Add schema2 list support
This commit is contained in:
Joseph Schorr
parent
52b12131f7
commit
a73cd9170a
7 changed files with 320 additions and 48 deletions
194
image/docker/schema2/list.py
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194
image/docker/schema2/list.py
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import json
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from cachetools import lru_cache
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from jsonschema import validate as validate_schema, ValidationError
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from image.docker.schema1 import DOCKER_SCHEMA1_MANIFEST_CONTENT_TYPE
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from image.docker.schema1 import DockerSchema1Manifest
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from image.docker.schema2 import (DOCKER_SCHEMA2_MANIFESTLIST_CONTENT_TYPE,
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DOCKER_SCHEMA2_MANIFEST_CONTENT_TYPE)
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from image.docker.schema2.manifest import DockerSchema2Manifest
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# Keys.
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DOCKER_SCHEMA2_MANIFESTLIST_VERSION_KEY = 'schemaVersion'
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DOCKER_SCHEMA2_MANIFESTLIST_MEDIATYPE_KEY = 'mediaType'
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DOCKER_SCHEMA2_MANIFESTLIST_SIZE_KEY = 'size'
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DOCKER_SCHEMA2_MANIFESTLIST_DIGEST_KEY = 'digest'
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DOCKER_SCHEMA2_MANIFESTLIST_MANIFESTS_KEY = 'manifests'
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DOCKER_SCHEMA2_MANIFESTLIST_PLATFORM_KEY = 'platform'
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DOCKER_SCHEMA2_MANIFESTLIST_ARCHITECTURE_KEY = 'architecture'
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DOCKER_SCHEMA2_MANIFESTLIST_OS_KEY = 'os'
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DOCKER_SCHEMA2_MANIFESTLIST_OS_VERSION_KEY = 'os.version'
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DOCKER_SCHEMA2_MANIFESTLIST_OS_FEATURES_KEY = 'os.features'
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DOCKER_SCHEMA2_MANIFESTLIST_FEATURES_KEY = 'features'
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DOCKER_SCHEMA2_MANIFESTLIST_VARIANT_KEY = 'variant'
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class MalformedSchema2ManifestList(Exception):
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"""
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Raised when a manifest list fails an assertion that should be true according to the
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Docker Manifest v2.2 Specification.
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"""
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pass
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class LazyManifestLoader(object):
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def __init__(self, manifest_data, lookup_manifest_fn):
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self._manifest_data = manifest_data
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self._lookup_manifest_fn = lookup_manifest_fn
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self._loaded_manifest = None
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@property
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def manifest_obj(self):
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if self._loaded_manifest is not None:
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return self._loaded_manifest
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self._loaded_manifest = self._load_manifest()
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return self._loaded_manifest
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def _load_manifest(self):
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digest = self._manifest_data[DOCKER_SCHEMA2_MANIFESTLIST_DIGEST_KEY]
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size = self._manifest_data[DOCKER_SCHEMA2_MANIFESTLIST_SIZE_KEY]
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manifest_bytes = self._lookup_manifest_fn(digest)
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if len(manifest_bytes) != size:
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raise MalformedSchema2ManifestList('Size of manifest does not match that retrieved: %s vs %s',
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len(manifest_bytes), size)
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content_type = self._manifest_data[DOCKER_SCHEMA2_MANIFESTLIST_MEDIATYPE_KEY]
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if content_type == DOCKER_SCHEMA2_MANIFEST_CONTENT_TYPE:
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return DockerSchema2Manifest(manifest_bytes)
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if content_type == DOCKER_SCHEMA1_MANIFEST_CONTENT_TYPE:
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return DockerSchema1Manifest(manifest_bytes, validate=False)
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raise MalformedSchema2ManifestList('Unknown manifest content type')
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class DockerSchema2ManifestList(object):
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METASCHEMA = {
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'type': 'object',
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'properties': {
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DOCKER_SCHEMA2_MANIFESTLIST_VERSION_KEY: {
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'type': 'number',
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'description': 'The version of the manifest list. Must always be `2`.',
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'minimum': 2,
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'maximum': 2,
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},
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DOCKER_SCHEMA2_MANIFESTLIST_MEDIATYPE_KEY: {
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'type': 'string',
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'description': 'The media type of the manifest list.',
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'enum': [DOCKER_SCHEMA2_MANIFESTLIST_CONTENT_TYPE],
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},
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DOCKER_SCHEMA2_MANIFESTLIST_MANIFESTS_KEY: {
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'type': 'array',
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'description': 'The manifests field contains a list of manifests for specific platforms',
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'items': {
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'type': 'object',
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'properties': {
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DOCKER_SCHEMA2_MANIFESTLIST_MEDIATYPE_KEY: {
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'type': 'string',
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'description': 'The MIME type of the referenced object. This will generally be ' +
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'application/vnd.docker.distribution.manifest.v2+json, but it ' +
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'could also be application/vnd.docker.distribution.manifest.v1+json ' +
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'if the manifest list references a legacy schema-1 manifest.',
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'enum': [DOCKER_SCHEMA2_MANIFEST_CONTENT_TYPE, DOCKER_SCHEMA1_MANIFEST_CONTENT_TYPE],
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},
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DOCKER_SCHEMA2_MANIFESTLIST_SIZE_KEY: {
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'type': 'number',
