util: make ExecComand return stdout and stderr as string

Most consumers of util.ExecCommand() need to convert the returned []byte
format of stdout and/or stderr to string. By having util.ExecCommand()
return strings instead, the code gets a little simpler.

A few commands return JSON that needs to be parsed. These commands will
be replaced by go-ceph implementations later on. For now, convert the
strings back to []byte when needed.

Signed-off-by: Niels de Vos <ndevos@redhat.com>

internal/cephfs/util.go

@@ -41,7 +41,7 @@ func execCommandJSON(ctx context.Context, v interface{}, program string, args ..
 		return err
 	}
 
-	if err = json.Unmarshal(stdout, v); err != nil {
+	if err = json.Unmarshal([]byte(stdout), v); err != nil {
 		return fmt.Errorf("failed to unmarshal JSON for %s %v: %s: %w", program, util.StripSecretInArgs(args), stdout, err)
 	}
 

internal/cephfs/volume.go

@@ -67,16 +67,15 @@ func getVolumeRootPathCeph(ctx context.Context, volOptions *volumeOptions, cr *u
 		"--keyfile="+cr.KeyFile)
 
 	if err != nil {
-		stdErrString := string(stderr)
+		klog.Errorf(util.Log(ctx, "failed to get the rootpath for the vol %s(%s) stdError %s"), string(volID), err, stderr)
-		klog.Errorf(util.Log(ctx, "failed to get the rootpath for the vol %s(%s) stdError %s"), string(volID), err, stdErrString)
 
-		if strings.HasPrefix(stdErrString, errNotFoundString) {
+		if strings.HasPrefix(stderr, errNotFoundString) {
 			return "", util.JoinErrors(ErrVolumeNotFound, err)
 		}
 
 		return "", err
 	}
-	return strings.TrimSuffix(string(stdout), "\n"), nil
+	return strings.TrimSuffix(stdout, "\n"), nil
 }
 
 type localClusterState struct {

internal/cephfs/volumemounter.go

@@ -176,7 +176,7 @@ func mountFuse(ctx context.Context, mountPoint string, cr *util.Credentials, vol
 	// We need "starting fuse" meaning the mount is ok
 	// and PID of the ceph-fuse daemon for unmount
 
-	match := fusePidRx.FindSubmatch(stderr)
+	match := fusePidRx.FindSubmatch([]byte(stderr))
 	// validMatchLength is set to 2 as match is expected
 	// to have 2 items, starting fuse and PID of the fuse daemon
 	const validMatchLength = 2

internal/rbd/rbd_attach.go

@@ -90,9 +90,9 @@ func rbdGetDeviceList(ctx context.Context, accessType string) ([]rbdDeviceInfo,
 	}
 
 	if accessType == accessTypeKRbd {
-		err = json.Unmarshal(stdout, &rbdDeviceList)
+		err = json.Unmarshal([]byte(stdout), &rbdDeviceList)
 	} else {
-		err = json.Unmarshal(stdout, &nbdDeviceList)
+		err = json.Unmarshal([]byte(stdout), &nbdDeviceList)
 	}
 	if err != nil {
 		return nil, fmt.Errorf("error to parse JSON output of device list for devices of type (%s): (%v)", accessType, err)
@@ -231,7 +231,7 @@ func createPath(ctx context.Context, volOpt *rbdVolume, cr *util.Credentials) (s
 	// Execute map
 	stdout, stderr, err := util.ExecCommand(ctx, rbd, mapOptions...)
 	if err != nil {
-		klog.Warningf(util.Log(ctx, "rbd: map error %v, rbd output: %s"), err, string(stderr))
+		klog.Warningf(util.Log(ctx, "rbd: map error %v, rbd output: %s"), err, stderr)
 		// unmap rbd image if connection timeout
 		if strings.Contains(err.Error(), rbdMapConnectionTimeout) {
 			detErr := detachRBDImageOrDeviceSpec(ctx, imagePath, true, isNbd, volOpt.Encrypted, volOpt.VolID)
@@ -239,9 +239,9 @@ func createPath(ctx context.Context, volOpt *rbdVolume, cr *util.Credentials) (s
 				klog.Warningf(util.Log(ctx, "rbd: %s unmap error %v"), imagePath, detErr)
 			}
 		}
-		return "", fmt.Errorf("rbd: map failed %v, rbd output: %s", err, string(stderr))
+		return "", fmt.Errorf("rbd: map failed with error %v, rbd error output: %s", err, stderr)
 	}
-	devicePath := strings.TrimSuffix(string(stdout), "\n")
+	devicePath := strings.TrimSuffix(stdout, "\n")
 
