#!/usr/bin/env python3

import re
import time
import os
import subprocess

# The WARN_THRESHOLD/CRIT_THRESHOLD settings makes it possible to
# configure specific queues to have a higher or lower limit then the
# default.
WARN_THRESHOLD_DEFAULT = 10
WARN_THRESHOLD = {
    'missedmessage_emails': WARN_THRESHOLD_DEFAULT,
    # The user_activity worker has high throughput and uses a
    # LoopQueueProcessingWorker, so it's normal to have a moderate
    # backlog.
    'user_activity': 100,
}
CRIT_THRESHOLD_DEFAULT = 50
CRIT_THRESHOLD = {
    'missedmessage_emails': CRIT_THRESHOLD_DEFAULT,
    # A backlog of hundreds of events for user_activity likely
    # indicates an outage of the processor.
    'user_activity': 500,
}

states = {
    0: "OK",
    1: "WARNING",
    2: "CRITICAL",
    3: "UNKNOWN"
}

pattern = re.compile(r'(\w+)\t(\d+)')
output = subprocess.check_output(['/usr/sbin/rabbitmqctl', 'list_queues'], universal_newlines=True)

status = 0
max_count = 0
warn_queues = []

if 'USER' in os.environ and not os.environ['USER'] in ['root', 'rabbitmq']:
    print("This script must be run as the root or rabbitmq user")

for line in output.split("\n"):
    line = line.strip()
    m = pattern.match(line)
    if m:
        queue = m.group(1)
        count = int(m.group(2))
        this_status = 0
        if count > CRIT_THRESHOLD.get(queue, CRIT_THRESHOLD_DEFAULT):
            this_status = 2
            warn_queues.append(queue)
        elif count > WARN_THRESHOLD.get(queue, WARN_THRESHOLD_DEFAULT):
            this_status = max(status, 1)
            warn_queues.append(queue)

        status = max(status, this_status)
        max_count = max(max_count, count)

warn_about = ", ".join(warn_queues)
now = int(time.time())
now_struct = time.gmtime(now)

# While we are sending digest emails, at 1800 hrs (UTC) each weekday, the mail
# queues can get backed up; don't alert on those. Additionally, certain workers
# (slow_queries and digest_emails) have a polling algorithm that means it's
# normal for them to accumulate items.
if not set(warn_queues) - set(("digest_emails", "slow_queries")) and \
        now_struct.tm_hour == 18 and now_struct.tm_min < 25:
    status = 0
    print("%s|%s|%s|processing digests, not alerting on elevated mail queues" % (
        now, status, states[status]))
    exit(0)

if status > 0:
    print("%s|%s|%s|max count %s, queues affected: %s" % (
        now, status, states[status], max_count, warn_about))
else:
    print("%s|%s|%s|queues normal, max count %s" % (now, status, states[status], max_count))