options.go

// MIT License
//
// Copyright (c) 2020 Lack
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

package env

import (
	"context"
	"strings"

	"github.com/vine-io/vine/lib/config/source"
)

type strippedPrefixKey struct{}
type prefixKey struct{}

// WithStrippedPrefix sets the environment variable prefixes to scope to.
// These prefixes will be removed from the actual config entries.
func WithStrippedPrefix(p ...string) source.Option {
	return func(o *source.Options) {
		if o.Context == nil {
			o.Context = context.Background()
		}

		o.Context = context.WithValue(o.Context, strippedPrefixKey{}, appendUnderscore(p))
	}
}

// WithPrefix sets the environment variable prefixes to scope to.
// These prefixes will not be removed. Each prefix will be considered a top level config entry.
func WithPrefix(p ...string) source.Option {
	return func(o *source.Options) {
		if o.Context == nil {
			o.Context = context.Background()
		}
		o.Context = context.WithValue(o.Context, prefixKey{}, appendUnderscore(p))
	}
}

func appendUnderscore(prefixes []string) []string {
	//nolint:prealloc
	var result []string
	for _, p := range prefixes {
		if !strings.HasSuffix(p, "_") {
			result = append(result, p+"_")
			continue
		}

		result = append(result, p)
	}

	return result
}