Class MinSurvivalConstraint

java.lang.Object

com.eqixiac.equinix.design.resilience.MinSurvivalConstraint

All Implemented Interfaces:

Constraint

public final class MinSurvivalConstraint
extends Object
implements Constraint

"min_survival": a portfolio must keep at least a minimum share of its baseline service through its worst single-element failure (see N1Survival). Opt-in: with no threshold the constraint passes everything without simulating.

The threshold, a percentage 0..100, comes from (first that is set wins): the constructor; the spec's constraints.minSurvivalPct; the spec label "design.min_survival_pct" (for example labels: {"design.min_survival_pct": "75"}). The label is the older, schema-free way to opt in and keeps working; when both are set the constraints.minSurvivalPct field wins. A malformed label fails every portfolio with a reason rather than being ignored. The Metro Optimizer adds this constraint itself when the spec sets constraints.minSurvivalPct, so the field never needs the ResiliencePlugin.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	ID	The constraint id.
static final String	LABEL	The spec label that sets the threshold (a percentage, 0..100).

Constructor Summary

Constructors

Constructor	Description
MinSurvivalConstraint()	Reads the threshold from the spec (constraints.minSurvivalPct, else the label "design.min_survival_pct"); inert without either.
MinSurvivalConstraint(Double thresholdPct, ResilienceOptions options)

Method Summary

Modifier and Type	Method	Description
ConstraintVerdict	check(MetroPortfolio portfolio, DesignContext context)	Checks a whole portfolio.
String	id()

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface Constraint

admits, usesCost

Modifier and Type	Method	Description
default boolean	admits(MetroFacts metro, DesignContext context)	Cheap per-metro pruning before portfolios are formed.
default boolean	usesCost()	Whether Constraint.check(MetroPortfolio, DesignContext) prices the portfolio through DesignContext.costModel().

Field Details

ID

public static final String ID

The constraint id.

See Also:

• Constant Field Values

LABEL

public static final String LABEL

The spec label that sets the threshold (a percentage, 0..100).

See Also:

• Constant Field Values

Constructor Details

MinSurvivalConstraint

public MinSurvivalConstraint()

Reads the threshold from the spec (constraints.minSurvivalPct, else the label "design.min_survival_pct"); inert without either.

MinSurvivalConstraint

public MinSurvivalConstraint(Double thresholdPct,
 ResilienceOptions options)

Parameters:

thresholdPct - the least share of service that must survive, 0..100; null to read the spec (constraints.minSurvivalPct, else the label "design.min_survival_pct")

options - graph and simulation options

Method Details

id

public String id()

Specified by:

id in interface Constraint

Returns:

a stable id, lower_snake_case (for example max_latency)

check

public ConstraintVerdict check(MetroPortfolio portfolio,
 DesignContext context)

Description copied from interface: Constraint

Checks a whole portfolio.

Specified by:

check in interface Constraint

Parameters:

portfolio - the candidate design

context - the facts of this run

Returns:

the verdict with its reason