packer-cn/packer/config_file.go

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package packer
import (
"log"
"os"
"os/user"
"path/filepath"
"strings"
)
// ConfigFile returns the default path to the configuration file. On
// Unix-like systems this is the ".packerconfig" file in the home directory.
// On Windows, this is the "packer.config" file in the application data
// directory.
func ConfigFile() (string, error) {
return configFile()
}
// ConfigDir returns the configuration directory for Packer.
func ConfigDir() (string, error) {
return configDir()
}
func homeDir() (string, error) {
// Prefer $HOME over user.Current due to glibc bug: golang.org/issue/13470
if home := os.Getenv("HOME"); home != "" {
log.Printf("Detected home directory from env var: %s", home)
return home, nil
}
if home := os.Getenv("APPDATA"); home != "" {
log.Printf("Detected home directory from env var: %s", home)
return home, nil
}
// Fall back to the passwd database if not found which follows
// the same semantics as bourne shell
u, err := user.Current()
// Get homedir from specified username
// if it is set and different than what we have
if username := os.Getenv("USER"); username != "" && err == nil && u.Username != username {
u, err = user.Lookup(username)
}
// Fail if we were unable to read the record
if err != nil {
return "", err
}
return u.HomeDir, nil
}
func configFile() (string, error) {
dir, err := homeDir()
if err != nil {
return "", err
}
return filepath.Join(dir, defaultConfigFile), nil
}
func configDir() (string, error) {
dir, err := homeDir()
if err != nil {
return "", err
}
return filepath.Join(dir, defaultConfigDir), nil
}
// Given a path, check to see if it's using ~ to reference a user directory.
// If so, then replace that component with the requested user directory.
// In "~/", "~" gets replaced by current user's home dir.
// In "~root/", "~user" gets replaced by root's home dir.
// ~ has to be the first character of path for ExpandUser change it.
func ExpandUser(path string) (string, error) {
var (
u *user.User
err error
)
// refuse to do anything with a zero-length path
if len(path) == 0 {
return path, nil
}
// If no expansion was specified, then refuse that too
if path[0] != '~' {
return path, nil
}
// Grab everything up to the first filepath.Separator
idx := strings.IndexAny(path, `/\`)
if idx == -1 {
idx = len(path)
}
// Now we should be able to extract the username
username := path[:idx]
// Check if the current user was requested
if username == "~" {
u, err = user.Current()
} else {
u, err = user.Lookup(username[1:])
}
// If we couldn't figure that out, then fail here
if err != nil {
return "", err
}
// Now we can replace the path with u.HomeDir
return filepath.Join(u.HomeDir, path[idx:]), nil
}