def load_check(name, config, agentConfig):
    checksd_path = get_checksd_path(get_os())
    if checksd_path not in sys.path:
        sys.path.append(checksd_path)

    check_module = __import__(name)
    check_class = None
    classes = inspect.getmembers(check_module, inspect.isclass)
    for _, clsmember in classes:
        if clsmember == AgentCheck:
            continue
        if issubclass(clsmember, AgentCheck):
            check_class = clsmember
            if AgentCheck in clsmember.__bases__:
                continue
            else:
                break
    if check_class is None:
        raise Exception("Unable to import check %s. Missing a class that inherits AgentCheck" % name)

    init_config = config.get('init_config', {})
    instances = config.get('instances')
    agentConfig['checksd_hostname'] = get_hostname(agentConfig)

    # init the check class
    try:
        return check_class(name, init_config=init_config, agentConfig=agentConfig, instances=instances)
    except Exception as e:
        raise Exception("Check is using old API, {0}".format(e))

def load_check(agentConfig, hostname, checkname):
    """Same logic as load_check_directory except it loads one specific check"""
    agentConfig['checksd_hostname'] = hostname
    osname = get_os()
    checks_places = get_checks_places(osname, agentConfig)
    for config_path in _file_configs_paths(osname, agentConfig):
        check_name = _conf_path_to_check_name(config_path)
        if check_name == checkname:
            conf_is_valid, check_config, invalid_check = _load_file_config(config_path, check_name, agentConfig)

            if invalid_check and not conf_is_valid:
                return invalid_check

            # try to load the check and return the result
            load_success, load_failure = load_check_from_places(check_config, check_name, checks_places, agentConfig)
            return load_success.values()[0] or load_failure

    # the check was not found, try with service discovery
    for check_name, service_disco_check_config in _service_disco_configs(agentConfig).iteritems():
        if check_name == checkname:
            sd_init_config, sd_instances = service_disco_check_config
            check_config = {'init_config': sd_init_config, 'instances': sd_instances}

            # try to load the check and return the result
            load_success, load_failure = load_check_from_places(check_config, check_name, checks_places, agentConfig)
            return load_success.values()[0] or load_failure

    return None

def load_check(name, config, agentConfig):
    checksd_path = get_checksd_path(get_os())
    if checksd_path not in sys.path:
        sys.path.append(checksd_path)

    check_module = __import__(name)
    check_class = None
    classes = inspect.getmembers(check_module, inspect.isclass)
    for name, clsmember in classes:
        if clsmember == AgentCheck:
            continue
        if issubclass(clsmember, AgentCheck):
            check_class = clsmember
            if AgentCheck in clsmember.__bases__:
                continue
            else:
                break
    if check_class is None:
        raise Exception("Unable to import check %s. Missing a class that inherits AgentCheck" % name)

    init_config = config.get("init_config", None)
    instances = config.get("instances")

    # init the check class
    try:
        return check_class(name, init_config=init_config, agentConfig=agentConfig, instances=instances)
    except:
        # Backwards compatitiblity for old checks that don't support the
        # instances argument.
        c = check_class(name, init_config=init_config, agentConfig=agentConfig)
        c.instances = instances
        return c

def run_check(name, path=None):
    from tests.common import get_check

    # Read the config file
    confd_path = path or os.path.join(get_confd_path(get_os()), '%s.yaml' % name)

    try:
        f = open(confd_path)
    except IOError:
        raise Exception('Unable to open configuration at %s' % confd_path)

    config_str = f.read()
    f.close()

    # Run the check
    check, instances = get_check(name, config_str)
    if not instances:
        raise Exception('YAML configuration returned no instances.')
    for instance in instances:
        check.check(instance)
        if check.has_events():
            print "Events:\n"
            pprint(check.get_events(), indent=4)
        print "Metrics:\n"
        pprint(check.get_metrics(), indent=4)

def run_check(name, path=None):
    """
    Test custom checks on Windows.
    """
    # Read the config file

    confd_path = path or os.path.join(get_confd_path(get_os()), "%s.yaml" % name)

    try:
        f = open(confd_path)
    except IOError:
        raise Exception("Unable to open configuration at %s" % confd_path)

    config_str = f.read()
    f.close()

