fixup group lag metric

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

broker.go

@@ -7,7 +7,7 @@ import (
 	"time"
 
 	"github.com/twmb/franz-go/pkg/kgo"
-	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v4/logger"
 )
 
 type hookEvent struct {

carrier.go

@@ -6,7 +6,7 @@ import (
 	"strings"
 
 	"github.com/twmb/franz-go/pkg/kgo"
-	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/metadata"
 )
 
 // RecordCarrier injects and extracts traces from a kgo.Record.
@@ -77,7 +77,7 @@ loop:
 		for i := 0; i < len(r.Headers); i++ {
 			if strings.EqualFold(r.Headers[i].Key, k) {
 				// Key exist, update the value.
-				r.Headers[i].Value = []byte(v)
+				r.Headers[i].Value = []byte(strings.Join(v, ","))
 				continue loop
 			}
 		}
@@ -85,7 +85,7 @@ loop:
 		// Key does not exist, append new header.
 		r.Headers = append(r.Headers, kgo.RecordHeader{
 			Key:   k,
-			Value: []byte(v),
+			Value: []byte(strings.Join(v, ",")),
 		})
 
 		seen[k] = struct{}{}

event.go

@@ -1,50 +0,0 @@
-package kgo
-
-import (
-	"context"
-	"sync"
-
-	"go.unistack.org/micro/v3/broker"
-)
-
-type event struct {
-	msg *broker.Message
-	err error
-	ctx context.Context
-
-	topic string
-
-	sync.RWMutex
-	ack bool
-}
-
-func (p *event) Context() context.Context {
-	return p.ctx
-}
-
-func (p *event) Topic() string {
-	return p.topic
-}
-
-func (p *event) Message() *broker.Message {
-	return p.msg
-}
-
-func (p *event) Ack() error {
-	p.ack = true
-	return nil
-}
-
-func (p *event) Error() error {
-	return p.err
-}
-
-func (p *event) SetError(err error) {
-	p.err = err
-}
-
-var eventPool = sync.Pool{
-	New: func() interface{} {
-		return &event{msg: &broker.Message{}}
-	},
-}

go.mod

@@ -1,27 +1,24 @@
-module go.unistack.org/micro-broker-kgo/v3
+module go.unistack.org/micro-broker-kgo/v4
 
 go 1.23.0
 
 require (
-	github.com/google/uuid v1.6.0
 	github.com/twmb/franz-go v1.18.1
 	github.com/twmb/franz-go/pkg/kadm v1.15.0
 	github.com/twmb/franz-go/pkg/kmsg v1.9.0
 	go.opentelemetry.io/otel v1.34.0
-	go.unistack.org/micro/v3 v3.11.41
+	go.unistack.org/micro/v4 v4.1.4
 )
 
