feat(metrics): track consumer-fetch-response-size

- add metrics registry to decode func - add metric to track the size of fetch response
IBM · Aug 10, 2022 · 5b04c98 · 5b04c98
1 parent b87a616
commit 5b04c98
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Showing 17 changed files with 66 additions and 36 deletions.
diff --git a/balance_strategy.go b/balance_strategy.go
@@ -609,9 +609,9 @@ func assignPartition(partition topicPartitionAssignment, sortedCurrentSubscripti
 // Deserialize topic partition assignment data to aid with creation of a sticky assignment.
 func deserializeTopicPartitionAssignment(userDataBytes []byte) (StickyAssignorUserData, error) {
 	userDataV1 := &StickyAssignorUserDataV1{}
-	if err := decode(userDataBytes, userDataV1); err != nil {
+	if err := decode(userDataBytes, userDataV1, nil); err != nil {
 		userDataV0 := &StickyAssignorUserDataV0{}
-		if err := decode(userDataBytes, userDataV0); err != nil {
+		if err := decode(userDataBytes, userDataV0, nil); err != nil {
 			return nil, err
 		}
 		return userDataV0, nil

diff --git a/broker.go b/broker.go
@@ -435,7 +435,7 @@ func (b *Broker) AsyncProduce(request *ProduceRequest, cb ProduceCallback) error
 					return
 				}
 
-				if err := versionedDecode(packets, res, request.version()); err != nil {
+				if err := versionedDecode(packets, res, request.version(), b.conf.MetricRegistry); err != nil {
 					// Malformed response
 					cb(nil, err)
 					return
@@ -1023,13 +1023,13 @@ func (b *Broker) sendAndReceive(req protocolBody, res protocolBody) error {
 		return nil
 	}
 
-	return handleResponsePromise(req, res, promise)
+	return b.handleResponsePromise(req, res, promise)
 }
 
-func handleResponsePromise(req protocolBody, res protocolBody, promise *responsePromise) error {
+func (b *Broker) handleResponsePromise(req protocolBody, res protocolBody, promise *responsePromise) error {
 	select {
 	case buf := <-promise.packets:
-		return versionedDecode(buf, res, req.version())
+		return versionedDecode(buf, res, req.version(), b.conf.MetricRegistry)
 	case err := <-promise.errors:
 		return err
 	}
@@ -1121,7 +1121,7 @@ func (b *Broker) responseReceiver() {
 		}
 
 		decodedHeader := responseHeader{}
-		err = versionedDecode(header, &decodedHeader, response.headerVersion)
+		err = versionedDecode(header, &decodedHeader, response.headerVersion, b.conf.MetricRegistry)
 		if err != nil {
 			b.updateIncomingCommunicationMetrics(bytesReadHeader, requestLatency)
 			dead = err
@@ -1182,7 +1182,7 @@ func (b *Broker) authenticateViaSASLv1() error {
 			Logger.Printf("Error while performing SASL handshake %s\n", b.addr)
 			return handshakeErr
 		}
-		handshakeErr = handleResponsePromise(handshakeRequest, handshakeResponse, prom)
+		handshakeErr = b.handleResponsePromise(handshakeRequest, handshakeResponse, prom)
 		if handshakeErr != nil {
 			Logger.Printf("Error while performing SASL handshake %s\n", b.addr)
 			return handshakeErr
@@ -1202,7 +1202,7 @@ func (b *Broker) authenticateViaSASLv1() error {
 			Logger.Printf("Error while performing SASL Auth %s\n", b.addr)
 			return nil, authErr
 		}
-		authErr = handleResponsePromise(authenticateRequest, authenticateResponse, prom)
+		authErr = b.handleResponsePromise(authenticateRequest, authenticateResponse, prom)
 		if authErr != nil {
 			Logger.Printf("Error while performing SASL Auth %s\n", b.addr)
 			return nil, authErr
@@ -1280,7 +1280,7 @@ func (b *Broker) sendAndReceiveSASLHandshake(saslType SASLMechanism, version int
 	b.updateIncomingCommunicationMetrics(n+8, time.Since(requestTime))
 	res := &SaslHandshakeResponse{}
 
