William Petit
fea0610346
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Cadoles/bouncer/pipeline/pr-develop This commit looks good
80 lines
1.4 KiB
Go
80 lines
1.4 KiB
Go
package rule
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import (
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"context"
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"github.com/expr-lang/expr"
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"github.com/expr-lang/expr/vm"
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"github.com/pkg/errors"
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)
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type Engine[V any] struct {
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rules []*vm.Program
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}
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func (e *Engine[V]) Apply(ctx context.Context, vars V) ([]any, error) {
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type Env[V any] struct {
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Context context.Context `expr:"ctx"`
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Vars V `expr:"vars"`
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}
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env := Env[V]{
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Context: ctx,
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Vars: vars,
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}
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results := make([]any, 0, len(e.rules))
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for i, r := range e.rules {
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result, err := expr.Run(r, env)
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if err != nil {
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return nil, errors.Wrapf(err, "could not run rule #%d", i)
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}
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results = append(results, result)
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}
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return results, nil
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}
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func NewEngine[E any](funcs ...OptionFunc) (*Engine[E], error) {
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opts := NewOptions(funcs...)
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engine := &Engine[E]{
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rules: make([]*vm.Program, 0, len(opts.Rules)),
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}
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for i, r := range opts.Rules {
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program, err := expr.Compile(r, opts.Expr...)
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if err != nil {
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return nil, errors.Wrapf(err, "could not compile rule #%d", i)
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}
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engine.rules = append(engine.rules, program)
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}
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return engine, nil
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}
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func Context[T any](ctx context.Context, key any) (T, bool) {
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raw := ctx.Value(key)
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if raw == nil {
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return *new(T), false
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}
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value, err := Assert[T](raw)
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if err != nil {
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return *new(T), false
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}
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return value, true
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}
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func Assert[T any](raw any) (T, error) {
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value, ok := raw.(T)
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if !ok {
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return *new(T), errors.Errorf("unexpected value '%T'", value)
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}
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return value, nil
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}
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