Factor command line parsing into an internal package for reuse.

cmd/csaf_checker/main.go

@@ -10,84 +10,11 @@
 package main
 
 import (
-	"bufio"
-	_ "embed" // Used for embedding.
-	"encoding/json"
-	"html/template"
-	"io"
 	"log"
-	"os"
+
+	"github.com/csaf-poc/csaf_distribution/v2/internal/options"
 )
 
-//go:embed tmpl/report.html
-var reportHTML string
-
-// writeJSON writes the JSON encoding of the given report to the given stream.
-// It returns nil, otherwise an error.
-func writeJSON(report *Report, w io.WriteCloser) error {
-	enc := json.NewEncoder(w)
-	enc.SetIndent("", "  ")
-	err := enc.Encode(report)
-	if e := w.Close(); err != nil {
-		err = e
-	}
-	return err
-}
-
-// writeHTML writes the given report to the given writer, it uses the template
-// in the "reportHTML" variable. It returns nil, otherwise an error.
-func writeHTML(report *Report, w io.WriteCloser) error {
-	tmpl, err := template.New("Report HTML").Parse(reportHTML)
-	if err != nil {
-		w.Close()
-		return err
-	}
-	buf := bufio.NewWriter(w)
-
-	if err := tmpl.Execute(buf, report); err != nil {
-		w.Close()
-		return err
-	}
-
-	err = buf.Flush()
-	if e := w.Close(); err == nil {
-		err = e
-	}
-	return err
-}
-
-type nopCloser struct{ io.Writer }
-
-func (nc *nopCloser) Close() error { return nil }
-
-// writeReport defines where to write the report according to the "output" flag option.
-// It calls also the "writeJSON" or "writeHTML" function according to the "format" flag option.
-func writeReport(report *Report, cfg *config) error {
-
-	var w io.WriteCloser
-
-	if cfg.Output == "" {
-		w = &nopCloser{os.Stdout}
-	} else {
-		f, err := os.Create(cfg.Output)
-		if err != nil {
-			return err
-		}
-		w = f
-	}
-
-	var writer func(*Report, io.WriteCloser) error
-
-	switch cfg.Format {
-	case "json":
-		writer = writeJSON
-	default:
-		writer = writeHTML
-	}
-
-	return writer(report, w)
-}
-
 // run uses a processor to check all the given domains or direct urls
 // and generates a report.
 func run(cfg *config, domains []string) (*Report, error) {
@@ -101,8 +28,8 @@ func run(cfg *config, domains []string) (*Report, error) {
 
 func main() {
 	domains, cfg, err := parseArgsConfig()
-
-	errCheck(cfg.prepare())
+	options.ErrorCheck(err)
+	options.ErrorCheck(cfg.prepare())
 
 	if len(domains) == 0 {
 		log.Println("No domain or direct url given.")
@@ -110,7 +37,7 @@ func main() {
 	}
 
 	report, err := run(cfg, domains)
-	errCheck(err)
+	options.ErrorCheck(err)
 
-	errCheck(writeReport(report, cfg))
+	options.ErrorCheck(report.write(cfg.Format, cfg.Output))
 }