From 08dcb18a941a80a3b37c14c8d64dd3a229e86ab1 Mon Sep 17 00:00:00 2001
From: Gabriel Arakaki Giovanini <mail@gabrielgio.me>
Date: Sun, 3 Sep 2023 21:33:46 +0200
Subject: ref: Better handle and outputs errors

---
 main.go     | 56 ++++++++++++++++++++++++++++++++++++++++++--------------
 template.go |  3 ++-
 2 files changed, 44 insertions(+), 15 deletions(-)

diff --git a/main.go b/main.go
index 314ecc8..3f3f40c 100644
--- a/main.go
+++ b/main.go
@@ -5,30 +5,54 @@ import (
 	"bufio"
 	"compress/gzip"
 	"errors"
+	"fmt"
 	"io"
 	"net/http"
 	"os"
+	"strconv"
 
 	flag "github.com/spf13/pflag"
 )
 
 func main() {
-	url := flag.StringP("url", "u", "", "Url to the APKINDEX.tar.gz")
-	output := flag.StringP("output", "o", "index.md", "Output path")
-	templateType := flag.StringP("template-type", "p", "text", "Template system to be used, options: html, text")
-	templateFile := flag.StringP("template-file", "t", "text", "Template file to be used")
+	var (
+		url          = flag.StringP("url", "u", "", "Url to the APKINDEX.tar.gz")
+		output       = flag.StringP("output", "o", "index.md", "Output path")
+		templateType = flag.StringP("template-type", "p", "text", "Template system to be used, options: html, text")
+		templateFile = flag.StringP("template-file", "t", "text", "Template file to be used")
+	)
 	flag.Parse()
 
-	tarStream, err := fechIndex(*url)
+	err := run(
+		*url,
+		*output,
+		*templateType,
+		*templateFile,
+	)
 	if err != nil {
-		panic("Error fecthing the index: " + err.Error())
+		fmt.Println(err)
+		os.Exit(1)
+	}
+}
+
+func run(
+	url string,
+	output string,
+	templateType string,
+	templateFile string,
+
+) error {
+
+	tarStream, err := fechIndex(url)
+	if err != nil {
+		return fmt.Errorf("Error fecthing index file: %w", err)
 	}
 
 	defer tarStream.Close()
 
 	archive, err := gzip.NewReader(tarStream)
 	if err != nil {
-		panic("Error creating gzip reader: " + err.Error())
+		return fmt.Errorf("Error creating gzip reader: %w", err)
 	}
 
 	tr := tar.NewReader(archive)
@@ -36,7 +60,7 @@ func main() {
 	for {
 		h, err := tr.Next()
 		if err != nil {
-			panic("Error reading next tar entry: " + err.Error())
+			return fmt.Errorf("Error reading next tar entry: %w", err)
 		}
 
 		if h.FileInfo().Name() == "APKINDEX" {
@@ -60,17 +84,21 @@ func main() {
 		}
 	}
 
-	outputFile, err := getOutputFile(*output)
+	outputFile, err := getOutputFile(output)
 	if err != nil {
-		panic("Error openning output file: " + err.Error())
+		return fmt.Errorf("Error openning output file: %w", err)
 	}
 
-	tmpl, err := GetTemplate(*templateType, *templateFile)
+	tmpl, err := GetTemplate(templateType, templateFile)
 	if err != nil {
-		panic("Error loading template file: " + err.Error())
+		return fmt.Errorf("Error loading template file: %w", err)
 	}
 
-	tmpl.Execute(outputFile, entries)
+	err = tmpl.Execute(outputFile, entries)
+	if err != nil {
+		return fmt.Errorf("Error executing template: %w", err)
+	}
+	return nil
 }
 
 func getOutputFile(output string) (*os.File, error) {
@@ -92,7 +120,7 @@ func fechIndex(url string) (io.ReadCloser, error) {
 	}
 
 	if resp.StatusCode != 200 {
-		return nil, errors.New("Invlid response")
+		return nil, errors.New("Http error " + strconv.Itoa(resp.StatusCode))
 	}
 
 	return resp.Body, nil
diff --git a/template.go b/template.go
index 503af64..8d84f2e 100644
--- a/template.go
+++ b/template.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	html "html/template"
 	"io"
 	"os"
@@ -39,6 +40,6 @@ func GetTemplate(templateType, filePath string) (Templater, error) {
 			Funcs(templateFunc).
 			Parse(string(tmpl))
 	default:
-		panic("Invalid template-type")
+		return nil, errors.New("Invalid template type")
 	}
 }
-- 
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