You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
434 lines
14 KiB
434 lines
14 KiB
#!/usr/bin/python3
|
|
#-*- encoding: utf-8 -*-
|
|
"""
|
|
This script can be used instead of the traditional `snap` command to download
|
|
snaps and accompanying assertions. It uses the new store API (v2) which allows
|
|
creating temporary snapshots of the channel map.
|
|
|
|
To create such a snapshot run
|
|
|
|
snap-tool cohort-create
|
|
|
|
This will print a "cohort-key" to stdout, which can then be passed to future
|
|
invocations of `snap-tool download`. Whenever a cohort key is provided, the
|
|
store will provide a view of the channel map as it existed when the key was
|
|
created.
|
|
"""
|
|
|
|
from textwrap import dedent
|
|
|
|
import argparse
|
|
import base64
|
|
import binascii
|
|
import getopt
|
|
import hashlib
|
|
import json
|
|
import os
|
|
import re
|
|
import shutil
|
|
import subprocess
|
|
import sys
|
|
import urllib.error
|
|
import urllib.request
|
|
|
|
EXIT_OK = 0
|
|
EXIT_ERR = 1
|
|
|
|
|
|
class SnapError(Exception):
|
|
"""Generic error thrown by the Snap class."""
|
|
pass
|
|
|
|
|
|
class SnapCraftError(SnapError):
|
|
"""Error thrown on problems with the snapcraft APIs."""
|
|
pass
|
|
|
|
|
|
class SnapAssertionError(SnapError):
|
|
"""Error thrown on problems with the assertions API."""
|
|
pass
|
|
|
|
|
|
class Snap:
|
|
"""This class provides methods to retrieve information about a snap and
|
|
download it together with its assertions."""
|
|
|
|
def __init__(self, name, channel="stable", arch="amd64", series=16,
|
|
cohort_key=None, assertion_url="https://assertions.ubuntu.com",
|
|
snapcraft_url="https://api.snapcraft.io", **kwargs):
|
|
"""
|
|
:param name:
|
|
The name of the snap.
|
|
:param channel:
|
|
The channel to operate on.
|
|
:param arch:
|
|
The Debian architecture of the snap (e.g. amd64, armhf, arm64, ...).
|
|
:param series:
|
|
The device series. This should always be 16.
|
|
:param cohort_key:
|
|
A cohort key to access a snapshot of the channel map.
|
|
"""
|
|
self._name = name
|
|
self._channel = channel
|
|
self._arch = arch
|
|
self._series = series
|
|
self._cohort_key = cohort_key
|
|
self._assertion_url = assertion_url
|
|
self._snapcraft_url = snapcraft_url
|
|
self._details = None
|
|
self._assertions = {}
|
|
|
|
@classmethod
|
|
def cohort_create(cls):
|
|
"""Get a cohort key for the current moment. A cohort key is valid
|
|
across all snaps, channels and architectures."""
|
|
return Snap("core")\
|
|
.get_details(cohort_create=True)\
|
|
.get("cohort-key")
|
|
|
|
def download(self, download_assertions=True):
|
|
"""Download the snap container. If download_assertions is True, the
|
|
corresponding assertions will be downloaded, as well."""
