vendor/github.com/fsouza/go-dockerclient/external/github.com/docker/docker/opts/envfile.go

   1 package opts
   2
   3 import (
   4         "bufio"
   5         "fmt"
   6         "os"
   7         "strings"
   8 )
   9
  10 // ParseEnvFile reads a file with environment variables enumerated by lines
  11 //
  12 // ``Environment variable names used by the utilities in the Shell and
  13 // Utilities volume of IEEE Std 1003.1-2001 consist solely of uppercase
  14 // letters, digits, and the '_' (underscore) from the characters defined in
  15 // Portable Character Set and do not begin with a digit. *But*, other
  16 // characters may be permitted by an implementation; applications shall
  17 // tolerate the presence of such names.''
  18 // -- http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap08.html
  19 //
  20 // As of #16585, it's up to application inside docker to validate or not
  21 // environment variables, that's why we just strip leading whitespace and
  22 // nothing more.
  23 func ParseEnvFile(filename string) ([]string, error) {
  24         fh, err := os.Open(filename)
  25         if err != nil {
  26                 return []string{}, err
  27         }
  28         defer fh.Close()
  29
  30         lines := []string{}
  31         scanner := bufio.NewScanner(fh)
  32         for scanner.Scan() {
  33                 // trim the line from all leading whitespace first
  34                 line := strings.TrimLeft(scanner.Text(), whiteSpaces)
  35                 // line is not empty, and not starting with '#'
  36                 if len(line) > 0 && !strings.HasPrefix(line, "#") {
  37                         data := strings.SplitN(line, "=", 2)
  38
  39                         // trim the front of a variable, but nothing else
  40                         variable := strings.TrimLeft(data[0], whiteSpaces)
  41                         if strings.ContainsAny(variable, whiteSpaces) {
  42                                 return []string{}, ErrBadEnvVariable{fmt.Sprintf("variable '%s' has white spaces", variable)}
  43                         }
  44
  45                         if len(data) > 1 {
  46
  47                                 // pass the value through, no trimming
  48                                 lines = append(lines, fmt.Sprintf("%s=%s", variable, data[1]))
  49                         } else {
  50                                 // if only a pass-through variable is given, clean it up.
  51                                 lines = append(lines, fmt.Sprintf("%s=%s", strings.TrimSpace(line), os.Getenv(line)))
  52                         }
  53                 }
  54         }
  55         return lines, scanner.Err()
  56 }
  57
  58 var whiteSpaces = " \t"
  59
  60 // ErrBadEnvVariable typed error for bad environment variable
  61 type ErrBadEnvVariable struct {
  62         msg string
  63 }
  64
  65 func (e ErrBadEnvVariable) Error() string {
  66         return fmt.Sprintf("poorly formatted environment: %s", e.msg)
  67 }