chore: Clean up lint errors

internal/tailer/logstream/filestream.go

@@ -111,7 +111,7 @@ func (fs *fileStream) stream(ctx context.Context, wg *sync.WaitGroup, waker wake
 				}
 			}
 
-			if err != nil && err != io.EOF {
+			if err != nil && !errors.Is(err, io.EOF) {
 				logErrors.Add(fs.sourcename, 1)
 				// TODO: This could be generalised to check for any retryable
 				// errors, and end on unretriables; e.g. ESTALE looks
@@ -129,7 +129,7 @@ func (fs *fileStream) stream(ctx context.Context, wg *sync.WaitGroup, waker wake
 			}
 
 			// If we have read no bytes and are at EOF, check for truncation and rotation.
-			if err == io.EOF && count == 0 {
+			if errors.Is(err, io.EOF) && count == 0 {
 				glog.V(2).Infof("stream(%s): eof an no bytes", fs.sourcename)
 				// Both rotation and truncation need to stat, so check for
 				// rotation first.  It is assumed that rotation is the more
@@ -193,7 +193,7 @@ func (fs *fileStream) stream(ctx context.Context, wg *sync.WaitGroup, waker wake
 		Sleep:
 			// If we get here it's because we've stalled.  First test to see if it's
 			// time to exit.
-			if err == io.EOF {
+			if errors.Is(err, io.EOF) {
 				if oneShot == OneShotEnabled {
 					// Exit now, because oneShot means read only to EOF.
 					glog.V(2).Infof("stream(%s): EOF in one shot mode, exiting", fs.sourcename)

internal/tailer/logstream/reader.go

@@ -6,14 +6,15 @@ package logstream
 import (
 	"bytes"
 	"context"
+	"expvar"
 	"io"
 	"time"
 
 	"github.com/google/mtail/internal/logline"
 )
 
 // logLines counts the number of lines read per log file.
-// var logLines = expvar.NewMap("log_lines_total")
+var logLines = expvar.NewMap("log_lines_total")
 
 // LineReader reads lines from input and sends lines through the channel
 type LineReader struct {
@@ -26,7 +27,6 @@ type LineReader struct {
 	size int
 	buf  []byte
 	off  int // tracks the start of the next line in buf
-	end  int // tracks the end of the next line in buf
 }
 
 // NewLineReader creates a new LineReader
@@ -44,9 +44,7 @@ func NewLineReader(sourcename string, lines chan<- *logline.LogLine, f io.Reader
 // ReadAndSend reads bytes from f, attempts to find line endings in the bytes read, and sends them to the lines channel.  It manages the read buffer size to make sure we can always read size bytes.
 func (lr *LineReader) ReadAndSend(ctx context.Context) (count int, err error) {
 	if cap(lr.buf)-len(lr.buf) < lr.size {
-		len := len(lr.buf)
-		lr.buf = append(make([]byte, 0, len+lr.size), lr.buf...)
-
+		lr.buf = append(make([]byte, 0, len(lr.buf)+lr.size), lr.buf...)
 	}
 	count, err = lr.f.Read(lr.buf[len(lr.buf):cap(lr.buf)])
 	if lr.staleTimer != nil {
@@ -55,7 +53,9 @@ func (lr *LineReader) ReadAndSend(ctx context.Context) (count int, err error) {
 	lr.buf = lr.buf[:len(lr.buf)+count] // reslice to set len
 	if count > 0 {
 		lr.staleTimer = time.AfterFunc(time.Hour*24, lr.cancel)
-		for ok := true; ok; ok = lr.send(ctx) {
+		ok := true
+		for ok {
+			ok = lr.send(ctx)
 		}
 		// reslice to drop earlier bytes
 		lr.buf = lr.buf[lr.off:len(lr.buf)]

internal/tailer/logstream/reader_test.go

@@ -6,6 +6,7 @@ package logstream
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"testing"
@@ -95,7 +96,7 @@ func TestReadAndSendSplitBytes(t *testing.T) {
 				}
 
 				count, err := lr.ReadAndSend(context.Background())
-				if err != nil && err != io.EOF {
+				if err != nil && !errors.Is(err, io.EOF) {
 					t.Errorf("ReadAndSend(%v) -> %v", origBytes[chunkOffset:chunkEnd], err)
 				}
 				byteCount += count