Replace io.ReadSeeker with io.Reader

log/slow/parser.go

@@ -61,7 +61,7 @@ var (
 
 // SlowLogParser parses a MySQL slow log. It implements the LogParser interface.
 type SlowLogParser struct {
-	reader io.ReadSeeker
+	reader io.Reader
 	opt    log.Options
 	// --
 	stopChan    chan bool
@@ -78,7 +78,7 @@ type SlowLogParser struct {
 }
 
 // NewSlowLogParser returns a new SlowLogParser that reads from the open file.
-func NewSlowLogParser(r io.ReadSeeker, opt log.Options) *SlowLogParser {
+func NewSlowLogParser(r io.Reader, opt log.Options) *SlowLogParser {
 	if opt.DefaultLocation == nil {
 		// Old MySQL format assumes time is taken from SYSTEM.
 		opt.DefaultLocation = time.Local
@@ -130,8 +130,14 @@ func (p *SlowLogParser) Start() error {
 	// Seek to the offset, if any.
 	// @todo error if start off > file size
 	if p.opt.StartOffset > 0 {
-		if _, err := p.reader.Seek(int64(p.opt.StartOffset), os.SEEK_SET); err != nil {
-			return err
+		if reader, ok := p.reader.(io.ReadSeeker); ok {
+			if _, err := reader.Seek(int64(p.opt.StartOffset), os.SEEK_SET); err != nil {
+				return err
+			}
+		} else {
+			if _, err := io.CopyN(io.Discard, p.reader, int64(p.opt.StartOffset)); err != nil {
+				return err
+			}
 		}
 	}
 

log/slow/parser_test.go

@@ -32,6 +32,7 @@ package slow_test
 
 import (
 	"bytes"
+	"io"
 	l "log"
 	"os"
 	"path"
@@ -1986,3 +1987,27 @@ SELECT fruit FROM trees;
 
 	assert.NotEqual(t, 0, len(got))
 }
+
+func TestParseFromMultiReader(t *testing.T) {
+	query1 := `
+# Time: 071218 11:48:27
+# User@Host: [SQL_SLAVE] @  []
+# Thread_id: 3  Schema: db1
+# Query_time: 0.000012  Lock_time: 0.000000  Rows_sent: 0  Rows_examined: 0`
+	query2 := `
+use db2;
+SELECT fruit FROM trees;
+`
+
+	buf1 := bytes.NewReader([]byte(query1))
+	buf2 := bytes.NewReader([]byte(query2))
+	p := parser.NewSlowLogParser(io.MultiReader(buf1, buf2), opt)
+
+	got := []log.Event{}
+	go p.Start()
+	for e := range p.EventChan() {
+		got = append(got, *e)
+	}
+
+	assert.NotEqual(t, 0, len(got))
+}