 	return devicePath, nil
 }
@@ -311,13 +311,13 @@ func detachRBDImageOrDeviceSpec(ctx context.Context, imageOrDeviceSpec string, i
 		// Messages for krbd and nbd differ, hence checking either of them for missing mapping
 		// This is not applicable when a device path is passed in
 		if isImageSpec &&
-			(strings.Contains(string(stderr), fmt.Sprintf(rbdUnmapCmdkRbdMissingMap, imageOrDeviceSpec)) ||
+			(strings.Contains(stderr, fmt.Sprintf(rbdUnmapCmdkRbdMissingMap, imageOrDeviceSpec)) ||
-				strings.Contains(string(stderr), fmt.Sprintf(rbdUnmapCmdNbdMissingMap, imageOrDeviceSpec))) {
+				strings.Contains(stderr, fmt.Sprintf(rbdUnmapCmdNbdMissingMap, imageOrDeviceSpec))) {
 			// Devices found not to be mapped are treated as a successful detach
 			util.TraceLog(ctx, "image or device spec (%s) not mapped", imageOrDeviceSpec)
 			return nil
 		}
-		return fmt.Errorf("rbd: unmap for spec (%s) failed (%v): (%s)", imageOrDeviceSpec, err, string(stderr))
+		return fmt.Errorf("rbd: unmap for spec (%s) failed (%v): (%s)", imageOrDeviceSpec, err, stderr)
 	}
 
 	return nil

internal/rbd/rbd_util.go

@@ -307,11 +307,11 @@ func addRbdManagerTask(ctx context.Context, pOpts *rbdVolume, arg []string) (boo
 
 	if err != nil {
 		switch {
-		case strings.Contains(string(stderr), rbdTaskRemoveCmdInvalidString1) &&
+		case strings.Contains(stderr, rbdTaskRemoveCmdInvalidString1) &&
-			strings.Contains(string(stderr), rbdTaskRemoveCmdInvalidString2):
+			strings.Contains(stderr, rbdTaskRemoveCmdInvalidString2):
 			klog.Warningf(util.Log(ctx, "cluster with cluster ID (%s) does not support Ceph manager based rbd commands (minimum ceph version required is v14.2.3)"), pOpts.ClusterID)
 			supported = false
-		case strings.HasPrefix(string(stderr), rbdTaskRemoveCmdAccessDeniedMessage):
+		case strings.HasPrefix(stderr, rbdTaskRemoveCmdAccessDeniedMessage):
 			klog.Warningf(util.Log(ctx, "access denied to Ceph MGR-based rbd commands on cluster ID (%s)"), pOpts.ClusterID)
 			supported = false
 		default:
@@ -883,17 +883,17 @@ func (rv *rbdVolume) updateVolWithImageInfo(cr *util.Credentials) error {
 		"info", rv.String())
 	if err != nil {
 		klog.Errorf("failed getting information for image (%s): (%s)", rv, err)
-		if strings.Contains(string(stderr), "rbd: error opening image "+rv.RbdImageName+
+		if strings.Contains(stderr, "rbd: error opening image "+rv.RbdImageName+
 			": (2) No such file or directory") {
 			return util.JoinErrors(ErrImageNotFound, err)
 		}
 		return err
 	}
 
