feat: add TALOSCONFIG env var (#422)

Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>

internal/app/osctl/cmd/root.go

@@ -10,6 +10,7 @@ import (
 	"os/user"
 	"path"
 
+	"github.com/autonomy/talos/internal/pkg/constants"
 	"github.com/spf13/cobra"
 )
 
@@ -37,11 +38,18 @@ var rootCmd = &cobra.Command{
 // Execute adds all child commands to the root command and sets flags appropriately.
 // This is called by main.main(). It only needs to happen once to the rootCmd.
 func Execute() {
-	u, err := user.Current()
+	var (
-	if err != nil {
+		defaultTalosConfig string
-		return
+		ok                 bool
+	)
+	if defaultTalosConfig, ok = os.LookupEnv(constants.TalosConfigEnvVar); !ok {
+		u, err := user.Current()
+		if err != nil {
+			return
+		}
+		defaultTalosConfig = path.Join(u.HomeDir, ".talos", "config")
 	}
-	rootCmd.PersistentFlags().StringVar(&talosconfig, "talosconfig", path.Join(u.HomeDir, ".talos", "config"), "The path to the Talos configuration file")
+	rootCmd.PersistentFlags().StringVar(&talosconfig, "talosconfig", defaultTalosConfig, "The path to the Talos configuration file")
 	if err := rootCmd.Execute(); err != nil {
 		fmt.Println(err)
 		os.Exit(1)

internal/pkg/constants/constants.go

@@ -99,6 +99,9 @@ const (
 
 	// SystemContainerdNamespace is the Containerd namespace for Talos services.
 	SystemContainerdNamespace = "system"
+
+	// TalosConfigEnvVar is the environment variable for setting the Talos configuration file path.
+	TalosConfigEnvVar = "TALOSCONFIG"
 )
 
 // See https://linux.die.net/man/3/klogctl