kfake: add support for OffsetForLeaderEpoch

pkg/kfake/23_offset_for_leader_epoch.go

@@ -0,0 +1,111 @@
+package kfake
+
+import (
+	"sort"
+
+	"github.com/twmb/franz-go/pkg/kerr"
+	"github.com/twmb/franz-go/pkg/kmsg"
+)
+
+func init() { regKey(23, 3, 4) }
+
+func (c *Cluster) handleOffsetForLeaderEpoch(b *broker, kreq kmsg.Request) (kmsg.Response, error) {
+	req := kreq.(*kmsg.OffsetForLeaderEpochRequest)
+	resp := req.ResponseKind().(*kmsg.OffsetForLeaderEpochResponse)
+
+	if err := checkReqVersion(req.Key(), req.Version); err != nil {
+		return nil, err
+	}
+
+	tidx := make(map[string]int)
+	donet := func(t string, errCode int16) *kmsg.OffsetForLeaderEpochResponseTopic {
+		if i, ok := tidx[t]; ok {
+			return &resp.Topics[i]
+		}
+		tidx[t] = len(resp.Topics)
+		st := kmsg.NewOffsetForLeaderEpochResponseTopic()
+		st.Topic = t
+		resp.Topics = append(resp.Topics, st)
+		return &resp.Topics[len(resp.Topics)-1]
+	}
+	donep := func(t string, p int32, errCode int16) *kmsg.OffsetForLeaderEpochResponseTopicPartition {
+		sp := kmsg.NewOffsetForLeaderEpochResponseTopicPartition()
+		sp.Partition = p
+		sp.ErrorCode = errCode
+		st := donet(t, 0)
+		st.Partitions = append(st.Partitions, sp)
+		return &st.Partitions[len(st.Partitions)-1]
+	}
+
+	for _, rt := range req.Topics {
+		ps, ok := c.data.tps.gett(rt.Topic)
+		for _, rp := range rt.Partitions {
+			if req.ReplicaID != 1 {
+				donep(rt.Topic, rp.Partition, kerr.UnknownServerError.Code)
+				continue
+			}
+			if !ok {
+				donep(rt.Topic, rp.Partition, kerr.UnknownTopicOrPartition.Code)
+				continue
+			}
+			pd, ok := ps[rp.Partition]
+			if !ok {
+				donep(rt.Topic, rp.Partition, kerr.UnknownTopicOrPartition.Code)
+				continue
+			}
+			if pd.leader != b {
+				donep(rt.Topic, rp.Partition, kerr.NotLeaderForPartition.Code)
+				continue
+			}
+			if rp.CurrentLeaderEpoch < pd.epoch {
+				donep(rt.Topic, rp.Partition, kerr.FencedLeaderEpoch.Code)
+				continue
+			} else if rp.CurrentLeaderEpoch > pd.epoch {
+				donep(rt.Topic, rp.Partition, kerr.UnknownLeaderEpoch.Code)
+				continue
+			}
+
+			sp := donep(rt.Topic, rp.Partition, 0)
+
+			// If the user is requesting our current epoch, we return the HWM.
+			if rp.LeaderEpoch == pd.epoch {
+				sp.LeaderEpoch = pd.epoch
+				sp.EndOffset = pd.highWatermark
+				continue
+			}
+
+			// What is the largest epoch after the requested epoch?
+			idx, _ := sort.Find(len(pd.batches), func(idx int) int {
+				batchEpoch := pd.batches[idx].epoch
+				switch {
+				case rp.LeaderEpoch <= batchEpoch:
+					return -1
+				default:
+					return 1
+				}
+			})
+
+			// Requested epoch is not yet known: keep -1 returns.
+			if idx == len(pd.batches) {
+				sp.LeaderEpoch = -1
+				sp.EndOffset = -1
+				continue
+			}
+
+			// Requested epoch is before the LSO: return the requested
+			// epoch and the LSO.
+			if idx == 0 && pd.batches[0].epoch > rp.LeaderEpoch {
+				sp.LeaderEpoch = rp.LeaderEpoch
+				sp.EndOffset = pd.logStartOffset
+				continue
+			}
+
+			// The requested epoch exists and is not the latest
+			// epoch, we return the end offset being the first
+			// offset of the next epoch.
+			sp.LeaderEpoch = pd.batches[idx].epoch
+			sp.EndOffset = pd.batches[idx+1].FirstOffset
+		}
+	}
+	return resp, nil
+}

pkg/kfake/cluster.go

@@ -229,6 +229,8 @@ func (c *Cluster) run() {
 			kresp, err = c.handleDeleteTopics(creq.cc.b, kreq)
 		case kmsg.InitProducerID:
 			kresp, err = c.handleInitProducerID(kreq)
+		case kmsg.OffsetForLeaderEpoch:
+			kresp, err = c.handleOffsetForLeaderEpoch(kreq)
 		case kmsg.CreatePartitions:
 			kresp, err = c.handleCreatePartitions(creq.cc.b, kreq)
 		default: