loadenv/main.go
2022-08-17 00:15:44 +02:00

73 lines
1.3 KiB
Go

package main
import (
"bufio"
"flag"
"fmt"
"io"
"os"
"os/exec"
"regexp"
)
var (
EnvFilePath = flag.String("f", ".env", "environment file")
EnvVarRegex = regexp.MustCompile(`^(.*?)=(.*?)$`)
EnvCommentRegex = regexp.MustCompile(`^[ \t]*#.*?$`)
)
func main() {
flag.Parse()
envFile, err := os.Open(*EnvFilePath)
if err != nil {
fmt.Fprintf(os.Stderr, "could not open file '%s': %s\n", *EnvFilePath, err.(*os.PathError).Err)
return
}
defer envFile.Close()
parseEnvFile(envFile)
args := flag.Args()
if len(args) == 0 {
for _, envVar := range os.Environ() {
fmt.Println(envVar)
}
return
}
cmd := exec.Command(args[0], args[1:]...)
cmd.Env = os.Environ()
cmd.Stdin = os.Stdin
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
if err := cmd.Run(); err != nil {
if exitErr, ok := err.(*exec.ExitError); ok {
os.Exit(exitErr.ExitCode())
return
} else {
panic(err)
}
}
}
func parseEnvFile(r io.Reader) {
s := bufio.NewScanner(r)
l := 0
for s.Scan() {
l++
matches := EnvVarRegex.FindStringSubmatch(s.Text())
if len(matches) != 0 {
key, value := matches[1], os.ExpandEnv(matches[2])
os.Setenv(key, value)
} else if s.Text() != "" && !EnvCommentRegex.MatchString(s.Text()) {
panic(fmt.Sprintf("invalid env syntax on line %d", l))
}
}
}