Improve RunMode / dev mode (#24886)

1. non-dev mode is treated as prod mode, to protect users from
accidentally running in dev mode if there is a typo in this value.
2. in dev mode, do not need to really exit if there are template errors,
because the template errors could be fixed by developer soon and the
templates get reloaded, help:
* https://github.com/go-gitea/gitea/issues/24845#issuecomment-1557615382
3. Fine tune the mail template loading message.

3 files changed, 32 insertions, 12 deletions

diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index 8f20ef0856..71cd9a12a9 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -251,7 +251,13 @@ func loadRunModeFrom(rootCfg ConfigProvider) {
 	if RunMode == "" {
 		RunMode = rootSec.Key("RUN_MODE").MustString("prod")
 	}
-	IsProd = strings.EqualFold(RunMode, "prod")
+
+	// non-dev mode is treated as prod mode, to protect users from accidentally running in dev mode if there is a typo in this value.
+	RunMode = strings.ToLower(RunMode)
+	if RunMode != "dev" {
+		RunMode = "prod"
+	}
+	IsProd = RunMode != "dev"
 
 	// check if we run as root
 	if os.Getuid() == 0 {
diff --git a/modules/templates/htmlrenderer.go b/modules/templates/htmlrenderer.go
index 21c268da78..e0cbc49ff4 100644
--- a/modules/templates/htmlrenderer.go
+++ b/modules/templates/htmlrenderer.go
@@ -97,6 +97,7 @@ func HTMLRenderer() *HTMLRender {
 }
 
 func ReloadHTMLTemplates() error {
+	log.Trace("Reloading HTML templates")
 	if err := htmlRender.CompileTemplates(); err != nil {
 		log.Error("Template error: %v\n%s", err, log.Stack(2))
 		return err
@@ -114,11 +115,11 @@ func initHTMLRenderer() {
 	htmlRender = &HTMLRender{}
 	if err := htmlRender.CompileTemplates(); err != nil {
 		p := &templateErrorPrettier{assets: AssetFS()}
-		wrapFatal(p.handleFuncNotDefinedError(err))
-		wrapFatal(p.handleUnexpectedOperandError(err))
-		wrapFatal(p.handleExpectedEndError(err))
-		wrapFatal(p.handleGenericTemplateError(err))
-		log.Fatal("HTMLRenderer CompileTemplates error: %v", err)
+		wrapTmplErrMsg(p.handleFuncNotDefinedError(err))
+		wrapTmplErrMsg(p.handleUnexpectedOperandError(err))
+		wrapTmplErrMsg(p.handleExpectedEndError(err))
+		wrapTmplErrMsg(p.handleGenericTemplateError(err))
+		wrapTmplErrMsg(fmt.Sprintf("CompileTemplates error: %v", err))
 	}
 
 	if !setting.IsProd {
@@ -128,11 +129,17 @@ func initHTMLRenderer() {
 	}
 }
 
-func wrapFatal(msg string) {
+func wrapTmplErrMsg(msg string) {
 	if msg == "" {
 		return
 	}
-	log.Fatal("Unable to compile templates, %s", msg)
+	if setting.IsProd {
+		// in prod mode, Gitea must have correct templates to run
+		log.Fatal("Gitea can't run with template errors: %s", msg)
+	} else {
+		// in dev mode, do not need to really exit, because the template errors could be fixed by developer soon and the templates get reloaded
+		log.Error("There are template errors but Gitea continues to run in dev mode: %s", msg)
+	}
 }
 
 type templateErrorPrettier struct {
diff --git a/modules/templates/mailer.go b/modules/templates/mailer.go
index ac1715fcd0..54d857a8f6 100644
--- a/modules/templates/mailer.go
+++ b/modules/templates/mailer.go
@@ -61,7 +61,10 @@ func Mailer(ctx context.Context) (*texttmpl.Template, *template.Template) {
 	bodyTemplates.Funcs(NewFuncMap())
 
 	assetFS := AssetFS()
-	refreshTemplates := func() {
+	refreshTemplates := func(firstRun bool) {
+		if !firstRun {
+			log.Trace("Reloading mail templates")
+		}
 		assetPaths, err := ListMailTemplateAssetNames(assetFS)
 		if err != nil {
 			log.Error("Failed to list mail templates: %v", err)
@@ -75,17 +78,21 @@ func Mailer(ctx context.Context) (*texttmpl.Template, *template.Template) {
 				continue
 			}
 			tmplName := strings.TrimPrefix(strings.TrimSuffix(assetPath, ".tmpl"), "mail/")
-			log.Trace("Adding mail template %s: %s by %s", tmplName, assetPath, layerName)
+			if firstRun {
+				log.Trace("Adding mail template %s: %s by %s", tmplName, assetPath, layerName)
+			}
 			buildSubjectBodyTemplate(subjectTemplates, bodyTemplates, tmplName, content)
 		}
 	}
 
-	refreshTemplates()
+	refreshTemplates(true)
 
 	if !setting.IsProd {
 		// Now subjectTemplates and bodyTemplates are both synchronized
 		// thus it is safe to call refresh from a different goroutine
-		go assetFS.WatchLocalChanges(ctx, refreshTemplates)
+		go assetFS.WatchLocalChanges(ctx, func() {
+			refreshTemplates(false)
+		})
 	}
 
 	return subjectTemplates, bodyTemplates