-	err = versionedDecode(payload, res, 0)
+	err = versionedDecode(payload, res, 0, b.conf.MetricRegistry)
 	if err != nil {
 		Logger.Printf("Failed to parse SASL handshake : %s\n", err.Error())
 		return err

diff --git a/consumer_group_members_test.go b/consumer_group_members_test.go
@@ -59,7 +59,7 @@ func TestConsumerGroupMemberMetadata(t *testing.T) {
 	}
 
 	meta2 := new(ConsumerGroupMemberMetadata)
-	err = decode(buf, meta2)
+	err = decode(buf, meta2, nil)
 	if err != nil {
 		t.Error("Failed to decode data", err)
 	} else if !reflect.DeepEqual(meta, meta2) {
@@ -69,10 +69,10 @@ func TestConsumerGroupMemberMetadata(t *testing.T) {
 
 func TestConsumerGroupMemberMetadataV1Decode(t *testing.T) {
 	meta := new(ConsumerGroupMemberMetadata)
-	if err := decode(groupMemberMetadataV1, meta); err != nil {
+	if err := decode(groupMemberMetadataV1, meta, nil); err != nil {
 		t.Error("Failed to decode V1 data", err)
 	}
-	if err := decode(groupMemberMetadataV1Bad, meta); err != nil {
+	if err := decode(groupMemberMetadataV1Bad, meta, nil); err != nil {
 		t.Error("Failed to decode V1 'bad' data", err)
 	}
 }
@@ -94,7 +94,7 @@ func TestConsumerGroupMemberAssignment(t *testing.T) {
 	}
 
 	amt2 := new(ConsumerGroupMemberAssignment)
-	err = decode(buf, amt2)
+	err = decode(buf, amt2, nil)
 	if err != nil {
 		t.Error("Failed to decode data", err)
 	} else if !reflect.DeepEqual(amt, amt2) {

diff --git a/consumer_metadata_response_test.go b/consumer_metadata_response_test.go
@@ -26,7 +26,7 @@ func TestConsumerMetadataResponseError(t *testing.T) {
 	testEncodable(t, "", response, consumerMetadataResponseError)
 
 	decodedResp := &ConsumerMetadataResponse{}
-	if err := versionedDecode(consumerMetadataResponseError, decodedResp, 0); err != nil {
+	if err := versionedDecode(consumerMetadataResponseError, decodedResp, 0, nil); err != nil {
 		t.Error("could not decode: ", err)
 	}
 

diff --git a/describe_groups_response.go b/describe_groups_response.go
@@ -250,7 +250,7 @@ func (gmd *GroupMemberDescription) GetMemberAssignment() (*ConsumerGroupMemberAs
 		return nil, nil
 	}
 	assignment := new(ConsumerGroupMemberAssignment)
-	err := decode(gmd.MemberAssignment, assignment)
+	err := decode(gmd.MemberAssignment, assignment, nil)
 	return assignment, err
 }
 
@@ -259,6 +259,6 @@ func (gmd *GroupMemberDescription) GetMemberMetadata() (*ConsumerGroupMemberMeta
 		return nil, nil
 	}
 	metadata := new(ConsumerGroupMemberMetadata)
-	err := decode(gmd.MemberMetadata, metadata)
+	err := decode(gmd.MemberMetadata, metadata, nil)
 	return metadata, err
 }
diff --git a/encoder_decoder.go b/encoder_decoder.go
@@ -57,12 +57,15 @@ type versionedDecoder interface {
 
 // decode takes bytes and a decoder and fills the fields of the decoder from the bytes,
 // interpreted using Kafka's encoding rules.
-func decode(buf []byte, in decoder) error {
+func decode(buf []byte, in decoder, metricRegistry metrics.Registry) error {
 	if buf == nil {
 		return nil
 	}
 
-	helper := realDecoder{raw: buf}
+	helper := realDecoder{
+		raw:      buf,
+		registry: metricRegistry,
+	}
 	err := in.decode(&helper)
 	if err != nil {
 		return err
@@ -75,12 +78,15 @@ func decode(buf []byte, in decoder) error {
 	return nil
 }
 
-func versionedDecode(buf []byte, in versionedDecoder, version int16) error {
+func versionedDecode(buf []byte, in versionedDecoder, version int16, metricRegistry metrics.Registry) error {
 	if buf == nil {
 		return nil
 	}
 
-	helper := realDecoder{raw: buf}
+	helper := realDecoder{
+		raw:      buf,
+		registry: metricRegistry,
+	}
 	err := in.decode(&helper, version)
 	if err != nil {
 		return err

diff --git a/fetch_response.go b/fetch_response.go
@@ -4,6 +4,8 @@ import (
 	"errors"
 	"sort"
 	"time"
+
+	"github.com/rcrowley/go-metrics"
 )
 
 const invalidPreferredReplicaID = -1
@@ -60,6 +62,12 @@ type FetchResponseBlock struct {
 }
 
 func (b *FetchResponseBlock) decode(pd packetDecoder, version int16) (err error) {
+	metricRegistry := pd.metricRegistry()
+	var sizeMetric metrics.Histogram
+	if metricRegistry != nil {
+		sizeMetric = getOrRegisterHistogram("consumer-fetch-response-size", metricRegistry)
+	}
+
 	tmp, err := pd.getInt16()
 	if err != nil {
 		return err
@@ -115,6 +123,9 @@ func (b *FetchResponseBlock) decode(pd packetDecoder, version int16) (err error)
 	if err != nil {
 		return err
 	}
+	if sizeMetric != nil {
+		sizeMetric.Update(int64(recordsSize))
+	}
 
 	recordsDecoder, err := pd.getSubset(int(recordsSize))
 	if err != nil {

diff --git a/join_group_response.go b/join_group_response.go
@@ -21,7 +21,7 @@ func (r *JoinGroupResponse) GetMembers() (map[string]ConsumerGroupMemberMetadata
 	members := make(map[string]ConsumerGroupMemberMetadata, len(r.Members))
 	for _, member := range r.Members {
 		meta := new(ConsumerGroupMemberMetadata)
-		if err := decode(member.Metadata, meta); err != nil {
+		if err := decode(member.Metadata, meta, nil); err != nil {
 			return nil, err
 		}
 		members[member.MemberId] = *meta

diff --git a/message_test.go b/message_test.go
@@ -236,7 +236,7 @@ func TestMessageDecodingVersion1(t *testing.T) {
 
 func TestMessageDecodingUnknownVersions(t *testing.T) {
 	message := Message{Version: 2}
-	err := decode(emptyV2Message, &message)
+	err := decode(emptyV2Message, &message, nil)
 	if err == nil {
 		t.Error("Decoding did not produce an error for an unknown magic byte")
 	}

diff --git a/packet_decoder.go b/packet_decoder.go
@@ -1,5 +1,7 @@
 package sarama
 
+import "github.com/rcrowley/go-metrics"
+
 // PacketDecoder is the interface providing helpers for reading with Kafka's encoding rules.
 // Types implementing Decoder only need to worry about calling methods like GetString,
 // not about how a string is represented in Kafka.
@@ -40,6 +42,9 @@ type packetDecoder interface {
 	// Stacks, see PushDecoder
 	push(in pushDecoder) error
 	pop() error
+
+	// To record metrics when provided
+	metricRegistry() metrics.Registry
 }
 
 // PushDecoder is the interface for decoding fields like CRCs and lengths where the validity

diff --git a/real_decoder.go b/real_decoder.go
@@ -3,6 +3,8 @@ package sarama
 import (
 	"encoding/binary"
 	"math"
+
+	"github.com/rcrowley/go-metrics"
 )
 
 var (
@@ -15,9 +17,10 @@ var (
 )
 
 type realDecoder struct {
-	raw   []byte
-	off   int
-	stack []pushDecoder
+	raw      []byte
+	off      int
+	stack    []pushDecoder
+	registry metrics.Registry
 }
 
