Mini Shell

"""
Manage modjk workers
====================

Send commands to a :strong:`modjk` load balancer via the peer system.

This module can be used with the :ref:`prereq <requisites-prereq>`
requisite to remove/add the worker from the load balancer before
deploying/restarting service.

Mandatory Settings:

- The minion needs to have permission to publish the :strong:`modjk.*`
  functions (see :ref:`here <peer>` for information on configuring
  peer publishing permissions)

- The modjk load balancer must be configured as stated in the :strong:`modjk`
  execution module :mod:`documentation <salt.modules.modjk>`
"""


def __virtual__():
    """
    Check if we have peer access ?
    """
    return True


def _send_command(cmd, worker, lbn, target, profile="default", tgt_type="glob"):
    """
    Send a command to the modjk loadbalancer
    The minion need to be able to publish the commands to the load balancer

    cmd:
        worker_stop - won't get any traffic from the lbn
        worker_activate - activate the worker
        worker_disable - will get traffic only for current sessions
    """

    ret = {
        "code": False,
        "msg": "OK",
        "minions": [],
    }

    # Send the command to target
    func = f"modjk.{cmd}"
    args = [worker, lbn, profile]
    response = __salt__["publish.publish"](target, func, args, tgt_type)

    # Get errors and list of affeced minions
    errors = []
    minions = []
    for minion in response:
        minions.append(minion)
        if not response[minion]:
            errors.append(minion)

    # parse response
    if not response:
        ret["msg"] = f"no servers answered the published command {cmd}"
        return ret
    elif len(errors) > 0:
        ret["msg"] = "the following minions return False"
        ret["minions"] = errors
        return ret
    else:
        ret["code"] = True
        ret["msg"] = "the commad was published successfully"
        ret["minions"] = minions
        return ret


def _worker_status(target, worker, activation, profile="default", tgt_type="glob"):
    """
    Check if the worker is in `activation` state in the targeted load balancers

    The function will return the following dictionary:
        result - False if no server returned from the published command
        errors - list of servers that couldn't find the worker
        wrong_state - list of servers that the worker was in the wrong state
                      (not activation)
    """

    ret = {
        "result": True,
        "errors": [],
        "wrong_state": [],
    }

    args = [worker, profile]
    status = __salt__["publish.publish"](target, "modjk.worker_status", args, tgt_type)

    # Did we got any respone from someone ?
    if not status:
        ret["result"] = False
        return ret

    # Search for errors & status
    for balancer in status:
        if not status[balancer]:
            ret["errors"].append(balancer)
        elif status[balancer]["activation"] != activation:
            ret["wrong_state"].append(balancer)

    return ret


def _talk2modjk(name, lbn, target, action, profile="default", tgt_type="glob"):
    """
    Wrapper function for the stop/disable/activate functions
    """

    ret = {"name": name, "result": True, "changes": {}, "comment": ""}

    action_map = {
        "worker_stop": "STP",
        "worker_disable": "DIS",
        "worker_activate": "ACT",
    }

    # Check what needs to be done
    status = _worker_status(target, name, action_map[action], profile, tgt_type)
    if not status["result"]:
        ret["result"] = False
        ret["comment"] = "no servers answered the published command modjk.worker_status"
        return ret
    if status["errors"]:
        ret["result"] = False
        ret["comment"] = (
            "the following balancers could not find the worker {}: {}".format(
                name, status["errors"]
            )
        )
        return ret
    if not status["wrong_state"]:
        ret["comment"] = (
            "the worker is in the desired activation state on all the balancers"
        )
        return ret
    else:
        ret["comment"] = "the action {} will be sent to the balancers {}".format(
            action, status["wrong_state"]
        )
        ret["changes"] = {action: status["wrong_state"]}

    if __opts__["test"]:
        ret["result"] = None
        return ret

    # Send the action command to target
    response = _send_command(action, name, lbn, target, profile, tgt_type)
    ret["comment"] = response["msg"]
    ret["result"] = response["code"]
    return ret


def stop(name, lbn, target, profile="default", tgt_type="glob"):
    """
    .. versionchanged:: 2017.7.0
        The ``expr_form`` argument has been renamed to ``tgt_type``, earlier
        releases must use ``expr_form``.

    Stop the named worker from the lbn load balancers at the targeted minions
    The worker won't get any traffic from the lbn

    Example:

    .. code-block:: yaml

        disable-before-deploy:
          modjk_worker.stop:
            - name: {{ grains['id'] }}
            - lbn: application
            - target: 'roles:balancer'
            - tgt_type: grain
    """
    return _talk2modjk(name, lbn, target, "worker_stop", profile, tgt_type)


def activate(name, lbn, target, profile="default", tgt_type="glob"):
    """
    .. versionchanged:: 2017.7.0
        The ``expr_form`` argument has been renamed to ``tgt_type``, earlier
        releases must use ``expr_form``.

    Activate the named worker from the lbn load balancers at the targeted
    minions

    Example:

    .. code-block:: yaml

        disable-before-deploy:
          modjk_worker.activate:
            - name: {{ grains['id'] }}
            - lbn: application
            - target: 'roles:balancer'
            - tgt_type: grain
    """
    return _talk2modjk(name, lbn, target, "worker_activate", profile, tgt_type)


def disable(name, lbn, target, profile="default", tgt_type="glob"):
    """
    .. versionchanged:: 2017.7.0
        The ``expr_form`` argument has been renamed to ``tgt_type``, earlier
        releases must use ``expr_form``.

    Disable the named worker from the lbn load balancers at the targeted
    minions. The worker will get traffic only for current sessions and won't
    get new ones.

    Example:

    .. code-block:: yaml

        disable-before-deploy:
          modjk_worker.disable:
            - name: {{ grains['id'] }}
            - lbn: application
            - target: 'roles:balancer'
            - tgt_type: grain
    """
    return _talk2modjk(name, lbn, target, "worker_disable", profile, tgt_type)