correcting some behaviors for $DOCKER_HOST, now uses container's private IP instead of localhost

internal/docker/inspect.go

@@ -7,13 +7,13 @@ import (
 	E "github.com/yusing/go-proxy/internal/error"
 )
 
-func (c Client) Inspect(containerID string) (Container, E.NestedError) {
+func (c Client) Inspect(containerID string) (*Container, E.NestedError) {
 	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
 	defer cancel()
 
 	json, err := c.ContainerInspect(ctx, containerID)
 	if err != nil {
-		return Container{}, E.From(err)
+		return nil, E.From(err)
 	}
-	return FromJson(json, c.key), nil
+	return FromJSON(json, c.key), nil
 }