 require (
 	github.com/ash3in/uuidv8 v1.2.0 // indirect
+	github.com/google/uuid v1.6.0 // indirect
 	github.com/klauspost/compress v1.18.0 // indirect
-	github.com/kr/pretty v0.3.1 // indirect
 	github.com/matoous/go-nanoid v1.5.1 // indirect
 	github.com/pierrec/lz4/v4 v4.1.22 // indirect
-	go.unistack.org/micro-proto/v3 v3.4.1 // indirect
+	github.com/spf13/cast v1.7.1 // indirect
-	golang.org/x/crypto v0.35.0 // indirect
+	go.unistack.org/micro-proto/v4 v4.1.0 // indirect
-	golang.org/x/sys v0.30.0 // indirect
+	golang.org/x/crypto v0.36.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20250224174004-546df14abb99 // indirect
-	google.golang.org/grpc v1.70.0 // indirect
 	google.golang.org/protobuf v1.36.5 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -2,17 +2,14 @@ github.com/DATA-DOG/go-sqlmock v1.5.2 h1:OcvFkGmslmlZibjAjaHm3L//6LiuBgolP7Oputl
 github.com/DATA-DOG/go-sqlmock v1.5.2/go.mod h1:88MAG/4G7SMwSE3CeA0ZKzrT5CiOU3OJ+JlNzwDqpNU=
 github.com/ash3in/uuidv8 v1.2.0 h1:2oogGdtCPwaVtyvPPGin4TfZLtOGE5F+W++E880G6SI=
 github.com/ash3in/uuidv8 v1.2.0/go.mod h1:BnU0wJBxnzdEKmVg4xckBkD+VZuecTFTUP3M0dWgyY4=
-github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
+github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHkI4W8=
-github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
+github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
-github.com/klauspost/compress v1.17.11 h1:In6xLpyWOi1+C7tXUUWv2ot1QvBjxevKAaI6IXrJmUc=
-github.com/klauspost/compress v1.17.11/go.mod h1:pMDklpSncoRMuLFrf1W9Ss9KT+0rH90U12bZKk7uwG0=
 github.com/klauspost/compress v1.18.0 h1:c/Cqfb0r+Yi+JtIEq73FWXVkRonBlf0CRNYc8Zttxdo=
 github.com/klauspost/compress v1.18.0/go.mod h1:2Pp+KzxcywXVXMr50+X0Q/Lsb43OQHYWRCY2AiWywWQ=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
@@ -23,56 +20,28 @@ github.com/matoous/go-nanoid v1.5.1 h1:aCjdvTyO9LLnTIi0fgdXhOPPvOHjpXN6Ik9DaNjIc
 github.com/matoous/go-nanoid v1.5.1/go.mod h1:zyD2a71IubI24efhpvkJz+ZwfwagzgSO6UNiFsZKN7U=
 github.com/pierrec/lz4/v4 v4.1.22 h1:cKFw6uJDK+/gfw5BcDL0JL5aBsAFdsIT18eRtLj7VIU=
 github.com/pierrec/lz4/v4 v4.1.22/go.mod h1:gZWDp/Ze/IJXGXf23ltt2EXimqmTUXEy0GFuRQyBid4=
-github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR38lUII=
 github.com/rogpeppe/go-internal v1.13.1/go.mod h1:uMEvuHeurkdAXX61udpOXGD/AzZDWNMNyH2VO9fmH0o=
+github.com/spf13/cast v1.7.1 h1:cuNEagBQEHWN1FnbGEjCXL2szYEXqfJPbP2HNUaca9Y=
+github.com/spf13/cast v1.7.1/go.mod h1:ancEpBxwJDODSW/UG4rDrAqiKolqNNh2DX3mk86cAdo=
 github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
-github.com/twmb/franz-go v1.18.0 h1:25FjMZfdozBywVX+5xrWC2W+W76i0xykKjTdEeD2ejw=
-github.com/twmb/franz-go v1.18.0/go.mod h1:zXCGy74M0p5FbXsLeASdyvfLFsBvTubVqctIaa5wQ+I=
 github.com/twmb/franz-go v1.18.1 h1:D75xxCDyvTqBSiImFx2lkPduE39jz1vaD7+FNc+vMkc=
 github.com/twmb/franz-go v1.18.1/go.mod h1:Uzo77TarcLTUZeLuGq+9lNpSkfZI+JErv7YJhlDjs9M=
-github.com/twmb/franz-go/pkg/kadm v1.14.0 h1:nAn1co1lXzJQocpzyIyOFOjUBf4WHWs5/fTprXy2IZs=
-github.com/twmb/franz-go/pkg/kadm v1.14.0/go.mod h1:XjOPz6ZaXXjrW2jVCfLuucP8H1w2TvD6y3PT2M+aAM4=
 github.com/twmb/franz-go/pkg/kadm v1.15.0 h1:Yo3NAPfcsx3Gg9/hdhq4vmwO77TqRRkvpUcGWzjworc=
 github.com/twmb/franz-go/pkg/kadm v1.15.0/go.mod h1:MUdcUtnf9ph4SFBLLA/XxE29rvLhWYLM9Ygb8dfSCvw=
 github.com/twmb/franz-go/pkg/kmsg v1.9.0 h1:JojYUph2TKAau6SBtErXpXGC7E3gg4vGZMv9xFU/B6M=
 github.com/twmb/franz-go/pkg/kmsg v1.9.0/go.mod h1:CMbfazviCyY6HM0SXuG5t9vOwYDHRCSrJJyBAe5paqg=
-go.opentelemetry.io/otel v1.33.0 h1:/FerN9bax5LoK51X/sI0SVYrjSE0/yUL7DpxW4K3FWw=
-go.opentelemetry.io/otel v1.33.0/go.mod h1:SUUkR6csvUQl+yjReHu5uM3EtVV7MBm5FHKRlNx4I8I=
 go.opentelemetry.io/otel v1.34.0 h1:zRLXxLCgL1WyKsPVrgbSdMN4c0FMkDAskSTQP+0hdUY=
 go.opentelemetry.io/otel v1.34.0/go.mod h1:OWFPOQ+h4G8xpyjgqo4SxJYdDQ/qmRH+wivy7zzx9oI=
-go.unistack.org/micro-proto/v3 v3.4.1 h1:UTjLSRz2YZuaHk9iSlVqqsA50JQNAEK2ZFboGqtEa9Q=
+go.unistack.org/micro-proto/v4 v4.1.0 h1:qPwL2n/oqh9RE3RTTDgt28XK3QzV597VugQPaw9lKUk=
-go.unistack.org/micro-proto/v3 v3.4.1/go.mod h1:okx/cnOhzuCX0ggl/vToatbCupi0O44diiiLLsZ93Zo=
+go.unistack.org/micro-proto/v4 v4.1.0/go.mod h1:ArmK7o+uFvxSY3dbJhKBBX4Pm1rhWdLEFf3LxBrMtec=
-go.unistack.org/micro/v3 v3.11.37 h1:ZcpnXAYEMcAwmnVb5b7o8/PylGnILxXMHaUlRrPmRI0=
+go.unistack.org/micro/v4 v4.1.4 h1:gyjVPP9g7UAFZlhEbla9Ih/BeKJfBLAbN/NvAhJCpKU=
-go.unistack.org/micro/v3 v3.11.37/go.mod h1:POGU5hstnAT9LH70m8FalyQSNi2GfIew71K75JenIZk=
+go.unistack.org/micro/v4 v4.1.4/go.mod h1:lr3oYED8Ay1vjK68QqRw30QOtdk/ffpZqMFDasOUhKw=
-go.unistack.org/micro/v3 v3.11.41 h1:dP4sBLIZpMo+MWGe5bbESewK8wBzYm4Yik/67x4dEtQ=
+golang.org/x/crypto v0.36.0 h1:AnAEvhDddvBdpY+uR+MyHmuZzzNqXSe/GvuDeob5L34=
-go.unistack.org/micro/v3 v3.11.41/go.mod h1:POGU5hstnAT9LH70m8FalyQSNi2GfIew71K75JenIZk=
+golang.org/x/crypto v0.36.0/go.mod h1:Y4J0ReaxCR1IMaabaSMugxJES1EpwhBHhv2bDHklZvc=
-golang.org/x/crypto v0.31.0 h1:ihbySMvVjLAeSH1IbfcRTkD/iNscyz8rGzjF/E5hV6U=
-golang.org/x/crypto v0.31.0/go.mod h1:kDsLvtWBEx7MV9tJOj9bnXsPbxwJQ6csT/x4KIN4Ssk=
-golang.org/x/crypto v0.35.0 h1:b15kiHdrGCHrP6LvwaQ3c03kgNhhiMgvlhxHQhmg2Xs=
-golang.org/x/crypto v0.35.0/go.mod h1:dy7dXNW32cAb/6/PRuTNsix8T+vJAqvuIy5Bli/x0YQ=
-golang.org/x/net v0.33.0 h1:74SYHlV8BIgHIFC/LrYkOGIwL19eTYXQ5wc6TBuO36I=
-golang.org/x/net v0.33.0/go.mod h1:HXLR5J+9DxmrqMwG9qjGCxZ+zKXxBru04zlTvWlWuN4=
-golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
-golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
-golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
-golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20241216192217-9240e9c98484 h1:Z7FRVJPSMaHQxD0uXU8WdgFh8PseLM8Q8NzhnpMrBhQ=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20241216192217-9240e9c98484/go.mod h1:lcTa1sDdWEIHMWlITnIczmw5w60CF9ffkb8Z+DVmmjA=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20250224174004-546df14abb99 h1:ZSlhAUqC4r8TPzqLXQ0m3upBNZeF+Y8jQ3c4CR3Ujms=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20250224174004-546df14abb99/go.mod h1:LuRYeWDFV6WOn90g357N17oMCaxpgCnbi/44qJvDn2I=
-google.golang.org/grpc v1.69.2 h1:U3S9QEtbXC0bYNvRtcoklF3xGtLViumSYxWykJS+7AU=
-google.golang.org/grpc v1.69.2/go.mod h1:vyjdE6jLBI76dgpDojsFGNaHlxdjXN9ghpnd2o7JGZ4=
-google.golang.org/grpc v1.70.0 h1:pWFv03aZoHzlRKHWicjsZytKAiYCtNS0dHbXnIdq7jQ=
-google.golang.org/grpc v1.70.0/go.mod h1:ofIJqVKDXx/JiXrwr2IG4/zwdH9txy3IlF40RmcJSQw=
-google.golang.org/protobuf v1.36.1 h1:yBPeRvTftaleIgM3PZ/WBIZ7XM/eEYAaEyCwvyjq/gk=
-google.golang.org/protobuf v1.36.1/go.mod h1:9fA7Ob0pmnwhb644+1+CVWFRbNajQ6iRojtC/QF5bRE=
 google.golang.org/protobuf v1.36.5 h1:tPhr+woSbjfYvY6/GPufUoYizxw1cF/yFoxJ2fmpwlM=
 google.golang.org/protobuf v1.36.5/go.mod h1:9fA7Ob0pmnwhb644+1+CVWFRbNajQ6iRojtC/QF5bRE=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

