1 files changed, 78 insertions, 0 deletions
diff --git a/plugin.go b/plugin.go
new file mode 100644
index 0000000..b94c330
--- /dev/null
+++ b/plugin.go
@@ -0,0 +1,78 @@
+package koushin
+
+import (
+	"fmt"
+	"path/filepath"
+
+	"github.com/labstack/echo/v4"
+	"github.com/yuin/gopher-lua"
+	"layeh.com/gopher-luar"
+)
+
+type Plugin interface {
+	Name() string
+	Render(name string, data interface{}) error
+	Close() error
+}
+
+type luaPlugin struct {
+	filename string
+	state    *lua.LState
+}
+
+func (p *luaPlugin) Name() string {
+	return p.filename
+}
+
+func (p *luaPlugin) Render(name string, data interface{}) error {
+	global := p.state.GetGlobal("render")
+	if global == nil {
+		return nil
+	}
+
+	if err := p.state.CallByParam(lua.P{
+		Fn:      global,
+		NRet:    0,
+		Protect: true,
+	}, lua.LString(name), luar.New(p.state, data)); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (p *luaPlugin) Close() error {
+	p.state.Close()
+	return nil
+}
+
+func loadLuaPlugin(filename string) (*luaPlugin, error) {
+	l := lua.NewState()
+	if err := l.DoFile(filename); err != nil {
+		return nil, err
+	}
+
+	return &luaPlugin{filename, l}, nil
+}
+
+func loadAllLuaPlugins(log echo.Logger) ([]Plugin, error) {
+	filenames, err := filepath.Glob("plugins/*.lua")
+	if err != nil {
+		return nil, fmt.Errorf("filepath.Glob failed: %v", err)
+	}
+
+	plugins := make([]Plugin, 0, len(filenames))
+	for _, filename := range filenames {
+		log.Printf("Loading Lua plugin '%v'", filename)
+		p, err := loadLuaPlugin(filename)
+		if err != nil {
+			for _, p := range plugins {
+				p.Close()
+			}
+			return nil, fmt.Errorf("failed to load Lua plugin '%v': %v", filename, err)
+		}
+		plugins = append(plugins, p)
+	}
+
+	return plugins, nil
+}