Add log formatting settings (#1926)

Adds a log format setting as ATHENS_LOG_FORMAT that can be either plain or JSON when CloudRuntime is none (the default). Does not break or change any existing behavior.

pkg/config/config.go

@@ -10,10 +10,10 @@ import (
 	"strings"
 
 	"github.com/BurntSushi/toml"
+	"github.com/go-playground/validator/v10"
 	"github.com/gomods/athens/pkg/download/mode"
 	"github.com/gomods/athens/pkg/errors"
 	"github.com/kelseyhightower/envconfig"
-	"gopkg.in/go-playground/validator.v9"
 )
 
 const defaultConfigFile = "athens.toml"
@@ -28,7 +28,8 @@ type Config struct {
 	GoGetDir         string    `envconfig:"ATHENS_GOGET_DIR"`
 	ProtocolWorkers  int       `validate:"required" envconfig:"ATHENS_PROTOCOL_WORKERS"`
 	LogLevel         string    `validate:"required" envconfig:"ATHENS_LOG_LEVEL"`
-	CloudRuntime     string    `validate:"required" envconfig:"ATHENS_CLOUD_RUNTIME"`
+	LogFormat        string    `validate:"oneof='' 'json' 'plain'" envconfig:"ATHENS_LOG_FORMAT"`
+	CloudRuntime     string    `validate:"required_without=LogFormat" envconfig:"ATHENS_CLOUD_RUNTIME"`
 	EnablePprof      bool      `envconfig:"ATHENS_ENABLE_PPROF"`
 	PprofPort        string    `envconfig:"ATHENS_PPROF_PORT"`
 	FilterFile       string    `envconfig:"ATHENS_FILTER_FILE"`
@@ -150,6 +151,7 @@ func defaultConfig() *Config {
 		GoGetWorkers:     10,
 		ProtocolWorkers:  30,
 		LogLevel:         "debug",
+		LogFormat:        "json",
 		CloudRuntime:     "none",
 		EnablePprof:      false,
 		PprofPort:        ":3001",

pkg/config/config_test.go

@@ -258,6 +258,7 @@ func TestParseExampleConfig(t *testing.T) {
 	expConf := &Config{
 		GoEnv:           "development",
 		LogLevel:        "debug",
+		LogFormat:       "json",
 		GoBinary:        "go",
 		GoGetWorkers:    10,
 		ProtocolWorkers: 30,

pkg/log/format.go

@@ -64,6 +64,10 @@ func sortFields(data logrus.Fields) []string {
 	return keys
 }
 
-func getDefaultFormatter() logrus.Formatter {
+func parseFormat(format string) logrus.Formatter {
+	if format == "plain" {
+		return &logrus.TextFormatter{}
+	}
+
 	return &logrus.JSONFormatter{}
 }

pkg/log/log.go

@@ -14,7 +14,7 @@ type Logger struct {
 // environment and the cloud platform it is
 // running on. TODO: take cloud arg and env
 // to construct the correct JSON formatter.
-func New(cloudProvider string, level logrus.Level) *Logger {
+func New(cloudProvider string, level logrus.Level, format string) *Logger {
 	l := logrus.New()
 	switch cloudProvider {
 	case "GCP":
@@ -22,7 +22,7 @@ func New(cloudProvider string, level logrus.Level) *Logger {
 	case "none":
 		l.Formatter = getDevFormatter()
 	default:
-		l.Formatter = getDefaultFormatter()
+		l.Formatter = parseFormat(format)
 	}
 	l.Level = level
 	return &Logger{Logger: l}

pkg/log/log_test.go

@@ -14,6 +14,7 @@ import (
 type input struct {
 	name          string
 	cloudProvider string
+	format        string
 	level         logrus.Level
 	fields        logrus.Fields
 	logFunc       func(e Entry) time.Time
@@ -82,10 +83,10 @@ var testCases = []input{
 		output: `{"message":"warn message","severity":"warning","timestamp":"%v"}` + "\n",
 	},
 	{
-		name:          "default",
-		cloudProvider: "default",
-		level:         logrus.DebugLevel,
-		fields:        logrus.Fields{"xyz": "abc", "abc": "xyz"},
+		name:   "default json",
+		format: "json",
+		level:  logrus.DebugLevel,
+		fields: logrus.Fields{"xyz": "abc", "abc": "xyz"},
 		logFunc: func(e Entry) time.Time {
 			t := time.Now()
 			e.Warnf("warn message")
@@ -98,7 +99,7 @@ var testCases = []input{
 func TestCloudLogger(t *testing.T) {
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			lggr := New(tc.cloudProvider, tc.level)
+			lggr := New(tc.cloudProvider, tc.level, "")
 			var buf bytes.Buffer
 			lggr.Out = &buf
 			e := lggr.WithFields(tc.fields)

pkg/middleware/log_entry_test.go

@@ -24,7 +24,7 @@ func TestLogContext(t *testing.T) {
 	r.HandleFunc("/test", h)
 
 	var buf bytes.Buffer
-	lggr := log.New("", logrus.DebugLevel)
+	lggr := log.New("", logrus.DebugLevel, "")
 	lggr.Formatter = &logrus.JSONFormatter{DisableTimestamp: true}
 	lggr.Out = &buf