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moby--moby/builder/support.go
Erik Hollensbe be49867cab builder: handle escapes without swallowing all of them.
Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
2014-10-27 17:38:24 +00:00

59 lines
1.6 KiB
Go

package builder
import (
"regexp"
"strings"
)
var (
// `\\\\+|[^\\]|\b|\A` - match any number of "\\" (ie, properly-escaped backslashes), or a single non-backslash character, or a word boundary, or beginning-of-line
// `\$` - match literal $
// `[[:alnum:]_]+` - match things like `$SOME_VAR`
// `{[[:alnum:]_]+}` - match things like `${SOME_VAR}`
tokenEnvInterpolation = regexp.MustCompile(`(\\|\\\\+|[^\\]|\b|\A)\$([[:alnum:]_]+|{[[:alnum:]_]+})`)
// this intentionally punts on more exotic interpolations like ${SOME_VAR%suffix} and lets the shell handle those directly
)
// handle environment replacement. Used in dispatcher.
func (b *Builder) replaceEnv(str string) string {
for _, match := range tokenEnvInterpolation.FindAllString(str, -1) {
idx := strings.Index(match, "\\$")
if idx != -1 {
if idx+2 >= len(match) {
str = strings.Replace(str, match, "\\$", -1)
continue
}
prefix := match[:idx]
stripped := match[idx+2:]
str = strings.Replace(str, match, prefix+"$"+stripped, -1)
continue
}
match = match[strings.Index(match, "$"):]
matchKey := strings.Trim(match, "${}")
for _, keyval := range b.Config.Env {
tmp := strings.SplitN(keyval, "=", 2)
if tmp[0] == matchKey {
str = strings.Replace(str, match, tmp[1], -1)
break
}
}
}
return str
}
func handleJsonArgs(args []string, attributes map[string]bool) []string {
if len(args) == 0 {
return []string{}
}
if attributes != nil && attributes["json"] {
return args
}
// literal string command, not an exec array
return []string{strings.Join(args, " ")}
}