open-vault/helper/kv-builder/builder.go
Mitchell Hashimoto 8e3746d347 helper/kv-builder
2015-04-07 22:30:25 -07:00

115 lines
2.3 KiB
Go

package kvbuilder
import (
"bytes"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"os"
"strings"
)
// Builder is a struct to build a key/value mapping based on a list
// of "k=v" pairs, where the value might come from stdin, a file, etc.
type Builder struct {
Stdin io.Reader
result map[string]interface{}
stdin bool
}
// Map returns the built map.
func (b *Builder) Map() map[string]interface{} {
return b.result
}
// Add adds to the mapping with the given args.
func (b *Builder) Add(args ...string) error {
for _, a := range args {
if err := b.add(a); err != nil {
return fmt.Errorf("Invalid key/value pair '%s': %s", a, err)
}
}
return nil
}
func (b *Builder) add(raw string) error {
// Regardless of validity, make sure we make our result
if b.result == nil {
b.result = make(map[string]interface{})
}
// Empty strings are fine, just ignored
if raw == "" {
return nil
}
// If the arg is exactly "-", then we need to read from stdin
// and merge the results into the resulting structure.
if raw == "-" {
if b.Stdin == nil {
return fmt.Errorf("stdin is not supported")
}
if b.stdin {
return fmt.Errorf("stdin already consumed")
}
b.stdin = true
return b.addReader(b.Stdin)
}
// If the arg begins with "@" then we need to read a file directly
if raw[0] == '@' {
f, err := os.Open(raw[1:])
if err != nil {
return err
}
defer f.Close()
return b.addReader(f)
}
// Split into key/value
parts := strings.SplitN(raw, "=", 2)
if len(parts) != 2 {
return fmt.Errorf("format must be key=value")
}
key, value := parts[0], parts[1]
if len(value) > 0 && value[0] == '@' {
contents, err := ioutil.ReadFile(value[1:])
if err != nil {
return fmt.Errorf("error reading file: %s", err)
}
value = string(contents)
} else if value[0] == '\\' && value[1] == '@' {
value = value[1:]
} else if value == "-" {
if b.Stdin == nil {
return fmt.Errorf("stdin is not supported")
}
if b.stdin {
return fmt.Errorf("stdin already consumed")
}
b.stdin = true
var buf bytes.Buffer
if _, err := io.Copy(&buf, b.Stdin); err != nil {
return err
}
value = buf.String()
}
b.result[key] = value
return nil
}
func (b *Builder) addReader(r io.Reader) error {
dec := json.NewDecoder(r)
return dec.Decode(&b.result)
}