kgo.go

@@ -11,19 +11,27 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/google/uuid"
 	"github.com/twmb/franz-go/pkg/kgo"
 	"github.com/twmb/franz-go/pkg/kmsg"
-	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v4/broker"
-	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v4/codec"
-	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v3/semconv"
+	"go.unistack.org/micro/v4/metadata"
-	"go.unistack.org/micro/v3/tracer"
+	"go.unistack.org/micro/v4/options"
-	mrand "go.unistack.org/micro/v3/util/rand"
+	"go.unistack.org/micro/v4/semconv"
+	"go.unistack.org/micro/v4/tracer"
+	"go.unistack.org/micro/v4/util/id"
+	mrand "go.unistack.org/micro/v4/util/rand"
 )
 
 var _ broker.Broker = (*Broker)(nil)
 
+var messagePool = sync.Pool{
+	New: func() interface{} {
+		return &kgoMessage{}
+	},
+}
+
 var ErrLostMessage = errors.New("message not marked for offsets commit and will be lost in next iteration")
 
 var DefaultRetryBackoffFn = func() func(int) time.Duration {
@@ -56,6 +64,8 @@ var DefaultRetryBackoffFn = func() func(int) time.Duration {
 }()
 
 type Broker struct {
+	funcPublish   broker.FuncPublish
+	funcSubscribe broker.FuncSubscribe
 	c             *kgo.Client
 	connected     *atomic.Uint32
 