-	err = json.Unmarshal(stdout, &imgInfo)
+	err = json.Unmarshal([]byte(stdout), &imgInfo)
 	if err != nil {
 		klog.Errorf("failed to parse JSON output of image info (%s): (%s)", rv, err)
-		return fmt.Errorf("unmarshal failed: %+v.  raw buffer response: %s", err, string(stdout))
+		return fmt.Errorf("unmarshal failed: %+v.  raw buffer response: %s", err, stdout)
 	}
 
 	rv.VolSize = imgInfo.Size
@@ -1051,7 +1051,7 @@ func resizeRBDImage(rbdVol *rbdVolume, cr *util.Credentials) error {
 	_, stderr, err := util.ExecCommand(context.TODO(), "rbd", args...)
 
 	if err != nil {
-		return fmt.Errorf("failed to resize rbd image (%w), command output: %s", err, string(stderr))
+		return fmt.Errorf("failed to resize rbd image (%w), command output: %s", err, stderr)
 	}
 
 	return nil
@@ -1129,17 +1129,17 @@ func (rv *rbdVolume) listSnapshots(ctx context.Context, cr *util.Credentials) ([
 		"--all", rv.String())
 	if err != nil {
 		klog.Errorf(util.Log(ctx, "failed getting information for image (%s): (%s)"), rv, err)
-		if strings.Contains(string(stderr), "rbd: error opening image "+rv.RbdImageName+
+		if strings.Contains(stderr, "rbd: error opening image "+rv.RbdImageName+
 			": (2) No such file or directory") {
 			return snapInfo, util.JoinErrors(ErrImageNotFound, err)
 		}
 		return snapInfo, err
 	}
 
-	err = json.Unmarshal(stdout, &snapInfo)
+	err = json.Unmarshal([]byte(stdout), &snapInfo)
 	if err != nil {
 		klog.Errorf(util.Log(ctx, "failed to parse JSON output of snapshot info (%s)"), err)
-		return snapInfo, fmt.Errorf("unmarshal failed: %w. raw buffer response: %s", err, string(stdout))
+		return snapInfo, fmt.Errorf("unmarshal failed: %w. raw buffer response: %s", err, stdout)
 	}
 	return snapInfo, nil
 }

internal/util/cephcmds.go

@@ -33,7 +33,7 @@ const InvalidPoolID int64 = -1
 // ExecCommand executes passed in program with args and returns separate stdout
 // and stderr streams. In case ctx is not set to context.TODO(), the command
 // will be logged after it was executed.
-func ExecCommand(ctx context.Context, program string, args ...string) (stdout, stderr []byte, err error) {
+func ExecCommand(ctx context.Context, program string, args ...string) (string, string, error) {
 	var (
 		cmd           = exec.Command(program, args...) // #nosec:G204, commands executing not vulnerable.
 		sanitizedArgs = StripSecretInArgs(args)
@@ -44,19 +44,23 @@ func ExecCommand(ctx context.Context, program string, args ...string) (stdout, s
 	cmd.Stdout = &stdoutBuf
 	cmd.Stderr = &stderrBuf
 
-	if err := cmd.Run(); err != nil {
+	err := cmd.Run()
+	stdout := stdoutBuf.String()
+	stderr := stderrBuf.String()
+
+	if err != nil {
 		err = fmt.Errorf("an error (%w) occurred while running %s args: %v", err, program, sanitizedArgs)
 		if ctx != context.TODO() {
 			UsefulLog(ctx, "%s", err)
 		}
-		return stdoutBuf.Bytes(), stderrBuf.Bytes(), err
+		return stdout, stderr, err
 	}
 
 	if ctx != context.TODO() {
 		UsefulLog(ctx, "command succeeded: %s %v", program, sanitizedArgs)
 	}
 
-	return stdoutBuf.Bytes(), nil, nil
+	return stdout, stderr, nil
 }
 
 // GetPoolID fetches the ID of the pool that matches the passed in poolName