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# Copyright 2016 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 package manipulates OCI image configuration metadata."""
from collections import namedtuple
import copy
import json
import os
import os.path
import sys
from tools.build_defs.docker import utils
from third_party.py import gflags
gflags.DEFINE_string('base', None, 'The parent image')
gflags.DEFINE_string('output', None, 'The output file to generate')
gflags.MarkFlagAsRequired('output')
gflags.DEFINE_multistring('layer', [],
'Layer sha256 hashes that make up this image')
gflags.DEFINE_list('entrypoint', None,
'Override the "Entrypoint" of the previous image')
gflags.DEFINE_list('command', None, 'Override the "Cmd" of the previous image')
gflags.DEFINE_string('user', None, 'The username to run commands under')
gflags.DEFINE_list('labels', None, 'Augment the "Label" of the previous image')
gflags.DEFINE_list('ports', None,
'Augment the "ExposedPorts" of the previous image')
gflags.DEFINE_list('volumes', None,
'Augment the "Volumes" of the previous image')
gflags.DEFINE_string('workdir', None, 'Set the working directory for the image')
gflags.DEFINE_list('env', None, 'Augment the "Env" of the previous image')
FLAGS = gflags.FLAGS
_ConfigOptionsT = namedtuple('ConfigOptionsT', ['layers', 'entrypoint', 'cmd',
'env', 'labels', 'ports',
'volumes', 'workdir', 'user'])
class ConfigOptions(_ConfigOptionsT):
"""Docker image configuration options."""
def __new__(cls,
layers=None,
entrypoint=None,
cmd=None,
user=None,
labels=None,
env=None,
ports=None,
volumes=None,
workdir=None):
"""Constructor."""
return super(ConfigOptions, cls).__new__(cls,
layers=layers,
entrypoint=entrypoint,
cmd=cmd,
user=user,
labels=labels,
env=env,
ports=ports,
volumes=volumes,
workdir=workdir)
_PROCESSOR_ARCHITECTURE = 'amd64'
_OPERATING_SYSTEM = 'linux'
def Resolve(value, environment):
"""Resolves environment variables embedded in the given value."""
outer_env = os.environ
try:
os.environ = environment
return os.path.expandvars(value)
finally:
os.environ = outer_env
def DeepCopySkipNull(data):
"""Do a deep copy, skipping null entry."""
if isinstance(data, dict):
return dict((DeepCopySkipNull(k), DeepCopySkipNull(v))
for k, v in data.iteritems() if v is not None)
return copy.deepcopy(data)
def KeyValueToDict(pair):
"""Converts an iterable object of key=value pairs to dictionary."""
d = dict()
for kv in pair:
(k, v) = kv.split('=', 1)
d[k] = v
return d
def CreateImageConfig(data, options):
"""Create an image config possibly based on an existing one.
Args:
data: A dict of Docker image config to base on top of.
options: Options specific to this image which will be merged with any
existing data
Returns:
Image config for the new image
"""
defaults = DeepCopySkipNull(data)
# dont propagate non-spec keys
output = dict()
output['created'] = '0001-01-01T00:00:00Z'
output['author'] = 'Bazel'
output['architecture'] = _PROCESSOR_ARCHITECTURE
output['os'] = _OPERATING_SYSTEM
output['config'] = defaults.get('config', {})
if options.entrypoint:
output['config']['Entrypoint'] = options.entrypoint
if options.cmd:
output['config']['Cmd'] = options.cmd
if options.user:
output['config']['User'] = options.user
def Dict2ConfigValue(d):
return ['%s=%s' % (k, d[k]) for k in sorted(d.keys())]
if options.env:
# Build a dictionary of existing environment variables (used by Resolve).
environ_dict = KeyValueToDict(output['config'].get('Env', []))
# Merge in new environment variables, resolving references.
for k, v in options.env.iteritems():
# Resolve handles scenarios like "PATH=$PATH:...".
environ_dict[k] = Resolve(v, environ_dict)
output['config']['Env'] = Dict2ConfigValue(environ_dict)
# TODO(babel-team) Label is currently docker specific
if options.labels:
label_dict = KeyValueToDict(output['config'].get('Label', []))
for k, v in options.labels.iteritems():
label_dict[k] = v
output['config']['Label'] = Dict2ConfigValue(label_dict)
if options.ports:
if 'ExposedPorts' not in output['config']:
output['config']['ExposedPorts'] = {}
for p in options.ports:
if '/' in p:
# The port spec has the form 80/tcp, 1234/udp
# so we simply use it as the key.
output['config']['ExposedPorts'][p] = {}
else:
# Assume tcp
output['config']['ExposedPorts'][p + '/tcp'] = {}
if options.volumes:
if 'Volumes' not in output['config']:
output['config']['Volumes'] = {}
for p in options.volumes:
output['config']['Volumes'][p] = {}
if options.workdir:
output['config']['WorkingDir'] = options.workdir
# diff_ids are ordered from bottom-most to top-most
diff_ids = defaults.get('rootfs', {}).get('diff_ids', [])
layers = options.layers if options.layers else []
diff_ids += ['sha256:%s' % l for l in layers]
output['rootfs'] = {
'type': 'layers',
'diff_ids': diff_ids,
}
# history is ordered from bottom-most layer to top-most layer
history = defaults.get('history', [])
# docker only allows the child to have one more history entry than the parent
history += [{
'created': '0001-01-01T00:00:00Z',
'created_by': 'bazel build ...',
'author': 'Bazel'}]
output['history'] = history
return output
def main(unused_argv):
base_json = '{}'
manifest = utils.GetLatestManifestFromTar(FLAGS.base)
if manifest:
config_file = manifest['Config']
base_json = utils.GetTarFile(FLAGS.base, config_file)
data = json.loads(base_json)
layers = []
for layer in FLAGS.layer:
layers.append(utils.ExtractValue(layer))
labels = KeyValueToDict(FLAGS.labels)
for label, value in labels.iteritems():
if value.startswith('@'):
with open(value[1:], 'r') as f:
labels[label] = f.read()
output = CreateImageConfig(data,
ConfigOptions(layers=layers,
entrypoint=FLAGS.entrypoint,
cmd=FLAGS.command,
user=FLAGS.user,
labels=labels,
env=KeyValueToDict(FLAGS.env),
ports=FLAGS.ports,
volumes=FLAGS.volumes,
workdir=FLAGS.workdir))
with open(FLAGS.output, 'w') as fp:
json.dump(output, fp, sort_keys=True)
fp.write('\n')
if __name__ == '__main__':
main(FLAGS(sys.argv))