108 lines
2.1 KiB
Go
108 lines
2.1 KiB
Go
package main
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import (
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"bufio"
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"flag"
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"fmt"
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"io"
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"os"
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"os/exec"
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"os/signal"
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"regexp"
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"syscall"
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)
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var (
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EnvVarRegex = regexp.MustCompile(`^(.*?)=(.*?)$`)
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EnvCommentRegex = regexp.MustCompile(`^[ \t]*#.*?$`)
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ExpandEnvFiles = map[string]string{}
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)
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var ( // flags
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FlagEnvFilePath = flag.String("f", ".env", "environment file")
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FlagExpandRecursively = flag.Bool("r", false, "expand references in reference definitions")
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FlagExpandEnvFiles = SliceFlag{}
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)
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func main() {
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flag.Var(&FlagExpandEnvFiles, "e", "files in which to expand environment variables")
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flag.Parse()
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envFile, err := os.Open(*FlagEnvFilePath)
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if err != nil {
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fmt.Fprintf(os.Stderr, "could not open file '%s': %s\n", *FlagEnvFilePath, err.(*os.PathError).Err)
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return
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}
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defer envFile.Close()
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parseEnvFile(envFile)
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args := flag.Args()
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if len(args) == 0 {
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for _, envVar := range os.Environ() {
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fmt.Println(envVar)
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}
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return
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}
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if err := expandEnvFiles(); err != nil {
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fmt.Fprintf(os.Stderr, "could not expand files: %s\n", err.Error())
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return
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}
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defer restoreFiles()
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sigs := make(chan os.Signal, 1)
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signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
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go func() { <-sigs; exit(1) }()
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cmd := exec.Command(args[0], args[1:]...)
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cmd.Env = os.Environ()
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cmd.Stdin = os.Stdin
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cmd.Stdout = os.Stdout
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cmd.Stderr = os.Stderr
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if err := cmd.Run(); err != nil {
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if exitErr, ok := err.(*exec.ExitError); ok {
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exit(exitErr.ExitCode())
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return
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} else {
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panic(err)
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}
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}
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}
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func parseEnvFile(r io.Reader) {
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s := bufio.NewScanner(r)
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l := 0
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for s.Scan() {
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l++
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matches := EnvVarRegex.FindStringSubmatch(s.Text())
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if len(matches) != 0 {
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key, value := matches[1], matches[2]
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if *FlagExpandRecursively {
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value = os.ExpandEnv(value)
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}
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os.Setenv(key, value)
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} else if s.Text() != "" && !EnvCommentRegex.MatchString(s.Text()) {
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panic(fmt.Sprintf("invalid env syntax on line %d", l))
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}
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}
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}
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func exit(errorCode int) {
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restoreFiles()
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os.Exit(errorCode)
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}
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func restoreFiles() {
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if err := restoreEnvFiles(); err != nil {
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fmt.Fprintf(os.Stderr, "could not restore expanded files: %s\n", err.Error())
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}
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}
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