#!/usr/bin/env python3

import requests
import re
from datetime import datetime, timedelta
from urllib.parse import urlparse, urlunparse


def get_indices():
    req = requests.get("{}/_cat/indices".format(es_url))
    data = req.text.strip().split("\n")
    data = [re.split(r'\s+', row)[2] for row in data]
    data = [item for item in filter(lambda x: logstash_pattern.match(x), data)]
    return sorted(data)


def delete_index(index, dry_run):
    if index:
        print("deleting {}".format(index))
        del_url = "{}/{}".format(es_url, index)
        if not dry_run:
            print(requests.delete(del_url).text)


def main(url, index, days, dry_run=False):
    global es_url
    global logstash_pattern

    es_url = urlunparse(urlparse(url)).rstrip("/")

    logstash_pattern = re.compile(r'%s\-(([0-9]{4})\.([0-9]{2})\.([0-9]{2}))' % index)

    deleteBefore = datetime.now() - timedelta(days=days)

    indexes = get_indices()

    for index in indexes:
        datematch = logstash_pattern.match(index)
        year =  int(datematch.group(2))
        month = int(datematch.group(3))
        day =   int(datematch.group(4))

        indexDate = datetime(year=year, month=month, day=day)

        if indexDate < deleteBefore:
            delete_index(index, dry_run)


def shell():
    import argparse

    parser = argparse.ArgumentParser(description='Delete logstash indexes by age')
    parser.add_argument('-u', '--url',   action='store', required=True,      help='Elasticsearch url')
    parser.add_argument('-d', '--days',  action='store', default=31,         help='Maximum index age that will be kept', type=int)
    parser.add_argument('-i', '--index', action='store', default="logstash", help='Index name to inspect. (Used as so: "%%s-YYYY.MM.DD")')
    parser.add_argument('-n', '--dry-run', action='store_true', help='Dry-run mode')
    args = parser.parse_args()

    main(args.url, args.index, args.days, args.dry_run)


if __name__ == '__main__':
    shell()