Source code for saltext.stalekey.engines.stalekey

"""
An engine that uses presence detection to keep track of which minions
have been recently connected and remove their keys if they have not been
connected for a certain period of time.

Requires that the :conf_master:`minion_data_cache` option be enabled.

.. versionadded:: 2017.7.0

:configuration:

    Example configuration:

    .. code-block:: yaml

        engines:
          - stalekey:
              interval: 3600
              expire: 86400

"""

import logging
import os
import time

import salt.config
import salt.key
import salt.utils.files
import salt.utils.minions
import salt.utils.msgpack
import salt.wheel

log = logging.getLogger(__name__)


def __virtual__():
    if not __opts__.get("minion_data_cache"):
        return (False, "stalekey engine requires minion_data_cache to be enabled")
    return True


def _get_keys():
    """
    Get the keys
    """
    with salt.key.get_key(__opts__) as keys:
        minions = keys.all_keys()
        return minions["minions"]


def _delete_keys(stale_keys, minions):
    """
    Delete the keys
    """
    wheel = salt.wheel.WheelClient(__opts__)
    for k in stale_keys:
        log.info("Removing stale key for %s", k)
        wheel.cmd("key.delete", [salt.utils.stringutils.to_unicode(k)])
        del minions[k]
    return minions


def _read_presence(presence_file):
    """
    Read minion data from presence file
    """
    error = False
    minions = {}
    if os.path.exists(presence_file):
        try:
            with salt.utils.files.fopen(presence_file, "rb") as f:
                _minions = salt.utils.msgpack.load(f)

                # ensure all keys are unicode, not bytes.
                for minion in _minions:
                    _minion = salt.utils.stringutils.to_unicode(minion)
                    minions[_minion] = _minions[minion]

        except OSError as e:
            error = True
            log.error("Could not open presence file %s: %s", presence_file, e)

    return error, minions


def _write_presence(presence_file, minions):
    """
    Write minion data to presence file
    """
    error = False
    try:
        with salt.utils.files.fopen(presence_file, "wb") as f:
            salt.utils.msgpack.dump(minions, f)
    except OSError as e:
        error = True
        log.error("Could not write to presence file %s: %s", presence_file, e)
    return error




def start(interval=3600, expire=604800):
    """
    Start the engine
    """
    ck = salt.utils.minions.CkMinions(__opts__)
    presence_file = f"{__opts__['cachedir']}/presence.p"
    _wheel = salt.wheel.WheelClient(__opts__)

    while True:
        log.debug("Checking for present minions")
        minions = {}
        error, minions = _read_presence(presence_file)
        if error:
            time.sleep(interval)
            continue

        minion_keys = _get_keys()
        now = time.time()
        present = ck.connected_ids()

        # For our existing keys, check which are present
        for m in minion_keys:
            # If we have a key that's not in the presence file,
            # it may be a new minion # It could also mean this
            # is the first time this engine is running and no
            # presence file was found
            if m not in minions:
                minions[m] = now
            elif m in present:
                minions[m] = now

        log.debug("Finished checking for present minions")
        # Delete old keys
        stale_keys = []
        for m, seen in minions.items():
            if now - expire > seen:
                stale_keys.append(m)

        if stale_keys:
            minions = _delete_keys(stale_keys, minions)

        error = _write_presence(presence_file, minions)

        time.sleep(interval)