Add optional syslog logrus hook (#343)

* add optional syslog logrus hook

* document syslog

internal/log/syslog_test.go

@@ -0,0 +1,70 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package log_test
+
+import (
+	"testing"
+
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/testrig"
+	"gopkg.in/mcuadros/go-syslog.v2"
+	"gopkg.in/mcuadros/go-syslog.v2/format"
+)
+
+type SyslogTestSuite struct {
+	suite.Suite
+	syslogServer  *syslog.Server
+	syslogChannel chan format.LogParts
+}
+
+func (suite *SyslogTestSuite) SetupTest() {
+	testrig.InitTestConfig()
+
+	viper.Set(config.Keys.SyslogEnabled, true)
+	viper.Set(config.Keys.SyslogProtocol, "udp")
+	viper.Set(config.Keys.SyslogAddress, "localhost:42069")
+	server, channel, err := testrig.InitTestSyslog()
+	if err != nil {
+		panic(err)
+	}
+	suite.syslogServer = server
+	suite.syslogChannel = channel
+
+	testrig.InitTestLog()
+}
+
+func (suite *SyslogTestSuite) TearDownTest() {
+	if err := suite.syslogServer.Kill(); err != nil {
+		panic(err)
+	}
+}
+
+func (suite *SyslogTestSuite) TestSyslog() {
+	logrus.Warn("this is a test of the emergency broadcast system!")
+
+	message := <-suite.syslogChannel
+	suite.Contains(message["content"], "this is a test of the emergency broadcast system!")
+}
+
+func TestSyslogTestSuite(t *testing.T) {
+	suite.Run(t, &SyslogTestSuite{})
+}