236 lines
7.3 KiB
Python
236 lines
7.3 KiB
Python
"""
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Implements validation and conversion for the Schema2 config JSON.
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Example:
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{
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"architecture": "amd64",
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"config": {
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"Hostname": "",
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"Domainname": "",
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"User": "",
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"AttachStdin": false,
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"AttachStdout": false,
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"AttachStderr": false,
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"Tty": false,
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"OpenStdin": false,
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"StdinOnce": false,
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"Env": [
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"HTTP_PROXY=http:\/\/localhost:8080",
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"http_proxy=http:\/\/localhost:8080",
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"PATH=\/usr\/local\/sbin:\/usr\/local\/bin:\/usr\/sbin:\/usr\/bin:\/sbin:\/bin"
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],
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"Cmd": [
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"sh"
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],
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"Image": "",
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"Volumes": null,
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"WorkingDir": "",
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"Entrypoint": null,
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"OnBuild": null,
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"Labels": {
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}
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},
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"container": "b7a43694b435c8e9932615643f61f975a9213e453b15cd6c2a386f144a2d2de9",
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"container_config": {
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"Hostname": "b7a43694b435",
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"Domainname": "",
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"User": "",
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"AttachStdin": true,
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"AttachStdout": true,
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"AttachStderr": true,
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"Tty": true,
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"OpenStdin": true,
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"StdinOnce": true,
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"Env": [
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"HTTP_PROXY=http:\/\/localhost:8080",
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"http_proxy=http:\/\/localhost:8080",
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"PATH=\/usr\/local\/sbin:\/usr\/local\/bin:\/usr\/sbin:\/usr\/bin:\/sbin:\/bin"
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],
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"Cmd": [
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"sh"
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],
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"Image": "somenamespace\/somerepo",
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"Volumes": null,
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"WorkingDir": "",
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"Entrypoint": null,
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"OnBuild": null,
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"Labels": {
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}
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},
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"created": "2018-04-16T10:41:19.079522722Z",
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"docker_version": "17.09.0-ce",
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"history": [
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{
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"created": "2018-04-03T18:37:09.284840891Z",
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"created_by": "\/bin\/sh -c #(nop) ADD file:9e4ca21cbd24dc05b454b6be21c7c639216ae66559b21ba24af0d665c62620dc in \/ "
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},
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{
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"created": "2018-04-03T18:37:09.613317719Z",
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"created_by": "\/bin\/sh -c #(nop) CMD [\"sh\"]",
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"empty_layer": true
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},
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{
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"created": "2018-04-16T10:37:44.418262777Z",
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"created_by": "sh"
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},
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{
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"created": "2018-04-16T10:41:19.079522722Z",
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"created_by": "sh"
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}
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],
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"os": "linux",
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"rootfs": {
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"type": "layers",
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"diff_ids": [
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"sha256:3e596351c689c8827a3c9635bc1083cff17fa4a174f84f0584bd0ae6f384195b",
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"sha256:4552be273c71275a88de0b8c8853dcac18cb74d5790f5383d9b38d4ac55062d5",
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"sha256:1319c76152ca37fbeb7fb71e0ffa7239bc19ffbe3b95c00417ece39d89d06e6e"
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]
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}
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}
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"""
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import copy
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import json
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from collections import namedtuple
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from jsonschema import validate as validate_schema, ValidationError
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from dateutil.parser import parse as parse_date
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from digest import digest_tools
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DOCKER_SCHEMA2_CONFIG_HISTORY_KEY = "history"
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DOCKER_SCHEMA2_CONFIG_ROOTFS_KEY = "rootfs"
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DOCKER_SCHEMA2_CONFIG_CREATED_KEY = "created"
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DOCKER_SCHEMA2_CONFIG_CREATED_BY_KEY = "created_by"
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DOCKER_SCHEMA2_CONFIG_EMPTY_LAYER_KEY = "empty_layer"
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DOCKER_SCHEMA2_CONFIG_TYPE_KEY = "type"
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LayerHistory = namedtuple('LayerHistory', ['created', 'created_datetime', 'command', 'is_empty'])
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class MalformedSchema2Config(Exception):
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"""
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Raised when a config fails an assertion that should be true according to the Docker Manifest
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v2.2 Config Specification.
