✏️ Editing: reloader_redis_lib.py Read Only

# coding=utf-8
#
# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2021 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENCE.TXT
#

# Redis manipulation library for reloader script

# pylint: disable=no-absolute-import

import pwd
import os
import re
import traceback
import subprocess
from logging import Logger
from typing import List, Optional

from secureio import write_file_via_tempfile
from clcommon.clpwd import drop_user_privileges
from clcommon.cpapi import userdomains
from clcommon.const import Feature
from clcommon.cpapi import is_panel_feature_supported
from clcommon.utils import demote

from clwpos import gettext as _
from clwpos.cl_wpos_exceptions import WposError
from clwpos.daemon_redis_lib import _get_redis_pid_from_pid_file_with_wait, kill_process_by_pid
from clwpos.utils import USER_WPOS_DIR, is_run_under_user
from clwpos.user.config import UserConfig, ConfigError
from clwpos.optimization_features import OBJECT_CACHE_FEATURE
from clwpos.feature_suites import get_allowed_modules
from clwpos.constants import REDIS_SERVER_BIN_FILE, MAXIMUM_MAX_CACHE_MEMORY, MINIMUM_MAX_CACHE_MEMORY
from clwpos.logsetup import NullLogger
from clcommon.cpapi.cpapiexceptions import NoPackage

_USER_REDIS_CONF_PATTERN = """# !!! WARNING !!! AUTO-GENERATED FILE, PLEASE DO NOT MODIFY IT
maxclients {maxclients}
databases 16
maxmemory-policy allkeys-lru
appendonly no
appendfsync always
loglevel warning
logfile {logfile}
# Disable TCP ports using
port 0
unixsocket {socket_path}
unixsocketperm 600
dir {clwpos_dir}
maxmemory {maxmemory}
save ""
pidfile {pidfile}
"""

logger = NullLogger()

def _read_maxclients_from_config(redis_config_path: str) -> str:
    """
    Read and return maxclients value from the Redis config file
    if config file exists maxclients is integer value.
    Return default value otherwise.
    :param redis_config_path: path to Redis configuration file
    :return: maxclients value from config or default
    """
    if os.path.exists(redis_config_path):
        with open(redis_config_path) as redis_config:
            config = redis_config.read()
            value = re.search(r'maxclients (\d+)$', config, flags=re.MULTILINE)

if value is not None:
                return value.group(1)

return '16'

def _write_redis_config_for_user(username: str, user_homedir: str, clwpos_dir: str, redis_socket_path: str,
                                 redis_config_path: str, maxmemory: str, pidfile_path: str):
    """
    Writes redis config for user (call under drop_privileges)
    :param username: User name for write config
    :param user_homedir: User's homedir
    :param redis_socket_path: Full path to user's redis socket
    :param redis_config_path: Full path to user's redis config file
    :param maxmemory: maxmemory value to write to redis config
    :param pidfile_path: Redis pid file path
    :return: None
    """
    maxclients = _read_maxclients_from_config(redis_config_path)

_maxmemory_match = re.fullmatch(r'([0-9]+)mb', str(maxmemory), re.IGNORECASE)
    if (_maxmemory_match is None
            or not MINIMUM_MAX_CACHE_MEMORY <= int(_maxmemory_match.group(1)) <= MAXIMUM_MAX_CACHE_MEMORY):
        maxmemory = UserConfig.DEFAULT_MAX_CACHE_MEMORY

redis_config_content = _USER_REDIS_CONF_PATTERN.format(
        maxclients=maxclients,
        logfile=os.path.join(os.path.dirname(redis_config_path), 'redis.log'),
        socket_path=redis_socket_path,
        clwpos_dir=clwpos_dir, maxmemory=maxmemory,
        pidfile=pidfile_path
    )
    try:
        clwpos_dir = os.path.join(user_homedir, USER_WPOS_DIR)
        try:
            os.makedirs(clwpos_dir, exist_ok=True)
        except (OSError, IOError,) as system_error:
            raise WposError(message=_("Can't create directory %(directory)s. "),
                            details=_("The operating system reported error: %(system_error)s"),
                            context={"directory": clwpos_dir, 'system_error': system_error})
        # Write redis config
        write_file_via_tempfile(redis_config_content, redis_config_path, 0o600)
    except (OSError, IOError) as system_error:
        raise WposError(message=_("Error happened while writing redis config for user '%(user)s' "),
                        details=_("The operating system reported error: %(system_error)s"),
                        context={"user": username, "system_error": system_error})