|
|
snap = self.get_details()
|
|
|
|
snap_name = snap["name"]
|
|
snap_revision = snap["revision"]
|
|
publisher_id = snap["publisher"]["id"]
|
|
snap_download_url = snap["download"]["url"]
|
|
snap_byte_size = snap["download"]["size"]
|
|
filename = snap_name + "_" + str(snap_revision)
|
|
snap_filename = filename + ".snap"
|
|
assert_filename = filename + ".assert"
|
|
|
|
skip_snap_download = False
|
|
|
|
if os.path.exists(snap_filename) and os.path.getsize(snap_filename) \
|
|
== snap_byte_size:
|
|
skip_snap_download = True
|
|
|
|
headers = {}
|
|
|
|
if os.environ.get("SNAPPY_STORE_NO_CDN", "0") != "0":
|
|
headers.update({
|
|
"X-Ubuntu-No-Cdn": "true",
|
|
"Snap-CDN": "none",
|
|
})
|
|
|
|
request = urllib.request.Request(snap_download_url, headers=headers)
|
|
|
|
if not skip_snap_download:
|
|
with urllib.request.urlopen(request) as response, \
|
|
open(snap_filename, "wb+") as fp:
|
|
shutil.copyfileobj(response, fp)
|
|
|
|
if not download_assertions:
|
|
return
|
|
|
|
required_assertions = [
|
|
"account-key",
|
|
"account",
|
|
"snap-declaration",
|
|
"snap-revision",
|
|
]
|
|
|
|
if publisher_id == "canonical":
|
|
required_assertions.remove("account")
|
|
|
|
for assertion_name in required_assertions:
|
|
attr_name = "get_assertion_" + assertion_name.replace("-", "_")
|
|
# This will populate self._assertions[<assertion_name>].
|
|
getattr(self, attr_name)()
|
|
|
|
with open(assert_filename, "w+", encoding="utf-8") as fp:
|
|
fp.write("\n".join(self._assertions[a] for a in
|
|
required_assertions))
|
|
|
|
def get_details(self, cohort_create=False):
|
|
"""Get details about the snap. On subsequent calls, the cached results
|
|
are returned. If cohort_create is set to True, a cohort key will be
|
|
created and included in the result."""
|
|
if self._details and not cohort_create:
|
|
return self._details
|
|
|
|
if self.is_core_snap() and self._channel.startswith("stable/ubuntu-"):
|
|
sys.stderr.write(
|
|
"WARNING: switching channel from '{}' to 'stable' for '{}' "
|
|
"snap.\n".format(self._channel, self._name)
|
|
)
|
|
self._channel = "stable"
|
|
|
|
path = "/v2/snaps/refresh"
|
|
|
|
data = {
|
|
"context": [],
|
|
"actions": [
|
|
{
|
|
"action": "download",
|
|
"instance-key": "0",
|
|
"name": self._name,
|
|
"channel": self._channel,
|
|
}
|
|
],
|
|
"fields": [
|
|
"base",
|
|
"created-at",
|
|
"download",
|
|
"license",
|
|
"name",
|
|
"prices",
|
|
"publisher",
|
|
"revision",
|
|
"snap-id",
|
|
"summary",
|
|
"title",
|
|
"type",
|
|
"version",
|
|
],
|
|
}
|
|
|
|
# These are mutually exclusive.
|
|
if cohort_create:
|
|
data["actions"][0]["cohort-create"] = True
|
|
elif self._cohort_key:
|
|
data["actions"][0]["cohort-key"] = self._cohort_key
|
|
|
|
request_json = json.dumps(data, ensure_ascii=False).encode("utf-8")
|
|
|
|
try:
|
|
response_dict = self._do_snapcraft_request(path, data=request_json)
|
|
except SnapCraftError as e:
|
|
raise SnapError("failed to get details for '{}': {}"
|
|
.format(self._name, str(e)))
|
|
|
|
snap_data = response_dict["results"][0]
|
|
|
|
# Have "base" initialized to something meaningful.
|
|
if self.is_core_snap() or snap_data["snap"].get("base") == "none":
|
|
snap_data["snap"]["base"] = ""
|
|
elif snap_data["snap"].get("base") is None:
|
|
snap_data["snap"]["base"] = "core"
|
|
|
|
# Copy the key into the snap details.
|
|
if "cohort-key" in snap_data:
|
|
snap_data["snap"]["cohort-key"] = snap_data["cohort-key"]
|
|
|
|
if "error" in snap_data:
|
|
raise SnapError(
|
|
"failed to get details for '{}' in '{}' on '{}': {}"
|
|
.format(self._name, self._channel, self._arch,
|
|
snap_data["error"]["message"])
|
|
)
|
|
|
|
self._details = snap_data["snap"]
|
|
return self._details
|
|
|
|
def get_assertion_snap_revision(self):
|
|
"""Download the snap-revision assertion associated with this snap. The
|
|
assertion is returned as a string."""
