[virt-tools-list] [virt-bootstrap] [PATCH v3 03/12] DockerSource: Add support for Manifest version 1

[Cedric Bosdonnat]

On Thu, 2017-07-20 at 12:29 +0100, Radostin Stoyanov wrote:
> Handle differences between version 1 and 2 of the Manifest file for
> Docker registry.
> 
> Layers' blob sums in v1 are stored in a list "fsLayers" and the digest
> is stored in following filed with name "blobSum". [1]
> 
> In v2 the layer list is stored in field with name "layers" and
> ordered starting from the base image (opposite order of v1). The digest
> is stored under a following field with name "digest". The size in bytes
> is included in a field with name "size". [2]
> 
> [1] https://docs.docker.com/registry/spec/manifest-v2-1/#manifest-field-descriptions
> [2] https://docs.docker.com/registry/spec/manifest-v2-2/#image-manifest-field-descriptions
> ---
>  src/virtBootstrap/sources.py | 18 +++++++++++++++---
>  src/virtBootstrap/utils.py   |  7 +++++--
>  2 files changed, 20 insertions(+), 5 deletions(-)
> 
> diff --git a/src/virtBootstrap/sources.py b/src/virtBootstrap/sources.py
> index 4f1b104..1e70f33 100644
> --- a/src/virtBootstrap/sources.py
> +++ b/src/virtBootstrap/sources.py
> @@ -128,10 +128,22 @@ class DockerSource(object):
>                                                  username=self.username,
>                                                  password=self.password)
>  
> -        for layer in self.manifest['layers']:
> -            sum_type, layer_sum = layer['digest'].split(':')
> +        if self.manifest['schemaVersion'] == 1:
> +            layers_list = self.manifest['fsLayers'][::-1]
> +            digest_filed = 'blobSum'

The variable name is looking weird to me. I would be better with something like
'digest_field', but that may be a repeated typo.

> +        elif self.manifest['schemaVersion'] == 2:
> +            layers_list = self.manifest['layers']
> +            digest_filed = 'digest'

Same here

> +        else:
> +            raise ValueError('Unsupported manifest schema.')
> +
> +        for layer in layers_list:
> +            layer_digest = layer[digest_filed]
> +            layer_size = layer['size'] if 'size' in layer else None
> +
> +            sum_type, layer_sum = layer_digest.split(':')
>              file_path = os.path.join(self.images_dir, layer_sum + '.tar')
> -            self.layers.append([sum_type, layer_sum, file_path, layer['size']])
> +            self.layers.append([sum_type, layer_sum, file_path, layer_size])
>  
>      def gen_valid_uri(self, uri):
>          """
> diff --git a/src/virtBootstrap/utils.py b/src/virtBootstrap/utils.py
> index daabd26..a65d3f5 100644
> --- a/src/virtBootstrap/utils.py
> +++ b/src/virtBootstrap/utils.py
> @@ -138,8 +138,11 @@ def log_layer_extract(layer, current, total, progress):
>      Create log message on layer extract.
>      """
>      sum_type, sum_value, layer_file, layer_size = layer
> -    progress("Extracting layer (%s/%s) with size: %s"
> -             % (current, total, bytes_to_size(layer_size)), logger=logger)
> +    msg = 'Extracting layer (%s/%s)' % (current, total)
> +
> +    if layer_size:
> +        msg += " with size: %s" % bytes_to_size(layer_size)
> +    progress(msg, logger=logger)
>      logger.debug('Untar layer: (%s:%s) %s', sum_type, sum_value, layer_file)
>  
>  

ACK with the variable name change

--
Cedric