def _get_valid_docroots_from_config(logger: Logger, username: str, user_homedir: str,
                                    docroot_list_to_validate: List[str]) -> List[str]:
    """
    Validates docroots from list
    :param logger: Logger to log errors
    :param username: User name
    :param user_homedir: User's homedir
    :param docroot_list_to_validate: Docroot list to validate
    :return: List of valid docroots
    """
    if not docroot_list_to_validate:
        # Nothing to validate
        return []
    try:
        # Get active docroots for user from panel
        userdomains_data_list = userdomains(username)
    except (OSError, IOError, IndexError, NoPackage) as e:
        # Skip all cpapi.userdomains errors
        logger.warning("Can't get user list from panel: %s", str(e))
        return []
    # Add some filename to all docroots to avoid any problems with / at the end of paths
    docroots_from_panel = []
    for _, document_root in userdomains_data_list:
        docroots_from_panel.append(os.path.normpath(document_root))
    # Validate docroots from config
    valid_docroot_list: List[str] = []
    for _dr in docroot_list_to_validate:
        tempname = os.path.normpath(os.path.join(user_homedir, _dr))
        if tempname in docroots_from_panel:
            valid_docroot_list.append(_dr)
    return valid_docroot_list

def _is_redis_plugin_enabled(logger: Logger, username: str, uid: int, user_homedir: str,
                             user_config_dict: dict) -> bool:
    """
    Get redis status according to user's and admin's configs
    :param logger: Logger to log errors
    :param username: User name
    :parem uid: User uid
    :param user_homedir: User's homedir
    :param user_config_dict: User's config
    :return: True - module enabled, False - disabled
    """
    # TODO: Refactor this function in LU-2613
    # # Admin's config example:
    # allowed_modules_list example: ['object_cache']
    allowed_modules_list = get_allowed_modules(uid)
    if OBJECT_CACHE_FEATURE not in allowed_modules_list:
        return False
    # WPOS enabled by admin, check user's config
    # User's config example:
    # {
    #     "docroots": {
    #         "public_html": {"": ["object_cache"], "1": []},
    #         "public_html/gggh.com": {"wp1": ["object_cache"], "wp2": []}
    #     },
    #     "maxmemory": "512mb"
    # }
    target_docroots = user_config_dict.get('docroots', {})
    docroots_to_validate: list = list(target_docroots.keys())
    valid_wp_docroots = _get_valid_docroots_from_config(logger, username, user_homedir, docroots_to_validate)
    for wp_docroot in valid_wp_docroots:
        wp_data = target_docroots.get(wp_docroot, {})
        for module_list in wp_data.values():  # By WP paths
            if isinstance(module_list, list) and OBJECT_CACHE_FEATURE in module_list:
                # Redis enabled
                return True
    return False

def __start_redis(is_cagefs_missing: bool, redis_config_path: str, username, _logger) -> None:
    """
    Run subprocess with redis
    """
    user_pwd = pwd.getpwnam(username)
    if is_cagefs_missing:
        command = [REDIS_SERVER_BIN_FILE, redis_config_path]
    else:
        # CL Shared
        # cagefs_enter.proxied brought by lve-wrappers which is required by lvemanager/lve-utils
        command = ['/bin/cagefs_enter.proxied', REDIS_SERVER_BIN_FILE, redis_config_path]

_logger.info('[Start redis] Executing command=%s', str(command))

stdout, stderr = b'', b''
    process = subprocess.Popen(
        command,
        preexec_fn=demote(user_pwd.pw_uid, user_pwd.pw_gid),
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE
    )

# to get errors if forking failed
    try:
        stdout, stderr = process.communicate(timeout=5)
    except subprocess.TimeoutExpired:
        pass

_logger.info('Captured stdout=%s, stderr=%s', str(stdout.decode()), str(stderr.decode()))

pidfile_path = os.path.join(user_pwd.pw_dir, USER_WPOS_DIR, 'redis.pid')
    redis_pid = _get_redis_pid_from_pid_file_with_wait(pidfile_path)
    _logger.info('[Start redis] Redis pid=%s', str(redis_pid))
    if redis_pid is None:
        raise OSError('Redis instance was not started for user')
    return None

