = c.selectExtraTopics(allTopics)
+	sort.Strings(c.extraTopics)
+
+	// Re-join consumer group
+	strategy, err := c.joinGroup()
+	switch {
+	case err == sarama.ErrUnknownMemberId:
+		c.membershipMu.Lock()
+		c.memberID = ""
+		c.membershipMu.Unlock()
+		return nil, err
+	case err != nil:
+		return nil, err
+	}
+
+	// Sync consumer group state, fetch subscriptions
+	subs, err := c.syncGroup(strategy)
+	switch {
+	case err == sarama.ErrRebalanceInProgress:
+		return nil, err
+	case err != nil:
+		_ = c.leaveGroup()
+		return nil, err
+	}
+	return subs, nil
+}
+
+// Performs the subscription, part of the mainLoop()
+func (c *Consumer) subscribe(tomb *loopTomb, subs map[string][]int32) error {
+	// fetch offsets
+	offsets, err := c.fetchOffsets(subs)
+	if err != nil {
+		_ = c.leaveGroup()
+		return err
+	}
+
+	// create consumers in parallel
+	var mu sync.Mutex
+	var wg sync.WaitGroup
+
+	for topic, partitions := range subs {
+		for _, partition := range partitions {
+			wg.Add(1)
+
+			info := offsets[topic][partition]
+			go func(topic string, partition int32) {
+				if e := c.createConsumer(tomb, topic, partition, info); e != nil {
+					mu.Lock()
+					err = e
+					mu.Unlock()
+				}
+				wg.Done()
+			}(topic, partition)
+		}
+	}
+	wg.Wait()
+
+	if err != nil {
+		_ = c.release()
+		_ = c.leaveGroup()
+	}
+	return err
+}
+
+// --------------------------------------------------------------------
+
+// Send a request to the broker to join group on rebalance()
+func (c *Consumer) joinGroup() (*balancer, error) {
+	memberID, _ := c.membership()
+	req := &sarama.JoinGroupRequest{
+		GroupId:        c.groupID,
+		MemberId:       memberID,
+		SessionTimeout: int32(c.client.config.Group.Session.Timeout / time.Millisecond),
+		ProtocolType:   "consumer",
+	}
+
+	meta := &sarama.ConsumerGroupMemberMetadata{
+		Version:  1,
+		Topics:   append(c.coreTopics, c.extraTopics...),
+		UserData: c.client.config.Group.Member.UserData,
+	}
+	err := req.AddGroupProtocolMetadata(string(StrategyRange), meta)
+	if err != nil {
+		return nil, err
+	}
+	err = req.AddGroupProtocolMetadata(string(StrategyRoundRobin), meta)
+	if err != nil {
+		return nil, err
+	}
+
+	broker, err := c.client.Coordinator(c.groupID)
+	if err != nil {
+		c.closeCoordinator(broker, err)
+		return nil, err
+	}
+
+	resp, err := broker.JoinGroup(req)
+	if err != nil {
+		c.closeCoordinator(broker, err)
+		return nil, err
+	} else if resp.Err != sarama.ErrNoError {
+		c.closeCoordinator(broker, resp.Err)
+		return nil, resp.Err
+	}
+
+	var strategy *balancer
+	if resp.LeaderId == resp.MemberId {
+		members, err := resp.GetMembers()
+		if err != nil {
+			return nil, err
+		}
+
+		strategy, err = newBalancerFromMeta(c.client, members)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	c.membershipMu.Lock()
+	c.memberID = resp.MemberId
+	c.generationID = resp.GenerationId
+	c.membershipMu.Unlock()
+
+	return strategy, nil
+}
+
+// Send a request to the broker to sync the group on rebalance().
+// Returns a list of topics and partitions to consume.
