bouncer/internal/rule/engine.go

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2024-06-25 14:03:49 +02:00
package rule
import (
"github.com/expr-lang/expr"
"github.com/expr-lang/expr/vm"
"github.com/pkg/errors"
)
type Engine[E any] struct {
rules []*vm.Program
}
func (e *Engine[E]) Apply(env E) ([]any, error) {
results := make([]any, 0, len(e.rules))
for i, r := range e.rules {
result, err := expr.Run(r, env)
if err != nil {
return nil, errors.Wrapf(err, "could not run rule #%d", i)
}
results = append(results, result)
}
return results, nil
}
func NewEngine[E any](funcs ...OptionFunc) (*Engine[E], error) {
opts := NewOptions(funcs...)
engine := &Engine[E]{
rules: make([]*vm.Program, 0, len(opts.Rules)),
}
for i, r := range opts.Rules {
program, err := expr.Compile(r, opts.Expr...)
if err != nil {
return nil, errors.Wrapf(err, "could not compile rule #%d", i)
}
engine.rules = append(engine.rules, program)
}
return engine, nil
}