optim egbuilder to provide build.yaml and corrent filter comments

cmd/builder/command/init.go

@@ -91,6 +91,7 @@ func initRun(cmd *cobra.Command, args []string) {
 		utils.ExitWithErrorf("directory %s is not empty, please call init in an empty directory", cwd)
 	}
 
+	initBuildYaml(cmd, cwd)
 	initGenerateFiles(cmd, cwd)
 	initGenerateMod(ctx, cmd)
 	err = initConfig.Save(cwd)
@@ -99,6 +100,14 @@ func initRun(cmd *cobra.Command, args []string) {
 	}
 }
 
+func initBuildYaml(_ *cobra.Command, cwd string) {
+	err := initConfig.GenBuildYaml(cwd)
+	if err != nil {
+		utils.ExitWithError(err)
+	}
+	fmt.Println("generate build.yaml success")
+}
+
 func initGenerateFiles(_ *cobra.Command, cwd string) {
 	err := initConfig.GenFilters(cwd)
 	if err != nil {

cmd/builder/gen/config.go

@@ -91,6 +91,29 @@ func (c *Config) CheckDuplicate(conf *Config) error {
 	return nil
 }
 
+func (c *Config) GenBuildYaml(dir string) error {
+	buildYaml := `
+# egVersion: the version of Easegress used for building. Supports versions v2.5.2 and later.
+# An empty egVersion value means using the latest version of Easegress.
+egVersion: ""
+
+# plugins: custom plugins.
+# It is recommended to use plugins created with "egbuilder init".
+# Generally, any plugin containing "registry/registry.go" can utilize the "egbuilder build" command.
+# You can initialize a project to see for yourself.
+plugins:
+- module: %s
+  version: ""
+  replacement: "."
+
+# output: path of output file.
+output: "./easegress-server"
+`
+	buildYaml = fmt.Sprintf(buildYaml, c.Repo)
+	fileName := path.Join(dir, "build.yaml")
+	return os.WriteFile(fileName, []byte(buildYaml), os.ModePerm)
+}
+
 func (c *Config) GenFilters(dir string) error {
 	for _, f := range c.Filters {
 		err := os.MkdirAll(getModulePath(dir, moduleFilter, f, false), os.ModePerm)

cmd/builder/gen/filters.go

@@ -177,7 +177,8 @@ func defineFilterMethods(file *j.File, info *FilterInfo) {
 	handleFunc.Params = []j.Code{j.Id("ctx").Op("*").Qual(egContext, "Context")}
 	handleFunc.Returns = []j.Code{j.String()}
 	handleFunc.Block = []j.Code{
-		j.Comment("hint: req := ctx.GetRequest().(*httpprot.Request)"),
+		j.Comment("hint: req := ctx.GetInputRequest().(*httpprot.Request)"),
+		j.Comment("hint: use req.HTTPHeader() to get the http headers"),
 		j.Comment("empty string means success"),
 		j.Comment(yourCodeHere),
 		j.Return(j.Lit("")),