func()

in gce-containers-startup/volumes/volumes.go [464:515]

• 38 lines of code
• 8 McCabe index (conditional complexity)

func (env Env) checkFilesystemAndFormatIfNeeded(devicePath string, configuredFsType string) error {
	// Should be const, but Go can't into map consts.
	filesystemCheckerMap := map[string][]string{
		ext4FsType: []string{"fsck.ext4", "-p"},
	}
	filesystemFormatterMap := map[string][]string{
		ext4FsType: []string{"mkfs.ext4"},
	}
	filesystemChecker := filesystemCheckerMap[configuredFsType]
	filesystemFormatter := filesystemFormatterMap[configuredFsType]
	if filesystemChecker == nil || filesystemFormatter == nil {
		return fmt.Errorf("Could not find checker or formatter for filesystem %s.", configuredFsType)
	}

	const lsblkFsType string = "FSTYPE"
	foundFsType, err := env.getSinglePropertyFromDeviceWithLsblk(devicePath, lsblkFsType)
	if err != nil {
		return err
	}
	// Unfortunately, lsblk(8) doesn't provide a way to tell apart a
	// nonexistent filesystem (e.g. a fresh drive) from device read problem
	// - in both cases not reporting any errors and returning an empty
	// FSTYPE field. Therefore, care must be taken to compensate for this
	// behaviour. The strategy below is deemed safe, because:
	//
	// - If lsblk(8) lacks privileges to read the filesystem and the
	//   decision is put forward to format it, mkfs(8) will fail as well.
	// - If lsblk(8) had privileges and still didn't detect the filesystem,
	//   it's OK to format it.
	if foundFsType == "" {
		// Need to format.
		log.Printf("Formatting device %s with filesystem %s...", devicePath, configuredFsType)
		output, err := env.OsCommandRunner.Run(append(filesystemFormatter, devicePath)...)
		if err != nil {
			return fmt.Errorf("Failed to format filesystem: %s", err)
		} else {
			log.Printf("%s\n", output)
		}
	} else if foundFsType == configuredFsType {
		// Need to fsck.
		log.Printf("Running filesystem checker on device %s...", devicePath)
		output, err := env.OsCommandRunner.Run(append(filesystemChecker, devicePath)...)
		if err != nil {
			return fmt.Errorf("Filesystem check failed: %s", err)
		} else {
			log.Printf("%s\n", output)
		}
	} else {
		return fmt.Errorf("Device %s: found filesystem type %s, expected %s.", devicePath, foundFsType, configuredFsType)
	}
	return nil
}