read from disk if not in memory

weed/mq/broker/broker_grpc_configure.go

@@ -8,10 +8,14 @@ import (
 	"github.com/seaweedfs/seaweedfs/weed/mq/pub_balancer"
 	"github.com/seaweedfs/seaweedfs/weed/mq/topic"
 	"github.com/seaweedfs/seaweedfs/weed/pb"
+	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
 	"github.com/seaweedfs/seaweedfs/weed/pb/mq_pb"
+	"github.com/seaweedfs/seaweedfs/weed/util"
 	"github.com/seaweedfs/seaweedfs/weed/util/log_buffer"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/proto"
+	"math"
 	"time"
 )
 
@@ -78,7 +82,7 @@ func (b *MessageQueueBroker) AssignTopicPartitions(c context.Context, request *m
 
 	// drain existing topic partition subscriptions
 	for _, assignment := range request.BrokerPartitionAssignments {
-		localPartition := topic.FromPbBrokerPartitionAssignment(self, assignment, b.genLogFlushFunc(request.Topic, assignment.Partition))
+		localPartition := topic.FromPbBrokerPartitionAssignment(self, assignment, b.genLogFlushFunc(request.Topic, assignment.Partition), b.genLogOnDiskReadFunc(request.Topic, assignment.Partition))
 		if request.IsDraining {
 			// TODO drain existing topic partition subscriptions
 
@@ -122,9 +126,10 @@ func (b *MessageQueueBroker) genLogFlushFunc(t *mq_pb.Topic, partition *mq_pb.Pa
 		}
 
 		startTime, stopTime = startTime.UTC(), stopTime.UTC()
-		fileName := startTime.Format(topic.TIME_FORMAT)
 
-		targetFile := fmt.Sprintf("%s/%s",partitionDir, fileName)
+		targetFile := fmt.Sprintf("%s/%s",partitionDir, startTime.Format(topic.TIME_FORMAT))
+
+		// TODO append block with more metadata
 
 		for {
 			if err := b.appendToFile(targetFile, buf); err != nil {
@@ -136,3 +141,126 @@ func (b *MessageQueueBroker) genLogFlushFunc(t *mq_pb.Topic, partition *mq_pb.Pa
 		}
 	}
 }
+
+func (b *MessageQueueBroker) genLogOnDiskReadFunc(t *mq_pb.Topic, partition *mq_pb.Partition) log_buffer.LogReadFromDiskFuncType {
+	topicDir := fmt.Sprintf("%s/%s/%s", filer.TopicsDir, t.Namespace, t.Name)
+	partitionGeneration := time.Unix(0, partition.UnixTimeNs).UTC().Format(topic.TIME_FORMAT)
+	partitionDir := fmt.Sprintf("%s/%s/%04d-%04d", topicDir, partitionGeneration, partition.RangeStart, partition.RangeStop)
+
+	lookupFileIdFn := func(fileId string) (targetUrls []string, err error) {
+		return b.MasterClient.LookupFileId(fileId)
+	}
+
+	eachChunkFn := func (buf []byte, eachLogEntryFn log_buffer.EachLogEntryFuncType, starTsNs, stopTsNs int64) (processedTsNs int64, err error) {
+		for pos := 0; pos+4 < len(buf); {
+
+			size := util.BytesToUint32(buf[pos : pos+4])
+			if pos+4+int(size) > len(buf) {
+				err = fmt.Errorf("LogOnDiskReadFunc: read [%d,%d) from [0,%d)", pos, pos+int(size)+4, len(buf))
+				return
+			}
+			entryData := buf[pos+4 : pos+4+int(size)]
+
+			logEntry := &filer_pb.LogEntry{}
+			if err = proto.Unmarshal(entryData, logEntry); err != nil {
+				pos += 4 + int(size)
+				err = fmt.Errorf("unexpected unmarshal mq_pb.Message: %v", err)
+				return
+			}
+			if logEntry.TsNs < starTsNs {
+				pos += 4 + int(size)
+				continue
+			}
+			if stopTsNs != 0 && logEntry.TsNs > stopTsNs {
+				println("stopTsNs", stopTsNs, "logEntry.TsNs", logEntry.TsNs)
+				return
+			}
+
+			if err = eachLogEntryFn(logEntry); err != nil {
+				err = fmt.Errorf("process log entry %v: %v", logEntry, err)
+				return
+			}
+
+			processedTsNs = logEntry.TsNs
+
+			pos += 4 + int(size)
+
+		}
+
+		return
+	}
+
+	eachFileFn := func(entry *filer_pb.Entry, eachLogEntryFn log_buffer.EachLogEntryFuncType, starTsNs, stopTsNs int64) (processedTsNs int64, err error) {
+		if len(entry.Content) > 0 {
+			glog.Warningf("this should not happen. unexpected content in %s/%s", partitionDir, entry.Name)
+			return
+		}
+		var urlStrings []string
+		for _, chunk := range entry.Chunks {
+			if chunk.Size == 0 {
+				continue
+			}
+			if chunk.IsChunkManifest{
+				glog.Warningf("this should not happen. unexpected chunk manifest in %s/%s", partitionDir, entry.Name)
+				return
+			}
+			urlStrings, err = lookupFileIdFn(chunk.FileId)
+			if err != nil {
+				err = fmt.Errorf("lookup %s: %v", chunk.FileId, err)
+				return
+			}
+			if len(urlStrings) == 0 {
+				err = fmt.Errorf("no url found for %s", chunk.FileId)
+				return
+			}
+
+			// try one of the urlString until util.Get(urlString) succeeds
+			var processed bool
+			for _, urlString := range urlStrings {
+				// TODO optimization opportunity: reuse the buffer
+				var data []byte
+				if data, _, err = util.Get(urlString); err == nil {
+					processed = true
+					if processedTsNs, err = eachChunkFn(data, eachLogEntryFn, starTsNs, stopTsNs); err != nil {
+						return
+					}
+					break
+				}
+			}
+			if !processed {
+				err = fmt.Errorf("no data processed for %s %s", entry.Name, chunk.FileId)
+				return
+			}
+
+		}
+		return
+	}
+
+	return func(startPosition log_buffer.MessagePosition, stopTsNs int64, eachLogEntryFn log_buffer.EachLogEntryFuncType) (lastReadPosition log_buffer.MessagePosition, isDone bool, err error) {
+		startFileName := startPosition.UTC().Format(topic.TIME_FORMAT)
+		startTsNs := startPosition.Time.UnixNano()
+		stopTime := time.Unix(0, stopTsNs)
+		var processedTsNs int64
+		err = b.WithFilerClient(false, func(client filer_pb.SeaweedFilerClient) error {
+			return filer_pb.SeaweedList(client, partitionDir, "", func(entry *filer_pb.Entry, isLast bool) error {
+				if entry.IsDirectory {
+					return nil
+				}
+				if stopTsNs!=0 && entry.Name > stopTime.UTC().Format(topic.TIME_FORMAT) {
+					isDone = true
+					return nil
+				}
+				if entry.Name < startPosition.UTC().Format(topic.TIME_FORMAT) {
+					return nil
+				}
+				if processedTsNs, err = eachFileFn(entry, eachLogEntryFn, startTsNs, stopTsNs); err != nil {
+					return err
+				}
+				return nil
+
+			}, startFileName, true, math.MaxInt32)
+		})
+		lastReadPosition = log_buffer.NewMessagePosition(processedTsNs, -2)
+		return
+	}
+}