Files
2020-04-08 10:39:44 -07:00

106 lines
3.5 KiB
Python

import re
from ..logger import get_logger
log = get_logger(__name__)
class CGroupInfo(object):
"""
CGroup class for container information parsed from a group cgroup file
"""
__slots__ = ("id", "groups", "path", "container_id", "controllers", "pod_id")
UUID_SOURCE_PATTERN = r"[0-9a-f]{8}[-_][0-9a-f]{4}[-_][0-9a-f]{4}[-_][0-9a-f]{4}[-_][0-9a-f]{12}"
CONTAINER_SOURCE_PATTERN = r"[0-9a-f]{64}"
LINE_RE = re.compile(r"^(\d+):([^:]*):(.+)$")
POD_RE = re.compile(r"pod({0})(?:\.slice)?$".format(UUID_SOURCE_PATTERN))
CONTAINER_RE = re.compile(r"({0}|{1})(?:\.scope)?$".format(UUID_SOURCE_PATTERN, CONTAINER_SOURCE_PATTERN))
def __init__(self, **kwargs):
# Initialize all attributes in __slots__ to `None`
# DEV: Otherwise we'll get `AttributeError` when trying to access if they are unset
for attr in self.__slots__:
setattr(self, attr, kwargs.get(attr))
@classmethod
def from_line(cls, line):
"""
Parse a new :class:`CGroupInfo` from the provided line
:param line: A line from a cgroup file (e.g. /proc/self/cgroup) to parse information from
:type line: str
:returns: A :class:`CGroupInfo` object with all parsed data, if the line is valid, otherwise `None`
:rtype: :class:`CGroupInfo` | None
"""
# Clean up the line
line = line.strip()
# Ensure the line is valid
match = cls.LINE_RE.match(line)
if not match:
return None
# Create our new `CGroupInfo` and set attributes from the line
info = cls()
info.id, info.groups, info.path = match.groups()
# Parse the controllers from the groups
info.controllers = [c.strip() for c in info.groups.split(",") if c.strip()]
# Break up the path to grab container_id and pod_id if available
# e.g. /docker/<container_id>
# e.g. /kubepods/test/pod<pod_id>/<container_id>
parts = [p for p in info.path.split("/")]
# Grab the container id from the path if a valid id is present
if len(parts):
match = cls.CONTAINER_RE.match(parts.pop())
if match:
info.container_id = match.group(1)
# Grab the pod id from the path if a valid id is present
if len(parts):
match = cls.POD_RE.match(parts.pop())
if match:
info.pod_id = match.group(1)
return info
def __str__(self):
return self.__repr__()
def __repr__(self):
return "{}(id={!r}, groups={!r}, path={!r}, container_id={!r}, controllers={!r}, pod_id={!r})".format(
self.__class__.__name__, self.id, self.groups, self.path, self.container_id, self.controllers, self.pod_id,
)
def get_container_info(pid="self"):
"""
Helper to fetch the current container id, if we are running in a container
We will parse `/proc/{pid}/cgroup` to determine our container id.
The results of calling this function are cached
:param pid: The pid of the cgroup file to parse (default: 'self')
:type pid: str | int
:returns: The cgroup file info if found, or else None
:rtype: :class:`CGroupInfo` | None
"""
try:
cgroup_file = "/proc/{0}/cgroup".format(pid)
with open(cgroup_file, mode="r") as fp:
for line in fp:
info = CGroupInfo.from_line(line)
if info and info.container_id:
return info
except Exception:
log.debug("Failed to parse cgroup file for pid %r", pid, exc_info=True)
return None