/
mapdecode.go
80 lines (68 loc) · 2.61 KB
/
mapdecode.go
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// Copyright (c) 2017 Uber Technologies, Inc.
//
// 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 config
import (
"fmt"
"reflect"
"strings"
"go.uber.org/yarpc/internal/interpolate"
"go.uber.org/yarpc/internal/mapdecode"
)
const (
_tagName = "config"
_interpolateOption = "interpolate"
)
func decodeInto(dst interface{}, src interface{}, opts ...mapdecode.Option) error {
opts = append(opts, mapdecode.TagName(_tagName))
return mapdecode.Decode(dst, src, opts...)
}
func interpolateWith(resolver interpolate.VariableResolver) mapdecode.Option {
return mapdecode.FieldHook(func(from reflect.Type, to reflect.StructField, data reflect.Value) (reflect.Value, error) {
shouldInterpolate := false
options := strings.Split(to.Tag.Get(_tagName), ",")[1:]
for _, option := range options {
if option == _interpolateOption {
shouldInterpolate = true
break
}
}
if !shouldInterpolate {
return data, nil
}
// Use Interface().(string) so that we handle the case where data is an
// interface{} holding a string.
v, ok := data.Interface().(string)
if !ok {
// Cannot interpolate non-string type. This shouldn't be an error
// because an integer field may be marked as interpolatable and may
// have received an integer as expected.
return data, nil
}
s, err := interpolate.Parse(v)
if err != nil {
return data, fmt.Errorf("failed to parse %q for interpolation: %v", v, err)
}
newV, err := s.Render(resolver)
if err != nil {
return data, fmt.Errorf("failed to render %q with environment variables: %v", v, err)
}
return reflect.ValueOf(newV), nil
})
}