@@ -92,6 +102,68 @@ func (k *Broker) Client() *kgo.Client {
 	return k.c
 }
 
+type kgoMessage struct {
+	c     codec.Codec
+	topic string
+	ctx   context.Context
+	body  []byte
+	hdr   metadata.Metadata
+	opts  broker.PublishOptions
+	ack   bool
+}
+
+func (m *kgoMessage) Ack() error {
+	m.ack = true
+	return nil
+}
+
+func (m *kgoMessage) Body() []byte {
+	return m.body
+}
+
+func (m *kgoMessage) Header() metadata.Metadata {
+	return m.hdr
+}
+
+func (m *kgoMessage) Context() context.Context {
+	return m.ctx
+}
+
+func (m *kgoMessage) Topic() string {
+	return ""
+}
+
+func (m *kgoMessage) Unmarshal(dst interface{}, opts ...codec.Option) error {
+	return m.c.Unmarshal(m.body, dst)
+}
+
+func (b *Broker) newCodec(ct string) (codec.Codec, error) {
+	if idx := strings.IndexRune(ct, ';'); idx >= 0 {
+		ct = ct[:idx]
+	}
+	b.RLock()
+	c, ok := b.opts.Codecs[ct]
+	b.RUnlock()
+	if ok {
+		return c, nil
+	}
+	return nil, codec.ErrUnknownContentType
+}
+
+func (b *Broker) NewMessage(ctx context.Context, hdr metadata.Metadata, body interface{}, opts ...broker.PublishOption) (broker.Message, error) {
+	options := broker.NewPublishOptions(opts...)
+	m := &kgoMessage{ctx: ctx, hdr: hdr, opts: options}
+	c, err := b.newCodec(m.opts.ContentType)
+	if err == nil {
+		m.body, err = c.Marshal(body)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return m, nil
+}
+
 func (k *Broker) connect(ctx context.Context, opts ...kgo.Opt) (*kgo.Client, *hookTracer, error) {
 	var c *kgo.Client
 	var err error
@@ -238,6 +310,18 @@ func (k *Broker) Init(opts ...broker.Option) error {
 		}
 	}
 
+	k.funcPublish = k.fnPublish
+	k.funcSubscribe = k.fnSubscribe
+
+	k.opts.Hooks.EachPrev(func(hook options.Hook) {
+		switch h := hook.(type) {
+		case broker.HookPublish:
+			k.funcPublish = h(k.funcPublish)
+		case broker.HookSubscribe:
+			k.funcSubscribe = h(k.funcSubscribe)
+		}
+	})
+
 	k.init = true
 
 	return nil
@@ -247,95 +331,88 @@ func (k *Broker) Options() broker.Options {
 	return k.opts
 }
 
-func (k *Broker) BatchPublish(ctx context.Context, msgs []*broker.Message, opts ...broker.PublishOption) error {
+func (b *Broker) Publish(ctx context.Context, topic string, messages ...broker.Message) error {
-	return k.publish(ctx, msgs, opts...)
+	return b.funcPublish(ctx, topic, messages...)
 }
 
-func (k *Broker) Publish(ctx context.Context, topic string, msg *broker.Message, opts ...broker.PublishOption) error {
+func (b *Broker) fnPublish(ctx context.Context, topic string, messages ...broker.Message) error {
-	msg.Header.Set(metadata.HeaderTopic, topic)
+	return b.publish(ctx, topic, messages...)
-	return k.publish(ctx, []*broker.Message{msg}, opts...)
 }
 
-func (k *Broker) publish(ctx context.Context, msgs []*broker.Message, opts ...broker.PublishOption) error {
+func (b *Broker) publish(ctx context.Context, topic string, messages ...broker.Message) error {
-	k.Lock()
+	if b.connected.Load() == 0 {
-	if k.connected.Load() == 0 {
+		c, _, err := b.connect(ctx, b.kopts...)
-		c, _, err := k.connect(ctx, k.kopts...)
 		if err != nil {
-			k.Unlock()
 			return err
 		}
-		k.c = c
+		b.Lock()
-		k.connected.Store(1)
+		b.c = c
+		b.Unlock()
 	}
-	k.Unlock()
 
-	options := broker.NewPublishOptions(opts...)
+	records := make([]*kgo.Record, 0, len(messages))
-	records := make([]*kgo.Record, 0, len(msgs))
 	var errs []string
-	var err error
 	var key []byte
 	var promise func(*kgo.Record, error)
 
-	if options.Context != nil {
+	for _, msg := range messages {
-		if k, ok := options.Context.Value(publishKey{}).([]byte); ok && k != nil {
+
+		if mctx := msg.Context(); mctx != nil {
+			if k, ok := mctx.Value(publishKey{}).([]byte); ok && k != nil {
 				key = k
 			}
-		if p, ok := options.Context.Value(publishPromiseKey{}).(func(*kgo.Record, error)); ok && p != nil {
+			if p, ok := mctx.Value(publishPromiseKey{}).(func(*kgo.Record, error)); ok && p != nil {
 				promise = p
 			}
 		}
 
-	for _, msg := range msgs {
+		rec := &kgo.Record{
-		rec := &kgo.Record{Context: ctx, Key: key}
+			Context: ctx,
-
+			Key:     key,
-		rec.Topic, _ = msg.Header.Get(metadata.HeaderTopic)
+			Topic:   topic,
-		msg.Header.Del(metadata.HeaderTopic)
+			Value:   msg.Body(),
-
-		k.opts.Meter.Counter(semconv.PublishMessageInflight, "endpoint", rec.Topic, "topic", rec.Topic).Inc()
-		if options.BodyOnly || k.opts.Codec.String() == "noop" {
-			rec.Value = msg.Body
-			setHeaders(rec, msg.Header)
-		} else {
-			rec.Value, err = k.opts.Codec.Marshal(msg)
-			if err != nil {
-				return err
-			}
 		}
+
+		b.opts.Meter.Counter(semconv.PublishMessageInflight, "endpoint", rec.Topic, "topic", rec.Topic).Inc()
+
+		setHeaders(rec, msg.Header())
+
 		records = append(records, rec)
 	}
 
