def download_task(url, headers, download_to, download_type='layer'):
'''download an image layer (.tar.gz) to a specified download folder.
This task is done by using local versions of the same download functions
that are used for the client.
core stream/download functions of the parent client.
Parameters
==========
image_id: the shasum id of the layer, already determined to not exist
repo_name: the image name (library/ubuntu) to retrieve
download_to: download to this folder. If not set, uses temp.
'''
# Update the user what we are doing
bot.verbose("Downloading %s from %s" % (download_type, url))
# Step 1: Download the layer atomically
file_name = "%s.%s" % (download_to,
next(tempfile._get_candidate_names()))
tar_download = download(url, file_name, headers=headers)
try:
shutil.move(tar_download, download_to)
except Exception:
msg = "Cannot untar layer %s," % tar_download
msg += " was there a problem with download?"
bot.error(msg)
sys.exit(1)
return download_to
def get_manifest(self, repo_name, digest=None, version="v1"):
'''
get_manifest should return an image manifest
for a particular repo and tag. The image details
are extracted when the client is generated.
Parameters
==========
repo_name: reference to the <username>/<repository>:<tag> to obtain
digest: a tag or shasum version
version: one of v1, v2, and config (for image config)
'''
accepts = {'config': "application/vnd.docker.container.image.v1+json",
'v1': "application/vnd.docker.distribution.manifest.v1+json",
'v2': "application/vnd.docker.distribution.manifest.v2+json" }
url = self._get_manifest_selfLink(repo_name, digest)
bot.verbose("Obtaining manifest: %s %s" % (url, version))
headers = {'Accept': accepts[version] }
try:
manifest = self._get(url, headers=headers, quiet=True)
manifest['selfLink'] = url
except:
manifest = None
return manifest
def get_layer(self, image_id, repo_name, download_folder=None):
'''download an image layer (.tar.gz) to a specified download folder.
Parameters
==========
download_folder: download to this folder. If not set, uses temp.
repo_name: the image name (library/ubuntu) to retrieve
'''
url = self._get_layerLink(repo_name, image_id)
bot.verbose("Downloading layers from %s" % url)
download_folder = get_tmpdir(download_folder)
download_folder = "%s/%s.tar.gz" % (download_folder, image_id)
# Update user what we are doing
bot.debug("Downloading layer %s" % image_id)
# Step 1: Download the layer atomically
file_name = "%s.%s" % (download_folder,
next(tempfile._get_candidate_names()))
tar_download = self.download(url, file_name)
try:
shutil.move(tar_download, download_folder)
except Exception:
msg = "Cannot untar layer %s," % tar_download
msg += " was there a problem with download?"
bot.error(msg)
sys.exit(1)
return download_folder
def getenv(variable_key, default=None, required=False, silent=True):
'''
getenv will attempt to get an environment variable. If the variable
is not found, None is returned.
:param variable_key: the variable name
:param required: exit with error if not found
:param silent: Do not print debugging information for variable
'''
variable = os.environ.get(variable_key, default)
if variable is None and required:
bot.error("Cannot find environment variable %s, exiting." %variable_key)
sys.exit(1)
if not silent and variable is not None:
bot.verbose("%s found as %s" %(variable_key,variable))
return variable
def get_config(self, key="Entrypoint", delim=None):
'''get_config returns a particular key (default is Entrypoint)
from a VERSION 1 manifest obtained with get_manifest.
Parameters
==========
key: the key to return from the manifest config
delim: Given a list, the delim to use to join the entries.
Default is newline
'''
if not hasattr(self,'manifests'):
bot.error('Please retrieve manifests for an image first.')
sys.exit(1)
cmd = None
# If we didn't find the config value in version 2
for version in ['config', 'v1']:
if cmd is None and 'config' in self.manifests:
# First try, version 2.0 manifest config has upper level config
manifest = self.manifests['config']
if "config" in manifest:
if key in manifest['config']:
cmd = manifest['config'][key]
# Second try, config manifest (not from verison 2.0 schema blob)
if cmd is None and "history" in manifest:
for entry in manifest['history']:
if 'v1Compatibility' in entry:
entry = json.loads(entry['v1Compatibility'])
if "config" in entry:
if key in entry["config"]:
cmd = entry["config"][key]
# Standard is to include commands like ['/bin/sh']
if isinstance(cmd, list):
if delim is not None:
cmd = delim.join(cmd)
bot.verbose("Found Docker config (%s) %s" % (key, cmd))
return cmd