    # Run the check
    check, instances = get_check(name, config_str)
    if not instances:
        raise Exception("YAML configuration returned no instances.")
    for instance in instances:
        check.check(instance)
        if check.has_events():
            print "Events:\n"
            pprint(check.get_events(), indent=4)
        print "Metrics:\n"
        pprint(check.get_metrics(), indent=4)

def get_config_path(cfg_path=None, os_name=None):
    # Check if there's an override and if it exists
    if cfg_path is not None and os.path.exists(cfg_path):
        return cfg_path

    # Check if there's a config stored in the current agent directory
    try:
        path = os.path.realpath(__file__)
        path = os.path.dirname(path)
        return _config_path(path)
    except PathNotFound as e:
        pass

    if os_name is None:
        os_name = get_os()

    # Check for an OS-specific path, continue on not-found exceptions
    bad_path = ''
    try:
        if os_name == 'windows':
            return _windows_config_path()
        elif os_name == 'mac':
            return _mac_config_path()
        else:
            return _unix_config_path()
    except PathNotFound as e:
        if len(e.args) > 0:
            bad_path = e.args[0]

    # If all searches fail, exit the agent with an error
    sys.stderr.write("Please supply a configuration file at %s or in the directory where "
                     "the Agent is currently deployed.\n" % bad_path)
    sys.exit(3)

def get_check(name, config_str):
    from checks import AgentCheck

    checksd_path = get_checksd_path(get_os())
    if checksd_path not in sys.path:
        sys.path.append(checksd_path)
    check_module = __import__(name)
    check_class = None
    classes = inspect.getmembers(check_module, inspect.isclass)

    max_hierarchy_len = 0
    for name, clsmember in classes:
        if AgentCheck in clsmember.__bases__:
            check_class = clsmember
            break
        class_hierarchy = inspect.getmro(clsmember)
        if AgentCheck in class_hierarchy:
            if len(class_hierarchy) > max_hierarchy_len:
               max_hierarchy_len = len(class_hierarchy)
               check_class = clsmember
    if check_class is None:
        raise Exception("Unable to import check %s. Missing a class that inherits AgentCheck" % name)

    agentConfig = {
        'version': '0.1',
        'api_key': 'tota'
    }

    return check_class.from_yaml(yaml_text=config_str, check_name=name,
                                 agentConfig=agentConfig)

def get_checksd_path(osname=None):
    if not osname:
        osname = get_os()
    if osname == 'windows':
        return _windows_checksd_path()
    else:
        return _unix_checksd_path()

def load_check_directory(agentConfig, hostname):
    ''' Return the initialized checks from checks.d, and a mapping of checks that failed to
    initialize. Only checks that have a configuration
    file in conf.d will be returned. '''
    from checks import AgentCheck, AGENT_METRICS_CHECK_NAME

    initialized_checks = {}
    init_failed_checks = {}
    deprecated_checks = {}
    agentConfig['checksd_hostname'] = hostname

    deprecated_configs_enabled = [v for k,v in OLD_STYLE_PARAMETERS if len([l for l in agentConfig if l.startswith(k)]) > 0]
    for deprecated_config in deprecated_configs_enabled:
        msg = "Configuring %s in datadog.conf is not supported anymore. Please use conf.d" % deprecated_config
        deprecated_checks[deprecated_config] = {'error': msg, 'traceback': None}
        log.error(msg)

    osname = get_os()
    checks_paths = [glob.glob(os.path.join(agentConfig['additional_checksd'], '*.py'))]

    try:
        checksd_path = get_checksd_path(osname)
        checks_paths.append(glob.glob(os.path.join(checksd_path, '*.py')))
    except PathNotFound, e:
        log.error(e.args[0])
        sys.exit(3)

    def __init__(self, agentConfig, emitters, systemStats):
        self.emit_duration = None
        self.agentConfig = agentConfig
        # system stats is generated by config.get_system_stats
        self.agentConfig["system_stats"] = systemStats
        # agent config is used during checks, system_stats can be accessed through the config
        self.os = get_os()
        self.plugins = None
        self.emitters = emitters
        self.metadata_interval = int(agentConfig.get("metadata_interval", 10 * 60))
        self.metadata_start = time.time()
        socket.setdefaulttimeout(15)
        self.run_count = 0
        self.continue_running = True
        self.metadata_cache = None
        self.initialized_checks_d = []
        self.init_failed_checks_d = []

        # Unix System Checks
        self._unix_system_checks = {
            "disk": u.Disk(log),
            "io": u.IO(log),
            "load": u.Load(log),
            "memory": u.Memory(log),
            "processes": u.Processes(log),
            "cpu": u.Cpu(log),
        }

        # Win32 System `Checks
        self._win32_system_checks = {
            "disk": w32.Disk(log),
            "io": w32.IO(log),
            "proc": w32.Processes(log),
            "memory": w32.Memory(log),
            "network": w32.Network(log),
            "cpu": w32.Cpu(log),
        }

        # Old-style metric checks
        self._ganglia = Ganglia(log)
        self._dogstream = Dogstreams.init(log, self.agentConfig)
        self._ddforwarder = DdForwarder(log, self.agentConfig)

        # Agent Metrics
        self._agent_metrics = CollectorMetrics(log)

        self._metrics_checks = []

        # Custom metric checks
        for module_spec in [s.strip() for s in self.agentConfig.get("custom_checks", "").split(",")]:
            if len(module_spec) == 0:
                continue
            try:
                self._metrics_checks.append(modules.load(module_spec, "Check")(log))
                log.info("Registered custom check %s" % module_spec)
                log.warning(
                    "Old format custom checks are deprecated. They should be moved to the checks.d interface as old custom checks will be removed in a next version"
                )
            except Exception, e:
                log.exception("Unable to load custom check module %s" % module_spec)

def load_check(name, config, agentConfig, is_sdk=False):
    if not is_sdk:
        checksd_path = get_checksd_path(get_os())

        # find (in checksd_path) and load the check module
        fd, filename, desc = imp.find_module(name, [checksd_path])
        check_module = imp.load_module(name, fd, filename, desc)
    else:
        check_module = __import__("check")

    check_class = None
    classes = inspect.getmembers(check_module, inspect.isclass)
    for _, clsmember in classes:
        if clsmember == AgentCheck:
            continue
        if issubclass(clsmember, AgentCheck):
            check_class = clsmember
            if AgentCheck in clsmember.__bases__:
                continue
            else:
                break
    if check_class is None:
        raise Exception("Unable to import check %s. Missing a class that inherits AgentCheck" % name)

    init_config = config.get('init_config', {})
    instances = config.get('instances')
    agentConfig['checksd_hostname'] = get_hostname(agentConfig)

    # init the check class
    try:
        return check_class(name, init_config=init_config, agentConfig=agentConfig, instances=instances)
    except TypeError as e:
        raise Exception("Check is using old API, {0}".format(e))
    except Exception:
        raise

    def __init__(self, agentConfig, emitters, systemStats):
        self.emit_duration = None
        self.agentConfig = agentConfig
        # system stats is generated by config.get_system_stats
        self.agentConfig['system_stats'] = systemStats
        # agent config is used during checks, system_stats can be accessed through the config
        self.os = get_os()
        self.plugins = None
        self.emitters = emitters            
        self.metadata_interval = int(agentConfig.get('metadata_interval', 10 * 60))
        self.metadata_start = time.time()
        socket.setdefaulttimeout(15)
        self.run_count = 0
        self.continue_running = True
        self.metadata_cache = None
        self.checks_d = []
        
        # Unix System Checks
        self._unix_system_checks = {
            'disk': u.Disk(log),
            'io': u.IO(log),
            'load': u.Load(log),
            'memory': u.Memory(log),
            'processes': u.Processes(log),
            'cpu': u.Cpu(log)
        }

        # Win32 System `Checks
        self._win32_system_checks = {
            'disk': w32.Disk(log),
            'io': w32.IO(log),
            'proc': w32.Processes(log),
            'memory': w32.Memory(log),
            'network': w32.Network(log),
            'cpu': w32.Cpu(log)
        }

        # Old-style metric checks
        self._ganglia = Ganglia(log)
        self._cassandra = Cassandra()
        self._dogstream = Dogstreams.init(log, self.agentConfig)
        self._ddforwarder = DdForwarder(log, self.agentConfig)

        # Agent Metrics
        self._agent_metrics = CollectorMetrics(log)

        # Metric Checks
        self._metrics_checks = [
            Memcache(log),
        ]

        # Custom metric checks
        for module_spec in [s.strip() for s in self.agentConfig.get('custom_checks', '').split(',')]:
            if len(module_spec) == 0: continue
            try:
                self._metrics_checks.append(modules.load(module_spec, 'Check')(log))
                log.info("Registered custom check %s" % module_spec)
            except Exception, e:
                log.exception('Unable to load custom check module %s' % module_spec)

def init(config_path=None):
    agentConfig = get_config(parse_args=False, cfg_path=config_path)
    osname = get_os()
    try:
        confd_path = get_confd_path(osname)
    except PathNotFound, e:
        log.error("No conf.d folder found at '%s' or in the directory where"
                  "the Agent is currently deployed.\n" % e.args[0])

def initialize_logging(logger_name):
    try:
        logging_config = get_logging_config()

        logging.basicConfig(
            format=get_log_format(logger_name),
            level=logging_config['log_level'] or logging.INFO,
        )

        log_file = logging_config.get('%s_log_file' % logger_name)
        if log_file is not None and not logging_config['disable_file_logging']:
            # make sure the log directory is writeable
            # NOTE: the entire directory needs to be writable so that rotation works
            if os.access(os.path.dirname(log_file), os.R_OK | os.W_OK):
                file_handler = logging.handlers.RotatingFileHandler(log_file, maxBytes=LOGGING_MAX_BYTES, backupCount=1)
                formatter = logging.Formatter(get_log_format(logger_name), get_log_date_format())
                file_handler.setFormatter(formatter)

                root_log = logging.getLogger()
                root_log.addHandler(file_handler)
            else:
                sys.stderr.write("Log file is unwritable: '%s'\n" % log_file)

        # set up syslog
        if logging_config['log_to_syslog']:
            try:
                from logging.handlers import SysLogHandler

                if logging_config['syslog_host'] is not None and logging_config['syslog_port'] is not None:
                    sys_log_addr = (logging_config['syslog_host'], logging_config['syslog_port'])
                else:
                    sys_log_addr = "/dev/log"
                    # Special-case BSDs
                    if Platform.is_darwin():
                        sys_log_addr = "/var/run/syslog"
                    elif Platform.is_freebsd():
                        sys_log_addr = "/var/run/log"

                handler = SysLogHandler(address=sys_log_addr, facility=SysLogHandler.LOG_DAEMON)
                handler.setFormatter(logging.Formatter(get_syslog_format(logger_name), get_log_date_format()))
                root_log = logging.getLogger()
                root_log.addHandler(handler)
            except Exception, e:
                sys.stderr.write("Error setting up syslog: '%s'\n" % str(e))
                traceback.print_exc()

        # Setting up logging in the event viewer for windows
        if get_os() == 'windows' and logging_config['log_to_event_viewer']:
            try:
                from logging.handlers import NTEventLogHandler
                nt_event_handler = NTEventLogHandler(logger_name, get_win32service_file('windows', 'win32service.pyd'), 'Application')
                nt_event_handler.setFormatter(logging.Formatter(get_syslog_format(logger_name), get_log_date_format()))
                nt_event_handler.setLevel(logging.ERROR)
                app_log = logging.getLogger(logger_name)
                app_log.addHandler(nt_event_handler)
            except Exception, e:
                sys.stderr.write("Error setting up Event viewer logging: '%s'\n" % str(e))
                traceback.print_exc()

def get_checksd_path(osname=None):
    if not osname:
        osname = get_os()
    if osname == "windows":
        return _windows_checksd_path()
    elif osname == "mac":
        return _mac_checksd_path()
    else:
        return _unix_checksd_path()

def initialize_logging(logger_name):

    try:
        if get_os() == 'windows':
            logging.config.fileConfig(get_config_path())

        else:
            logging_config = get_logging_config()

            logging.basicConfig(
                format=get_log_format(logger_name),
                level=logging_config['log_level'] or logging.INFO,
            )

            # set up file loggers
            log_file = logging_config.get('%s_log_file' % logger_name)
            if log_file is not None and not logging_config['disable_file_logging']:
                # make sure the log directory is writeable
                # NOTE: the entire directory needs to be writable so that rotation works
                if os.access(os.path.dirname(log_file), os.R_OK | os.W_OK):
                    file_handler = logging.handlers.RotatingFileHandler(log_file, maxBytes=LOGGING_MAX_BYTES, backupCount=1)
                    file_handler.setFormatter(logging.Formatter(get_log_format(logger_name)))
                    root_log = logging.getLogger()
                    root_log.addHandler(file_handler)
                else:
                    sys.stderr.write("Log file is unwritable: '%s'\n" % log_file)

