open-consul/lib/template/hil.go

55 lines
1.1 KiB
Go

// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0
package template
import (
"fmt"
"strings"
"github.com/hashicorp/hil"
"github.com/hashicorp/hil/ast"
)
// InterpolateHIL processes the string as if it were HIL and interpolates only
// the provided string->string map as possible variables.
func InterpolateHIL(s string, vars map[string]string, lowercase bool) (string, error) {
if strings.Index(s, "${") == -1 {
// Skip going to the trouble of parsing something that has no HIL.
return s, nil
}
tree, err := hil.Parse(s)
if err != nil {
return "", err
}
vm := make(map[string]ast.Variable)
for k, v := range vars {
if lowercase {
v = strings.ToLower(v)
}
vm[k] = ast.Variable{
Type: ast.TypeString,
Value: v,
}
}
config := &hil.EvalConfig{
GlobalScope: &ast.BasicScope{
VarMap: vm,
},
}
result, err := hil.Eval(tree, config)
if err != nil {
return "", err
}
if result.Type != hil.TypeString {
return "", fmt.Errorf("generated unexpected hil type: %s", result.Type)
}
return result.Value.(string), nil
}