colorized stdout logger if stdout is tty

Gopkg.lock

@@ -17,6 +17,14 @@
   revision = "346938d642f2ec3594ed81d874461961cd0faa76"
   version = "v1.1.0"
 
+[[projects]]
+  digest = "1:e988ed0ca0d81f4d28772760c02ee95084961311291bdfefc1b04617c178b722"
+  name = "github.com/fatih/color"
+  packages = ["."]
+  pruneopts = ""
+  revision = "5b77d2a35fb0ede96d138fc9a99f5c9b6aef11b4"
+  version = "v1.7.0"
+
 [[projects]]
   branch = "master"
   digest = "1:5d0a2385edf4ba44f3b7b76bc0436ceb8f62bf55aa5d540a9eb9ec6c58d86809"
@@ -81,6 +89,14 @@
   pruneopts = ""
   revision = "7cafcd837844e784b526369c9bce262804aebc60"
 
+[[projects]]
+  digest = "1:9ea83adf8e96d6304f394d40436f2eb44c1dc3250d223b74088cc253a6cd0a1c"
+  name = "github.com/mattn/go-colorable"
+  packages = ["."]
+  pruneopts = ""
+  revision = "167de6bfdfba052fa6b2d3664c8f5272e23c9072"
+  version = "v0.0.9"
+
 [[projects]]
   digest = "1:78229b46ddb7434f881390029bd1af7661294af31f6802e0e1bedaad4ab0af3c"
   name = "github.com/mattn/go-isatty"
@@ -255,6 +271,7 @@
   analyzer-name = "dep"
   analyzer-version = 1
   input-imports = [
+    "github.com/fatih/color",
     "github.com/go-logfmt/logfmt",
     "github.com/go-yaml/yaml",
     "github.com/golang/protobuf/proto",

Gopkg.toml

@@ -67,3 +67,6 @@ ignored = [ "github.com/inconshreveable/mousetrap" ]
 [[constraint]]
   name = "github.com/nsf/termbox-go"
   branch = "master"
+[[constraint]]
+  name = "github.com/fatih/color"
+  version = "1.7.0"

config/config.go

@@ -197,6 +197,7 @@ type LoggingOutletCommon struct {
 type StdoutLoggingOutlet struct {
 	LoggingOutletCommon `yaml:",inline"`
 	Time                bool `yaml:"time,default=true"`
+	Color               bool `yaml:"color,default=true""`
 }
 
 type SyslogLoggingOutlet struct {

daemon/logging/build_logging.go

@@ -8,12 +8,12 @@ import (
 	"github.com/pkg/errors"
 	"github.com/problame/go-streamrpc"
 	"github.com/zrepl/zrepl/config"
+	"github.com/zrepl/zrepl/daemon/pruner"
 	"github.com/zrepl/zrepl/endpoint"
 	"github.com/zrepl/zrepl/logger"
 	"github.com/zrepl/zrepl/replication"
 	"github.com/zrepl/zrepl/tlsconf"
 	"os"
-	"github.com/zrepl/zrepl/daemon/pruner"
 )
 
 func OutletsFromConfig(in []config.LoggingOutletEnum) (*logger.Outlets, error) {
@@ -145,6 +145,9 @@ func parseStdoutOutlet(in *config.StdoutLoggingOutlet, formatter EntryFormatter)
 	if !isatty.IsTerminal(writer.Fd()) && !in.Time {
 		flags &= ^MetadataTime
 	}
+	if isatty.IsTerminal(writer.Fd()) && !in.Color {
+		flags &= ^MetadataColor
+	}
 
 	formatter.SetMetadataFlags(flags)
 	return WriterOutlet{

daemon/logging/logging_formatters.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
+	"github.com/fatih/color"
 	"github.com/go-logfmt/logfmt"
 	"github.com/pkg/errors"
 	"github.com/zrepl/zrepl/logger"
@@ -26,6 +27,7 @@ type MetadataFlags int64
 const (
 	MetadataTime MetadataFlags = 1 << iota
 	MetadataLevel
+	MetadataColor
 
 	MetadataNone MetadataFlags = 0
 	MetadataAll  MetadataFlags = ^0
@@ -69,12 +71,16 @@ func (f *HumanFormatter) ignored(field string) bool {
 func (f *HumanFormatter) Format(e *logger.Entry) (out []byte, err error) {
 
 	var line bytes.Buffer
+	col := color.New()
+	if f.metadataFlags&MetadataColor != 0 {
+		col = e.Color()
+	}
 
 	if f.metadataFlags&MetadataTime != 0 {
 		fmt.Fprintf(&line, "%s ", e.Time.Format(HumanFormatterDateFormat))
 	}
 	if f.metadataFlags&MetadataLevel != 0 {
-		fmt.Fprintf(&line, "[%s]", e.Level.Short())
+		fmt.Fprintf(&line, "[%s]", col.Sprint(e.Level.Short()))
 	}
 
 	prefixFields := []string{JobField, SubsysField}
@@ -85,7 +91,7 @@ func (f *HumanFormatter) Format(e *logger.Entry) (out []byte, err error) {
 			continue
 		}
 		if !f.ignored(field) {
-			fmt.Fprintf(&line, "[%s]", val)
+			fmt.Fprintf(&line, "[%s]", col.Sprint(val))
 			prefixed[field] = true
 		}
 	}
@@ -96,15 +102,11 @@ func (f *HumanFormatter) Format(e *logger.Entry) (out []byte, err error) {
 	fmt.Fprint(&line, e.Message)
 
 	if len(e.Fields)-len(prefixed) > 0 {
-		fmt.Fprint(&line, " ")
-		enc := logfmt.NewEncoder(&line)
 		for field, value := range e.Fields {
 			if prefixed[field] || f.ignored(field) {
 				continue
 			}
-			if err := logfmtTryEncodeKeyval(enc, field, value); err != nil {
+			fmt.Fprintf(&line, " %s=%q", col.Sprint(field), fmt.Sprint(value))
-				return nil, err
-			}
 		}
 	}
 

logger/datastructures.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
+	"github.com/fatih/color"
 	"github.com/pkg/errors"
 	"sync"
 	"time"
@@ -105,6 +106,21 @@ type Entry struct {
 	Fields  Fields
 }
 
+func (e Entry) Color() *color.Color {
+	c := color.New()
+	switch e.Level {
+	case Debug:
+		c.Add(color.FgHiBlue)
+	case Info:
+		c.Add(color.FgHiGreen)
+	case Warn:
+		c.Add(color.FgHiYellow)
+	case Error:
+		c.Add(color.FgHiRed)
+	}
+	return c
+}
+
 // An outlet receives log entries produced by the Logger and writes them to some destination.
 type Outlet interface {
 	// Write the entry to the destination.