fix: enable env vars in setup steps (and deprecate admin subcommand) (#3871)

* fix: enable env vars in setup steps (and deprecate admin subcommand)

* fix tests and error text

cmd/key/masterkey.go

@@ -0,0 +1,67 @@
+package key
+
+import (
+	"errors"
+	"io/ioutil"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+const (
+	flagMasterKey      = "masterkeyFile"
+	flagMasterKeyShort = "m"
+	flagMasterKeyArg   = "masterkey"
+	flagMasterKeyEnv   = "masterkeyFromEnv"
+	envMasterKey       = "ZITADEL_MASTERKEY"
+)
+
+var (
+	ErrNotSingleFlag = errors.New("masterkey must either be provided by file path, value or environment variable")
+)
+
+func AddMasterKeyFlag(cmd *cobra.Command) {
+	if cmd.PersistentFlags().Lookup(flagMasterKey) != nil {
+		return
+	}
+	cmd.PersistentFlags().StringP(flagMasterKey, flagMasterKeyShort, "", "path to the masterkey for en/decryption keys")
+	cmd.PersistentFlags().String(flagMasterKeyArg, "", "masterkey as argument for en/decryption keys")
+	cmd.PersistentFlags().Bool(flagMasterKeyEnv, false, "read masterkey for en/decryption keys from environment variable (ZITADEL_MASTERKEY)")
+}
+
+func MasterKey(cmd *cobra.Command) (string, error) {
+	masterKeyFile, _ := cmd.Flags().GetString(flagMasterKey)
+	masterKeyFromArg, _ := cmd.Flags().GetString(flagMasterKeyArg)
+	masterKeyFromEnv, _ := cmd.Flags().GetBool(flagMasterKeyEnv)
+	if err := checkSingleFlag(masterKeyFile, masterKeyFromArg, masterKeyFromEnv); err != nil {
+		return "", err
+	}
+	if masterKeyFromArg != "" {
+		return masterKeyFromArg, nil
+	}
+	if masterKeyFromEnv {
+		return os.Getenv(envMasterKey), nil
+	}
+	data, err := ioutil.ReadFile(masterKeyFile)
+	if err != nil {
+		return "", err
+	}
+	return string(data), nil
+}
+
+func checkSingleFlag(masterKeyFile, masterKeyFromArg string, masterKeyFromEnv bool) error {
+	var flags int
+	if masterKeyFile != "" {
+		flags++
+	}
+	if masterKeyFromArg != "" {
+		flags++
+	}
+	if masterKeyFromEnv {
+		flags++
+	}
+	if flags != 1 {
+		return ErrNotSingleFlag
+	}
+	return nil
+}