fix: extract io writer in recipe generator (#466)

meteor new command allows user to generate recipe, although
the functionality is fine, I want use this method to generate
recipe outside of meteor as well. If this is being called programmatically
printing it to hard coded stdout blocked me to take the output as a string.

Signed-off-by: Kush Sharma <thekushsharma@gmail.com>

Author: kushsharma

cmd/new.go

@@ -2,6 +2,7 @@ package cmd
 
 import (
 	"errors"
+	"os"
 	"strings"
 
 	"github.com/AlecAivazis/survey/v2"
@@ -89,13 +90,13 @@ func NewRecipeCmd() *cobra.Command {
 				}
 			}
 
-			return generator.Recipe(generator.RecipeParams{
+			return generator.RecipeWriteTo(generator.RecipeParams{
 				Name:       args[0],
 				Source:     extractor,
 				Scope:      scope,
 				Sinks:      sinkList,
 				Processors: procList,
-			})
+			}, os.Stdout)
 		},
 	}
 

generator/recipe.go

@@ -1,8 +1,8 @@
 package generator
 
 import (
-	"embed"
-	"os"
+	_ "embed"
+	"io"
 	"strings"
 	"text/template"
 
@@ -11,10 +11,10 @@ import (
 )
 
 //go:embed recipe.yaml
-var file embed.FS
+var RecipeTemplate string
 
-// templateData represents the template for generating a recipe.
-type templateData struct {
+// TemplateData represents the template for generating a recipe.
+type TemplateData struct {
 	Name    string
 	Version string
 	Source  struct {
@@ -26,7 +26,7 @@ type templateData struct {
 	Processors map[string]string
 }
 
-var templateFuncs = map[string]interface{}{
+var TemplateFuncs = map[string]interface{}{
 	"indent": indent,
 	"rawfmt": rawfmt,
 }
@@ -42,8 +42,8 @@ type RecipeParams struct {
 }
 
 // Recipe checks if the recipe is valid and returns a Template
-func Recipe(p RecipeParams) error {
-	tem := templateData{
+func Recipe(p RecipeParams) (*TemplateData, error) {
+	tem := &TemplateData{
 		Name:    p.Name,
 		Version: recipeVersions[len(recipeVersions)-1],
 	}
@@ -54,7 +54,7 @@ func Recipe(p RecipeParams) error {
 
 		sourceInfo, err := registry.Extractors.Info(p.Source)
 		if err != nil {
-			return errors.Wrap(err, "failed to provide extractor information")
+			return nil, errors.Wrap(err, "failed to provide extractor information")
 		}
 
 		tem.Source.SampleConfig = sourceInfo.SampleConfig
@@ -64,7 +64,7 @@ func Recipe(p RecipeParams) error {
 		for _, sink := range p.Sinks {
 			info, err := registry.Sinks.Info(sink)
 			if err != nil {
-				return errors.Wrap(err, "failed to provide sink information")
+				return nil, errors.Wrap(err, "failed to provide sink information")
 			}
 			tem.Sinks[sink] = info.SampleConfig
 		}
@@ -74,16 +74,25 @@ func Recipe(p RecipeParams) error {
 		for _, procc := range p.Processors {
 			info, err := registry.Processors.Info(procc)
 			if err != nil {
-				return errors.Wrap(err, "failed to provide processor information")
+				return nil, errors.Wrap(err, "failed to provide processor information")
 			}
 			tem.Processors[procc] = info.SampleConfig
 		}
 	}
 
+	return tem, nil
+}
+
+// RecipeWriteTo build and apply recipe to provided io writer
+func RecipeWriteTo(p RecipeParams, writer io.Writer) error {
+	tem, err := Recipe(p)
+	if err != nil {
+		return err
+	}
 	tmpl := template.Must(
-		template.New("recipe.yaml").Funcs(templateFuncs).ParseFS(file, "*"),
+		template.New("recipe.yaml").Funcs(TemplateFuncs).Parse(RecipeTemplate),
 	)
-	if err := tmpl.Execute(os.Stdout, tem); err != nil {
+	if err := tmpl.Execute(writer, *tem); err != nil {
 		return errors.Wrap(err, "failed to execute template")
 	}
 	return nil