samueleresca

// QuorumSystem describes a read-write quorum system.
type QuorumSystem struct {
	// reads describes the read-quorum.
	reads Expr
	// writes describes the write-quorum.
	writes Expr
	// nameToNode keeps track the name of a node to a GetNodeByName.
	nameToNode nameToNode
}

samueleresca

// ExprOperator that wraps the Add and Multiply methods needed to build a quorum from a set of Node.
type ExprOperator interface {
	// Add method aggregate a Node to an Expr with a logical Or (a ∨ b)
	// returns the resulting Or operation.
	Add(expr Expr) Or
	// Multiply method aggregate a Node to an Expr with a logical And (a ∧ b)
	// returns the resulting And operation.
	Multiply(expr Expr) And
}

samueleresca

def search(nodes: List[Node[T]],
           read_fraction: Optional[Distribution] = None,
           write_fraction: Optional[Distribution] = None,
           optimize: str = LOAD,
           resilience: int = 0,
           load_limit: Optional[float] = None,
           network_limit: Optional[float] = None,
           latency_limit: Optional[datetime.timedelta] = None,
           f: int = 0,
           timeout: datetime.timedelta = datetime.timedelta(seconds=0)) \

samueleresca

"""
Original code available at: https://github.com/mwhittaker/quoracle/blob/d83a811a905a51fc13ebc00ddac036d559463380/quoracle/quorum_system.py#L276
"""

def _f_resilient_quorums(self,
                         f: int,
                         xs: List[T],
                         e: Expr) -> Iterator[Set[T]]:
    """
    Consider a set X of elements in xs. We say X is f-resilient if, despite

samueleresca

"""
Original code available at: https://github.com/mwhittaker/quoracle/blob/master/quoracle/quorum_system.py#L639
"""
class Strategy(Generic[T]):
  
    # ...

    def load(self,
             read_fraction: Optional[Distribution] = None,
             write_fraction: Optional[Distribution] = None) -> float:

samueleresca

"""
Original code available at: https://github.com/mwhittaker/quoracle/blob/master/quoracle/quorum_system.py#L622
"""
class Strategy(Generic[T]):
    
    # ...

    def quorum_system(self) -> QuorumSystem[T]:
        return self.qs

samueleresca

"""
Original code available at: https://github.com/mwhittaker/quoracle/blob/main/quoracle/quorum_system.py#L596
"""
class Strategy(Generic[T]):
    def __init__(self,
                 qs: QuorumSystem[T],
                 sigma_r: Dict[FrozenSet[T], float],
                 sigma_w: Dict[FrozenSet[T], float]) -> None:
        self.qs = qs
        self.sigma_r = sigma_r

samueleresca

"""
Original code available at: https://github.com/mwhittaker/quoracle/blob/d83a811a905a51fc13ebc00ddac036d559463380/quoracle/quorum_system.py#L509
"""
def latency() -> pulp.LpAffineExpression:
    reads = fr * sum(
        v * self._read_quorum_latency(quorum).total_seconds()
        for (rq, v) in zip(read_quorums, read_quorum_vars)
        for quorum in [{self.node(x) for x in rq}]
    )
    writes = (1 - fr) * sum(

samueleresca

"""
Original code available at: https://github.com/mwhittaker/quoracle/blob/master/quoracle/quorum_system.py#L498
"""
def network() -> pulp.LpAffineExpression:
    reads = fr * sum(
        v * len(rq)
        for (rq, v) in zip(read_quorums, read_quorum_vars)
    )
    writes = (1 - fr) * sum(
        v * len(wq)

samueleresca

'''
Original code available at:  https://github.com/mwhittaker/quoracle/blob/main/quoracle/quorum_system.py#L541
'''

#...

def load(problem: pulp.LpProblem,
         read_fraction: Dict[float, float]) -> pulp.LpAffineExpression:
    return sum(p * fr_load(problem, fr)
               for (fr, p) in read_fraction.items())