-	if promise != nil {
 	ts := time.Now()
+
+	if promise != nil {
+
 		for _, rec := range records {
-			k.c.Produce(ctx, rec, func(r *kgo.Record, err error) {
+			b.c.Produce(ctx, rec, func(r *kgo.Record, err error) {
 				te := time.Since(ts)
-				k.opts.Meter.Counter(semconv.PublishMessageInflight, "endpoint", rec.Topic, "topic", rec.Topic).Dec()
+				b.opts.Meter.Counter(semconv.PublishMessageInflight, "endpoint", rec.Topic, "topic", rec.Topic).Dec()
-				k.opts.Meter.Summary(semconv.PublishMessageLatencyMicroseconds, "endpoint", rec.Topic, "topic", rec.Topic).Update(te.Seconds())
+				b.opts.Meter.Summary(semconv.PublishMessageLatencyMicroseconds, "endpoint", rec.Topic, "topic", rec.Topic).Update(te.Seconds())
-				k.opts.Meter.Histogram(semconv.PublishMessageDurationSeconds, "endpoint", rec.Topic, "topic", rec.Topic).Update(te.Seconds())
+				b.opts.Meter.Histogram(semconv.PublishMessageDurationSeconds, "endpoint", rec.Topic, "topic", rec.Topic).Update(te.Seconds())
 				if err != nil {
-					k.opts.Meter.Counter(semconv.PublishMessageTotal, "endpoint", rec.Topic, "topic", rec.Topic, "status", "failure").Inc()
+					b.opts.Meter.Counter(semconv.PublishMessageTotal, "endpoint", rec.Topic, "topic", rec.Topic, "status", "failure").Inc()
 				} else {
-					k.opts.Meter.Counter(semconv.PublishMessageTotal, "endpoint", rec.Topic, "topic", rec.Topic, "status", "success").Inc()
+					b.opts.Meter.Counter(semconv.PublishMessageTotal, "endpoint", rec.Topic, "topic", rec.Topic, "status", "success").Inc()
 				}
 				promise(r, err)
 			})
 		}
 		return nil
 	}
-	ts := time.Now()
 
-	results := k.c.ProduceSync(ctx, records...)
+	results := b.c.ProduceSync(ctx, records...)
 
 	te := time.Since(ts)
 	for _, result := range results {
-		k.opts.Meter.Summary(semconv.PublishMessageLatencyMicroseconds, "endpoint", result.Record.Topic, "topic", result.Record.Topic).Update(te.Seconds())
+		b.opts.Meter.Summary(semconv.PublishMessageLatencyMicroseconds, "endpoint", result.Record.Topic, "topic", result.Record.Topic).Update(te.Seconds())
-		k.opts.Meter.Histogram(semconv.PublishMessageDurationSeconds, "endpoint", result.Record.Topic, "topic", result.Record.Topic).Update(te.Seconds())
+		b.opts.Meter.Histogram(semconv.PublishMessageDurationSeconds, "endpoint", result.Record.Topic, "topic", result.Record.Topic).Update(te.Seconds())
-		k.opts.Meter.Counter(semconv.PublishMessageInflight, "endpoint", result.Record.Topic, "topic", result.Record.Topic).Dec()
+		b.opts.Meter.Counter(semconv.PublishMessageInflight, "endpoint", result.Record.Topic, "topic", result.Record.Topic).Dec()
 		if result.Err != nil {
-			k.opts.Meter.Counter(semconv.PublishMessageTotal, "endpoint", result.Record.Topic, "topic", result.Record.Topic, "status", "failure").Inc()
+			b.opts.Meter.Counter(semconv.PublishMessageTotal, "endpoint", result.Record.Topic, "topic", result.Record.Topic, "status", "failure").Inc()
 			errs = append(errs, result.Err.Error())
 		} else {
-			k.opts.Meter.Counter(semconv.PublishMessageTotal, "endpoint", result.Record.Topic, "topic", result.Record.Topic, "status", "success").Inc()
+			b.opts.Meter.Counter(semconv.PublishMessageTotal, "endpoint", result.Record.Topic, "topic", result.Record.Topic, "status", "success").Inc()
 		}
 	}
 
@@ -362,31 +439,44 @@ func (k *Broker) TopicExists(ctx context.Context, topic string) error {
 	return nil
 }
 
-func (k *Broker) BatchSubscribe(_ context.Context, _ string, _ broker.BatchHandler, _ ...broker.SubscribeOption) (broker.Subscriber, error) {
+func (b *Broker) Subscribe(ctx context.Context, topic string, handler interface{}, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
-	return nil, nil
+	return b.funcSubscribe(ctx, topic, handler, opts...)
 }
 
-func (k *Broker) Subscribe(ctx context.Context, topic string, handler broker.Handler, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
+func (b *Broker) fnSubscribe(ctx context.Context, topic string, handler interface{}, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
+	if err := broker.IsValidHandler(handler); err != nil {
+		return nil, err
+	}
+
 	options := broker.NewSubscribeOptions(opts...)
 
