Nagios plugin to check that CouchDB replications are working

check_couchdb_replications.py

#!/usr/bin/env python
'''Check to make sure that all the replications on the local CouchDB server
are actually running.'''

import argparse
from datetime import datetime, timedelta
from operator import itemgetter
import requests
import sys
import tempfile

# Nagios status codes
OK, WARNING, CRITICAL, UNKNOWN = range(4)

def main(host, replicator, auth, age_timeout):
    headers = {
        'Content-type': 'application/json'
    }

    if auth:
        headers['Authorization'] = 'Basic %s' % auth.encode('base64').rstrip()

    # Query the server and parse into objects
    try:
        replicator_url = host + replicator + '/_all_docs?include_docs=true'
        replications = requests.get(replicator_url, headers=headers)
        active_tasks = requests.get(host + '/_active_tasks', headers=headers)
    except Exception:
        print 'REPLICATION STATUS UNKNOWN - Error connecting to server'
        return UNKNOWN

    if replications.status_code >= 400:
        print 'REPLICATION STATUS UNKNOWN - Error connecting to server (HTTP %i)' % replications.status_code
        return UNKNOWN

    if active_tasks.status_code >= 400:
        print 'REPLICATION STATUS UNKNOWN - Error connecting to server (HTTP %i)' % replications.status_code
        return UNKNOWN

    reps = filter(lambda x: 'source' in x, [x['doc'] for x in replications.json()['rows']])
    reps = sorted(reps, key=itemgetter('source'))

    tasks = {}
    for at in active_tasks.json():
        rep_id = at.get('replication_id', '')
        if '+' in rep_id:
            r_id = rep_id.split('+')[0]
        else:
            r_id = rep_id
        tasks[r_id] = at

    # Merge and check
    status = OK
    problems = []
    for rep in reps:
        if '_replication_id' in rep:
            task = tasks.get(rep['_replication_id'])
            if task:
                rep.update(task)

        doc_id = rep['_id']
        rep_state = rep.get('_replication_state', 'N/A')
        reason = rep.get('_replication_state_reason', '')
        updated = rep.get('updated_on', 0)
        age = datetime.now() - datetime.fromtimestamp(updated)

        rep_problems = {}

        # Check that all replications are in the triggered state
        if rep_state != 'triggered':
            rep_problems['state'] = rep_state
            if reason:
                rep_problems['state'] += ', ' + reason
            status = CRITICAL

        # Check that all replications have updated recently
        if age > timedelta(seconds=age_timeout):
            if updated > 0:
                rep_problems['age'] = str(age)
            else:
                rep_problems['age'] = 'infinity'
            status = max(status, WARNING)

        if len(rep_problems) > 0:
            problem_list = []
            for k, v in rep_problems.items():
                problem_list.append('%s: %s' % (k, v))
            problems.append('%s (%s)' % (doc_id, '; '.join(problem_list)))

    # Build the output string
    if status == OK:
        s = 'OK'
    elif status == WARNING:
        s = 'WARNING'
    elif status == CRITICAL:
        s = 'CRITICAL'
    else:
        s = 'UNKNOWN'

    output = 'REPLICATION STATUS %s - %i replications, %i problems' % (s, len(reps), len(problems))
    if len(problems) > 0:
        output += ': ' + ', '.join(problems)

    print output
    return status


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('--host', '-s', default='http://localhost:5984')
    parser.add_argument('--replicator', '-d', default='/_replicator')
    parser.add_argument('--age-timeout', '-t', default=120,
                        help='Warning time for stale replications, in s')
    parser.add_argument('--auth', '-a',
                        help='Basic HTTP authentication string as "username:password"')
    args = parser.parse_args()

    try:
        status = main(args.host, args.replicator, args.auth, args.age_timeout)
    except Exception as e:
        print 'REPLICATION STATUS UNKNOWN - Python exception %s' % str(e)
        status = UNKNOWN

    sys.exit(status)