Effector

The Effect is the outcome of a policy rule (allow or deny). The Effector interface defines how the enforcer combines multiple matching effects into a single decision.

MergeEffects()

MergeEffects() takes all effects from matched policies and produces one final allow/deny result.

Effect, explainIndex, err = e.MergeEffects(expr, effects, matches, policyIndex, policyLength)

Parameters:

Parameter	Description
expr	Policy effect expression string (e.g. from the model).
effects	Slice of effects: Allow, Deny, or Indeterminate.
matches	Which policy indices matched.
policyIndex	Current policy index.
policyLength	Total number of policies.

Return values:

• Effect — Final decision (Allow, Deny, or Indeterminate).
• explainIndex — Index of the policy that determined the result (-1 if not applicable).
• err — Non-nil if the effector does not support the expression.

Using a custom Effector:

var e Effector
Effect, explainIndex, err = e.MergeEffects(expr, effects, matches, policyIndex, policyLength)

For the standard allow-override effect, the result is allow if any matched policy allows and none deny. Custom effectors implement other semantics (e.g. deny-override, priority).

nota

Unless the effect expression is priority(p_eft) || deny, the enforcer may short-circuit: once the result is determined, remaining policies are not evaluated. So when policyIndex < policyLength-1, some effects may be skipped.