+	switch handler.(type) {
+	default:
+		return nil, broker.ErrInvalidHandler
+	case func(broker.Message) error:
+		break
+	case func([]broker.Message) error:
+		break
+	}
+
 	if options.Group == "" {
-		uid, err := uuid.NewRandom()
+		uid, err := id.New()
 		if err != nil {
 			return nil, err
 		}
-		options.Group = uid.String()
+		options.Group = uid
 	}
 
 	commitInterval := DefaultCommitInterval
-	if k.opts.Context != nil {
+	if b.opts.Context != nil {
-		if v, ok := k.opts.Context.Value(commitIntervalKey{}).(time.Duration); ok && v > 0 {
+		if v, ok := b.opts.Context.Value(commitIntervalKey{}).(time.Duration); ok && v > 0 {
 			commitInterval = v
 		}
 	}
 
 	var fatalOnError bool
-	if k.opts.Context != nil {
+	if b.opts.Context != nil {
-		if v, ok := k.opts.Context.Value(fatalOnErrorKey{}).(bool); ok && v {
+		if v, ok := b.opts.Context.Value(fatalOnErrorKey{}).(bool); ok && v {
 			fatalOnError = v
 		}
 	}
@@ -401,14 +491,14 @@ func (k *Broker) Subscribe(ctx context.Context, topic string, handler broker.Han
 		topic:        topic,
 		opts:         options,
 		handler:      handler,
-		kopts:        k.opts,
+		kopts:        b.opts,
 		consumers:    make(map[tp]*consumer),
 		done:         make(chan struct{}),
 		fatalOnError: fatalOnError,
-		connected:    k.connected,
+		connected:    b.connected,
 	}
 
-	kopts := append(k.kopts,
+	kopts := append(b.kopts,
 		kgo.ConsumerGroup(options.Group),
 		kgo.ConsumeTopics(topic),
 		kgo.ConsumeResetOffset(kgo.NewOffset().AtStart()),
@@ -428,7 +518,7 @@ func (k *Broker) Subscribe(ctx context.Context, topic string, handler broker.Han
 		}
 	}
 
-	c, htracer, err := k.connect(ctx, kopts...)
+	c, htracer, err := b.connect(ctx, kopts...)
 	if err != nil {
 		return nil, err
 	}
@@ -450,9 +540,10 @@ func (k *Broker) Subscribe(ctx context.Context, topic string, handler broker.Han
 
 	go sub.poll(ctx)
 
-	k.Lock()
+	b.Lock()
-	k.subs = append(k.subs, sub)
+	b.subs = append(b.subs, sub)
-	k.Unlock()
+	b.Unlock()
+
 	return sub, nil
 }
 

kgo_test.go

@@ -9,11 +9,11 @@ import (
 	"time"
 
 	kg "github.com/twmb/franz-go/pkg/kgo"
-	kgo "go.unistack.org/micro-broker-kgo/v3"
+	kgo "go.unistack.org/micro-broker-kgo/v4"
-	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v4/broker"
-	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v3/logger/slog"
+	"go.unistack.org/micro/v4/logger/slog"
-	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/metadata"
 )
 
 var (
@@ -23,11 +23,6 @@ var (
 	loglevel = logger.DebugLevel
 )
 
-var bm = &broker.Message{
-	Header: map[string]string{"hkey": "hval", metadata.HeaderTopic: "test"},
-	Body:   []byte(`"body"`),
-}
-
 func TestFail(t *testing.T) {
 	if tr := os.Getenv("INTEGRATION_TESTS"); len(tr) > 0 {
 		t.Skip()
@@ -72,9 +67,10 @@ func TestFail(t *testing.T) {
 	}()
 
 	t.Logf("broker health %v", b.Health())
-	msgs := make([]*broker.Message, 0, msgcnt)
+	msgs := make([]broker.Message, 0, msgcnt)
 	for i := int64(0); i < msgcnt; i++ {
-		msgs = append(msgs, bm)
+		m, _ := b.NewMessage(ctx, metadata.Pairs("hkey", "hval"), []byte(`test`))
+		msgs = append(msgs, m)
 	}
 
 	for _, msg := range msgs {
@@ -86,7 +82,7 @@ func TestFail(t *testing.T) {
 	//	t.Skip()
 
 	idx := int64(0)
-	fn := func(msg broker.Event) error {
+	fn := func(msg broker.Message) error {
 		atomic.AddInt64(&idx, 1)
 		time.Sleep(500 * time.Millisecond)
 		t.Logf("ack")
@@ -170,19 +166,20 @@ func TestPubSub(t *testing.T) {
 		}
 	}()
 	if prefill {
-		msgs := make([]*broker.Message, 0, msgcnt)
+		msgs := make([]broker.Message, 0, msgcnt)
 		for i := int64(0); i < msgcnt; i++ {
-			msgs = append(msgs, bm)
+			m, _ := b.NewMessage(ctx, metadata.Pairs("hkey", "hval"), []byte(`test`))
+			msgs = append(msgs, m)
 		}
 
-		if err := b.BatchPublish(ctx, msgs); err != nil {
+		if err := b.Publish(ctx, "test", msgs...); err != nil {
 			t.Fatal(err)
 		}
 		//	t.Skip()
 	}
 	done := make(chan bool, 1)
 	idx := int64(0)
-	fn := func(msg broker.Event) error {
+	fn := func(msg broker.Message) error {
 		atomic.AddInt64(&idx, 1)
 		// time.Sleep(200 * time.Millisecond)
 		return msg.Ack()

logger.go

@@ -4,7 +4,7 @@ import (
 	"context"
 
 	"github.com/twmb/franz-go/pkg/kgo"
-	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v4/logger"
 )
 
 type mlogger struct {

meter.go

@@ -6,7 +6,7 @@ import (
 	"time"
 
 	"github.com/twmb/franz-go/pkg/kgo"
-	"go.unistack.org/micro/v3/meter"
+	"go.unistack.org/micro/v4/meter"
 )
 
 type hookMeter struct {

options.go

@@ -5,8 +5,7 @@ import (
 	"time"
 