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'description': 'The size in bytes of the object. This field exists so that a ' +
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'client will have an expected size for the content before ' +
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'validating. If the length of the retrieved content does not ' +
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'match the specified length, the content should not be trusted.',
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},
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DOCKER_SCHEMA2_MANIFESTLIST_DIGEST_KEY: {
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'type': 'string',
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'description': 'The content addressable digest of the manifest in the blob store',
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},
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DOCKER_SCHEMA2_MANIFESTLIST_PLATFORM_KEY: {
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'type': 'object',
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'description': 'The platform object describes the platform which the image in ' +
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'the manifest runs on',
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'properties': {
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DOCKER_SCHEMA2_MANIFESTLIST_ARCHITECTURE_KEY: {
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'type': 'string',
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'description': 'Specifies the CPU architecture, for example amd64 or ppc64le.',
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},
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DOCKER_SCHEMA2_MANIFESTLIST_OS_KEY: {
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'type': 'string',
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'description': 'Specifies the operating system, for example linux or windows',
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},
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DOCKER_SCHEMA2_MANIFESTLIST_OS_VERSION_KEY: {
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'type': 'string',
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'description': 'Specifies the operating system version, for example 10.0.10586',
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},
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DOCKER_SCHEMA2_MANIFESTLIST_OS_FEATURES_KEY: {
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'type': 'array',
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'description': 'specifies an array of strings, each listing a required OS ' +
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'feature (for example on Windows win32k)',
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'items': {
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'type': 'string',
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},
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},
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DOCKER_SCHEMA2_MANIFESTLIST_VARIANT_KEY: {
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'type': 'string',
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'description': 'Specifies a variant of the CPU, for example armv6l to specify ' +
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'a particular CPU variant of the ARM CPU',
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},
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DOCKER_SCHEMA2_MANIFESTLIST_FEATURES_KEY: {
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'type': 'array',
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'description': 'specifies an array of strings, each listing a required CPU ' +
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'feature (for example sse4 or aes).',
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'items': {
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'type': 'string',
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},
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},
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},
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'required': [DOCKER_SCHEMA2_MANIFESTLIST_ARCHITECTURE_KEY,
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DOCKER_SCHEMA2_MANIFESTLIST_OS_KEY],
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},
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},
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'required': [DOCKER_SCHEMA2_MANIFESTLIST_MEDIATYPE_KEY,
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DOCKER_SCHEMA2_MANIFESTLIST_SIZE_KEY,
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DOCKER_SCHEMA2_MANIFESTLIST_DIGEST_KEY,
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DOCKER_SCHEMA2_MANIFESTLIST_PLATFORM_KEY],
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},
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},
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},
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'required': [DOCKER_SCHEMA2_MANIFESTLIST_VERSION_KEY,
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DOCKER_SCHEMA2_MANIFESTLIST_MEDIATYPE_KEY,
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DOCKER_SCHEMA2_MANIFESTLIST_MANIFESTS_KEY],
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}
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def __init__(self, manifest_bytes):
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self._layers = None
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try:
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self._parsed = json.loads(manifest_bytes)
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except ValueError as ve:
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raise MalformedSchema2ManifestList('malformed manifest data: %s' % ve)
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try:
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validate_schema(self._parsed, DockerSchema2ManifestList.METASCHEMA)
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except ValidationError as ve:
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raise MalformedSchema2ManifestList('manifest data does not match schema: %s' % ve)
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@lru_cache(maxsize=1)
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def manifests(self, lookup_manifest_fn):
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""" Returns the manifests in the list. The `lookup_manifest_fn` is a function
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that returns the manifest bytes for the specified digest.
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"""
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manifests = self._parsed[DOCKER_SCHEMA2_MANIFESTLIST_MANIFESTS_KEY]
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return [LazyManifestLoader(m, lookup_manifest_fn) for m in manifests]
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def get_v1_compatible_manifest(self, lookup_manifest_fn):
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""" Returns the manifest that is compatible with V1, by virtue of being `amd64` and `linux`.
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If none, returns None.
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"""
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for manifest in self.manifests(lookup_manifest_fn):
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platform = manifest._manifest_data[DOCKER_SCHEMA2_MANIFESTLIST_PLATFORM_KEY]
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architecture = platform[DOCKER_SCHEMA2_MANIFESTLIST_ARCHITECTURE_KEY]
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os = platform[DOCKER_SCHEMA2_MANIFESTLIST_OS_KEY]
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if architecture == 'amd64' and os == 'linux':
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return manifest
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return None
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