def _start_redis_server_for_user(_logger: Logger, username: str, maxmemory: str) -> dict:
    """
    Start redis server for supplied user (calls under user)
    :param _logger: Daemon's logger
    :param username: Username to setup redis
    :param maxmemory: maxmemory value to write to redis config
    :return: dict
      If redis was started for user - {"result": "success"}
      else - redis was not started  - {"result": "error", "context": "...."}
    """
    user_pwd = pwd.getpwnam(username)
    # /home/username/.clwpos/
    _logger.info('Starting redis for username=%s', username)
    wpos_dir = os.path.join(user_pwd.pw_dir, USER_WPOS_DIR)
    redis_socket_path = os.path.join(wpos_dir, 'redis.sock')
    redis_config_path = os.path.join(wpos_dir, 'redis.conf')
    pidfile_path = os.path.join(wpos_dir, 'redis.pid')
    _write_redis_config_for_user(username, user_pwd.pw_dir, wpos_dir, redis_socket_path, redis_config_path,
                                 maxmemory, pidfile_path)
    _logger.info('Redis config for user=%s is saved with parameters:'
                 'socket_path=%s, '
                 'config_path=%s, '
                 'pidfile_path=%s',
                 username,
                 redis_socket_path,
                 redis_socket_path,
                 pidfile_path)
    try:
        is_cagefs_available = is_panel_feature_supported(Feature.CAGEFS)
        __start_redis(not is_cagefs_available, redis_config_path, username, _logger)
        return {"result": "success", "redis_enabled": True}
    except (OSError, IOError) as e:
        str_exc = traceback.format_exc()
        _logger.warning("Error while starting redis server for user %s. Error is: %s", username, str_exc)
        return {"result": _("Error while starting redis server: %(error)s"),
                "context": {"error": str(e)}}

def _check_redis_process_and_kill(old_redis_pid: int) -> bool:
    """
    Check existing process by PID and kill it:
        - If old_redis_pid == -1, nothing will kill, return False
        - else check process existance.
            if exi
    :param old_redis_pid: PID to check and kill
    :return: True - Can't kill process not owned by current user, this is error, continue work not allowed
            False - Process absent or was killed succesfully, continue work allowed
    """
    if old_redis_pid == -1:
        # Process absent or was killed succesfully, continue work allowed
        return False

if not is_run_under_user():
        raise WposError("Internal error! Trying to kill process with root privileges")

try:
        os.kill(old_redis_pid, 0)
    except PermissionError:
        # process not owned by current user -- error, exit
        return True
    except ProcessLookupError:
        # No such process - no error
        pass
    kill_process_by_pid(logger, old_redis_pid)
    # Process absent or was killed succesfully, continue work allowed
    return False

def reload_redis_for_user(username: str, old_redis_pid: int, _logger: Optional[Logger] = None,
                          is_log_debug_level: bool = False, force_reload: str = 'no') -> dict:
    """
    Reloads redis for supplied user without logging and killing old redis process
    Calls only from redis_reloader.py script
    :param username: Username to setup redis
    :param old_redis_pid: Redis PID to kill, -1 - no PID to kill
    :param _logger: Daemon's logger
    :param is_log_debug_level: True - log messages/ False - no
    :param force_reload: reload redis w/o conditions
    :return: dict
      If redis was started for user - {"result": "success"}
      else - redis was not started  - {"result": "error", "context": "...."}
    """
    if _logger is None:
        _logger = logger

_logger.info('[Reload redis for user]: Request to reload redis for '
                 'username=%s, '
                 'old redis pid=%s,'
                 'force_reload',
                 username,
                 str(old_redis_pid),
                 str(force_reload))
    drop_user_privileges(username, effective_or_real=False, set_env=False)
    if _check_redis_process_and_kill(old_redis_pid):
        return {"result": _("Can't kill old redis process for user '%(user)s'. PID is %(pid)s"),
                "context": {"user": username, "pid": old_redis_pid}}
    try:
        user_config_class = UserConfig(username)
        user_config = user_config_class.read_config()
    except ConfigError as e:
        # User's config read error
        if is_log_debug_level:
            _logger.warning("Can't reload redis for user %s. User's config read error: %s", username, str(e))
        if not force_reload:
            return {"result": _("Can't reload redis for user '%(user)s'. User's config read error"),
                    "context": {"user": username}}
        else:
            _logger.info('Cannot read user config, but force_reload was passed ---> unconditional reload')
            user_config = {}
    pw_user = pwd.getpwnam(username)
    is_redis_enable = _is_redis_plugin_enabled(_logger, username,
                                               pw_user.pw_uid, pw_user.pw_dir, user_config)
    if is_redis_enable or force_reload == 'yes':
        _logger.info('Starting redis for username=%s', username)
        # Start redis
        return _start_redis_server_for_user(_logger, username,
                                            user_config.get('max_cache_memory',
                                                            UserConfig.DEFAULT_MAX_CACHE_MEMORY))
    # Redis is disabled by user's config
    return {"result": "success", "redis_enabled": False}

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