 	"github.com/twmb/franz-go/pkg/kgo"
-	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v4/broker"
-	"go.unistack.org/micro/v3/client"
 )
 
 var (
@@ -35,11 +34,6 @@ func PublishKey(key []byte) broker.PublishOption {
 	return broker.SetPublishOption(publishKey{}, key)
 }
 
-// ClientPublishKey set the kafka message key (client option)
-func ClientPublishKey(key []byte) client.PublishOption {
-	return client.SetPublishOption(publishKey{}, key)
-}
-
 type optionsKey struct{}
 
 // Options pass additional options to broker
@@ -115,8 +109,3 @@ type publishPromiseKey struct{}
 func PublishPromise(fn func(*kgo.Record, error)) broker.PublishOption {
 	return broker.SetPublishOption(publishPromiseKey{}, fn)
 }
-
-// ClientPublishKey set the kafka message key (client option)
-func ClientPublishPromise(fn func(*kgo.Record, error)) client.PublishOption {
-	return client.SetPublishOption(publishPromiseKey{}, fn)
-}

subscriber.go

@@ -11,11 +11,11 @@ import (
 	"github.com/twmb/franz-go/pkg/kadm"
 	"github.com/twmb/franz-go/pkg/kgo"
 	"github.com/twmb/franz-go/pkg/kmsg"
-	"go.unistack.org/micro/v3/broker"
+	"go.unistack.org/micro/v4/broker"
-	"go.unistack.org/micro/v3/logger"
+	"go.unistack.org/micro/v4/logger"
-	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/metadata"
-	"go.unistack.org/micro/v3/semconv"
+	"go.unistack.org/micro/v4/semconv"
-	"go.unistack.org/micro/v3/tracer"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 type tp struct {
@@ -33,7 +33,7 @@ type consumer struct {
 	kopts     broker.Options
 	partition int32
 	opts      broker.SubscribeOptions
-	handler   broker.Handler
+	handler   interface{}
 	connected *atomic.Uint32
 }
 
@@ -43,7 +43,7 @@ type Subscriber struct {
 	htracer   *hookTracer
 	topic     string
 
-	handler broker.Handler
+	handler interface{}
 	done    chan struct{}
 	kopts   broker.Options
 	opts    broker.SubscribeOptions
@@ -119,7 +119,7 @@ func (s *Subscriber) poll(ctx context.Context) {
 
 				s.Lock()
 				for p, l := range lmap {
-					s.kopts.Meter.Counter(semconv.BrokerGroupLag, "topic", s.topic, "group", s.opts.Group, "partition", strconv.Itoa(int(p)), "lag", strconv.Itoa(int(l.Lag)))
+					s.kopts.Meter.Counter(semconv.BrokerGroupLag, "topic", s.topic, "group", s.opts.Group, "partition", strconv.Itoa(int(p))).Set(uint64(l.Lag))
 				}
 				s.Unlock()
 
@@ -160,7 +160,10 @@ func (s *Subscriber) killConsumers(ctx context.Context, lost map[string][]int32)
 	for topic, partitions := range lost {
 		for _, partition := range partitions {
 			tps := tp{topic, partition}
-			pc := s.consumers[tps]
+			pc, ok := s.consumers[tps]
+			if !ok {
+				continue
+			}
 			delete(s.consumers, tps)
 			close(pc.quit)
 			if s.kopts.Logger.V(logger.DebugLevel) {
@@ -225,17 +228,14 @@ func (s *Subscriber) assigned(_ context.Context, c *kgo.Client, assigned map[str
 }
 
 func (pc *consumer) consume() {
+	var err error
+
 	defer close(pc.done)
 	if pc.kopts.Logger.V(logger.DebugLevel) {
 		pc.kopts.Logger.Debug(pc.kopts.Context, fmt.Sprintf("starting, topic %s partition %d", pc.topic, pc.partition))
 		defer pc.kopts.Logger.Debug(pc.kopts.Context, fmt.Sprintf("killing, topic %s partition %d", pc.topic, pc.partition))
 	}
 
