main.go

package main

import (
	"encoding/json"
	"fmt"
	"time"

	"go.uber.org/zap"
)

func main() {
	fmt.Printf("\n*** Using the Example logger\n\n")

	logger := zap.NewExample()
	logger.Debug("This is a DEBUG message")
	logger.Info("This is an INFO message")
	logger.Info("This is an INFO message with fields", zap.String("region", "us-west"), zap.Int("id", 2))
	logger.Warn("This is a WARN message")
	logger.Error("This is an ERROR message")
	// logger.Fatal("This is a FATAL message")  // would exit if uncommented
	logger.DPanic("This is a DPANIC message")
	//logger.Panic("This is a PANIC message")   // would exit if uncommented

	fmt.Println()

	fmt.Printf("*** Using the Development logger\n\n")

	logger, _ = zap.NewDevelopment()
	logger.Debug("This is a DEBUG message")
	logger.Info("This is an INFO message")
	logger.Info("This is an INFO message with fields", zap.String("region", "us-west"), zap.Int("id", 2))
	logger.Warn("This is a WARN message")
	logger.Error("This is an ERROR message")
	// logger.Fatal("This is a FATAL message")   // would exit if uncommented
	// logger.DPanic("This is a DPANIC message") // would exit if uncommented
	//logger.Panic("This is a PANIC message")    // would exit if uncommented

	fmt.Println()

	fmt.Printf("*** Using the Production logger\n\n")

	logger, _ = zap.NewProduction()
	logger.Debug("This is a DEBUG message")
	logger.Info("This is an INFO message")
	logger.Info("This is an INFO message with fields", zap.String("region", "us-west"), zap.Int("id", 2))
	logger.Warn("This is a WARN message")
	logger.Error("This is an ERROR message")
	// logger.Fatal("This is a FATAL message")   // would exit if uncommented
	logger.DPanic("This is a DPANIC message")
	// logger.Panic("This is a PANIC message")   // would exit if uncommented

	fmt.Println()

	fmt.Printf("*** Using the Sugar logger\n\n")

	logger, _ = zap.NewDevelopment()
	slogger := logger.Sugar()
	slogger.Info("Info() uses sprint")
	slogger.Infof("Infof() uses %s", "sprintf")
	slogger.Infow("Infow() allows tags", "name", "Legolas", "type", 1)

	fmt.Println("*** Build a logger from a json ****")

	rawJSONConfig := []byte(`{
      "level": "info",
      "encoding": "console",
      "outputPaths": ["stdout", "/tmp/logs"],
      "errorOutputPaths": ["/tmp/errorlogs"],
      "initialFields": {"initFieldKey": "fieldValue"},
      "encoderConfig": {
        "messageKey": "message",
        "levelKey": "level",
        "nameKey": "logger",
        "timeKey": "time",
        "callerKey": "logger",
        "stacktraceKey": "stacktrace",
        "callstackKey": "callstack",
        "errorKey": "error",
        "timeEncoder": "iso8601",
        "fileKey": "file",
        "levelEncoder": "capitalColor",
        "durationEncoder": "second",
        "callerEncoder": "full",
        "nameEncoder": "full",
        "sampling": {
            "initial": "3",
            "thereafter": "10"
        }
      }
    }`)

	config := zap.Config{}
	if err := json.Unmarshal(rawJSONConfig, &config); err != nil {
		panic(err)
	}
	logger, err := config.Build()
	if err != nil {
		panic(err)
	}

	logger.Debug("This is a DEBUG message")
	logger.Info("This should have an ISO8601 based time stamp")
	logger.Warn("This is a WARN message")
	logger.Error("This is an ERROR message")
	//logger.Fatal("This is a FATAL message")   // would exit if uncommented
	//logger.DPanic("This is a DPANIC message") // would exit if uncommented

	const url = "http://example.com"
	logger.Info("Failed to fetch URL.",
		// Structured context as strongly typed fields.
		zap.String("url", url),
		zap.Int("attempt", 3),
		zap.Duration("backoff", time.Second))
	// {"level":"info","msg":"Failed to fetch URL.","url":"http://example.com","attempt":3,"backoff":"1"}

}