Merge pull request #39477 from dashpole/zombie_wc

Automatic merge from submit-queue (batch tested with PRs 39486, 37288, 39477, 39455, 39542) Fix wc zombie goroutine issue in volume util See [Cadvisor #1558](google/cadvisor#1558). This should solve problems for those using images that do not support "wc". cc: @timstclair
kubernetes · Jan 10, 2017 · c03ec46 · c03ec46
2 parents dd544bb + 094cfd7
commit c03ec46
Showing 1 changed file with 19 additions and 26 deletions.
diff --git a/pkg/volume/util/fs.go b/pkg/volume/util/fs.go
@@ -22,7 +22,6 @@ import (
 	"bytes"
 	"fmt"
 	"os/exec"
-	"strconv"
 	"strings"
 	"syscall"
 
@@ -69,35 +68,29 @@ func Du(path string) (*resource.Quantity, error) {
 	return &used, nil
 }
 
-// Find uses the command `find <path> -dev -printf '.' | wc -c` to count files and directories.
+// Find uses the equivalent of the command `find <path> -dev -printf '.' | wc -c` to count files and directories.
 // While this is not an exact measure of inodes used, it is a very good approximation.
 func Find(path string) (int64, error) {
-	var stdout, stdwcerr, stdfinderr bytes.Buffer
-	var err error
+	if path == "" {
+		return 0, fmt.Errorf("invalid directory")
+	}
+	var counter byteCounter
+	var stderr bytes.Buffer
 	findCmd := exec.Command("find", path, "-xdev", "-printf", ".")
-	wcCmd := exec.Command("wc", "-c")
-	if wcCmd.Stdin, err = findCmd.StdoutPipe(); err != nil {
-		return 0, fmt.Errorf("failed to setup stdout for cmd %v - %v", findCmd.Args, err)
+	findCmd.Stdout, findCmd.Stderr = &counter, &stderr
+	if err := findCmd.Start(); err != nil {
+		return 0, fmt.Errorf("failed to exec cmd %v - %v; stderr: %v", findCmd.Args, err, stderr.String())
 	}
-	wcCmd.Stdout, wcCmd.Stderr, findCmd.Stderr = &stdout, &stdwcerr, &stdfinderr
-	if err = findCmd.Start(); err != nil {
-		return 0, fmt.Errorf("failed to exec cmd %v - %v; stderr: %v", findCmd.Args, err, stdfinderr.String())
+	if err := findCmd.Wait(); err != nil {
+		return 0, fmt.Errorf("cmd %v failed. stderr: %s; err: %v", findCmd.Args, stderr.String(), err)
 	}
+	return counter.bytesWritten, nil
+}
 
-	if err = wcCmd.Start(); err != nil {
-		return 0, fmt.Errorf("failed to exec cmd %v - %v; stderr %v", wcCmd.Args, err, stdwcerr.String())
-	}
-	err = findCmd.Wait()
-	if err != nil {
-		return 0, fmt.Errorf("cmd %v failed. stderr: %s; err: %v", findCmd.Args, stdfinderr.String(), err)
-	}
-	err = wcCmd.Wait()
-	if err != nil {
-		return 0, fmt.Errorf("cmd %v failed. stderr: %s; err: %v", wcCmd.Args, stdwcerr.String(), err)
-	}
-	inodeUsage, err := strconv.ParseInt(strings.TrimSpace(stdout.String()), 10, 64)
-	if err != nil {
-		return 0, fmt.Errorf("cannot parse cmds: %v, %v output %s - %s", findCmd.Args, wcCmd.Args, stdout.String(), err)
-	}
-	return inodeUsage, nil
+// Simple io.Writer implementation that counts how many bytes were written.
+type byteCounter struct{ bytesWritten int64 }
+
+func (b *byteCounter) Write(p []byte) (int, error) {
+	b.bytesWritten += int64(len(p))
+	return len(p), nil
 }