Logging to syslog instead of stderr

cmd/funnel/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"log/syslog"
 	"os"
 
 	"github.com/agnivade/funnel"
@@ -14,6 +15,11 @@ const (
 )
 
 func main() {
+	logger, err := syslog.New(syslog.LOG_ERR, AppName)
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
 	// Verifying whether the app has a piped stdin or not
 	fi, err := os.Stdin.Stat()
 	if err != nil {
@@ -33,7 +39,7 @@ func main() {
 	v.AddConfigPath(".")
 
 	// Read config
-	cfg, reloadChan, err := funnel.GetConfig(v)
+	cfg, reloadChan, err := funnel.GetConfig(v, logger)
 	if err != nil {
 		fmt.Println("Error in config file: ", err)
 		os.Exit(1)
@@ -47,6 +53,7 @@ func main() {
 		Config:        cfg,
 		LineProcessor: lp,
 		ReloadChan:    reloadChan,
+		Logger:        logger,
 	}
 	c.Start(os.Stdin)
 }

config.go

@@ -2,8 +2,7 @@ package funnel
 
 import (
 	"errors"
-	"fmt"
-	"os"
+	"log/syslog"
 	"strconv"
 	"strings"
 
@@ -67,7 +66,7 @@ func init() {
 
 // GetConfig returns the config struct which is then passed
 // to the consumer
-func GetConfig(v *viper.Viper) (*Config, chan *Config, error) {
+func GetConfig(v *viper.Viper, logger *syslog.Writer) (*Config, chan *Config, error) {
 	// Set default values. They are overridden by config file values, if provided
 	setDefaults(v)
 	// Create a chan to signal any config reload events
@@ -93,7 +92,7 @@ func GetConfig(v *viper.Viper) (*Config, chan *Config, error) {
 	v.OnConfigChange(func(e fsnotify.Event) {
 		if e.Op == fsnotify.Write {
 			if err := validateConfig(v); err != nil {
-				fmt.Fprintln(os.Stderr, err)
+				logger.Err(err.Error())
 				return
 			}
 			reloadChan <- getConfigStruct(v)

config_test.go

@@ -1,6 +1,7 @@
 package funnel
 
 import (
+	"log/syslog"
 	"os"
 	"reflect"
 	"testing"
@@ -13,8 +14,9 @@ func TestSanity(t *testing.T) {
 	v := viper.New()
 	v.SetConfigName("goodconfig")
 	v.AddConfigPath("./testdata/")
+	logger, _ := syslog.New(syslog.LOG_ERR, "test")
 
-	cfg, _, err := GetConfig(v)
+	cfg, _, err := GetConfig(v, logger)
 	if err != nil {
 		t.Fatal(err)
 		return
@@ -48,8 +50,9 @@ func TestBadFile(t *testing.T) {
 	v := viper.New()
 	v.SetConfigName("badsyntaxconfig")
 	v.AddConfigPath("./testdata/")
+	logger, _ := syslog.New(syslog.LOG_ERR, "test")
 
-	_, _, err := GetConfig(v)
+	_, _, err := GetConfig(v, logger)
 	if err == nil {
 		t.Error("Expected error in config file, got none")
 	}
@@ -59,8 +62,9 @@ func TestInvalidConfigValue(t *testing.T) {
 	v := viper.New()
 	v.SetConfigName("invalidvalueconfig")
 	v.AddConfigPath("./testdata/")
+	logger, _ := syslog.New(syslog.LOG_ERR, "test")
 
-	_, _, err := GetConfig(v)
+	_, _, err := GetConfig(v, logger)
 	if err == nil {
 		t.Error("Expected error in config file, got none")
 	}
@@ -75,12 +79,12 @@ func TestNoConfigFile(t *testing.T) {
 	v := viper.New()
 	v.SetConfigName("noconfig")
 	v.AddConfigPath("./testdata/")
+	logger, _ := syslog.New(syslog.LOG_ERR, "test")
 
-	_, _, err := GetConfig(v)
+	_, _, err := GetConfig(v, logger)
 	if err != nil {
 		t.Error("Did not expect an error for config file not being present. Got - ", err)
 	}
-
 }
 
 func TestEnvVars(t *testing.T) {
@@ -89,8 +93,9 @@ func TestEnvVars(t *testing.T) {
 	v.AddConfigPath("./testdata/")
 	envValue := "env_var_value"
 	os.Setenv("LOGGING_DIRECTORY", envValue)
+	logger, _ := syslog.New(syslog.LOG_ERR, "test")
 
-	cfg, _, err := GetConfig(v)
+	cfg, _, err := GetConfig(v, logger)
 	if err != nil {
 		t.Fatal(err)
 		return

consumer.go

@@ -2,8 +2,8 @@ package funnel
 
 import (
 	"bufio"
-	"fmt"
 	"io"
+	"log/syslog"
 	"os"
 	"os/signal"
 	"path"
@@ -17,6 +17,7 @@ import (
 type Consumer struct {
 	Config        *Config
 	LineProcessor LineProcessor
+	Logger        *syslog.Writer
 
 	// internal stuff
 	currFile *os.File
@@ -46,13 +47,13 @@ func (c *Consumer) Start(inputStream io.Reader) {
 
 	// Make the dir along with parents
 	if err := os.MkdirAll(c.Config.DirName, 0775); err != nil {
-		fmt.Fprintln(os.Stderr, err)
+		c.Logger.Err(err.Error())
 		return
 	}
 
 	// Create the file
 	if err := c.createNewFile(); err != nil {
-		fmt.Fprintln(os.Stderr, err)
+		c.Logger.Err(err.Error())
 		return
 	}
 
@@ -96,7 +97,7 @@ outer:
 			}
 		case err := <-c.errChan: // error channel to get any errors happening
 			// elsewhere. After printing to stderr, it breaks from the loop
-			fmt.Fprintln(os.Stderr, err)
+			c.Logger.Err(err.Error())
 			break outer
 		default:
 			// This will return a line until delimiter
@@ -120,7 +121,7 @@ outer:
 
 			if err != nil {
 				if err != io.EOF {
-					fmt.Fprintln(os.Stderr, err)
+					c.Logger.Err(err.Error())
 				}
 				break outer
 			}
@@ -138,24 +139,24 @@ func (c *Consumer) cleanUp() {
 	var err error
 	// Close file handle
 	if err = c.currFile.Sync(); err != nil {
-		fmt.Fprintln(os.Stderr, err)
+		c.Logger.Err(err.Error())
 		return
 	}
 
 	if err = c.currFile.Close(); err != nil {
-		fmt.Fprintln(os.Stderr, err)
+		c.Logger.Err(err.Error())
 		return
 	}
 
 	// Rename the currfile to a rolled up one
 	var fileName string
 	if fileName, err = c.rename(); err != nil {
-		fmt.Fprintln(os.Stderr, err)
+		c.Logger.Err(err.Error())
 		return
 	}
 
 	if err = c.compress(fileName); err != nil {
-		fmt.Fprintln(os.Stderr, err)
+		c.Logger.Err(err.Error())
 		return
 	}
 }
@@ -260,7 +261,7 @@ func (c *Consumer) startFeed() {
 		case <-c.done: // Done signal received, close shop
 			ticker.Stop()
 			if err := c.writer.Flush(); err != nil {
-				fmt.Fprintln(os.Stderr, err)
+				c.Logger.Err(err.Error())
 			}
 			c.cleanUp()
 			c.wg.Done()