|
|
if "snap-revision" in self._assertions:
|
|
return self._assertions["snap-revision"]
|
|
snap = self.get_details()
|
|
|
|
snap_sha3_384 = base64.urlsafe_b64encode(
|
|
binascii.a2b_hex(snap["download"]["sha3-384"])
|
|
).decode("us-ascii")
|
|
|
|
data = self._do_assertion_request("/v1/assertions/snap-revision/{}"
|
|
.format(snap_sha3_384))
|
|
self._assertions["snap-revision"] = data
|
|
return data
|
|
|
|
def get_assertion_snap_declaration(self):
|
|
"""Download the snap-declaration assertion associated with this snap.
|
|
The assertion is returned as a string."""
|
|
if "snap-declaration" in self._assertions:
|
|
return self._assertions["snap-declaration"]
|
|
snap = self.get_details()
|
|
series = self._series
|
|
snap_id = snap["snap-id"]
|
|
|
|
data = self._do_assertion_request(
|
|
"/v1/assertions/snap-declaration/{}/{}"
|
|
.format(series, snap_id))
|
|
|
|
self._assertions["snap-declaration"] = data
|
|
return data
|
|
|
|
def get_assertion_account(self):
|
|
"""Download the account assertion associated with this snap. The
|
|
assertion is returned as a string."""
|
|
if "account" in self._assertions:
|
|
return self._assertions["account"]
|
|
snap = self.get_details()
|
|
publisher_id = snap["publisher"]["id"]
|
|
data = self._do_assertion_request("/v1/assertions/account/{}"
|
|
.format(publisher_id))
|
|
self._assertions["account"] = data
|
|
return data
|
|
|
|
def get_assertion_account_key(self):
|
|
"""Download the account-key assertion associated with this snap. The
|
|
assertion will be returned as a string."""
|
|
if "account-key" in self._assertions:
|
|
return self._assertions["account-key"]
|
|
|
|
declaration_data = self.get_assertion_snap_declaration()
|
|
sign_key_sha3 = None
|
|
|
|
for line in declaration_data.splitlines():
|
|
if line.startswith("sign-key-sha3-384:"):
|
|
sign_key_sha3 = line.split(":")[1].strip()
|
|
|
|
data = self._do_assertion_request("/v1/assertions/account-key/{}"
|
|
.format(sign_key_sha3))
|
|
|
|
self._assertions["account-key"] = data
|
|
return data
|
|
|
|
def is_core_snap(self):
|
|
return re.match(r"^core\d*$", self._name) != None
|
|
|
|
def _do_assertion_request(self, path):
|
|
url = self._assertion_url + path
|
|
|
|
headers = {
|
|
"Accept": "application/x.ubuntu.assertion",
|
|
}
|
|
|
|
request = urllib.request.Request(url, headers=headers)
|
|
|
|
try:
|
|
with urllib.request.urlopen(request) as response:
|
|
body = response.read()
|
|
except urllib.error.HTTPError as e:
|
|
raise SnapAssertionError(str(e))
|
|
|
|
return body.decode("utf-8")
|
|
|
|
def _do_snapcraft_request(self, path, data=None):
|
|
url = self._snapcraft_url + "/" + path
|
|
|
|
headers = {
|
|
"Snap-Device-Series": str(self._series),
|
|
"Snap-Device-Architecture": self._arch,
|
|
"Content-Type": "application/json",
|
|
}
|
|
|
|
request = urllib.request.Request(url, data=data, headers=headers)
|
|
|
|
try:
|
|
with urllib.request.urlopen(request) as response:
|
|
body = response.read()
|
|
except urllib.error.HTTPError as e:
|
|
raise SnapCraftError(str(e))
|
|
|
|
try:
|
|
response_data = json.loads(body, encoding="utf-8")
|
|
except json.JSONDecodeError as e:
|
|
raise SnapCraftError("failed to decode response body: " + str(e))
|
|
|
|
return response_data
|
|
|
|
|
|
class SnapCli:
|
|
|
|
def __call__(self, args):
|
|
"""Parse the command line arguments and execute the selected command."""
