Logrus hooks for terminal vs log-file output (#16102)

## Review after #16059 

**What type of PR is this?**
Feature

**What does this PR do?**
This PR introduces logrus writer hooks into the logging of prysm.
when log-format is text:
- set the default logrus output to be `io.Discard`
- create a writer hook for terminal, with formatting and coloring
enabled.
- create a separate writer hook for log-file (if enabled), without
coloring.

This immediately allows for having formatted/colored terminal logs,
while keeping the log-file clean.

changelog/bastin_logrus-hooks-add.md

@@ -0,0 +1,4 @@
+### Added
+
+- Added separate logrus hooks for handling the formatting and output of terminal logs vs log-file logs, instead of the
+  default logrus output.

cmd/beacon-chain/main.go

@@ -4,6 +4,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	runtimeDebug "runtime/debug"
@@ -172,14 +173,20 @@ func before(ctx *cli.Context) error {
 
 	switch format {
 	case "text":
+		// disabling logrus default output so we can control it via different hooks
+		logrus.SetOutput(io.Discard)
+
+		// create a custom formatter and hook for terminal output
 		formatter := new(prefixed.TextFormatter)
 		formatter.TimestampFormat = "2006-01-02 15:04:05.00"
 		formatter.FullTimestamp = true
+		formatter.ForceFormatting = true
+		formatter.ForceColors = true
 
-		// If persistent log files are written - we disable the log messages coloring because
+		logrus.AddHook(&logs.WriterHook{
-		// the colors are ANSI codes and seen as gibberish in the log files.
+			Formatter: formatter,
-		formatter.DisableColors = ctx.String(cmd.LogFileName.Name) != ""
+			Writer:    os.Stderr,
-		logrus.SetFormatter(formatter)
+		})
 	case "fluentd":
 		f := joonix.NewFormatter()
 
@@ -202,7 +209,7 @@ func before(ctx *cli.Context) error {
 
 	logFileName := ctx.String(cmd.LogFileName.Name)
 	if logFileName != "" {
-		if err := logs.ConfigurePersistentLogging(logFileName); err != nil {
+		if err := logs.ConfigurePersistentLogging(logFileName, format); err != nil {
 			log.WithError(err).Error("Failed to configuring logging to disk.")
 		}
 	}

cmd/client-stats/main.go

@@ -86,7 +86,7 @@ func main() {
 
 		logFileName := ctx.String(cmd.LogFileName.Name)
 		if logFileName != "" {
-			if err := logs.ConfigurePersistentLogging(logFileName); err != nil {
+			if err := logs.ConfigurePersistentLogging(logFileName, format); err != nil {
 				log.WithError(err).Error("Failed to configuring logging to disk.")
 			}
 		}

cmd/validator/main.go

@@ -5,6 +5,7 @@ package main
 
 import (
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	runtimeDebug "runtime/debug"
@@ -151,13 +152,20 @@ func main() {
 			format := ctx.String(cmd.LogFormat.Name)
 			switch format {
 			case "text":
+				// disabling logrus default output so we can control it via different hooks
+				logrus.SetOutput(io.Discard)
+
+				// create a custom formatter and hook for terminal output
 				formatter := new(prefixed.TextFormatter)
 				formatter.TimestampFormat = "2006-01-02 15:04:05.00"
 				formatter.FullTimestamp = true
-				// If persistent log files are written - we disable the log messages coloring because
+				formatter.ForceFormatting = true
-				// the colors are ANSI codes and seen as gibberish in the log files.
+				formatter.ForceColors = true
-				formatter.DisableColors = logFileName != ""
+
-				logrus.SetFormatter(formatter)
+				logrus.AddHook(&logs.WriterHook{
+					Formatter: formatter,
+					Writer:    os.Stderr,
+				})
 			case "fluentd":
 				f := joonix.NewFormatter()
 				if err := joonix.DisableTimestampFormat(f); err != nil {
@@ -177,7 +185,7 @@ func main() {
 			}
 
 			if logFileName != "" {
-				if err := logs.ConfigurePersistentLogging(logFileName); err != nil {
+				if err := logs.ConfigurePersistentLogging(logFileName, format); err != nil {
 					log.WithError(err).Error("Failed to configuring logging to disk.")
 				}
 			}

io/logs/BUILD.bazel

@@ -3,6 +3,7 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
     name = "go_default_library",
     srcs = [
+        "hook.go",
         "logutil.go",
         "stream.go",
     ],
@@ -14,6 +15,7 @@ go_library(
         "//config/params:go_default_library",
         "//crypto/rand:go_default_library",
         "//io/file:go_default_library",
+        "//runtime/logging/logrus-prefixed-formatter:go_default_library",
         "@com_github_hashicorp_golang_lru//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
     ],

