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"""Tools for working with the host system"""
# Copyright 2012 Canonical Ltd.
#
# Authors:
# Nick Moffitt <nick.moffitt@canonical.com>
# Matthew Wedgwood <matthew.wedgwood@canonical.com>
import apt_pkg
import os
import pwd
import grp
import random
import string
import subprocess
import hashlib
from collections import OrderedDict
from hookenv import log
def service_start(service_name):
return service('start', service_name)
def service_stop(service_name):
return service('stop', service_name)
def service_restart(service_name):
return service('restart', service_name)
def service_reload(service_name, restart_on_failure=False):
service_result = service('reload', service_name)
if not service_result and restart_on_failure:
service_result = service('restart', service_name)
return service_result
def service(action, service_name):
cmd = ['service', service_name, action]
return subprocess.call(cmd) == 0
def service_running(service):
try:
output = subprocess.check_output(['service', service, 'status'])
except subprocess.CalledProcessError:
return False
else:
if ("start/running" in output or "is running" in output):
return True
else:
return False
def adduser(username, password=None, shell='/bin/bash', system_user=False):
"""Add a user"""
try:
user_info = pwd.getpwnam(username)
log('user {0} already exists!'.format(username))
except KeyError:
log('creating user {0}'.format(username))
cmd = ['useradd']
if system_user or password is None:
cmd.append('--system')
else:
cmd.extend([
'--create-home',
'--shell', shell,
'--password', password,
])
cmd.append(username)
subprocess.check_call(cmd)
user_info = pwd.getpwnam(username)
return user_info
def add_user_to_group(username, group):
"""Add a user to a group"""
cmd = [
'gpasswd', '-a',
username,
group
]
log("Adding user {} to group {}".format(username, group))
subprocess.check_call(cmd)
def rsync(from_path, to_path, flags='-r', options=None):
"""Replicate the contents of a path"""
options = options or ['--delete', '--executability']
cmd = ['/usr/bin/rsync', flags]
cmd.extend(options)
cmd.append(from_path)
cmd.append(to_path)
log(" ".join(cmd))
return subprocess.check_output(cmd).strip()
def symlink(source, destination):
"""Create a symbolic link"""
log("Symlinking {} as {}".format(source, destination))
cmd = [
'ln',
'-sf',
source,
destination,
]
subprocess.check_call(cmd)
def mkdir(path, owner='root', group='root', perms=0555, force=False):
"""Create a directory"""
log("Making dir {} {}:{} {:o}".format(path, owner, group,
perms))
uid = pwd.getpwnam(owner).pw_uid
gid = grp.getgrnam(group).gr_gid
realpath = os.path.abspath(path)
if os.path.exists(realpath):
if force and not os.path.isdir(realpath):
log("Removing non-directory file {} prior to mkdir()".format(path))
os.unlink(realpath)
else:
os.makedirs(realpath, perms)
os.chown(realpath, uid, gid)
def write_file(path, content, owner='root', group='root', perms=0444):
"""Create or overwrite a file with the contents of a string"""
log("Writing file {} {}:{} {:o}".format(path, owner, group, perms))
uid = pwd.getpwnam(owner).pw_uid
gid = grp.getgrnam(group).gr_gid
with open(path, 'w') as target:
os.fchown(target.fileno(), uid, gid)
os.fchmod(target.fileno(), perms)
target.write(content)
def filter_installed_packages(packages):
"""Returns a list of packages that require installation"""
apt_pkg.init()
cache = apt_pkg.Cache()
_pkgs = []
for package in packages:
try:
p = cache[package]
p.current_ver or _pkgs.append(package)
except KeyError:
log('Package {} has no installation candidate.'.format(package),
level='WARNING')
_pkgs.append(package)
return _pkgs
def apt_install(packages, options=None, fatal=False):
"""Install one or more packages"""
options = options or []
cmd = ['apt-get', '-y']
cmd.extend(options)
cmd.append('install')
if isinstance(packages, basestring):
cmd.append(packages)
else:
cmd.extend(packages)
log("Installing {} with options: {}".format(packages,
options))
if fatal:
subprocess.check_call(cmd)
else:
subprocess.call(cmd)
def apt_update(fatal=False):
"""Update local apt cache"""
cmd = ['apt-get', 'update']
if fatal:
subprocess.check_call(cmd)
else:
subprocess.call(cmd)
def mount(device, mountpoint, options=None, persist=False):
'''Mount a filesystem'''
cmd_args = ['mount']
if options is not None:
cmd_args.extend(['-o', options])
cmd_args.extend([device, mountpoint])
try:
subprocess.check_output(cmd_args)
except subprocess.CalledProcessError, e:
log('Error mounting {} at {}\n{}'.format(device, mountpoint, e.output))
return False
if persist:
# TODO: update fstab
pass
return True
def umount(mountpoint, persist=False):
'''Unmount a filesystem'''
cmd_args = ['umount', mountpoint]
try:
subprocess.check_output(cmd_args)
except subprocess.CalledProcessError, e:
log('Error unmounting {}\n{}'.format(mountpoint, e.output))
return False
if persist:
# TODO: update fstab
pass
return True
def mounts():
'''List of all mounted volumes as [[mountpoint,device],[...]]'''
with open('/proc/mounts') as f:
# [['/mount/point','/dev/path'],[...]]
system_mounts = [m[1::-1] for m in [l.strip().split()
for l in f.readlines()]]
return system_mounts
def file_hash(path):
''' Generate a md5 hash of the contents of 'path' or None if not found '''
if os.path.exists(path):
h = hashlib.md5()
with open(path, 'r') as source:
h.update(source.read()) # IGNORE:E1101 - it does have update
return h.hexdigest()
else:
return None
def restart_on_change(restart_map):
''' Restart services based on configuration files changing
This function is used a decorator, for example
@restart_on_change({
'/etc/ceph/ceph.conf': [ 'cinder-api', 'cinder-volume' ]
})
def ceph_client_changed():
...
In this example, the cinder-api and cinder-volume services
would be restarted if /etc/ceph/ceph.conf is changed by the
ceph_client_changed function.
'''
def wrap(f):
def wrapped_f(*args):
checksums = {}
for path in restart_map:
checksums[path] = file_hash(path)
f(*args)
restarts = []
for path in restart_map:
if checksums[path] != file_hash(path):
restarts += restart_map[path]
for service_name in list(OrderedDict.fromkeys(restarts)):
service('restart', service_name)
return wrapped_f
return wrap
def lsb_release():
'''Return /etc/lsb-release in a dict'''
d = {}
with open('/etc/lsb-release', 'r') as lsb:
for l in lsb:
k, v = l.split('=')
d[k.strip()] = v.strip()
return d
def pwgen(length=None):
'''Generate a random pasword.'''
if length is None:
length = random.choice(range(35, 45))
alphanumeric_chars = [
l for l in (string.letters + string.digits)
if l not in 'l0QD1vAEIOUaeiou']
random_chars = [
random.choice(alphanumeric_chars) for _ in range(length)]
return(''.join(random_chars))
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