checks rust nightly for rls support or finds the last version for you

check_nightly_for_rls.py

import urllib.request
import sys
from datetime import datetime, timedelta
from urllib.error import HTTPError
import pytoml as toml


def is_rls_availble_on_nightly(day, month, year, target='x86_64-apple-darwin', do_print=False):
    url = 'https://static.rust-lang.org/dist/{}-{:02d}-{:02d}/channel-rust-nightly.toml'.format(
        year,
        month,
        day,
    )
    print("Checking nightly-{}-{:02d}-{:02d}".format(year, month, day))

    try:
        response = urllib.request.urlopen(url)
        data = response.read()
        rust_info = toml.loads(data)
        is_available = rust_info['pkg']['rls-preview']['target'][target]['available']
        if do_print:
            print("\tHas rls-preview? %s" % ("Yes" if is_available else "No"))
        return is_available

    except HTTPError:
        print('\tNo nighly exists.')
        return None

    except KeyError:
        print('\tNo "rls-preview" section exists for target=%s.' % target)
        return None


def find_last_version_with_rls():
    LAST_X_DAYS = 60
    now = datetime.now()

    for day_delta in range(LAST_X_DAYS):
        test_date = now - timedelta(days=day_delta)
        did_find = is_rls_availble_on_nightly(
            day=test_date.day,
            month=test_date.month,
            year=test_date.year,
            do_print=True,
        )
        if did_find:
            return True
    return False


def parse_date_arg(date_arg):
    [y, m, d] = [int(n) for n in date_arg.split('-')]
    if m < 1 or m > 12 or d < 1 or d > 31:
        raise ValueError
    return (y, m, d)


if __name__ == "__main__":
    try:
        if len(sys.argv) > 1:
            if sys.argv[1] == '--find':
                find_last_version_with_rls()
                sys.exit()
            else:
                (y, m, d) = parse_date_arg(sys.argv[1])
        else:
            now = datetime.now()
            (y, m, d) = (now.year, now.month, now.day)
        is_rls_availble_on_nightly(
            day=d,
            month=m,
            year=y,
            do_print=True,
        )
    except ValueError:
        print('You must pass valid date as "YYYY-MM-DD"')