Extract Lua infrastructure into a plugin

.gitignore

@@ -3,3 +3,4 @@
 !/public/themes/sourcehut
 /plugins/*
 !/plugins/base
+!/plugins/lua

cmd/koushin/main.go

@@ -13,6 +13,7 @@ import (
 	"github.com/labstack/gommon/log"
 
 	_ "git.sr.ht/~emersion/koushin/plugins/base"
+	_ "git.sr.ht/~emersion/koushin/plugins/lua"
 )
 
 func main() {

plugin.go

@@ -6,7 +6,8 @@ import (
 	"github.com/labstack/echo/v4"
 )
 
-const pluginDir = "plugins"
+// PluginDir is the path to the plugins directory.
+const PluginDir = "plugins"
 
 // Plugin extends koushin with additional functionality.
 type Plugin interface {

plugin_go.go

@@ -19,7 +19,7 @@ func (p *goPlugin) Name() string {
 func (p *goPlugin) LoadTemplate(t *template.Template) error {
 	t.Funcs(p.p.templateFuncs)
 
-	paths, err := filepath.Glob(pluginDir + "/" + p.p.Name + "/public/*.html")
+	paths, err := filepath.Glob(PluginDir + "/" + p.p.Name + "/public/*.html")
 	if err != nil {
 		return err
 	}
@@ -40,7 +40,7 @@ func (p *goPlugin) SetRoutes(group *echo.Group) {
 		})
 	}
 
-	group.Static("/plugins/"+p.p.Name+"/assets", pluginDir+"/"+p.p.Name+"/public/assets")
+	group.Static("/plugins/"+p.p.Name+"/assets", PluginDir+"/"+p.p.Name+"/public/assets")
 }
 
 func (p *goPlugin) Inject(ctx *Context, name string, data RenderData) error {

plugins/lua/lua.go

@@ -1,4 +1,4 @@
-package koushin
+package koushinlua
 
 import (
 	"fmt"
@@ -8,6 +8,7 @@ import (
 	"github.com/labstack/echo/v4"
 	"github.com/yuin/gopher-lua"
 	"layeh.com/gopher-luar"
+	"git.sr.ht/~emersion/koushin"
 )
 
 type luaRoute struct {
@@ -68,7 +69,7 @@ func (p *luaPlugin) setRoute(l *lua.LState) int {
 	return 0
 }
 
-func (p *luaPlugin) inject(name string, data RenderData) error {
+func (p *luaPlugin) inject(name string, data koushin.RenderData) error {
 	f, ok := p.renderCallbacks[name]
 	if !ok {
 		return nil
@@ -86,7 +87,7 @@ func (p *luaPlugin) inject(name string, data RenderData) error {
 	return nil
 }
 
-func (p *luaPlugin) Inject(ctx *Context, name string, data RenderData) error {
+func (p *luaPlugin) Inject(ctx *koushin.Context, name string, data koushin.RenderData) error {
 	if err := p.inject("*", data); err != nil {
 		return err
 	}
@@ -157,21 +158,24 @@ func loadLuaPlugin(filename string) (*luaPlugin, error) {
 	return p, nil
 }
 
-func loadAllLuaPlugins(log echo.Logger) ([]Plugin, error) {
-	filenames, err := filepath.Glob(pluginDir + "/*/main.lua")
+func loadAllLuaPlugins(s *koushin.Server) ([]koushin.Plugin, error) {
+	log := s.Logger()
+
+	filenames, err := filepath.Glob(koushin.PluginDir + "/*/main.lua")
 	if err != nil {
 		return nil, fmt.Errorf("filepath.Glob failed: %v", err)
 	}
 
-	plugins := make([]Plugin, 0, len(filenames))
+	plugins := make([]koushin.Plugin, 0, len(filenames))
 	for _, filename := range filenames {
-		log.Printf("Loading Lua plugin '%v'", filename)
+		log.Printf("Loading Lua plugin %q", 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)
+			return nil, fmt.Errorf("failed to load Lua plugin %q: %v", filename, err)
 		}
 		plugins = append(plugins, p)
 	}

plugins/lua/plugin.go

@@ -0,0 +1,9 @@
+package koushinlua
+
+import (
+	"git.sr.ht/~emersion/koushin"
+)
+
+func init() {
+	koushin.RegisterPluginLoader(loadAllLuaPlugins)
+}

server.go

@@ -18,9 +18,8 @@ type Server struct {
 	e        *echo.Echo
 	Sessions *SessionManager
 
-	mutex      sync.RWMutex // used for server reload
-	plugins    []Plugin
-	luaPlugins []Plugin
+	mutex   sync.RWMutex // used for server reload
+	plugins []Plugin
 
 	// maps protocols to URLs (protocol can be empty for auto-discovery)
 	upstreams map[string]*url.URL
@@ -188,12 +187,6 @@ func (s *Server) load() error {
 		plugins = append(plugins, l...)
 	}
 
-	luaPlugins, err := loadAllLuaPlugins(s.e.Logger)
-	if err != nil {
-		return fmt.Errorf("failed to load plugins: %v", err)
-	}
-	plugins = append(plugins, luaPlugins...)
-
 	renderer := newRenderer(s.e.Logger, s.defaultTheme)
 	if err := renderer.Load(plugins); err != nil {
 		return fmt.Errorf("failed to load templates: %v", err)
@@ -204,15 +197,14 @@ func (s *Server) load() error {
 	s.mutex.Lock()
 	defer s.mutex.Unlock()
 
-	// Close previous Lua plugins
-	for _, p := range s.luaPlugins {
+	// Close previous plugins
+	for _, p := range s.plugins {
 		if err := p.Close(); err != nil {
-			s.e.Logger.Printf("Failed to unload plugin '%v': %v", p.Name(), err)
+			s.e.Logger.Printf("Failed to unload plugin %q: %v", p.Name(), err)
 		}
 	}
 
 	s.plugins = plugins
-	s.luaPlugins = luaPlugins
 	s.e.Renderer = renderer
 
 	for _, p := range plugins {