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quay/image/docker/schema2/list.py
2018-06-15 16:00:39 -04:00

194 lines
8.3 KiB
Python

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