Move common go-junit-report code into separate internal package

There was some code duplication between the go-junit-report binary, its
tests and the testdata/generate-golden script. This has been moved into
an internal package. The go-junit-report binary can now just focus on
flag parsing and validation, and it should be less likely that the
binary, tests and golden report generator behave differently.

main.go

@@ -0,0 +1,134 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"github.com/jstemmer/go-junit-report/v2/internal/gojunitreport"
+)
+
+var (
+	Version   = "v2.0.0-dev"
+	Revision  = "HEAD"
+	BuildTime string
+)
+
+var (
+	noXMLHeader = flag.Bool("no-xml-header", false, "do not print xml header")
+	packageName = flag.String("package-name", "", "specify a default package `name` to use if output does not contain a package name")
+	setExitCode = flag.Bool("set-exit-code", false, "set exit code to 1 if tests failed")
+	version     = flag.Bool("version", false, "print version")
+	input       = flag.String("in", "", "read go test log from `file`")
+	output      = flag.String("out", "", "write XML report to `file`")
+	iocopy      = flag.Bool("iocopy", false, "copy input to stdout; can only be used in conjunction with -out")
+	properties  = make(keyValueFlag)
+	parser      = flag.String("parser", "gotest", "set input parser: gotest, gojson")
+
+	// debug flags
+	printEvents = flag.Bool("debug.print-events", false, "print events generated by the go test parser")
+
+	// deprecated flags
+	goVersionFlag = flag.String("go-version", "", "(deprecated, use -prop) the value to use for the go.version property in the generated XML")
+)
+
+func main() {
+	flag.Var(&properties, "p", "add `key=value` property to generated report; repeat this flag to add multiple properties.")
+	flag.Parse()
+
+	if *iocopy && *output == "" {
+		exitf("you must specify an output file with -out when using -iocopy")
+	}
+
+	if *version {
+		fmt.Printf("go-junit-report %s %s (%s)\n", Version, BuildTime, Revision)
+		return
+	}
+
+	if *goVersionFlag != "" {
+		fmt.Fprintf(os.Stderr, "the -go-version flag is deprecated and will be removed in the future, use the -p flag instead.\n")
+		properties["go.version"] = *goVersionFlag
+	}
+
+	if flag.NArg() != 0 {
+		fmt.Fprintf(os.Stderr, "invalid argument(s): %s\n", strings.Join(flag.Args(), " "))
+		fmt.Fprintf(os.Stderr, "%s does not accept positional arguments\n", os.Args[0])
+		flag.Usage()
+		exitf("")
+	}
+
+	var in io.Reader = os.Stdin
+	if *input != "" {
+		f, err := os.Open(*input)
+		if err != nil {
+			exitf("error opening input file: %v", err)
+		}
+		defer f.Close()
+		in = f
+	}
+
+	var out io.Writer = os.Stdout
+	if *output != "" {
+		f, err := os.Create(*output)
+		if err != nil {
+			exitf("error creating output file: %v", err)
+		}
+		defer f.Close()
+		out = f
+	}
+
+	if *iocopy {
+		in = io.TeeReader(in, os.Stdout)
+	}
+
+	hostname, _ := os.Hostname() // ignore error
+
+	config := gojunitreport.Config{
+		Parser:        *parser,
+		Hostname:      hostname,
+		PackageName:   *packageName,
+		SkipXMLHeader: *noXMLHeader,
+		Properties:    properties,
+		PrintEvents:   *printEvents,
+	}
+	report, err := config.Run(in, out)
+	if err != nil {
+		exitf("error: %v\n", err)
+	}
+
+	if *setExitCode && !report.IsSuccessful() {
+		os.Exit(1)
+	}
+}
+
+func exitf(msg string, args ...interface{}) {
+	if msg != "" {
+		fmt.Fprintf(os.Stderr, msg+"\n", args...)
+	}
+	os.Exit(2)
+}
+
+type keyValueFlag map[string]string
+
+func (f *keyValueFlag) String() string {
+	if f != nil {
+		var pairs []string
+		for k, v := range *f {
+			pairs = append(pairs, fmt.Sprintf("%s=%s", k, v))
+		}
+		return strings.Join(pairs, ",")
+	}
+	return ""
+}
+
+func (f *keyValueFlag) Set(value string) error {
+	idx := strings.IndexByte(value, '=')
+	if idx == -1 {
+		return fmt.Errorf("%v is not specified as \"key=value\"", value)
+	}
+	k, v := value[:idx], value[idx+1:]
+	(*f)[k] = v
+	return nil
+}