sdk_hosts.py

'''Utilities relating to mapping tasks and services to hostnames

************************************************************************
FOR THE TIME BEING WHATEVER MODIFICATIONS ARE APPLIED TO THIS FILE
SHOULD ALSO BE APPLIED TO sdk_hosts IN ANY OTHER PARTNER REPOS
************************************************************************
'''
import json
import retrying

import sdk_cmd
import sdk_utils


SYSTEM_HOST_SUFFIX = 'mesos'
AUTOIP_HOST_SUFFIX = 'autoip.dcos.thisdcos.directory'
VIP_HOST_SUFFIX = 'l4lb.thisdcos.directory'


def system_host(service_name, task_name, port=-1):
    '''Returns the mesos DNS name for the host machine of a given task, with handling of foldered services.
    This maps to the host IP, which may be different from the container IP if CNI is enabled.

    service=marathon task=/path/to/scheduler =>  scheduler-to-path.marathon.mesos
    service=/path/to/scheduler task=node-0   =>  node-0.pathtoscheduler.mesos

    See also: https://dcos.io/docs/1.8/usage/service-discovery/dns-overview/'''
    return _to_host(
        _safe_mesos_dns_taskname(task_name),
        _safe_name(service_name),
        SYSTEM_HOST_SUFFIX,
        port)


def autoip_host(service_name, task_name, port=-1):
    '''Returns the autoip hostname for the container of a given task, with handling of foldered services.
    In CNI cases, this may vary from the host of the agent system.'''
    return _to_host(
        _safe_name(task_name),
        _safe_name(service_name),
        AUTOIP_HOST_SUFFIX,
        port)


def custom_host(service_name, task_name, custom_domain, port=-1):
    """
    Returns a properly constructed hostname for the container of the given task using the
    supplied custom domain.
    """
    return _to_host(
        _safe_name(task_name),
        _safe_name(service_name),
        custom_domain,
        port)


def vip_host(service_name, vip_name, port=-1):
    '''Returns the hostname of a specified service VIP, with handling of foldered services.'''
    return _to_host(
        _safe_name(vip_name),
        _safe_name(service_name),
        VIP_HOST_SUFFIX,
        port)


def _safe_name(name):
    '''Converts a potentially slash-delimited name to one that works for 'thisdcos.directory'
    hostnames used by autoip and vips. In both cases the slashes may just be stripped out.'''
    return name.replace('/', '')


def _safe_mesos_dns_taskname(task_name):
    '''Converts a potentially slash-delimited task name to one that works for '.mesos' task names
    Mesos DNS task names handle folders like this: /path/to/myservice => myservice-to-path'''
    elems = task_name.strip('/').split('/')
    elems.reverse()
    return '-'.join(elems)


def _to_host(host_first, host_second, host_third, port):
    host = '{}.{}.{}'.format(host_first, host_second, host_third)
    if port != -1:
        return '{}:{}'.format(host, port)
    return host


def get_foldered_dns_name(service_name):
    if sdk_utils.dcos_version_less_than('1.10'):
        return service_name
    return sdk_utils.get_foldered_name(service_name).replace("/", "")


@retrying.retry(
    wait_fixed=2000,
    stop_max_delay=5*60*1000)
def get_crypto_id_domain():
    """
    Returns the cluster cryptographic ID equivalent of autoip.dcos.thisdcos.directory.

    These addresses are routable within the cluster but can be used to test setting a custom
    service domain.
    """
    ok, lashup_response = sdk_cmd.master_ssh("curl localhost:62080/lashup/key/")
    assert ok

    crypto_id = json.loads(lashup_response.strip())["zbase32_public_key"]

    return "autoip.dcos.{}.dcos.directory".format(crypto_id)