Custom filters

If you define custom feature filters on the server, you can register a matching evaluator in Go.

Register an evaluator

type RegionFilter struct{}

func (RegionFilter) Evaluate(featureKey string, params map[string]any, ctx eval.Context) (bool, error) {
  // Example: params["Region"] == "EU" etc.
  region, _ := params["Region"].(string)
  userRegion, _ := ctx.Traits["region"].(string)
  return region != "" && userRegion == region, nil
}

client.RegisterFilter("Region", RegionFilter{})

Naming

The evaluator name must match the filter name stored in definitions, for example:

• Targeting
• MyCompany.Region