 // primitives
@@ -459,3 +462,7 @@ func (rd *realDecoder) pop() error {
 
 	return in.check(rd.off, rd.raw)
 }
+
+func (rd *realDecoder) metricRegistry() metrics.Registry {
+	return rd.registry
+}
diff --git a/record_batch.go b/record_batch.go
@@ -186,7 +186,7 @@ func (b *RecordBatch) decode(pd packetDecoder) (err error) {
 	}
 
 	b.recordsLen = len(recBuffer)
-	err = decode(recBuffer, recordsArray(b.Records))
+	err = decode(recBuffer, recordsArray(b.Records), nil)
 	if errors.Is(err, ErrInsufficientData) {
 		b.PartialTrailingRecord = true
 		b.Records = nil

diff --git a/records_test.go b/records_test.go
@@ -33,11 +33,11 @@ func TestLegacyRecords(t *testing.T) {
 	set = &MessageSet{}
 	r = Records{}
 
-	err = decode(exp, set)
+	err = decode(exp, set, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
-	err = decode(buf, &r)
+	err = decode(buf, &r, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -110,11 +110,11 @@ func TestDefaultRecords(t *testing.T) {
 	batch = &RecordBatch{}
 	r = Records{}
 
-	err = decode(exp, batch)
+	err = decode(exp, batch, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
-	err = decode(buf, &r)
+	err = decode(buf, &r, nil)
 	if err != nil {
 		t.Fatal(err)
 	}

diff --git a/request.go b/request.go
@@ -109,7 +109,7 @@ func decodeRequest(r io.Reader) (*request, int, error) {
 	bytesRead += len(encodedReq)
 
 	req := &request{}
-	if err := decode(encodedReq, req); err != nil {
+	if err := decode(encodedReq, req, nil); err != nil {
 		return nil, bytesRead, err
 	}
 

diff --git a/request_test.go b/request_test.go
@@ -21,14 +21,14 @@ func testEncodable(t *testing.T, name string, in encoder, expect []byte) {
 }
 
 func testDecodable(t *testing.T, name string, out decoder, in []byte) {
-	err := decode(in, out)
+	err := decode(in, out, nil)
 	if err != nil {
 		t.Error("Decoding", name, "failed:", err)
 	}
 }
 
 func testVersionDecodable(t *testing.T, name string, out versionedDecoder, in []byte, version int16) {
-	err := versionedDecode(in, out, version)
+	err := versionedDecode(in, out, version, nil)
 	if err != nil {
 		t.Error("Decoding", name, "version", version, "failed:", err)
 	}
@@ -99,7 +99,7 @@ func testResponse(t *testing.T, name string, res protocolBody, expected []byte)
 	}
 
 	decoded := reflect.New(reflect.TypeOf(res).Elem()).Interface().(versionedDecoder)
-	if err := versionedDecode(encoded, decoded, res.version()); err != nil {
+	if err := versionedDecode(encoded, decoded, res.version(), nil); err != nil {
 		t.Error("Decoding", name, "failed:", err)
 	}
 

diff --git a/sarama.go b/sarama.go
@@ -71,6 +71,7 @@ Consumer related metrics:
 	| consumer-fetch-rate                       | meter      | Fetch requests/second sent to all brokers                                            |
 	| consumer-fetch-rate-for-broker-<broker>   | meter      | Fetch requests/second sent to a given broker                                         |
 	| consumer-fetch-rate-for-topic-<topic>     | meter      | Fetch requests/second sent for a given topic                                         |
+	| consumer-fetch-response-size              | histogram  | Distribution of the fetch response size in bytes                                     |
 	| consumer-group-join-total-<GroupID>       | counter    | Total count of consumer group join attempts                                          |
 	| consumer-group-join-failed-<GroupID>      | counter    | Total count of consumer group join failures                                          |
 	| consumer-group-sync-total-<GroupID>       | counter    | Total count of consumer group sync attempts                                          |

diff --git a/sync_group_response.go b/sync_group_response.go
@@ -15,7 +15,7 @@ type SyncGroupResponse struct {
 
 func (r *SyncGroupResponse) GetMemberAssignment() (*ConsumerGroupMemberAssignment, error) {
 	assignment := new(ConsumerGroupMemberAssignment)
-	err := decode(r.MemberAssignment, assignment)
+	err := decode(r.MemberAssignment, assignment, nil)
 	return assignment, err
 }