overrides.go

package cloudevents

import (
	"encoding/json"

	duckv1 "knative.dev/pkg/apis/duck/v1"
)

// OverridesJSON returns the JSON representation of a duckv1.CloudEventOverrides,
// after applying some optional transformations to it.
func OverridesJSON(ceo *duckv1.CloudEventOverrides, overrides ...ceOverrideOption) string {
	for _, o := range overrides {
		ceo = o(ceo)
	}

	var ceoStr string
	if b, err := json.Marshal(ceo); err == nil {
		ceoStr = string(b)
	}

	return ceoStr
}

// ceOverrideOption is a functional option that can alter a duckv1.CloudEventOverrides.
type ceOverrideOption func(*duckv1.CloudEventOverrides) *duckv1.CloudEventOverrides

// SetExtension returns a ceOverrideOption which sets a given CloudEvents
// extension to an arbitrary value, if this extension isn't already set.
func SetExtension(key, value string) ceOverrideOption {
	return func(ceo *duckv1.CloudEventOverrides) *duckv1.CloudEventOverrides {
		if ceo == nil {
			ceo = &duckv1.CloudEventOverrides{}
		}

		ext := &ceo.Extensions
		if *ext == nil {
			*ext = make(map[string]string, 1)
		}

		if _, isSet := (*ext)[key]; !isSet {
			(*ext)[key] = value
		}

		return ceo
	}
}