CasperSecurity
import logging
import re
from typing import List, NamedTuple, Optional
from uaclient import (
api,
apt,
event_logger,
exceptions,
http,
messages,
system,
util,
)
SNAP_CMD = "/usr/bin/snap"
SNAP_INSTALL_RETRIES = [0.5, 1.0, 5.0]
HTTP_PROXY_OPTION = "proxy.http"
HTTPS_PROXY_OPTION = "proxy.https"
SNAPD_SOCKET_PATH = "/run/snapd.socket"
SNAPD_SNAPS_API = "/v2/snaps/{}"
event = event_logger.get_event_logger()
LOG = logging.getLogger(util.replace_top_level_logger_name(__name__))
SnapPackage = NamedTuple(
"SnapPackage",
[
("name", str),
("version", str),
("revision", str),
("channel", str),
("publisher", str),
],
)
def is_snapd_installed() -> bool:
"""Returns whether or not snap is installed"""
return "snapd" in apt.get_installed_packages_names()
def is_snapd_installed_as_a_snap() -> bool:
"""Returns whether or not snapd is installed as a snap"""
return any((snap.name == "snapd" for snap in get_installed_snaps()))
def configure_snap_proxy(
http_proxy: Optional[str] = None,
https_proxy: Optional[str] = None,
retry_sleeps: Optional[List[float]] = None,
) -> None:
"""
Configure snap to use http and https proxies.
:param http_proxy: http proxy to be used by snap. If None, it will
not be configured
:param https_proxy: https proxy to be used by snap. If None, it will
not be configured
:param retry_sleeps: Optional list of sleep lengths to apply between
retries. Specifying a list of [0.5, 1] tells subp to retry twice
on failure; sleeping half a second before the first retry and 1 second
before the second retry.
"""
if not is_snapd_installed():
LOG.debug("Skipping configure snap proxy. snapd is not installed.")
return
if http_proxy or https_proxy:
event.info(messages.SETTING_SERVICE_PROXY.format(service="snap"))
if http_proxy:
system.subp(
["snap", "set", "system", "proxy.http={}".format(http_proxy)],
retry_sleeps=retry_sleeps,
)
if https_proxy:
system.subp(
["snap", "set", "system", "proxy.https={}".format(https_proxy)],
retry_sleeps=retry_sleeps,
)
def unconfigure_snap_proxy(
protocol_type: str, retry_sleeps: Optional[List[float]] = None
) -> None:
"""
Unset snap configuration settings for http and https proxies.
:param protocol_type: String either http or https
:param retry_sleeps: Optional list of sleep lengths to apply between
retries. Specifying a list of [0.5, 1] tells subp to retry twice
on failure; sleeping half a second before the first retry and 1 second
before the second retry.
"""
if not is_snapd_installed():
LOG.debug("Skipping unconfigure snap proxy. snapd is not installed.")
return
system.subp(
["snap", "unset", "system", "proxy.{}".format(protocol_type)],
retry_sleeps=retry_sleeps,
)
def get_config_option_value(key: str) -> Optional[str]:
"""
Gets the config value from snap.
:param protocol: can be any valid snap config option
:return: the value of the snap config option, or None if not set
"""
try:
out, _ = system.subp(["snap", "get", "system", key])
return out.strip()
except exceptions.ProcessExecutionError:
return None
def get_installed_snaps() -> List[SnapPackage]:
out, _ = system.subp(
["snap", "list", "--color", "never", "--unicode", "never"]
)
apps = out.splitlines()
apps = apps[1:]
snaps = []
for line in apps:
snap = line.split()[0]
snaps.append(get_snap_info(snap))
return snaps
def install_snapd():
event.info(messages.APT_UPDATING_LIST.format(name="standard Ubuntu"))
try:
apt.update_sources_list(apt.get_system_sources_file())
except exceptions.UbuntuProError as e:
LOG.debug(
"Trying to install snapd. Ignoring apt-get update failure: %s",
str(e),
)
try:
system.subp(
["apt-get", "install", "--assume-yes", "snapd"],
retry_sleeps=apt.APT_RETRIES,
)
except exceptions.ProcessExecutionError:
raise exceptions.CannotInstallSnapdError()
def run_snapd_wait_cmd(progress: api.ProgressWrapper):
try:
system.subp([SNAP_CMD, "wait", "system", "seed.loaded"], capture=True)
except exceptions.ProcessExecutionError as e:
if re.search(r"unknown command .*wait", str(e).lower()):
LOG.warning(
"Detected version of snapd that does not have wait command"
)
progress.emit("info", messages.SNAPD_DOES_NOT_HAVE_WAIT_CMD)
else:
raise
def install_snap(
snap: str,
channel: Optional[str] = None,
classic_confinement_support: bool = False,
):
cmd = [SNAP_CMD, "install", snap]
if classic_confinement_support:
cmd += ["--classic"]
if channel:
cmd += ["--channel={}".format(channel)]
system.subp(
cmd,
capture=True,
retry_sleeps=SNAP_INSTALL_RETRIES,
)
def refresh_snap(snap: str):
system.subp([SNAP_CMD, "refresh", snap], capture=True)
def get_snap_info(snap: str) -> SnapPackage:
url = SNAPD_SNAPS_API.format(snap)
try:
resp = http.unix_socket_request(SNAPD_SOCKET_PATH, "GET", url)
# This means that the snap doesn't exist or is not installed
if resp.code != 200:
if (
resp.code == 404
and resp.json_dict.get("result", {}).get("kind")
== "snap-not-found"
):
raise exceptions.SnapNotInstalledError(snap=snap)
else:
error_msg = resp.json_dict.get("result", {}).get("message")
raise exceptions.UnexpectedSnapdAPIError(error=error_msg)
except ConnectionRefusedError:
raise exceptions.SnapdAPIConnectionRefused()
snap_info = resp.json_dict.get("result", {})
return SnapPackage(
name=snap_info.get("name", ""),
version=snap_info.get("version", ""),
revision=snap_info.get("revision", ""),
channel=snap_info.get("channel", ""),
publisher=snap_info.get("publisher", {}).get("username", ""),
)