Files
mgmt/hil/interpolate.go
2017-09-11 18:07:47 -04:00

90 lines
2.2 KiB
Go

// Mgmt
// Copyright (C) 2013-2017+ James Shubin and the project contributors
// Written by James Shubin <james@shubin.ca> and the project contributors
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package hil
import (
"fmt"
"strings"
"github.com/hashicorp/hil/ast"
)
// Variable defines an interpolated variable.
type Variable interface {
Key() string
}
// ResourceVariable defines a variable type used to reference fields of a resource
// e.g. ${file.file1.Content}
type ResourceVariable struct {
Kind, Name, Field string
}
// Key returns a string representation of the variable key.
func (r *ResourceVariable) Key() string {
return fmt.Sprintf("%s.%s.%s", r.Kind, r.Name, r.Field)
}
// NewInterpolatedVariable takes a variable key and return the interpolated variable
// of the required type.
func NewInterpolatedVariable(k string) (Variable, error) {
// for now resource variables are the only thing.
parts := strings.SplitN(k, ".", 3)
return &ResourceVariable{
Kind: parts[0],
Name: parts[1],
Field: parts[2],
}, nil
}
// ParseVariables will traverse a HIL tree looking for variables and returns a
// list of them.
func ParseVariables(tree ast.Node) ([]Variable, error) {
var result []Variable
var finalErr error
visitor := func(n ast.Node) ast.Node {
if finalErr != nil {
return n
}
switch nt := n.(type) {
case *ast.VariableAccess:
v, err := NewInterpolatedVariable(nt.Name)
if err != nil {
finalErr = err
return n
}
result = append(result, v)
default:
return n
}
return n
}
tree.Accept(visitor)
if finalErr != nil {
return nil, finalErr
}
return result, nil
}