            # set up syslog
            if logging_config['log_to_syslog']:
                try:
                    from logging.handlers import SysLogHandler

                    if logging_config['syslog_host'] is not None and logging_config['syslog_port'] is not None:
                        sys_log_addr = (logging_config['syslog_host'], logging_config['syslog_port'])
                    else:
                        sys_log_addr = "/dev/log"
                        # Special-case macs
                        if sys.platform == 'darwin':
                            sys_log_addr = "/var/run/syslog"

                    handler = SysLogHandler(address=sys_log_addr, facility=SysLogHandler.LOG_DAEMON)
                    handler.setFormatter(logging.Formatter(get_syslog_format(logger_name)))
                    root_log = logging.getLogger()
                    root_log.addHandler(handler)
                except Exception, e:
                    sys.stderr.write("Error setting up syslog: '%s'\n" % str(e))
                    traceback.print_exc()

    except Exception, e:
        sys.stderr.write("Couldn't initialize logging: %s\n" % str(e))
        traceback.print_exc()

        # if config fails entirely, enable basic stdout logging as a fallback
        logging.basicConfig(
            format=get_log_format(logger_name),
            level=logging.INFO,
        )

def get_confd_path(osname=None):
    if not osname:
        osname = get_os()
    bad_path = ''
    if osname == 'windows':
        try:
            return _windows_confd_path()
        except PathNotFound, e:
            if len(e.args) > 0:
                bad_path = e.args[0]

def get_sdk_integrations_path(osname=None):
    if not osname:
        osname = get_os()
    if osname in ['windows', 'mac']:
        raise PathNotFound()

    cur_path = os.path.dirname(os.path.realpath(__file__))
    path = os.path.join(cur_path, '..', SDK_INTEGRATIONS_DIR)
    if os.path.exists(path):
        return path
    raise PathNotFound(path)

def get_3rd_party_path(osname=None):
    if not osname:
        osname = get_os()
    if osname in ['windows', 'mac']:
        raise PathNotFound()

    cur_path = os.path.dirname(os.path.realpath(__file__))
    path = os.path.join(cur_path, '../3rd-party')
    if os.path.exists(path):
        return path
    raise PathNotFound(path)

def get_logging_config(cfg_path=None):
    logging_config = {
        'log_level': None,
        'collector_log_file': '/var/log/datadog/collector.log',
        'forwarder_log_file': '/var/log/datadog/forwarder.log',
        'dogstatsd_log_file': '/var/log/datadog/dogstatsd.log',
        'pup_log_file': '/var/log/datadog/pup.log',
        'log_to_syslog': True,
        'syslog_host': None,
        'syslog_port': None,
    }

    config_path = get_config_path(cfg_path, os_name=get_os())
    config = ConfigParser.ConfigParser()
    config.readfp(skip_leading_wsp(open(config_path)))

    if config.has_section('handlers') or config.has_section('loggers') or config.has_section('formatters'):
        sys.stderr.write("Python logging config is no longer supported and will be ignored.\nTo configure logging, update the logging portion of 'datadog.conf' to match:\n  'https://github.com/DataDog/dd-agent/blob/master/datadog.conf.example'.\n")

    for option in logging_config:
        if config.has_option('Main', option):
            logging_config[option] = config.get('Main', option)

    levels = {
        'CRITICAL': logging.CRITICAL,
        'DEBUG': logging.DEBUG,
        'ERROR': logging.ERROR,
        'FATAL': logging.FATAL,
        'INFO': logging.INFO,
        'WARN': logging.WARN,
        'WARNING': logging.WARNING,
    }
    if config.has_option('Main', 'log_level'):
        logging_config['log_level'] = levels.get(config.get('Main', 'log_level'))

    if config.has_option('Main', 'log_to_syslog'):
        logging_config['log_to_syslog'] = config.get('Main', 'log_to_syslog').strip().lower() in ['yes', 'true', 1]

    if config.has_option('Main', 'syslog_host'):
        host = config.get('Main', 'syslog_host').strip()
        if host:
            logging_config['syslog_host'] = host
        else:
            logging_config['syslog_host'] = None

    if config.has_option('Main', 'syslog_port'):
        port = config.get('Main', 'syslog_port').strip()
        try:
            logging_config['syslog_port'] = int(port)
        except:
            logging_config['syslog_port'] = None

    return logging_config