-	eh := pc.kopts.ErrorHandler
-	if pc.opts.ErrorHandler != nil {
-		eh = pc.opts.ErrorHandler
-	}
-
 	for {
 		select {
 		case <-pc.quit:
@@ -245,98 +245,48 @@ func (pc *consumer) consume() {
 				ctx, sp := pc.htracer.WithProcessSpan(record)
 				ts := time.Now()
 				pc.kopts.Meter.Counter(semconv.SubscribeMessageInflight, "endpoint", record.Topic, "topic", record.Topic).Inc()
-				p := eventPool.Get().(*event)
+				p := messagePool.Get().(*kgoMessage)
-				p.msg.Header = nil
+
-				p.msg.Body = nil
+				p.body = record.Value
 				p.topic = record.Topic
-				p.err = nil
 				p.ack = false
-				p.msg.Header = metadata.New(len(record.Headers))
+				p.hdr = metadata.New(len(record.Headers))
 				p.ctx = ctx
 				for _, hdr := range record.Headers {
-					p.msg.Header.Set(hdr.Key, string(hdr.Value))
+					p.hdr.Set(hdr.Key, string(hdr.Value))
 				}
-				if pc.kopts.Codec.String() == "noop" {
+
-					p.msg.Body = record.Value
+				switch h := pc.handler.(type) {
-				} else if pc.opts.BodyOnly {
+				case func(broker.Message) error:
-					p.msg.Body = record.Value
+					err = h(p)
-				} else {
+				case func([]broker.Message) error:
-					sp.AddEvent("codec unmarshal start")
+					err = h([]broker.Message{p})
-					err := pc.kopts.Codec.Unmarshal(record.Value, p.msg)
+				}
-					sp.AddEvent("codec unmarshal stop")
+
+				pc.kopts.Meter.Counter(semconv.SubscribeMessageInflight, "endpoint", record.Topic, "topic", record.Topic).Dec()
 				if err != nil {
 					sp.SetStatus(tracer.SpanStatusError, err.Error())
 					pc.kopts.Meter.Counter(semconv.SubscribeMessageTotal, "endpoint", record.Topic, "topic", record.Topic, "status", "failure").Inc()
-						p.err = err
+				} else if pc.opts.AutoAck {
-						p.msg.Body = record.Value
-						if eh != nil {
-							_ = eh(p)
-							pc.kopts.Meter.Counter(semconv.SubscribeMessageInflight, "endpoint", record.Topic, "topic", record.Topic).Dec()
-							if p.ack {
-								pc.c.MarkCommitRecords(record)
-							} else {
-								eventPool.Put(p)
-								pc.connected.Store(0)
-								pc.kopts.Logger.Fatal(pc.kopts.Context, "[kgo] ErrLostMessage wtf?")
-								return
-							}
-							eventPool.Put(p)
-							te := time.Since(ts)
-							pc.kopts.Meter.Summary(semconv.SubscribeMessageLatencyMicroseconds, "endpoint", record.Topic, "topic", record.Topic).Update(te.Seconds())
-							pc.kopts.Meter.Histogram(semconv.SubscribeMessageDurationSeconds, "endpoint", record.Topic, "topic", record.Topic).Update(te.Seconds())
-							continue
-						} else {
-							pc.kopts.Logger.Error(pc.kopts.Context, "[kgo]: unmarshal error", err)
-						}
-						te := time.Since(ts)
-						pc.kopts.Meter.Counter(semconv.SubscribeMessageInflight, "endpoint", record.Topic, "topic", record.Topic).Dec()
-						pc.kopts.Meter.Summary(semconv.SubscribeMessageLatencyMicroseconds, "endpoint", record.Topic, "topic", record.Topic).Update(te.Seconds())
-						pc.kopts.Meter.Histogram(semconv.SubscribeMessageDurationSeconds, "endpoint", record.Topic, "topic", record.Topic).Update(te.Seconds())
-						eventPool.Put(p)
-						pc.connected.Store(0)
-						pc.kopts.Logger.Fatal(pc.kopts.Context, "[kgo] Unmarshal err not handled wtf?")
-						sp.Finish()
-						return
-					}
-				}
-				sp.AddEvent("handler start")
-				err := pc.handler(p)
-				sp.AddEvent("handler stop")
-				if err == nil {
-					pc.kopts.Meter.Counter(semconv.SubscribeMessageTotal, "endpoint", record.Topic, "topic", record.Topic, "status", "success").Inc()
-				} else {
-					sp.SetStatus(tracer.SpanStatusError, err.Error())
-					pc.kopts.Meter.Counter(semconv.SubscribeMessageTotal, "endpoint", record.Topic, "topic", record.Topic, "status", "failure").Inc()
-				}
-				pc.kopts.Meter.Counter(semconv.SubscribeMessageInflight, "endpoint", record.Topic, "topic", record.Topic).Dec()
-				if err == nil && pc.opts.AutoAck {
 					p.ack = true
-				} else if err != nil {
-					p.err = err
-					if eh != nil {
-						sp.AddEvent("error handler start")
-						_ = eh(p)
-						sp.AddEvent("error handler stop")
-					} else {
-						if pc.kopts.Logger.V(logger.ErrorLevel) {
-							pc.kopts.Logger.Error(pc.kopts.Context, "[kgo]: subscriber error", err)
-						}
-					}
 				}
+
 				te := time.Since(ts)
 				pc.kopts.Meter.Summary(semconv.SubscribeMessageLatencyMicroseconds, "endpoint", record.Topic, "topic", record.Topic).Update(te.Seconds())
 				pc.kopts.Meter.Histogram(semconv.SubscribeMessageDurationSeconds, "endpoint", record.Topic, "topic", record.Topic).Update(te.Seconds())
-				if p.ack {
+
-					eventPool.Put(p)
+				ack := p.ack
+				messagePool.Put(p)
+
+				if ack {
 					pc.c.MarkCommitRecords(record)
 				} else {
-					eventPool.Put(p)
-					pc.connected.Store(0)
-					pc.kopts.Logger.Fatal(pc.kopts.Context, "[kgo] ErrLostMessage wtf?")
-					sp.SetStatus(tracer.SpanStatusError, "ErrLostMessage")
 					sp.Finish()
+					pc.connected.Store(0)
+					pc.kopts.Logger.Fatal(pc.kopts.Context, "[kgo] message not commited")
 					return
 				}
+
 				sp.Finish()
 			}
 		}

tracer.go

@@ -6,8 +6,8 @@ import (
 
 	"github.com/twmb/franz-go/pkg/kgo"
 	semconv "go.opentelemetry.io/otel/semconv/v1.18.0"
-	"go.unistack.org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/metadata"
-	"go.unistack.org/micro/v3/tracer"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 type hookTracer struct {