composer: add support for logrus syslog hook

Which will be used on crc in the log forwarding setup
NeededBy: COMPOSER-1285

cmd/osbuild-composer/config.go

@@ -11,11 +11,12 @@ import (
 )
 
 type ComposerConfigFile struct {
-	Koji      KojiAPIConfig   `toml:"koji"`
-	Worker    WorkerAPIConfig `toml:"worker"`
-	WeldrAPI  WeldrAPIConfig  `toml:"weldr_api"`
-	LogLevel  string          `toml:"log_level"`
-	LogFormat string          `toml:"log_format"`
+	Koji         KojiAPIConfig   `toml:"koji"`
+	Worker       WorkerAPIConfig `toml:"worker"`
+	WeldrAPI     WeldrAPIConfig  `toml:"weldr_api"`
+	SyslogServer string          `toml:"syslog_server" env:"SYSLOG_SERVER"`
+	LogLevel     string          `toml:"log_level"`
+	LogFormat    string          `toml:"log_format"`
 }
 
 type KojiAPIConfig struct {

cmd/osbuild-composer/main.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/coreos/go-systemd/activation"
 	"github.com/sirupsen/logrus"
+	"github.com/sirupsen/logrus/hooks/syslog"
 )
 
 const (
@@ -69,6 +70,15 @@ func main() {
 		logrus.Fatal("CACHE_DIRECTORY is not set. Is the service file missing CacheDirectory=?")
 	}
 
+	if len(config.SyslogServer) > 0 {
+		hook, err := syslog.NewSyslogHook("tcp", config.SyslogServer, 0, "osbuild-composer")
+		if err != nil {
+			logrus.Fatal("Error connecting to syslog: " + err.Error())
+		}
+
+		logrus.AddHook(hook)
+	}
+
 	composer, err := NewComposer(config, stateDir, cacheDir)
 	if err != nil {
 		logrus.Fatalf("%v", err)