expire.py

import boto3

import lib


def expireHosts(session=None, max_age=None):
    '''
    Expire all hostnames that have not been updated
    more recently than max_age seconds ago, and that
    are not marked hold.

    Active hostnames are those with files having a
    PING extension. Hostnames being held have files
    with a HOLD extension. To expire a host, we
    delete the PING file and replace it with an
    EXPIRED file.
    '''
    bucket = lib.S3Bucket(session)

    holds = set(f.host for f in bucket.iterStateFiles(ext=bucket.HOLD_EXT))
    expiry_time = lib.getExpiryTime(max_age)
    expired = []

    for f in (x for x in bucket.iterStateFiles(ext=bucket.PING_EXT)
              if x.file.last_modified < expiry_time and x.host not in holds):

        bucket.setHostIP(f.host, None)
        bucket.writeStateFile(
            f.host, bucket.EXPIRED_EXT, f.file.get()['Body'].read())
        f.file.delete()
        expired.append(f.host)

    if expired:
        lib.kickManager(bucket.session)

    return expired