|
|
options = self._parse_opts(args)
|
|
|
|
try:
|
|
options.func(getattr(options, "snap", None), **vars(options))
|
|
except SnapError as e:
|
|
sys.stderr.write("snap-tool {}: {}\n".format(
|
|
options.command, str(e)))
|
|
return EXIT_ERR
|
|
return EXIT_OK
|
|
|
|
@staticmethod
|
|
def _get_host_deb_arch():
|
|
result = subprocess.run(["dpkg", "--print-architecture"],
|
|
stdout=subprocess.PIPE, stderr=subprocess.PIPE,
|
|
universal_newlines=True, check=True)
|
|
|
|
return result.stdout.strip()
|
|
|
|
def _parse_opts(self, args):
|
|
main_parser = argparse.ArgumentParser()
|
|
subparsers = main_parser.add_subparsers(dest="command")
|
|
|
|
parser_cohort_create = subparsers.add_parser("cohort-create",
|
|
help="Create a cohort key for the snap store channel map.")
|
|
parser_cohort_create.set_defaults(func=self._cohort_create)
|
|
|
|
parser_download = subparsers.add_parser("download",
|
|
help="Download a snap from the store.")
|
|
parser_download.set_defaults(func=self._download)
|
|
|
|
parser_info = subparsers.add_parser("info",
|
|
help="Retrieve information about a snap.")
|
|
parser_info.set_defaults(func=self._info)
|
|
|
|
# Add common parameters.
|
|
for parser in [parser_download, parser_info]:
|
|
parser.add_argument("--cohort-key", dest="cohort_key",
|
|
help="A cohort key to pin the channel map to.", type=str)
|
|
parser.add_argument("--channel", dest="channel",
|
|
help="The publication channel to query (default: stable).",
|
|
type=str, default="stable")
|
|
parser.add_argument("--series", dest="series",
|
|
help="The device series (default: 16)",
|
|
type=int, default=16)
|
|
parser.add_argument("--arch", dest="arch",
|
|
help="The Debian architecture (default: amd64).",
|
|
type=str, default=self._get_host_deb_arch())
|
|
parser.add_argument("snap", help="The name of the snap.")
|
|
|
|
if not args:
|
|
main_parser.print_help()
|
|
sys.exit(EXIT_ERR)
|
|
|
|
return main_parser.parse_args(args)
|
|
|
|
def _cohort_create(self, _, **kwargs):
|
|
print(Snap.cohort_create())
|
|
|
|
def _download(self, snap_name, **kwargs):
|
|
Snap(snap_name, **kwargs).download()
|
|
|
|
def _info(self, snap_name, **kwargs):
|
|
snap = Snap(snap_name, **kwargs)
|
|
info = snap.get_details()
|
|
|
|
print(dedent("""\
|
|
name: {}
|
|
summary: {}
|
|
arch: {}
|
|
base: {}
|
|
channel: {}
|
|
publisher: {}
|
|
license: {}
|
|
snap-id: {}
|
|
revision: {}"""
|
|
.format(
|
|
snap_name,
|
|
info.get("summary", ""),
|
|
snap._arch,
|
|
info.get("base"),
|
|
snap._channel,
|
|
info.get("publisher", {}).get("display-name", ""),
|
|
info.get("license", ""),
|
|
info.get("snap-id", ""),
|
|
info.get("revision", "")
|
|
))
|
|
)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
try:
|
|
rval = SnapCli()(sys.argv[1:])
|
|
except KeyboardInterrupt:
|
|
sys.stderr.write("snap-tool: caught keyboard interrupt, exiting.\n")
|
|
sys.exit(EXIT_ERR)
|
|
sys.exit(rval)
|