cobald.interfaces package

Interfaces for primitives of the cobald model

Each Pool provides a varying number of resources. A Controller adjusts the number of resources that a Pool must provide. Several Pools can be combined in a single CompositePool to appear as one. To modify how a Pool presents or digests data, any number of PoolDecorator may proceed it.

digraph graphname { graph [rankdir=LR, splines=lines, bgcolor="transparent"] controller [label=Controller] composite [label=CompositePool] decoa [label=PoolDecorator] poola, poolb [label=Pool] controller -> decoa -> composite composite -> poola composite -> poolb }

class cobald.interfaces.CompositePool[source]

Bases: Pool

Concatenation of multiple providers for a number of indistinguishable resources

abstract property allocation: float: Fraction of the provided resources which are assigned for usage

abstract property children: List[Pool]: The individual resource providers making up this pool

abstract property demand: The volume of resources to be provided by this pool

abstract property supply: The volume of resources that is provided by this pool

abstract property utilisation: float: Fraction of the provided resources which are actively used

class cobald.interfaces.Controller(target: Pool)[source]

Bases: object

Controller adjusting the demand in a Pool

Parameters:: target – the resource pool for which demand is adjusted

classmethod s(*args, **kwargs) → Partial[C][source]

Create an unbound prototype of this class, partially applying arguments

controller = Controller.s(interval=20)

pipeline = controller(rate=10) >> pool

class cobald.interfaces.Partial(ctor: Type[C_co], *args, __leaf__, **kwargs)[source]

Bases: Generic[C_co]

Partial application and chaining of Pool Controllers and Decorators

This class acts similar to functools.partial, but allows for repeated application (currying) and explicit binding via the >> operator.

# incrementally prepare controller parameters
control = Partial(Controller, rate=10, interval=10)
control = control(low_utilisation=0.5, high_allocation=0.9)

# apply target by chaining
pipeline = control >> Decorator() >> Pool()

Note:: The keyword argument __leaf__ is reserved for internal usage.
Note:: Binding Controllers and Decorators creates a temporary PartialBind. Only binding to a Pool as the last element creates a concrete binding.

args

ctor

kwargs

leaf

class cobald.interfaces.Pool[source]

Bases: object

Individual provider for a number of indistinguishable resources

abstract property allocation: float: Fraction of the provided resources which are assigned for usage

abstract property demand: float: The volume of resources to be provided by this pool

classmethod s(*args, **kwargs) → Partial[C][source]

Create an unbound prototype of this class, partially applying arguments

pool = RemotePool.s(port=1337)

pipeline = controller >> pool(host='localhost')

abstract property supply: float: The volume of resources that is provided by this pool

abstract property utilisation: float: Fraction of the provided resources which are actively used

class cobald.interfaces.PoolDecorator(target: Pool)[source]

Bases: Pool

Decorator modifying how a pool provides resources

Parameters:: target – the resource pool for which demand is adjusted

property allocation: float: Fraction of the provided resources which is assigned for usage

property demand: The volume of resources to be provided by this site

classmethod s(*args, **kwargs) → Partial[C][source]

Create an unbound prototype of this class, partially applying arguments

decorator = Buffer.s(window=20)

pipeline = controller >> decorator >> pool

property supply: The volume of resources that is provided by this site

property utilisation: float: Fraction of the provided resources which is actively used