+func (c *Consumer) syncGroup(strategy *balancer) (map[string][]int32, error) {
+	memberID, generationID := c.membership()
+	req := &sarama.SyncGroupRequest{
+		GroupId:      c.groupID,
+		MemberId:     memberID,
+		GenerationId: generationID,
+	}
+
+	if strategy != nil {
+		for memberID, topics := range strategy.Perform(c.client.config.Group.PartitionStrategy) {
+			if err := req.AddGroupAssignmentMember(memberID, &sarama.ConsumerGroupMemberAssignment{
+				Topics: topics,
+			}); err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	broker, err := c.client.Coordinator(c.groupID)
+	if err != nil {
+		c.closeCoordinator(broker, err)
+		return nil, err
+	}
+
+	resp, err := broker.SyncGroup(req)
+	if err != nil {
+		c.closeCoordinator(broker, err)
+		return nil, err
+	} else if resp.Err != sarama.ErrNoError {
+		c.closeCoordinator(broker, resp.Err)
+		return nil, resp.Err
+	}
+
+	// Return if there is nothing to subscribe to
+	if len(resp.MemberAssignment) == 0 {
+		return nil, nil
+	}
+
+	// Get assigned subscriptions
+	members, err := resp.GetMemberAssignment()
+	if err != nil {
+		return nil, err
+	}
+
+	// Sort partitions, for each topic
+	for topic := range members.Topics {
+		sort.Sort(int32Slice(members.Topics[topic]))
+	}
+	return members.Topics, nil
+}
+
+// Fetches latest committed offsets for all subscriptions
+func (c *Consumer) fetchOffsets(subs map[string][]int32) (map[string]map[int32]offsetInfo, error) {
+	offsets := make(map[string]map[int32]offsetInfo, len(subs))
+	req := &sarama.OffsetFetchRequest{
+		Version:       1,
+		ConsumerGroup: c.groupID,
+	}
+
+	for topic, partitions := range subs {
+		offsets[topic] = make(map[int32]offsetInfo, len(partitions))
+		for _, partition := range partitions {
+			offsets[topic][partition] = offsetInfo{Offset: -1}
+			req.AddPartition(topic, partition)
+		}
+	}
+
+	broker, err := c.client.Coordinator(c.groupID)
+	if err != nil {
+		c.closeCoordinator(broker, err)
+		return nil, err
+	}
+
+	resp, err := broker.FetchOffset(req)
+	if err != nil {
+		c.closeCoordinator(broker, err)
+		return nil, err
+	}
+
+	for topic, partitions := range subs {
+		for _, partition := range partitions {
+			block := resp.GetBlock(topic, partition)
+			if block == nil {
+				return nil, sarama.ErrIncompleteResponse
+			}
+
+			if block.Err == sarama.ErrNoError {
+				offsets[topic][partition] = offsetInfo{Offset: block.Offset, Metadata: block.Metadata}
+			} else {
+				return nil, block.Err
+			}
+		}
+	}
+	return offsets, nil
+}
+
+// Send a request to the broker to leave the group on failes rebalance() and on Close()
+func (c *Consumer) leaveGroup() error {
+	broker, err := c.client.Coordinator(c.groupID)
+	if err != nil {
+		c.closeCoordinator(broker, err)
+		return err
+	}
+
+	memberID, _ := c.membership()
+	if _, err = broker.LeaveGroup(&sarama.LeaveGroupRequest{
+		GroupId:  c.groupID,
+		MemberId: memberID,
+	}); err != nil {
+		c.closeCoordinator(broker, err)
+	}
+	return err
+}
+
+// --------------------------------------------------------------------
+
+func (c *Consumer) createConsumer(tomb *loopTomb, topic string, partition int32, info offsetInfo) error {
+	memberID, _ := c.membership()
+	sarama.Logger.Printf("cluster/consumer %s consume %s/%d from %d\n", memberID, topic, partition, info.NextOffset(c.client.config.Consumer.Offsets.Initial))
+
+	// Create partitionConsumer
+	pc, err := newPartitionConsumer(c.consumer, topic, partition, info, c.client.config.Consumer.Offsets.Initial)
+	if err != nil {
+		return err
+	}
+
+	// Store in subscriptions
+	c.subs.Store(topic, partition, pc)
+
+	// Start partition consumer goroutine
+	tomb.Go(func(stopper <-chan none) {
+		if c.client.config.Group.Mode == ConsumerModePartitions {
+			pc.waitFor(stopper, c.errors)
+		} else {
+			pc.multiplex(stopper, c.messages, c.errors)
+		}
+	})
+
+	if c.client.config.Group.Mode == ConsumerModePartitions {
+		c.partitions <- pc
+	}
+	return nil
+}
+
+func (c *Consumer) commitOffsetsWithRetry(retries int) error {
+	err := c.CommitOffsets()
+	if err != nil && retries > 0 {
+		return c.commitOffsetsWithRetry(retries - 1)
+	}
+	return err
+}
+
+func (c *Consumer) closeCoordinator(broker *sarama.Broker, err error) {
+	if broker != nil {
+		_ = broker.Close()
+	}
+
+	switch err {
+	case sarama.ErrConsumerCoordinatorNotAvailable, sarama.ErrNotCoordinatorForConsumer:
+		_ = c.client.RefreshCoordinator(c.groupID)
+	}
+}
+
+func (c *Consumer) selectExtraTopics(allTopics []string) []string {
+	extra := allTopics[:0]
+	for _, topic := range allTopics {
+		if !c.isKnownCoreTopic(topic) && c.isPotentialExtraTopic(topic) {
+			extra = append(extra, topic)
+		}
+	}
+	return extra
+}
+
+func (c *Consumer) isKnownCoreTopic(topic string) bool {
+	pos := sort.SearchStrings(c.coreTopics, topic)
+	return pos < len(c.coreTopics) && c.coreTopics[pos] == topic
+}
+
+func (c *Consumer) isKnownExtraTopic(topic string) bool {
+	pos := sort.SearchStrings(c.extraTopics, topic)
+	return pos < len(c.extraTopics) && c.extraTopics[pos] == topic
+}
+
+func (c *Consumer) isPotentialExtraTopic(topic string) bool {
+	rx := c.client.config.Group.Topics
+	if rx.Blacklist != nil && rx.Blacklist.MatchString(topic) {
+		return false
+	}
+	if rx.Whitelist != nil && rx.Whitelist.MatchString(topic) {
+		return true
+	}
+	return false
+}
+
+func (c *Consumer) refreshCoordinator() error {
+	if err := c.refreshMetadata(); err != nil {
+		return err
+	}
+	return c.client.RefreshCoordinator(c.groupID)
+}
+
+func (c *Consumer) refreshMetadata() (err error) {
+	if c.client.config.Metadata.Full {
+		err = c.client.RefreshMetadata()
+	} else {
+		var topics []string
+		if topics, err = c.client.Topics(); err == nil && len(topics) != 0 {
+			err = c.client.RefreshMetadata(topics...)
+		}
+	}
+
+	// maybe we didn't have authorization to describe all topics
+	switch err {
+	case sarama.ErrTopicAuthorizationFailed:
+		err = c.client.RefreshMetadata(c.coreTopics...)
+	}
+	return
+}
+
+func (c *Consumer) membership() (memberID string, generationID int32) {
+	c.membershipMu.RLock()
+	memberID, generationID = c.memberID, c.generationID
+	c.membershipMu.RUnlock()
+	return
+}
diff --git a/vendor/github.com/bsm/sarama-cluster/doc.go b/vendor/github.com/bsm/sarama-cluster/doc.go
new file mode 100644
index 0000000..9c8ff16
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/doc.go
@@ -0,0 +1,8 @@
+/*
+Package cluster provides cluster extensions for Sarama, enabing users
+to consume topics across from multiple, balanced nodes.
