gitaly-git2go: Add flags to configure log level and format

The usage of FlagSet here was incorrect as the parser is not expecting
the binary name in the list.

Configure logging to output to stderr so it will not interfere with gob
encoding on stdout.

1 files changed, 20 insertions, 7 deletions

diff --git a/cmd/gitaly-git2go-v14/main.go b/cmd/gitaly-git2go-v14/main.go
index 1bbdf6e20..39cb817cc 100644
--- a/cmd/gitaly-git2go-v14/main.go
+++ b/cmd/gitaly-git2go-v14/main.go
@@ -12,6 +12,7 @@ import (
 
 	git "github.com/libgit2/git2go/v33"
 	"gitlab.com/gitlab-org/gitaly/v14/internal/git2go"
+	glog "gitlab.com/gitlab-org/gitaly/v14/internal/log"
 )
 
 type subcmd interface {
@@ -43,27 +44,39 @@ func fatalf(encoder *gob.Encoder, format string, args ...interface{}) {
 	os.Exit(0)
 }
 
+func configureLogging(format, level string) {
+	// Gitaly logging by default goes to stdout, which would interfere with gob
+	// encoding.
+	for _, l := range glog.Loggers {
+		l.Out = os.Stderr
+	}
+	glog.Configure(glog.Loggers, format, level)
+}
+
 func main() {
 	decoder := gob.NewDecoder(os.Stdin)
 	encoder := gob.NewEncoder(os.Stdout)
 
-	flags := flag.NewFlagSet(git2go.BinaryName, flag.ContinueOnError)
+	var logFormat, logLevel string
 
-	if err := flags.Parse(os.Args); err != nil {
-		fatalf(encoder, "parsing flags: %s", err)
-	}
+	flags := flag.NewFlagSet(git2go.BinaryName, flag.PanicOnError)
+	flags.StringVar(&logFormat, "log-format", "", "logging format")
+	flags.StringVar(&logLevel, "log-level", "", "logging level")
+	_ = flags.Parse(os.Args[1:])
+
+	configureLogging(logFormat, logLevel)
 
-	if flags.NArg() < 2 {
+	if flags.NArg() < 1 {
 		fatalf(encoder, "missing subcommand")
 	}
 
-	subcmd, ok := subcommands[flags.Arg(1)]
+	subcmd, ok := subcommands[flags.Arg(0)]
 	if !ok {
 		fatalf(encoder, "unknown subcommand: %q", flags.Arg(0))
 	}
 
 	subcmdFlags := subcmd.Flags()
-	if err := subcmdFlags.Parse(flags.Args()[2:]); err != nil {
+	if err := subcmdFlags.Parse(flags.Args()[1:]); err != nil {
 		fatalf(encoder, "parsing flags of %q: %s", subcmdFlags.Name(), err)
 	}