options.go

// Copyright 2018 Philipp Brüll <pb@simia.tech>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 		http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package env

// Option defines an Option that can modify the options struct.
type Option func(*options)

type options struct {
	required      bool
	allowedValues []string
	desc          string
}

func newOptions(opts []Option) *options {
	o := &options{}
	for _, opt := range opts {
		opt(o)
	}
	return o
}

// Required returns an Option that makes the environment field required.
func Required() Option {
	return func(o *options) {
		o.required = true
	}
}

// AllowedValues returns an Option that defines all allowed values for the environment field.
func AllowedValues(values ...string) Option {
	return func(o *options) {
		o.allowedValues = values
	}
}

// Description returns an Option that sets the description of the environment field.
func Description(text string) Option {
	return func(o *options) {
		o.desc = text
	}
}

func (o *options) isAllowedValue(value string) bool {
	if o == nil || o.allowedValues == nil {
		return true
	}
	for _, allowedValue := range o.allowedValues {
		if value == allowedValue {
			return true
		}
	}
	return false
}