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"""
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pass
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class DockerSchema2Config(object):
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METASCHEMA = {
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'type': 'object',
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'description': 'The container configuration found in a schema 2 manifest',
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'required': [DOCKER_SCHEMA2_CONFIG_HISTORY_KEY, DOCKER_SCHEMA2_CONFIG_ROOTFS_KEY],
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'properties': {
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DOCKER_SCHEMA2_CONFIG_HISTORY_KEY: {
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'type': 'array',
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'description': 'The history used to create the container image',
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'items': {
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'type': 'object',
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'properties': {
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DOCKER_SCHEMA2_CONFIG_EMPTY_LAYER_KEY: {
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'type': 'boolean',
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'description': 'If present, this layer is empty',
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},
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DOCKER_SCHEMA2_CONFIG_CREATED_KEY: {
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'type': 'string',
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'description': 'The date/time that the layer was created',
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'format': 'date-time',
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'x-example': '2018-04-03T18:37:09.284840891Z',
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},
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DOCKER_SCHEMA2_CONFIG_CREATED_BY_KEY: {
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'type': 'string',
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'description': 'The command used to create the layer',
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'x-example': '\/bin\/sh -c #(nop) ADD file:somesha in /',
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},
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},
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'required': [DOCKER_SCHEMA2_CONFIG_CREATED_KEY, DOCKER_SCHEMA2_CONFIG_CREATED_BY_KEY],
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'additionalProperties': True,
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},
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},
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DOCKER_SCHEMA2_CONFIG_ROOTFS_KEY: {
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'type': 'object',
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'description': 'Describes the root filesystem for this image',
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'properties': {
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DOCKER_SCHEMA2_CONFIG_TYPE_KEY: {
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'type': 'string',
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'description': 'The type of the root file system entries',
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},
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},
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'required': [DOCKER_SCHEMA2_CONFIG_TYPE_KEY],
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'additionalProperties': True,
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},
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},
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'additionalProperties': True,
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}
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def __init__(self, config_bytes):
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self._config_bytes = config_bytes
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try:
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self._parsed = json.loads(config_bytes)
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except ValueError as ve:
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raise MalformedSchema2Config('malformed config data: %s' % ve)
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try:
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validate_schema(self._parsed, DockerSchema2Config.METASCHEMA)
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except ValidationError as ve:
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raise MalformedSchema2Config('config data does not match schema: %s' % ve)
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@property
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def digest(self):
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""" Returns the digest of this config object. """
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return digest_tools.sha256_digest(self._config_bytes)
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@property
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def size(self):
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""" Returns the size of this config object. """
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return len(self._config_bytes)
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@property
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def labels(self):
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""" Returns a dictionary of all the labels defined in this configuration. """
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return self._parsed.get('config', {}).get('Labels', {}) or {}
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@property
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def history(self):
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""" Returns the history of the image, started at the base layer. """
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for history_entry in self._parsed[DOCKER_SCHEMA2_CONFIG_HISTORY_KEY]:
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created_datetime = parse_date(history_entry[DOCKER_SCHEMA2_CONFIG_CREATED_KEY])
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yield LayerHistory(created_datetime=created_datetime,
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created=history_entry[DOCKER_SCHEMA2_CONFIG_CREATED_KEY],
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command=history_entry[DOCKER_SCHEMA2_CONFIG_CREATED_BY_KEY],
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is_empty=history_entry.get(DOCKER_SCHEMA2_CONFIG_EMPTY_LAYER_KEY, False))
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def build_v1_compatibility(self, layer_index, v1_id, v1_parent_id):
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""" Builds the V1 compatibility block for the given layer.
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Note that the layer_index is 0-indexed, with the *base* layer being 0, and the leaf
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layer being last.
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"""
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history = list(self.history)
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assert layer_index < len(history)
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# If the layer is the leaf, it gets the full config (minus 2 fields). Otherwise, it gets only
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# IDs.
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v1_compatibility = copy.deepcopy(self._parsed) if layer_index == len(history) - 1 else {}
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v1_compatibility['id'] = v1_id
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if v1_parent_id is not None:
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v1_compatibility['parent'] = v1_parent_id
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if 'created' not in v1_compatibility:
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v1_compatibility['created'] = history[layer_index].created
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if 'container_config' not in v1_compatibility:
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v1_compatibility['container_config'] = {
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'Cmd': history[layer_index].command,
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}
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# The history and rootfs keys are schema2-config specific.
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v1_compatibility.pop(DOCKER_SCHEMA2_CONFIG_HISTORY_KEY, None)
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v1_compatibility.pop(DOCKER_SCHEMA2_CONFIG_ROOTFS_KEY, None)
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return v1_compatibility
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