go.uber.org/yarpc@v1.72.1/yarpcconfig/option.go

// Copyright (c) 2022 Uber Technologies, Inc.
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// of this software and associated documentation files (the "Software"), to deal
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// 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.
//
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// THE SOFTWARE.

package yarpcconfig

// Option customizes a Configurator.
type Option func(*Configurator)

// InterpolationResolver changes how interpolated variables in the
// configuration are resolved. By default, environment variables are used.
//
// Variables will be interpolated using this function if a parsed
// field inside a configuration structure was annotated with
// config:",interpolate" or config:"$name,interpolate" where $name is encoded
// name of that field.
//
// Only primitive types (numbers, strings, and time.Duration) are
// interpolated.
//
// 	type myConfig struct {
// 		Host string `config:"host,interpolate"`
// 		Port int `config:",interpolate"`
// 		Timeout time.Duration `config:",interpolate"`
// 	}
func InterpolationResolver(f func(k string) (v string, ok bool)) Option {
	return func(c *Configurator) {
		c.resolver = f
	}
}