io/logs/hook.go

@@ -0,0 +1,29 @@
+package logs
+
+import (
+	"io"
+
+	"github.com/sirupsen/logrus"
+)
+
+type WriterHook struct {
+	AllowedLevels []logrus.Level
+	Writer        io.Writer
+	Formatter     logrus.Formatter
+}
+
+func (hook *WriterHook) Levels() []logrus.Level {
+	if hook.AllowedLevels == nil || len(hook.AllowedLevels) == 0 {
+		return logrus.AllLevels
+	}
+	return hook.AllowedLevels
+}
+
+func (hook *WriterHook) Fire(entry *logrus.Entry) error {
+	line, err := hook.Formatter.Format(entry)
+	if err != nil {
+		return err
+	}
+	_, err = hook.Writer.Write(line)
+	return err
+}

io/logs/logutil.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/OffchainLabs/prysm/v7/config/params"
 	"github.com/OffchainLabs/prysm/v7/io/file"
+	prefixed "github.com/OffchainLabs/prysm/v7/runtime/logging/logrus-prefixed-formatter"
 	"github.com/sirupsen/logrus"
 )
 
@@ -20,7 +21,7 @@ func addLogWriter(w io.Writer) {
 }
 
 // ConfigurePersistentLogging adds a log-to-file writer. File content is identical to stdout.
-func ConfigurePersistentLogging(logFileName string) error {
+func ConfigurePersistentLogging(logFileName string, format string) error {
 	logrus.WithField("logFileName", logFileName).Info("Logs will be made persistent")
 	if err := file.MkdirAll(filepath.Dir(logFileName)); err != nil {
 		return err
@@ -30,7 +31,25 @@ func ConfigurePersistentLogging(logFileName string) error {
 		return err
 	}
 
-	addLogWriter(f)
+	if format != "text" {
+		addLogWriter(f)
+
+		logrus.Info("File logging initialized")
+		return nil
+	}
+
+	// Create formatter and writer hook
+	formatter := new(prefixed.TextFormatter)
+	formatter.TimestampFormat = "2006-01-02 15:04:05.00"
+	formatter.FullTimestamp = true
+	// If persistent log files are written - we disable the log messages coloring because
+	// the colors are ANSI codes and seen as gibberish in the log files.
+	formatter.DisableColors = true
+
+	logrus.AddHook(&WriterHook{
+		Formatter: formatter,
+		Writer:    f,
+	})
 
 	logrus.Info("File logging initialized")
 	return nil

io/logs/logutil_test.go

@@ -34,13 +34,13 @@ func TestConfigurePersistantLogging(t *testing.T) {
 	logFileName := "test.log"
 	existingDirectory := "test-1-existing-testing-dir"
 
-	err := ConfigurePersistentLogging(fmt.Sprintf("%s/%s/%s", testParentDir, existingDirectory, logFileName))
+	err := ConfigurePersistentLogging(fmt.Sprintf("%s/%s/%s", testParentDir, existingDirectory, logFileName), "text")
 	require.NoError(t, err)
 
 	// 2. Test creation of file along with parent directory
 	nonExistingDirectory := "test-2-non-existing-testing-dir"
 
-	err = ConfigurePersistentLogging(fmt.Sprintf("%s/%s/%s", testParentDir, nonExistingDirectory, logFileName))
+	err = ConfigurePersistentLogging(fmt.Sprintf("%s/%s/%s", testParentDir, nonExistingDirectory, logFileName), "text")
 	require.NoError(t, err)
 
 	// 3. Test creation of file in an existing parent directory with a non-existing sub-directory
@@ -51,7 +51,7 @@ func TestConfigurePersistantLogging(t *testing.T) {
 		return
 	}
 
-	err = ConfigurePersistentLogging(fmt.Sprintf("%s/%s/%s/%s", testParentDir, existingDirectory, nonExistingSubDirectory, logFileName))
+	err = ConfigurePersistentLogging(fmt.Sprintf("%s/%s/%s/%s", testParentDir, existingDirectory, nonExistingSubDirectory, logFileName), "text")
 	require.NoError(t, err)
 
 	//4. Create log file in a directory without 700 permissions

tools/bootnode/bootnode.go

@@ -71,7 +71,7 @@ func main() {
 	flag.Parse()
 
 	if *logFileName != "" {
-		if err := logs.ConfigurePersistentLogging(*logFileName); err != nil {
+		if err := logs.ConfigurePersistentLogging(*logFileName, "text"); err != nil {
 			log.WithError(err).Error("Failed to configuring logging to disk.")
 		}
 	}