implement context cancellation on db error

pkg/file/file.go

@@ -7,7 +7,6 @@ import (
 	"io"
 	"log"
 	"os"
-	"time"
 
 	"git.k-space.ee/k-space/logmower-shipper/pkg/globals"
 	"git.k-space.ee/k-space/logmower-shipper/pkg/lines"
@@ -29,20 +28,8 @@ type File struct {
 
 // TODO: caller could call duplicate shipFile of same name on file replace: sends might not work properly
 func (f File) Process(ctx context.Context, db *mongo.Collection, recordLimitBytes int) {
-	lineChan := make(chan lines.Raw)
-	defer close(lineChan)
-
-	dbQueue := make(chan m.Record, SendQueueLimit)
-	go lines.RawC(lineChan).Process(recordLimitBytes, dbQueue)
-
-	waitGo := util.GoWg(func() {
-		sender.Queue(dbQueue).Sender(db, f.MetricsName)
-	})
-	defer waitGo()
-
-	// TODO: better way to kill or wait for sendQueue before retrying (or duplicates?)
 	_ = wait.ManagedExponentialBackoffWithContext(ctx, globals.Backoff(), func() (done bool, _ error) {
-		err := f.trySubmit(ctx, db, lineChan)
+		err := f.process(ctx, db, recordLimitBytes)
 		if err == nil {
 			return true, nil
 		}
@@ -55,20 +42,39 @@ func (f File) Process(ctx context.Context, db *mongo.Collection, recordLimitByte
 	})
 }
 
-// use submitter(), don't use directly
-func (f File) trySubmit(ctx context.Context, db *mongo.Collection, sendQueue chan<- lines.Raw) error {
-	lFile := lines.File(f) // file.File, but avoiding import cycle
+func (f File) launchChannels(cancel func(), db *mongo.Collection, recordLimitBytes int) (_ chan<- lines.Raw, deferFn func()) {
+	lineOut := make(chan lines.Raw)
 
-	// TODO: better way for respecting ?killing sender for retry
-	for {
-		if len(sendQueue) == 0 {
-			break
-		}
-		time.Sleep(time.Second)
+	sctx, scancel := context.WithCancel(context.Background())
+	cancelAll := func() {
+		cancel()
+		scancel()
 	}
 
+	dbQueue := make(chan m.Record, SendQueueLimit)
+	go lines.RawC(lineOut).Process(sctx, recordLimitBytes, dbQueue)
+
+	waitBatchSend := util.GoWg(func() {
+		sender.Queue(dbQueue).Sender(db, f.MetricsName, cancelAll)
+	})
+
+	return lineOut, func() {
+		close(lineOut)
+		waitBatchSend()
+	}
+}
+
+// use submitter(), don't use directly
+func (f File) process(ctx context.Context, db *mongo.Collection, recordLimitBytes int) error {
+	lFile := lines.File(f) // file.File, but avoiding import cycle
+
+	sctx, cancel := context.WithCancel(ctx)
+
+	lineOut, dfn := f.launchChannels(cancel, db, recordLimitBytes)
+	defer dfn()
+
 	// get files with offset
-	offsetResult, _ := mongoWithErr(db.FindOne(globals.MongoTimeout(ctx),
+	offsetResult, _ := mongoWithErr(db.FindOne(globals.MongoTimeout(sctx),
 		bson.D{{Key: m.RecordKeyHostId, Value: f.Host.Id}, {Key: m.RecordKeyFilePath, Value: f.Path}},
 		&mongoOpt.FindOneOptions{Sort: bson.D{{Key: m.RecordKeyOffset, Value: -1}}}, // sort descending (get largest)
 	))
@@ -77,24 +83,20 @@ func (f File) trySubmit(ctx context.Context, db *mongo.Collection, sendQueue cha
 	if err != nil && !errors.Is(err, mongo.ErrNoDocuments) {
 		return fmt.Errorf("retrieving offset from database: %w", err)
 	}
-
 	dbOffset := m.RecordOffsetFromBson(&offsetResultBytes)
 
+	// for promFileChatcupDone
 	fi, err := os.Stat(f.Path)
 	if err != nil {
 		return fmt.Errorf("getting original file size: %w", err)
 	}
 	startSize := fi.Size()
 
-	sctx, cancel := context.WithCancel(ctx)
-	defer cancel()
-
-	promFileInitialSeekSkipped.WithLabelValues(f.MetricsName).Set(float64(dbOffset))
-
-	lineChan, errChan, err := util.TailFile(sctx, f.Path, dbOffset, io.SeekStart)
+	lineIn, errChan, err := util.TailFile(sctx, f.Path, dbOffset, io.SeekStart)
 	if err != nil {
 		return fmt.Errorf("tailing file: %w", err)
 	}
+	promFileInitialSeekSkipped.WithLabelValues(f.MetricsName).Set(float64(dbOffset))
 
 	var catchUpped bool
 	promFileCatchupDone.WithLabelValues(f.MetricsName).Set(0)
@@ -104,7 +106,7 @@ func (f File) trySubmit(ctx context.Context, db *mongo.Collection, sendQueue cha
 		case err := <-errChan:
 			return fmt.Errorf("tailing file: %w", err)
 
-		case line, ok := <-lineChan:
+		case line, ok := <-lineIn:
 			if !ok {
 				return nil
 			}
@@ -123,11 +125,15 @@ func (f File) trySubmit(ctx context.Context, db *mongo.Collection, sendQueue cha
 				continue
 			}
 
-			sendQueue <- lines.Raw{
+			select {
+			case <-sctx.Done():
+
+			case lineOut <- lines.Raw{
 				File: &lFile,
 
 				Offset: line.EndOffset,
 				B:      line.Bytes,
+			}:
 			}
 		}
 	}