config: better memory management for libucl

config/import_tree.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"io"
 	"fmt"
 	"path/filepath"
 )
@@ -63,6 +64,21 @@ func loadTree(root string) (*importTree, error) {
 	}, nil
 }
 
+// Close releases any resources we might be holding open for the importTree.
+//
+// This can safely be called even while ConfigTree results are alive. The
+// importTree is not bound to these.
+func (t *importTree) Close() error {
+	if c, ok := t.Raw.(io.Closer); ok {
+		c.Close()
+	}
+	for _, ct := range t.Children {
+		ct.Close()
+	}
+
+	return nil
+}
+
 // ConfigTree traverses the importTree and turns each node into a *Config
 // object, ultimately returning a *configTree.
 func (t *importTree) ConfigTree() (*configTree, error) {

config/loader.go

@@ -11,6 +11,11 @@ func Load(path string) (*Config, error) {
 	}
 
 	configTree, err := importTree.ConfigTree()
+
+	// Close the importTree now so that we can clear resources as quickly
+	// as possible.
+	importTree.Close()
+
 	if err != nil {
 		return nil, err
 	}

config/loader_libucl.go

@@ -17,6 +17,10 @@ type libuclConfigurable struct {
 	Object *libucl.Object
 }
 
+func (t *libuclConfigurable) Close() error {
+	return t.Object.Close()
+}
+
 func (t *libuclConfigurable) Config() (*Config, error) {
 	var rawConfig struct {
 		Variable map[string]Variable

config/loader_libucl_test.go

@@ -0,0 +1,14 @@
+package config
+
+import (
+	"io"
+	"testing"
+)
+
+func TestLibuclConfigurableCloser(t *testing.T) {
+	var _ io.Closer = new(libuclConfigurable)
+}
+
+func TestLibuclConfigurableConfigurable(t *testing.T) {
+	var _ configurable = new(libuclConfigurable)
+}