+
+It requires Kafka v0.9+ and follows the steps guide, described in:
+https://cwiki.apache.org/confluence/display/KAFKA/Kafka+0.9+Consumer+Rewrite+Design
+*/
+package cluster
diff --git a/vendor/github.com/bsm/sarama-cluster/offsets.go b/vendor/github.com/bsm/sarama-cluster/offsets.go
new file mode 100644
index 0000000..4223ac5
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/offsets.go
@@ -0,0 +1,69 @@
+package cluster
+
+import (
+	"sync"
+
+	"github.com/Shopify/sarama"
+)
+
+// OffsetStash allows to accumulate offsets and
+// mark them as processed in a bulk
+type OffsetStash struct {
+	offsets map[topicPartition]offsetInfo
+	mu      sync.Mutex
+}
+
+// NewOffsetStash inits a blank stash
+func NewOffsetStash() *OffsetStash {
+	return &OffsetStash{offsets: make(map[topicPartition]offsetInfo)}
+}
+
+// MarkOffset stashes the provided message offset
+func (s *OffsetStash) MarkOffset(msg *sarama.ConsumerMessage, metadata string) {
+	s.MarkPartitionOffset(msg.Topic, msg.Partition, msg.Offset, metadata)
+}
+
+// MarkPartitionOffset stashes the offset for the provided topic/partition combination
+func (s *OffsetStash) MarkPartitionOffset(topic string, partition int32, offset int64, metadata string) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	key := topicPartition{Topic: topic, Partition: partition}
+	if info := s.offsets[key]; offset >= info.Offset {
+		info.Offset = offset
+		info.Metadata = metadata
+		s.offsets[key] = info
+	}
+}
+
+// ResetPartitionOffset stashes the offset for the provided topic/partition combination.
+// Difference between ResetPartitionOffset and MarkPartitionOffset is that, ResetPartitionOffset supports earlier offsets
+func (s *OffsetStash) ResetPartitionOffset(topic string, partition int32, offset int64, metadata string) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	key := topicPartition{Topic: topic, Partition: partition}
+	if info := s.offsets[key]; offset <= info.Offset {
+		info.Offset = offset
+		info.Metadata = metadata
+		s.offsets[key] = info
+	}
+}
+
+// ResetOffset stashes the provided message offset
+// See ResetPartitionOffset for explanation
+func (s *OffsetStash) ResetOffset(msg *sarama.ConsumerMessage, metadata string) {
+	s.ResetPartitionOffset(msg.Topic, msg.Partition, msg.Offset, metadata)
+}
+
+// Offsets returns the latest stashed offsets by topic-partition
+func (s *OffsetStash) Offsets() map[string]int64 {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	res := make(map[string]int64, len(s.offsets))
+	for tp, info := range s.offsets {
+		res[tp.String()] = info.Offset
+	}
+	return res
+}
diff --git a/vendor/github.com/bsm/sarama-cluster/partitions.go b/vendor/github.com/bsm/sarama-cluster/partitions.go
new file mode 100644
index 0000000..bfaa587
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/partitions.go
@@ -0,0 +1,290 @@
+package cluster
+
+import (
+	"sort"
+	"sync"
+	"time"
+
+	"github.com/Shopify/sarama"
+)
+
+// PartitionConsumer allows code to consume individual partitions from the cluster.
+//
+// See docs for Consumer.Partitions() for more on how to implement this.
+type PartitionConsumer interface {
+	sarama.PartitionConsumer
+
+	// Topic returns the consumed topic name
+	Topic() string
+
+	// Partition returns the consumed partition
+	Partition() int32
+
+	// InitialOffset returns the offset used for creating the PartitionConsumer instance.
+	// The returned offset can be a literal offset, or OffsetNewest, or OffsetOldest
+	InitialOffset() int64
+  
+	// MarkOffset marks the offset of a message as preocessed.
+	MarkOffset(offset int64, metadata string)
+
+	// ResetOffset resets the offset to a previously processed message.
