Release v0.2.0

internal/config/config.go

@@ -21,13 +21,23 @@ type Config struct {
 	ClientSecret string `toml:"-"`
 }
 
+const configPathEnvVar = "NIX_CACHE_LOGIN_CONFIG"
+
+var systemConfigPath = "/etc/nix-cache-login/config.toml"
+
 // Load reads the config from the given path, or from the default XDG location.
 func Load(path string) (*Config, error) {
-	if path == "" {
-		path = filepath.Join(xdg.ConfigHome, "nix-cache-login", "config.toml")
-	}
-
+	path = resolveConfigPath(path)
 	data, err := os.ReadFile(path)
+	if err != nil && path == defaultXDGConfigPath() {
+		// On servers, allow a system-wide fallback when per-user XDG config is absent.
+		if systemData, systemErr := os.ReadFile(systemConfigPath); systemErr == nil {
+			data = systemData
+			err = nil
+		} else {
+			return nil, fmt.Errorf("reading config file: %w", err)
+		}
+	}
 	if err != nil {
 		return nil, fmt.Errorf("reading config file: %w", err)
 	}
@@ -55,6 +65,20 @@ func Load(path string) (*Config, error) {
 	return &cfg, nil
 }
 
+func resolveConfigPath(path string) string {
+	if path != "" {
+		return path
+	}
+	if envPath := strings.TrimSpace(os.Getenv(configPathEnvVar)); envPath != "" {
+		return envPath
+	}
+	return defaultXDGConfigPath()
+}
+
+func defaultXDGConfigPath() string {
+	return filepath.Join(xdg.ConfigHome, "nix-cache-login", "config.toml")
+}
+
 func (c *Config) validate() error {
 	if c.Issuer == "" {
 		return fmt.Errorf("config: issuer is required")