WIP: domain listing with Gandi

Rethinking the interface already.

pkg/dns/common.go

@@ -0,0 +1,28 @@
+package dns
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/AlecAivazis/survey/v2"
+	"github.com/sirupsen/logrus"
+)
+
+// NewToken constructs a new DNS provider token.
+func NewToken(provider, providerTokenEnvVar string) (string, error) {
+	if token, present := os.LookupEnv(providerTokenEnvVar); present {
+		return token, nil
+	}
+
+	logrus.Debugf("no %s in environment, asking via stdin", providerTokenEnvVar)
+
+	var token string
+	prompt := &survey.Input{
+		Message: fmt.Sprintf("%s API token?", provider),
+	}
+	if err := survey.AskOne(prompt, &token); err != nil {
+		return "", err
+	}
+
+	return token, nil
+}