+	ResetOffset(offset int64, metadata string)
+}
+
+type partitionConsumer struct {
+	sarama.PartitionConsumer
+
+	state partitionState
+	mu    sync.Mutex
+
+	topic         string
+	partition     int32
+	initialOffset int64
+
+	closeOnce sync.Once
+	closeErr  error
+
+	dying, dead chan none
+}
+
+func newPartitionConsumer(manager sarama.Consumer, topic string, partition int32, info offsetInfo, defaultOffset int64) (*partitionConsumer, error) {
+	offset := info.NextOffset(defaultOffset)
+	pcm, err := manager.ConsumePartition(topic, partition, offset)
+
+	// Resume from default offset, if requested offset is out-of-range
+	if err == sarama.ErrOffsetOutOfRange {
+		info.Offset = -1
+		offset = defaultOffset
+		pcm, err = manager.ConsumePartition(topic, partition, offset)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return &partitionConsumer{
+		PartitionConsumer: pcm,
+		state:             partitionState{Info: info},
+
+		topic:         topic,
+		partition:     partition,
+		initialOffset: offset,
+
+		dying: make(chan none),
+		dead:  make(chan none),
+	}, nil
+}
+
+// Topic implements PartitionConsumer
+func (c *partitionConsumer) Topic() string { return c.topic }
+
+// Partition implements PartitionConsumer
+func (c *partitionConsumer) Partition() int32 { return c.partition }
+
+// InitialOffset implements PartitionConsumer
+func (c *partitionConsumer) InitialOffset() int64 { return c.initialOffset }
+
+// AsyncClose implements PartitionConsumer
+func (c *partitionConsumer) AsyncClose() {
+	c.closeOnce.Do(func() {
+		c.closeErr = c.PartitionConsumer.Close()
+		close(c.dying)
+	})
+}
+
+// Close implements PartitionConsumer
+func (c *partitionConsumer) Close() error {
+	c.AsyncClose()
+	<-c.dead
+	return c.closeErr
+}
+
+func (c *partitionConsumer) waitFor(stopper <-chan none, errors chan<- error) {
+	defer close(c.dead)
+
+	for {
+		select {
+		case err, ok := <-c.Errors():
+			if !ok {
+				return
+			}
+			select {
+			case errors <- err:
+			case <-stopper:
+				return
+			case <-c.dying:
+				return
+			}
+		case <-stopper:
+			return
+		case <-c.dying:
+			return
+		}
+	}
+}
+
+func (c *partitionConsumer) multiplex(stopper <-chan none, messages chan<- *sarama.ConsumerMessage, errors chan<- error) {
+	defer close(c.dead)
+
+	for {
+		select {
+		case msg, ok := <-c.Messages():
+			if !ok {
+				return
+			}
+			select {
+			case messages <- msg:
+			case <-stopper:
+				return
+			case <-c.dying:
+				return
+			}
+		case err, ok := <-c.Errors():
+			if !ok {
+				return
+			}
+			select {
+			case errors <- err:
+			case <-stopper:
+				return
+			case <-c.dying:
+				return
+			}
+		case <-stopper:
+			return
+		case <-c.dying:
+			return
+		}
+	}
+}
+
+func (c *partitionConsumer) getState() partitionState {
+	c.mu.Lock()
+	state := c.state
+	c.mu.Unlock()
+
+	return state
+}
+
+func (c *partitionConsumer) markCommitted(offset int64) {
+	c.mu.Lock()
+	if offset == c.state.Info.Offset {
+		c.state.Dirty = false
+	}
+	c.mu.Unlock()
+}
+
+// MarkOffset implements PartitionConsumer
+func (c *partitionConsumer) MarkOffset(offset int64, metadata string) {
+	c.mu.Lock()
+	if next := offset + 1; next > c.state.Info.Offset {
+		c.state.Info.Offset = next
+		c.state.Info.Metadata = metadata
+		c.state.Dirty = true
+	}
+	c.mu.Unlock()
+}
+
+// ResetOffset implements PartitionConsumer
+func (c *partitionConsumer) ResetOffset(offset int64, metadata string) {
+	c.mu.Lock()
+	if next := offset + 1; next <= c.state.Info.Offset {
+		c.state.Info.Offset = next
+		c.state.Info.Metadata = metadata
+		c.state.Dirty = true
+	}
+	c.mu.Unlock()
+}
+
