Prioritize fresh process log sessions

spool/log_spool.go

@@ -10,6 +10,7 @@ import (
 	"sort"
 	"strings"
 	"sync"
+	"time"
 
 	"browser.local/run/protocol"
 )
@@ -44,8 +45,9 @@ type durableLogBatch struct {
 }
 
 type pendingLogSegment struct {
-	path  string
-	batch durableLogBatch
+	path    string
+	modTime time.Time
+	batch   durableLogBatch
 }
 
 func NewLogSpool(dir string) (LogSpool, error) {
@@ -317,11 +319,41 @@ func (spool LogSpool) pendingSegmentsLocked() ([]pendingLogSegment, error) {
 			}
 			return nil, err
 		}
-		segments = append(segments, pendingLogSegment{path: path, batch: batch})
+		var modTime time.Time
+		if info, statErr := os.Stat(path); statErr == nil {
+			modTime = info.ModTime()
+		}
+		segments = append(segments, pendingLogSegment{path: path, modTime: modTime, batch: batch})
 	}
+	sort.SliceStable(segments, func(i, j int) bool { return pendingLogSegmentBefore(segments[i], segments[j]) })
 	return segments, nil
 }
 
+func pendingLogSegmentBefore(left pendingLogSegment, right pendingLogSegment) bool {
+	leftBatch := left.batch.LogBatchIngestRequest
+	rightBatch := right.batch.LogBatchIngestRequest
+	if leftBatch.LogStreamID == rightBatch.LogStreamID {
+		if leftBatch.FirstSeq != rightBatch.FirstSeq {
+			return leftBatch.FirstSeq < rightBatch.FirstSeq
+		}
+		return leftBatch.LastSeq < rightBatch.LastSeq
+	}
+	leftTime := pendingLogSegmentPriorityTime(left)
+	rightTime := pendingLogSegmentPriorityTime(right)
+	if !leftTime.Equal(rightTime) {
+		return leftTime.After(rightTime)
+	}
+	return left.path < right.path
+}
+
+func pendingLogSegmentPriorityTime(segment pendingLogSegment) time.Time {
+	batch := segment.batch.LogBatchIngestRequest
+	if batch.Source == "process" && strings.TrimSpace(batch.LogSessionID) != "" && !batch.SessionStartedAt.IsZero() {
+		return batch.SessionStartedAt
+	}
+	return segment.modTime
+}
+
 func (spool LogSpool) Ack(response protocol.LogBatchIngestResponse) error {
 	if response.AcceptedFrom == 0 || response.AcceptedTo < response.AcceptedFrom {
 		return nil