path: root/events/src/utils.py

# -*- coding: utf-8 -*-
#
#  Copyright (c) 2016 Red Hat, Inc. <http://www.redhat.com>
#  This file is part of GlusterFS.
#
#  This file is licensed to you under your choice of the GNU Lesser
#  General Public License, version 3 or any later version (LGPLv3 or
#  later), or the GNU General Public License, version 2 (GPLv2), in all
#  cases as published by the Free Software Foundation.
#

import json
import os
import logging
import fcntl
from errno import ESRCH, EBADF

from eventsapiconf import (LOG_FILE,
                           WEBHOOKS_FILE,
                           DEFAULT_CONFIG_FILE,
                           CUSTOM_CONFIG_FILE,
                           UUID_FILE)
import eventtypes


# Webhooks list
_webhooks = {}
# Default Log Level
_log_level = "INFO"
# Config Object
_config = {}

# Init Logger instance
logger = logging.getLogger(__name__)
NodeID = None


def boolify(value):
    value = str(value)
    if value.lower() in ["1", "on", "true", "yes"]:
        return True
    else:
        return False


def get_node_uuid():
    val = None
    with open(UUID_FILE) as f:
        for line in f:
            if line.startswith("UUID="):
                val = line.strip().split("=")[-1]
                break
    return val


def get_config(key):
    if not _config:
        load_config()
    return _config.get(key, None)


def get_event_type_name(idx):
    """
    Returns Event Type text from the index. For example, VOLUME_CREATE
    """
    return eventtypes.all_events[idx].replace("EVENT_", "")


def setup_logger():
    """
    Logging initialization, Log level by default will be INFO, once config
    file is read, respective log_level will be set.
    """
    global logger
    logger.setLevel(logging.INFO)

    # create the logging file handler
    fh = logging.FileHandler(LOG_FILE)

    formatter = logging.Formatter("[%(asctime)s] %(levelname)s "
                                  "[%(module)s - %(lineno)s:%(funcName)s] "
                                  "- %(message)s")

    fh.setFormatter(formatter)

    # add handler to logger object
    logger.addHandler(fh)


def load_config():
    """
    Load/Reload the config from REST Config files. This function will
    be triggered during init and when SIGUSR2.
    """
    global _config
    _config = {}
    if os.path.exists(DEFAULT_CONFIG_FILE):
        _config = json.load(open(DEFAULT_CONFIG_FILE))
    if os.path.exists(CUSTOM_CONFIG_FILE):
        _config.update(json.load(open(CUSTOM_CONFIG_FILE)))


def load_log_level():
    """
    Reads log_level from Config file and sets accordingly. This function will
    be triggered during init and when SIGUSR2.
    """
    global logger, _log_level
    new_log_level = _config.get("log_level", "INFO")
    if _log_level != new_log_level:
        logger.setLevel(getattr(logging, new_log_level.upper()))
        _log_level = new_log_level.upper()


def load_webhooks():
    """
    Load/Reload the webhooks list. This function will
    be triggered during init and when SIGUSR2.
    """
    global _webhooks
    _webhooks = {}
    if os.path.exists(WEBHOOKS_FILE):
        _webhooks = json.load(open(WEBHOOKS_FILE))


def load_all():
    """
    Wrapper function to call all load/reload functions. This function will
    be triggered during init and when SIGUSR2.
    """
    load_config()
    load_webhooks()
    load_log_level()


def publish(ts, event_key, data):
    global NodeID
    if NodeID is None:
        NodeID = get_node_uuid()

    message = {
        "nodeid": NodeID,
        "ts": int(ts),
        "event": get_event_type_name(event_key),
        "message": data
    }
    if _webhooks:
        plugin_webhook(message)
    else:
        # TODO: Default action?
        pass


def plugin_webhook(message):
    # Import requests here since not used in any other place
    import requests

    message_json = json.dumps(message, sort_keys=True)
    logger.debug("EVENT: {0}".format(message_json))
    for url, token in _webhooks.items():
        http_headers = {"Content-Type": "application/json"}
        if token != "" and token is not None:
            http_headers["Authorization"] = "Bearer " + token

        try:
            resp = requests.post(url, headers=http_headers, data=message_json)
        except requests.ConnectionError as e:
            logger.warn("Event push failed to URL: {url}, "
                        "Event: {event}, "
                        "Status: {error}".format(
                            url=url,
                            event=message_json,
                            error=e))
            continue

        if resp.status_code != 200:
            logger.warn("Event push failed to URL: {url}, "
                        "Event: {event}, "
                        "Status Code: {status_code}".format(
                            url=url,
                            event=message_json,
                            status_code=resp.status_code))


class LockedOpen(object):

    def __init__(self, filename, *args, **kwargs):
        self.filename = filename
        self.open_args = args
        self.open_kwargs = kwargs
        self.fileobj = None

    def __enter__(self):
        """
        If two processes compete to update a file, The first process
        gets the lock and the second process is blocked in the fcntl.flock()
        call. When first process replaces the file and releases the lock,
        the already open file descriptor in the second process now points
        to a  "ghost" file(not reachable by any path name) with old contents.
        To avoid that conflict, check the fd already opened is same or
        not. Open new one if not same
        """
        f = open(self.filename, *self.open_args, **self.open_kwargs)
        while True:
            fcntl.flock(f, fcntl.LOCK_EX)
            fnew = open(self.filename, *self.open_args, **self.open_kwargs)
            if os.path.sameopenfile(f.fileno(), fnew.fileno()):
                fnew.close()
                break
            else:
                f.close()
                f = fnew
        self.fileobj = f
        return f

    def __exit__(self, _exc_type, _exc_value, _traceback):
        self.fileobj.close()


class PidFileLockFailed(Exception):
    pass


class PidFile(object):
    def __init__(self, filename):
        self.filename = filename
        self.pid = os.getpid()
        self.fh = None

    def cleanup(self, remove_file=True):
        try:
            if self.fh is not None:
                self.fh.close()
        except IOError as exc:
            if exc.errno != EBADF:
                raise
        finally:
            if os.path.isfile(self.filename) and remove_file:
                os.remove(self.filename)

    def __enter__(self):
        self.fh = open(self.filename, 'a+')
        try:
            fcntl.flock(self.fh.fileno(), fcntl.LOCK_EX | fcntl.LOCK_NB)
        except IOError as exc:
            self.cleanup(remove_file=False)
            raise PidFileLockFailed(exc)

        self.fh.seek(0)
        self.fh.truncate()
        self.fh.write("%d\n" % self.pid)
        self.fh.flush()
        self.fh.seek(0)
        return self

    def __exit__(self, _exc_type, _exc_value, _traceback):
        self.cleanup()