1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
# Copyright 2015 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""This tool creates a docker image from a layer and the various metadata."""
import json
import re
import sys
import tarfile
from tools.build_defs.docker import utils
from tools.build_defs.pkg import archive
from third_party.py import gflags
# Hardcoded docker versions that we are claiming to be.
DATA_FORMAT_VERSION = '1.0'
gflags.DEFINE_string(
'output', None,
'The output file, mandatory')
gflags.MarkFlagAsRequired('output')
gflags.DEFINE_multistring(
'layer', [],
'Layer tar files and their identifiers that make up this image')
gflags.DEFINE_string(
'id', None,
'The hex identifier of this image (hexstring or @filename), mandatory.')
gflags.MarkFlagAsRequired('id')
gflags.DEFINE_string('config', None,
'The JSON configuration file for this image, mandatory.')
gflags.MarkFlagAsRequired('config')
gflags.DEFINE_string('base', None, 'The base image file for this image.')
gflags.DEFINE_string(
'legacy_id', None,
'The legacy hex identifier of this layer (hexstring or @filename).')
gflags.DEFINE_string('metadata', None,
'The legacy JSON metadata file for this layer.')
gflags.DEFINE_string('legacy_base', None,
'The legacy base image file for this image.')
gflags.DEFINE_string(
'repository', None,
'The name of the repository to add this image.')
gflags.DEFINE_string(
'name', None,
'The symbolic name of this image.')
gflags.DEFINE_multistring('tag', None,
'The repository tags to apply to the image')
FLAGS = gflags.FLAGS
def _base_name_filter(name):
"""Do not add multiple times 'top' and 'repositories' when merging images."""
filter_names = ['top', 'repositories', 'manifest.json']
return all([not name.endswith(s) for s in filter_names])
def create_image(output,
identifier,
layers,
config,
tags=None,
base=None,
legacy_base=None,
metadata_id=None,
metadata=None,
name=None,
repository=None):
"""Creates a Docker image.
Args:
output: the name of the docker image file to create.
identifier: the identifier for this image (sha256 of the metadata).
layers: the layer content (a sha256 and a tar file).
config: the configuration file for the image.
tags: tags that apply to this image.
base: a base layer (optional) to build on top of.
legacy_base: a base layer (optional) to build on top of.
metadata_id: the identifier of the top layer for this image.
metadata: the json metadata file for the top layer.
name: symbolic name for this docker image.
repository: repository name for this docker image.
"""
tar = archive.TarFileWriter(output)
# add the image config referenced by the Config section in the manifest
# the name can be anything but docker uses the format below
config_file_name = identifier + '.json'
tar.add_file(config_file_name, file_content=config)
layer_file_names = []
if metadata_id:
# Write our id to 'top' as we are now the topmost layer.
tar.add_file('top', content=metadata_id)
# Each layer is encoded as a directory in the larger tarball of the form:
# {id}\
# layer.tar
# VERSION
# json
# Create the directory for us to now fill in.
tar.add_file(metadata_id + '/', tarfile.DIRTYPE)
# VERSION generally seems to contain 1.0, not entirely sure
# what the point of this is.
tar.add_file(metadata_id + '/VERSION', content=DATA_FORMAT_VERSION)
# Add the layer file
layer_file_name = metadata_id + '/layer.tar'
layer_file_names.append(layer_file_name)
tar.add_file(layer_file_name, file_content=layers[0]['layer'])
# Now the json metadata
tar.add_file(metadata_id + '/json', file_content=metadata)
# Merge the base if any
if legacy_base:
tar.add_tar(legacy_base, name_filter=_base_name_filter)
else:
for layer in layers:
# layers can be called anything, so just name them by their sha256
layer_file_name = identifier + '/' + layer['name'] + '.tar'
layer_file_names.append(layer_file_name)
tar.add_file(layer_file_name, file_content=layer['layer'])
base_layer_file_names = []
parent = None
if base:
latest_item = utils.GetLatestManifestFromTar(base)
if latest_item:
base_layer_file_names = latest_item.get('Layers', [])
config_file = latest_item['Config']
parent_search = re.search('^(.+)\\.json$', config_file)
if parent_search:
parent = parent_search.group(1)
manifest_item = {
'Config': config_file_name,
'Layers': base_layer_file_names + layer_file_names,
'RepoTags': tags or []
}
if parent:
manifest_item['Parent'] = 'sha256:' + parent
manifest = [manifest_item]
manifest_content = json.dumps(manifest, sort_keys=True)
tar.add_file('manifest.json', content=manifest_content)
# In addition to N layers of the form described above, there is
# a single file at the top of the image called repositories.
# This file contains a JSON blob of the form:
# {
# 'repo':{
# 'tag-name': 'top-most layer hex',
# ...
# },
# ...
# }
if repository:
tar.add_file('repositories', content='\n'.join([
'{',
' "%s": {' % repository,
' "%s": "%s"' % (name, identifier),
' }',
'}']))
# Main program to create a docker image. It expect to be run with:
# create_image --output=output_file \
# --id=@identifier \
# [--base=base] \
# --layer=@identifier=layer.tar \
# --metadata=metadata.json \
# --name=myname --repository=repositoryName \
# --tag=repo/image:tag
# See the gflags declaration about the flags argument details.
def main(unused_argv):
identifier = utils.ExtractValue(FLAGS.id)
legacy_id = utils.ExtractValue(FLAGS.legacy_id)
layers = []
for kv in FLAGS.layer:
(k, v) = kv.split('=', 1)
layers.append({
'name': utils.ExtractValue(k),
'layer': v,
})
create_image(FLAGS.output, identifier, layers, FLAGS.config, FLAGS.tag,
FLAGS.base, FLAGS.legacy_base, legacy_id, FLAGS.metadata,
FLAGS.name, FLAGS.repository)
if __name__ == '__main__':
main(FLAGS(sys.argv))
|
