Optional command line flag to disable zerolog journald logger (#15)

Author: SR-G

.gitignore

@@ -1 +1,2 @@
 .idea/
+netbootd

README.md

@@ -214,12 +214,19 @@ Usage:
   netbootd server [flags]
 
 Flags:
-  -a, --address string     IP address to listen on (DHCP, TFTP, HTTP)
-  -r, --api-port int       HTTP API port to listen on (default 8081)
-  -h, --help               help for server
-  -p, --http-port int      HTTP port to listen on (default 8080)
-  -i, --interface string   interface to listen on, e.g. eth0 (DHCP)
-  -m, --manifests string   load manifests from directory
+  -a, --address string        IP address to listen on (DHCP, TFTP, HTTP)
+  -r, --api-port int          HTTP API port to listen on (default 8081)
+      --api-tls-cert string   Path to TLS certificate API
+      --api-tls-key string    Path to TLS certificate for API
+  -h, --help                  help for server
+  -p, --http-port int         HTTP port to listen on (default 8080)
+  -i, --interface string      interface to listen on, e.g. eth0 (DHCP)
+  -m, --manifests string      load manifests from directory
+
+Global Flags:
+  -d, --debug                    enable debug logging
+      --disable-journal-logger   disable zerolog journald logger
+      --trace                    enable trace logging
 ```
 
 Run e.g. `./netbootd --trace server -m ./examples/`

cmd/arpinject.go

@@ -1,10 +1,12 @@
 package cmd
 
 import (
+	"net"
+
+	"github.com/DSpeichert/netbootd/config"
 	"github.com/DSpeichert/netbootd/dhcpd/arp"
 	"github.com/rs/zerolog/log"
 	"github.com/spf13/cobra"
-	"net"
 )
 
 var (
@@ -24,6 +26,7 @@ func init() {
 var arpInjectCmd = &cobra.Command{
 	Use: "arpinject",
 	Run: func(cmd *cobra.Command, args []string) {
+		config.InitZeroLog()
 		parsedIp := net.ParseIP(ip)
 		parsedMac, err := net.ParseMAC(mac)
 		if err != nil {

cmd/root.go

@@ -2,10 +2,11 @@ package cmd
 
 import (
 	"fmt"
+	"os"
+
 	"github.com/DSpeichert/netbootd/config"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
-	"os"
 )
 
 var (
@@ -23,6 +24,9 @@ func init() {
 
 	rootCmd.PersistentFlags().BoolVar(&trace, "trace", false, "enable trace logging")
 	viper.BindPFlag("trace", rootCmd.Flags().Lookup("trace"))
+
+	rootCmd.PersistentFlags().BoolVar(&config.ZeroLogJournalDEnabled, "disable-journal-logger", false, "disable zerolog journald logger")
+	viper.BindPFlag("disable-journal-logger", rootCmd.Flags().Lookup("disable-journal-logger"))
 }
 
 var rootCmd = &cobra.Command{
@@ -36,6 +40,7 @@ allows for complete flexibility in provisioning machines.`,
 
 func Execute() {
 	if err := rootCmd.Execute(); err != nil {
+		config.InitZeroLog()
 		fmt.Println(err)
 		os.Exit(1)
 	}

cmd/server.go

@@ -1,7 +1,12 @@
 package cmd
 
 import (
+	"net"
+	"os"
+	"os/signal"
+
 	"github.com/DSpeichert/netbootd/api"
+	"github.com/DSpeichert/netbootd/config"
 	"github.com/DSpeichert/netbootd/dhcpd"
 	"github.com/DSpeichert/netbootd/httpd"
 	"github.com/DSpeichert/netbootd/store"
@@ -11,9 +16,6 @@ import (
 	"github.com/rs/zerolog/log"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
-	"net"
-	"os"
-	"os/signal"
 )
 
 var (
@@ -55,6 +57,7 @@ var serverCmd = &cobra.Command{
 	Use: "server",
 	Run: func(cmd *cobra.Command, args []string) {
 		// configure logging
+		config.InitZeroLog()
 		if viper.GetBool("trace") {
 			zerolog.SetGlobalLevel(zerolog.TraceLevel)
 		} else if viper.GetBool("debug") {

config/viper.go

@@ -23,6 +23,7 @@ func InitConfig() {
 
 	err := viper.ReadInConfig()
 	if err != nil {
+		InitZeroLog()
 		log.Debug().
 			Err(err).
 			Msg("error reading config file")

config/zerolog.go

@@ -0,0 +1,37 @@
+package config
+
+import (
+	"io"
+	"os"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/journald"
+	"github.com/rs/zerolog/log"
+)
+
+var (
+	zerologInitDone        bool // to prevent zerolog to be initialized twice in specific situations (like parsing error of viper configuration file)
+	ZeroLogJournalDEnabled bool // used by viper to store the status of the --disable-journal-logger flag
+)
+
+func init() {
+	// UNIX Time is faster and smaller than most timestamps
+	// If you set zerolog.TimeFieldFormat to an empty string,
+	// logs will write with UNIX time
+	zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+}
+
+func InitZeroLog() {
+	if !zerologInitDone {
+		if ZeroLogJournalDEnabled {
+			log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})
+			log.Debug().Msg("Enabled console writer")
+		} else {
+			journalWriter := journald.NewJournalDWriter()
+			multi := io.MultiWriter(zerolog.ConsoleWriter{Out: os.Stderr}, journalWriter)
+			log.Logger = log.Output(multi)
+			log.Debug().Msg("Enabled journald writer")
+		}
+		zerologInitDone = true
+	}
+}

journald_logger.go

@@ -2,27 +2,10 @@ package main
 
 import (
 	"github.com/DSpeichert/netbootd/cmd"
-	"github.com/rs/zerolog"
-	"github.com/rs/zerolog/log"
-	"os"
 )
 
 //go:generate protoc proto/*.proto --go_out=. --go_opt=paths=source_relative --go-grpc_out=. --go-grpc_opt=paths=source_relative
 
-var (
-	journalLoggerEnabled bool
-)
-
-func init() {
-	// UNIX Time is faster and smaller than most timestamps
-	// If you set zerolog.TimeFieldFormat to an empty string,
-	// logs will write with UNIX time
-	zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
-	if !journalLoggerEnabled {
-		log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})
-	}
-}
-
 func main() {
 	cmd.Execute()
 }