Share HTML template renderers and create a watcher framework (#20218)

The recovery, API, Web and package frameworks all create their own HTML
Renderers. This increases the memory requirements of Gitea
unnecessarily with duplicate templates being kept in memory.

Further the reloading framework in dev mode for these involves locking
and recompiling all of the templates on each load. This will potentially
hide concurrency issues and it is inefficient.

This PR stores the templates renderer in the context and stores this
context in the NormalRoutes, it then creates a fsnotify.Watcher
framework to watch files.

The watching framework is then extended to the mailer templates which
were previously not being reloaded in dev.

Then the locales are simplified to a similar structure.

Fix #20210 
Fix #20211
Fix #20217

Signed-off-by: Andrew Thornton <art27@cantab.net>

routers/install/install.go

@@ -6,6 +6,7 @@
 package install
 
 import (
+	goctx "context"
 	"fmt"
 	"net/http"
 	"os"
@@ -51,39 +52,41 @@ func getSupportedDbTypeNames() (dbTypeNames []map[string]string) {
 }
 
 // Init prepare for rendering installation page
-func Init(next http.Handler) http.Handler {
-	rnd := templates.HTMLRenderer()
+func Init(ctx goctx.Context) func(next http.Handler) http.Handler {
+	_, rnd := templates.HTMLRenderer(ctx)
 	dbTypeNames := getSupportedDbTypeNames()
-	return http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
-		if setting.InstallLock {
-			resp.Header().Add("Refresh", "1; url="+setting.AppURL+"user/login")
-			_ = rnd.HTML(resp, http.StatusOK, string(tplPostInstall), nil)
-			return
-		}
-		locale := middleware.Locale(resp, req)
-		startTime := time.Now()
-		ctx := context.Context{
-			Resp:    context.NewResponse(resp),
-			Flash:   &middleware.Flash{},
-			Locale:  locale,
-			Render:  rnd,
-			Session: session.GetSession(req),
-			Data: map[string]interface{}{
-				"locale":        locale,
-				"Title":         locale.Tr("install.install"),
-				"PageIsInstall": true,
-				"DbTypeNames":   dbTypeNames,
-				"AllLangs":      translation.AllLangs(),
-				"PageStartTime": startTime,
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
+			if setting.InstallLock {
+				resp.Header().Add("Refresh", "1; url="+setting.AppURL+"user/login")
+				_ = rnd.HTML(resp, http.StatusOK, string(tplPostInstall), nil)
+				return
+			}
+			locale := middleware.Locale(resp, req)
+			startTime := time.Now()
+			ctx := context.Context{
+				Resp:    context.NewResponse(resp),
+				Flash:   &middleware.Flash{},
+				Locale:  locale,
+				Render:  rnd,
+				Session: session.GetSession(req),
+				Data: map[string]interface{}{
+					"locale":        locale,
+					"Title":         locale.Tr("install.install"),
+					"PageIsInstall": true,
+					"DbTypeNames":   dbTypeNames,
+					"AllLangs":      translation.AllLangs(),
+					"PageStartTime": startTime,
 
-				"PasswordHashAlgorithms": user_model.AvailableHashAlgorithms,
-			},
-		}
-		defer ctx.Close()
+					"PasswordHashAlgorithms": user_model.AvailableHashAlgorithms,
+				},
+			}
+			defer ctx.Close()
 
-		ctx.Req = context.WithContext(req, &ctx)
-		next.ServeHTTP(resp, ctx.Req)
-	})
+			ctx.Req = context.WithContext(req, &ctx)
+			next.ServeHTTP(resp, ctx.Req)
+		})
+	}
 }
 
 // Install render installation page

routers/install/routes.go

@@ -5,6 +5,7 @@
 package install
 
 import (
+	goctx "context"
 	"fmt"
 	"net/http"
 	"path"
@@ -29,8 +30,8 @@ func (d *dataStore) GetData() map[string]interface{} {
 	return *d
 }
 
-func installRecovery() func(next http.Handler) http.Handler {
-	rnd := templates.HTMLRenderer()
+func installRecovery(ctx goctx.Context) func(next http.Handler) http.Handler {
+	_, rnd := templates.HTMLRenderer(ctx)
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
 			defer func() {
@@ -82,7 +83,7 @@ func installRecovery() func(next http.Handler) http.Handler {
 }
 
 // Routes registers the install routes
-func Routes() *web.Route {
+func Routes(ctx goctx.Context) *web.Route {
 	r := web.NewRoute()
 	for _, middle := range common.Middlewares() {
 		r.Use(middle)
@@ -105,8 +106,8 @@ func Routes() *web.Route {
 		Domain:         setting.SessionConfig.Domain,
 	}))
 
-	r.Use(installRecovery())
-	r.Use(Init)
+	r.Use(installRecovery(ctx))
+	r.Use(Init(ctx))
 	r.Get("/", Install)
 	r.Post("/", web.Bind(forms.InstallForm{}), SubmitInstall)
 	r.Get("/api/healthz", healthcheck.Check)

routers/install/routes_test.go

@@ -5,13 +5,16 @@
 package install
 
 import (
+	"context"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
 func TestRoutes(t *testing.T) {
-	routes := Routes()
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	routes := Routes(ctx)
 	assert.NotNil(t, routes)
 	assert.EqualValues(t, "/", routes.R.Routes()[0].Pattern)
 	assert.Nil(t, routes.R.Routes()[0].SubRoutes)

routers/install/setting.go

@@ -24,7 +24,7 @@ func PreloadSettings(ctx context.Context) bool {
 		log.Info("Log path: %s", setting.LogRootPath)
 		log.Info("Configuration file: %s", setting.CustomConf)
 		log.Info("Prepare to run install page")
-		translation.InitLocales()
+		translation.InitLocales(ctx)
 		if setting.EnableSQLite3 {
 			log.Info("SQLite3 is supported")
 		}