DockerCLI/compose/interpolation/interpolation.go

91 lines
1.8 KiB
Go

package interpolation
import (
"fmt"
"github.com/docker/docker/cli/compose/template"
"github.com/docker/docker/cli/compose/types"
)
// Interpolate replaces variables in a string with the values from a mapping
func Interpolate(config types.Dict, section string, mapping template.Mapping) (types.Dict, error) {
out := types.Dict{}
for name, item := range config {
if item == nil {
out[name] = nil
continue
}
interpolatedItem, err := interpolateSectionItem(name, item.(types.Dict), section, mapping)
if err != nil {
return nil, err
}
out[name] = interpolatedItem
}
return out, nil
}
func interpolateSectionItem(
name string,
item types.Dict,
section string,
mapping template.Mapping,
) (types.Dict, error) {
out := types.Dict{}
for key, value := range item {
interpolatedValue, err := recursiveInterpolate(value, mapping)
if err != nil {
return nil, fmt.Errorf(
"Invalid interpolation format for %#v option in %s %#v: %#v. You may need to escape any $ with another $.",
key, section, name, err.Template,
)
}
out[key] = interpolatedValue
}
return out, nil
}
func recursiveInterpolate(
value interface{},
mapping template.Mapping,
) (interface{}, *template.InvalidTemplateError) {
switch value := value.(type) {
case string:
return template.Substitute(value, mapping)
case types.Dict:
out := types.Dict{}
for key, elem := range value {
interpolatedElem, err := recursiveInterpolate(elem, mapping)
if err != nil {
return nil, err
}
out[key] = interpolatedElem
}
return out, nil
case []interface{}:
out := make([]interface{}, len(value))
for i, elem := range value {
interpolatedElem, err := recursiveInterpolate(elem, mapping)
if err != nil {
return nil, err
}
out[i] = interpolatedElem
}
return out, nil
default:
return value, nil
}
}