HGKeeper

* Convey

* 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 environment

import (

"os"

"strings"

)

type envMapper struct {

env []string

}

func (e *envMapper) Map(name string) string {

for _, item := range e.env {

if parts := strings.SplitN(item, "=", 2); parts[0] == name {

if len(parts) == 2 {

return parts[1]

}

return os.Getenv(name)

}

return "$" + name

}

// Mapper will replace ${TEMPLATE} patterns in the string with the KEY=VAL pairs

// in the given environment. This function will replace patterns recursively, so

// if VAL has the form ${TEMPLATE}, it will be replaced again.

func Mapper(str string, env []string) string {

mapper := envMapper{env}

last := str

next := os.Expand(last, mapper.Map)

// TODO - add a max-depth or a list to detect replacement loops

for last != next {

last = next

next = os.Expand(last, mapper.Map)

}

return next

}

// SliceMapper calls Mapper for each item in a slice and returns a new slice.

func SliceMapper(slice []string, env []string) []string {

mapped := []string{}

for _, template := range slice {

mapped = append(mapped, Mapper(template, env))

}

return mapped

}

grim/convey