+// --------------------------------------------------------------------
+
+type partitionState struct {
+	Info       offsetInfo
+	Dirty      bool
+	LastCommit time.Time
+}
+
+// --------------------------------------------------------------------
+
+type partitionMap struct {
+	data map[topicPartition]*partitionConsumer
+	mu   sync.RWMutex
+}
+
+func newPartitionMap() *partitionMap {
+	return &partitionMap{
+		data: make(map[topicPartition]*partitionConsumer),
+	}
+}
+
+func (m *partitionMap) IsSubscribedTo(topic string) bool {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	for tp := range m.data {
+		if tp.Topic == topic {
+			return true
+		}
+	}
+	return false
+}
+
+func (m *partitionMap) Fetch(topic string, partition int32) *partitionConsumer {
+	m.mu.RLock()
+	pc, _ := m.data[topicPartition{topic, partition}]
+	m.mu.RUnlock()
+	return pc
+}
+
+func (m *partitionMap) Store(topic string, partition int32, pc *partitionConsumer) {
+	m.mu.Lock()
+	m.data[topicPartition{topic, partition}] = pc
+	m.mu.Unlock()
+}
+
+func (m *partitionMap) Snapshot() map[topicPartition]partitionState {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	snap := make(map[topicPartition]partitionState, len(m.data))
+	for tp, pc := range m.data {
+		snap[tp] = pc.getState()
+	}
+	return snap
+}
+
+func (m *partitionMap) Stop() {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	var wg sync.WaitGroup
+	for tp := range m.data {
+		wg.Add(1)
+		go func(p *partitionConsumer) {
+			_ = p.Close()
+			wg.Done()
+		}(m.data[tp])
+	}
+	wg.Wait()
+}
+
+func (m *partitionMap) Clear() {
+	m.mu.Lock()
+	for tp := range m.data {
+		delete(m.data, tp)
+	}
+	m.mu.Unlock()
+}
+
+func (m *partitionMap) Info() map[string][]int32 {
+	info := make(map[string][]int32)
+	m.mu.RLock()
+	for tp := range m.data {
+		info[tp.Topic] = append(info[tp.Topic], tp.Partition)
+	}
+	m.mu.RUnlock()
+
+	for topic := range info {
+		sort.Sort(int32Slice(info[topic]))
+	}
+	return info
+}
diff --git a/vendor/github.com/bsm/sarama-cluster/util.go b/vendor/github.com/bsm/sarama-cluster/util.go
new file mode 100644
index 0000000..e7cb5dd
--- /dev/null
+++ b/vendor/github.com/bsm/sarama-cluster/util.go
@@ -0,0 +1,75 @@
+package cluster
+
+import (
+	"fmt"
+	"sort"
+	"sync"
+)
+
+type none struct{}
+
+type topicPartition struct {
+	Topic     string
+	Partition int32
+}
+
+func (tp *topicPartition) String() string {
+	return fmt.Sprintf("%s-%d", tp.Topic, tp.Partition)
+}
+
+type offsetInfo struct {
+	Offset   int64
+	Metadata string
+}
+
+func (i offsetInfo) NextOffset(fallback int64) int64 {
+	if i.Offset > -1 {
+		return i.Offset
+	}
+	return fallback
+}
+
+type int32Slice []int32
+
+func (p int32Slice) Len() int           { return len(p) }
+func (p int32Slice) Less(i, j int) bool { return p[i] < p[j] }
+func (p int32Slice) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+
+func (p int32Slice) Diff(o int32Slice) (res []int32) {
+	on := len(o)
+	for _, x := range p {
+		n := sort.Search(on, func(i int) bool { return o[i] >= x })
+		if n < on && o[n] == x {
+			continue
+		}
+		res = append(res, x)
+	}
+	return
+}
+
+// --------------------------------------------------------------------
+
+type loopTomb struct {
+	c chan none
+	o sync.Once
+	w sync.WaitGroup
+}
+
+func newLoopTomb() *loopTomb {
+	return &loopTomb{c: make(chan none)}
+}
+
+func (t *loopTomb) stop()  { t.o.Do(func() { close(t.c) }) }
+func (t *loopTomb) Close() { t.stop(); t.w.Wait() }
+
+func (t *loopTomb) Dying() <-chan none { return t.c }
+func (t *loopTomb) Go(f func(<-chan none)) {
+	t.w.Add(1)
+
+	go func() {
+		defer t.stop()
+		defer t.w.Done()
+
+		f(t.c)
+	}()
+}