Add logger

pkg/log/log.go

@@ -0,0 +1,87 @@
+package log
+
+import (
+	"fmt"
+	"time"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+type Logger interface {
+	Debugw(msg string, v ...interface{})
+	Infow(msg string, v ...interface{})
+	Errorw(msg string, v ...interface{})
+}
+
+func NewZapLogger(debug, pretty bool) (*zap.Logger, error) {
+	var config zap.Config
+
+	if debug {
+		config = zap.Config{
+			Level:       zap.NewAtomicLevelAt(zap.DebugLevel),
+			Development: debug,
+			Encoding:    "json",
+			EncoderConfig: zapcore.EncoderConfig{
+				TimeKey:        "ts",
+				LevelKey:       "level",
+				NameKey:        "logger",
+				CallerKey:      "caller",
+				FunctionKey:    zapcore.OmitKey,
+				MessageKey:     "message",
+				StacktraceKey:  "stacktrace",
+				LineEnding:     zapcore.DefaultLineEnding,
+				EncodeLevel:    zapcore.LowercaseLevelEncoder,
+				EncodeTime:     zapcore.RFC3339TimeEncoder,
+				EncodeDuration: zapcore.SecondsDurationEncoder,
+				EncodeCaller:   zapcore.ShortCallerEncoder,
+			},
+			OutputPaths:      []string{"stderr"},
+			ErrorOutputPaths: []string{"stderr"},
+		}
+	} else {
+		config = zap.NewProductionConfig()
+	}
+
+	if pretty {
+		config.Encoding = "console"
+		config.EncoderConfig = zapcore.EncoderConfig{
+			TimeKey:          "T",
+			LevelKey:         "L",
+			NameKey:          "N",
+			CallerKey:        zapcore.OmitKey,
+			FunctionKey:      zapcore.OmitKey,
+			MessageKey:       "M",
+			StacktraceKey:    zapcore.OmitKey,
+			ConsoleSeparator: " ",
+			LineEnding:       zapcore.DefaultLineEnding,
+			EncodeLevel:      zapcore.CapitalColorLevelEncoder,
+			EncodeTime: func(t time.Time, enc zapcore.PrimitiveArrayEncoder) {
+				enc.AppendString(t.Format("2006/01/02 15:04:05"))
+			},
+			EncodeName: func(loggerName string, enc zapcore.PrimitiveArrayEncoder) {
+				// Print logger name in cyan (ANSI code 36).
+				enc.AppendString(fmt.Sprintf("\x1b[%dm%s\x1b[0m", uint8(36), "["+loggerName+"]"))
+			},
+			EncodeDuration: zapcore.StringDurationEncoder,
+			EncodeCaller:   zapcore.ShortCallerEncoder,
+		}
+
+		if debug {
+			config.EncoderConfig.CallerKey = "C"
+			config.EncoderConfig.StacktraceKey = "S"
+		}
+	}
+
+	return config.Build()
+}
+
+type NopLogger struct{}
+
+func (nop NopLogger) Debugw(_ string, _ ...interface{}) {}
+func (nop NopLogger) Infow(_ string, _ ...interface{})  {}
+func (nop NopLogger) Errorw(_ string, _ ...interface{}) {}
+
+func NewNopLogger() NopLogger {
+	return NopLogger{}
+}