Add local and NetBox server notes and improve reliability

internal/config/config.go

@@ -69,7 +69,13 @@ func Load() (*Config, error) {
 	}
 
 	v.SetEnvPrefix("NETSSH")
+	v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
 	v.AutomaticEnv()
+	for _, key := range []string{"netbox.url", "netbox.token", "netbox.token_version", "resolver.strategies", "resolver.management_subnets", "resolver.interface_name", "cache.ttl", "cache.path", "ssh.default_user", "ssh.default_port", "shortcuts.domains", "shortcuts.strip_hyphens"} {
+		if err := v.BindEnv(key); err != nil {
+			return nil, err
+		}
+	}
 
 	if err := v.ReadInConfig(); err != nil {
 		if _, ok := err.(viper.ConfigFileNotFoundError); !ok {

internal/config/config_test.go

@@ -143,3 +143,17 @@ func TestPath_ReturnsNonEmpty(t *testing.T) {
 		t.Errorf("Path() base: got %q, want netssh.yaml", filepath.Base(p))
 	}
 }
+
+func TestEnvironmentOverridesWithoutConfigKeys(t *testing.T) {
+	t.Setenv("XDG_CONFIG_HOME", t.TempDir())
+	t.Setenv("NETSSH_NETBOX_URL", "https://env.example")
+	t.Setenv("NETSSH_NETBOX_TOKEN", "nbt_env")
+	t.Setenv("NETSSH_SSH_DEFAULT_PORT", "2222")
+	cfg, err := Load()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cfg.NetBox.URL != "https://env.example" || cfg.NetBox.Token != "nbt_env" || cfg.NetBox.TokenVersion != 2 || cfg.SSH.DefaultPort != 2222 {
+		t.Fatalf("env ignored: %+v", cfg)
+	}
+}