trigger.changemgmt — Change management library

Abstract interface to bounce windows and moratoria.

class trigger.changemgmt.BounceStatus(status_name)

An object that represents a bounce window risk-level status.

  • green: Low risk

  • yellow: Medium risk

  • red: High risk

Objects stringify to ‘red’, ‘green’, or ‘yellow’, and can be compared against those strings. Objects can also be compared against each other. ‘red’ > ‘yellow’ > ‘green’.

>>> green = BounceStatus('green')
>>> yellow = BounceStatus('yellow')
>>> print green
green
>>> yellow > green
True
Parameters:

status_name – The colored risk-level status name.

class trigger.changemgmt.BounceWindow(status_by_hour=None, green=None, yellow=None, red=None, default='red')

Build a bounce window of 24 BounceStatus objects.

You may either specify your own list of 24 BounceStatus objects using status_by_hour, or you may omit this argument and specify your ‘green’, ‘yellow’, and ‘red’ risk levels by using hyphenated and comma-separated text strings.

You may use digits (“14”) or hyphenated ranges (“0-5”) and may join these together using a comma (“,”) with or without spacing separating them. For example “0-5, 14” will be parsed into [0, 1, 2, 3, 4, 5, 14].

The default color is used to fill in the gaps between the other colors, so that the total is always 24 in the resultant list status objects.

>>> b = BounceWindow(green='0-3, 23', red='10', default='yellow')
>>> b.status()
<BounceStatus: yellow>
>>> b.next_ok('green')
datetime.datetime(2012, 12, 5, 4, 0, tzinfo=<UTC>)
>>> b.dump()
{0: <BounceStatus: green>,
 1: <BounceStatus: green>,
 2: <BounceStatus: green>,
 3: <BounceStatus: green>,
 4: <BounceStatus: yellow>,
 5: <BounceStatus: yellow>,
 6: <BounceStatus: yellow>,
 7: <BounceStatus: yellow>,
 8: <BounceStatus: yellow>,
 9: <BounceStatus: yellow>,
 10: <BounceStatus: red>,
 11: <BounceStatus: yellow>,
 12: <BounceStatus: yellow>,
 13: <BounceStatus: yellow>,
 14: <BounceStatus: yellow>,
 15: <BounceStatus: yellow>,
 16: <BounceStatus: yellow>,
 17: <BounceStatus: yellow>,
 18: <BounceStatus: yellow>,
 19: <BounceStatus: yellow>,
 20: <BounceStatus: yellow>,
 21: <BounceStatus: yellow>,
 22: <BounceStatus: yellow>,
 23: <BounceStatus: green>}

You may modify the global default fallback color by setting BOUNCE_DEFAULT_COLOR in your settings.py.

Although the query API is generic and could accomodate any sort of bounce window policy, this constructor knows only about AOL’s bounce windows, which operate on “US/Eastern” time (worldwide), always change on hour boundaries, and are the same every day. If that ever changes, only this class will need to be updated.

End-users are not expected to create new BounceWindow objects; instead, use bounce() or bounce to get an object, then query its methods.

Parameters:

  • status_by_hour – (Optional) A list of 24 BounceStatus objects.

  • green – Representative string of hours.

  • yellow – Representative string of hours.

  • red – Representative string of hours.

  • default – The color used to fill in the gaps between other risk levels.

dump()

Dump a mapping of hour to status.

next_ok(status, when=None)

Return the next time at or after the specified time (default now) that it the bounce status will be at equal to or less than the given status.

For example, next_ok('yellow') will return the time that the bounce window becomes ‘yellow’ or ‘green’. Returns UTC time.

Parameters:

  • status – The colored risk-level status name.

  • when – A datetime object.

status(when=None)

Return a BounceStatus object for the specified time or now.

Parameters:

when – A datetime object.

trigger.changemgmt.bounce(device, default=BounceWindow(green='5-7', yellow='0-4, 8-15', red='16-23', default='red'))

Return the bounce window for a given device.

Parameters: