import datetime
import logging
import re

import pytz
from gunicorn.glogging import Logger

# Gunicorn configuration file.
#
# Server socket
#
#   bind - The socket to bind.
#
#       A string of the form: 'HOST', 'HOST:PORT', 'unix:PATH'.
#       An IP is a valid HOST.
#
#   backlog - The number of pending connections. This refers
#       to the number of clients that can be waiting to be
#       served. Exceeding this number results in the client
#       getting an error when attempting to connect. It should
#       only affect servers under significant load.
#
#       Must be a positive integer. Generally set in the 64-2048
#       range.
#

bind = "0.0.0.0:8080"
backlog = 2048

#
# Worker processes
#
#   workers - The number of worker processes that this server
#       should keep alive for handling requests.
#
#       A positive integer generally in the 2-4 x $(NUM_CORES)
#       range. You'll want to vary this a bit to find the best
#       for your particular application's work load.
#
#   worker_class - The type of workers to use. The default
#       sync class should handle most 'normal' types of work
#       loads. You'll want to read
#       http://docs.gunicorn.org/en/latest/design.html#choosing-a-worker-type
#       for information on when you might want to choose one
#       of the other worker classes.
#
#       A string referring to a Python path to a subclass of
#       gunicorn.workers.base.Worker. The default provided values
#       can be seen at
#       http://docs.gunicorn.org/en/latest/settings.html#worker-class
#
#   worker_connections - For the eventlet and gevent worker classes
#       this limits the maximum number of simultaneous clients that
#       a single process can handle.
#
#       A positive integer generally set to around 1000.
#
#   timeout - If a worker does not notify the master process in this
#       number of seconds it is killed and a new worker is spawned
#       to replace it.
#
#       Generally set to thirty seconds. Only set this noticeably
#       higher if you're sure of the repercussions for sync workers.
#       For the non sync workers it just means that the worker
#       process is still communicating and is not tied to the length
#       of time required to handle a single request.
#
#   keepalive - The number of seconds to wait for the next request
#       on a Keep-Alive HTTP connection.
#
#       A positive integer. Generally set in the 1-5 seconds range.
#

workers = 3
worker_class = "gevent"
worker_connections = 1000
timeout = 30
keepalive = 2

#
#   spew - Install a trace function that spews every line of Python
#       that is executed when running the server. This is the
#       nuclear option.
#
#       True or False
#

spew = False

#
# Server mechanics
#
#   daemon - Detach the main Gunicorn process from the controlling
#       terminal with a standard fork/fork sequence.
#
#       True or False
#
#   raw_env - Pass environment variables to the execution environment.
#
#   pidfile - The path to a pid file to write
#
#       A path string or None to not write a pid file.
#
#   user - Switch worker processes to run as this user.
#
#       A valid user id (as an integer) or the name of a user that
#       can be retrieved with a call to pwd.getpwnam(value) or None
#       to not change the worker process user.
#
#   group - Switch worker process to run as this group.
#
#       A valid group id (as an integer) or the name of a user that
#       can be retrieved with a call to pwd.getgrnam(value) or None
#       to change the worker processes group.
#
#   umask - A mask for file permissions written by Gunicorn. Note that
#       this affects unix socket permissions.
#
#       A valid value for the os.umask(mode) call or a string
#       compatible with int(value, 0) (0 means Python guesses
#       the base, so values like "0", "0xFF", "0022" are valid
#       for decimal, hex, and octal representations)
#
#   tmp_upload_dir - A directory to store temporary request data when
#       requests are read. This will most likely be disappearing soon.
#
#       A path to a directory where the process owner can write. Or
#       None to signal that Python should choose one on its own.
#

daemon = False
raw_env = [
    # 'SPAM=eggs',
]
pidfile = None
umask = 0
user = None
group = None
tmp_upload_dir = None

#
#   Logging
#
#   logfile - The path to a log file to write to.
#
#       A path string. "-" means log to stdout.
#
#   loglevel - The granularity of log output
#
#       A string of "debug", "info", "warning", "error", "critical"
#


class CustomLogger(Logger):
    def now(self):
        return datetime.datetime.now(tz=pytz.timezone("Europe/London")).strftime("%d-%b-%y %H:%M:%S")


logger_class = CustomLogger

errorlog = "-"
loglevel = "info"
accesslog = "-"
access_log_format = '{"logType": "gunicorn-access", "remote_ip":"%({x-forwarded-for}i)s","request_id":"%({X-Amzn-Trace-Id}i)s","response_code":"%(s)s","request_method":"%(m)s","request_path":"%(U)s","request_querystring":"%(q)s","request_timetaken":"%(D)s","response_length":"%(B)s"}'  # noqa

#
# Process naming
#
#   proc_name - A base to use with setproctitle to change the way
#       that Gunicorn processes are reported in the system process
#       table. This affects things like 'ps' and 'top'. If you're
#       going to be running more than one instance of Gunicorn you'll
#       probably want to set a name to tell them apart. This requires
#       that you install the setproctitle module.
#
#       A string or None to choose a default of something like 'gunicorn'.
#

proc_name = None

#
# Server hooks
#
#   post_fork - Called just after a worker has been forked.
#
#       A callable that takes a server and worker instance
#       as arguments.
#
#   pre_fork - Called just prior to forking the worker subprocess.
#
#       A callable that accepts the same arguments as after_fork
#
#   pre_exec - Called just prior to forking off a secondary
#       master process during things like config reloading.
#
#       A callable that takes a server instance as the sole argument.
#


def post_fork(server, worker):
    server.log.info("Worker spawned (pid: %s)", worker.pid)


def pre_fork(server, worker):
    pass


def pre_exec(server):
    server.log.info("Forked child, re-executing.")


def when_ready(server):
    server.log.info("Server is ready. Spawning workers")


def worker_int(worker):
    worker.log.info("worker received INT or QUIT signal")

    # get traceback info
    import sys
    import threading
    import traceback

    id2name = {th.ident: th.name for th in threading.enumerate()}
    code = []
    for threadId, stack in sys._current_frames().items():
        code.append("\n# Thread: %s(%d)" % (id2name.get(threadId, ""), threadId))
        for filename, lineno, name, line in traceback.extract_stack(stack):
            code.append('File: "%s", line %d, in %s' % (filename, lineno, name))
            if line:
                code.append("  %s" % (line.strip()))
    worker.log.debug("\n".join(code))


def worker_abort(worker):
    worker.log.info("worker received SIGABRT signal")


class RequestPathFilter(logging.Filter):
    def __init__(self, *args, path_re, **kwargs):
        super().__init__(*args, **kwargs)
        self.path_filter = re.compile(path_re)

    def filter(self, record):
        req_path = record.args["U"]
        if req_path:
            if not self.path_filter.match(req_path):
                return True  # log this entry
        # ... additional conditions can be added here ...
        return False  # do not log this entry


def on_starting(server):
    server.log.access_log.addFilter(RequestPathFilter(path_re=r"^/healthcheck$"))
