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Merge pull request #50 from featalion/newline-fix 

PR #40 with test case

closes #35 and closes #40
This commit is contained in:
Sridhar Ratnakumar 2015-06-17 15:59:14 -07:00
parent 068b72961a fe151849bb
commit f9f753ab01
2 changed files with 40 additions and 6 deletions
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29
tail.go
View File

@ -211,10 +211,17 @@ func (tail *Tail) tailFileSync() {
// Read line by line. // Read line by line.
for { for {
// grab the position in case we need to back up in the event of a half-line
offset, err := tail.Tell()
if err != nil {
tail.Kill(err)
return
}
line, err := tail.readLine() line, err := tail.readLine()
// Process `line` even if err is EOF. // Process `line` even if err is EOF.
if err == nil || (err == io.EOF && line != "") { if err == nil {
cooloff := !tail.sendLine(line) cooloff := !tail.sendLine(line)
if cooloff { if cooloff {
// Wait a second before seeking till the end of // Wait a second before seeking till the end of
@ -236,8 +243,22 @@ func (tail *Tail) tailFileSync() {
} }
} else if err == io.EOF { } else if err == io.EOF {
if !tail.Follow { if !tail.Follow {
if line != "" {
tail.sendLine(line)
}
return return
} }
if tail.Follow && line != "" {
// this has the potential to never return the last line if
// it's not followed by a newline; seems a fair trade here
err := tail.seekTo(SeekInfo{Offset: offset, Whence: 0})
if err != nil {
tail.Kill(err)
return
}
}
// When EOF is reached, wait for more data to become // When EOF is reached, wait for more data to become
// available. Wait strategy is based on the `tail.watcher` // available. Wait strategy is based on the `tail.watcher`
// implementation (inotify or polling). // implementation (inotify or polling).
@ -317,7 +338,11 @@ func (tail *Tail) openReader() {
} }
func (tail *Tail) seekEnd() error { func (tail *Tail) seekEnd() error {
_, err := tail.file.Seek(0, 2) return tail.seekTo(SeekInfo{Offset: 0, Whence: 2})
}
func (tail *Tail) seekTo(pos SeekInfo) error {
_, err := tail.file.Seek(pos.Offset, pos.Whence)
if err != nil { if err != nil {
return fmt.Errorf("Seek error on %s: %s", tail.Filename, err) return fmt.Errorf("Seek error on %s: %s", tail.Filename, err)
} }

17
tail_test.go
View File

@ -54,11 +54,11 @@ func TestStop(t *testing.T) {
Cleanup() Cleanup()
} }
func TestMaxLineSize(_t *testing.T) { func MaxLineSizeT(_t *testing.T, follow bool, fileContent string, expected []string) {
t := NewTailTest("maxlinesize", _t) t := NewTailTest("maxlinesize", _t)
t.CreateFile("test.txt", "hello\nworld\nfin\nhe") t.CreateFile("test.txt", fileContent)
tail := t.StartTail("test.txt", Config{Follow: true, Location: nil, MaxLineSize: 3}) tail := t.StartTail("test.txt", Config{Follow: follow, Location: nil, MaxLineSize: 3})
go t.VerifyTailOutput(tail, []string{"hel", "lo", "wor", "ld", "fin", "he"}) go t.VerifyTailOutput(tail, expected)
// Delete after a reasonable delay, to give tail sufficient time // Delete after a reasonable delay, to give tail sufficient time
// to read all lines. // to read all lines.
@ -68,6 +68,15 @@ func TestMaxLineSize(_t *testing.T) {
Cleanup() Cleanup()
} }
func TestMaxLineSizeFollow(_t *testing.T) {
// As last file line does not end with newline, it will not be present in tail's output
MaxLineSizeT(_t, true, "hello\nworld\nfin\nhe", []string{"hel", "lo", "wor", "ld", "fin"})
}
func TestMaxLineSizeNoFollow(_t *testing.T) {
MaxLineSizeT(_t, false, "hello\nworld\nfin\nhe", []string{"hel", "lo", "wor", "ld", "fin", "he"})
}
func TestOver4096ByteLine(_t *testing.T) { func TestOver4096ByteLine(_t *testing.T) {
t := NewTailTest("Over4096ByteLine", _t) t := NewTailTest("Over4096ByteLine", _t)
testString := strings.Repeat("a", 4097) testString := strings.Repeat("a", 4097)