simplify logging

pkg/app/app.go

@@ -3,11 +3,12 @@ package app
 import (
 	"context"
 	"errors"
+	"io"
+	"log"
 	"os"
 
 	"github.com/peterbourgon/ff/v4"
 	"github.com/peterbourgon/ff/v4/ffhelp"
-	"go.uber.org/zap"
 )
 
 const (
@@ -16,21 +17,24 @@ const (
 
 // struct for receivers to use common app pieces
 type app struct {
-	logger *zap.SugaredLogger
-	cmd    *ff.Command
-	config *config
+	stdLogger   *log.Logger
+	debugLogger *log.Logger
+	errLogger   *log.Logger
+	cmd         *ff.Command
+	config      *config
 }
 
 // actual application start
 func Start(args []string) {
-	// make app w/ initial logger pre-config
-	initLogLevel := "debug"
+	// make app w/ logger
 	app := &app{
-		logger: makeZapLogger(&initLogLevel),
+		stdLogger:   log.New(os.Stdout, "", 0),
+		debugLogger: log.New(io.Discard, "", 0), // discard debug logging by default
+		errLogger:   log.New(os.Stderr, "", 0),
 	}
 
 	// log start
-	app.logger.Infof("apc-p15-tool v%s", appVersion)
+	app.stdLogger.Printf("apc-p15-tool v%s", appVersion)
 
 	// get os.Args if args unspecified in func
 	if args == nil {
@@ -40,8 +44,8 @@ func Start(args []string) {
 	// get & parse config
 	err := app.getConfig(args)
 
-	// re-init logger with configured log level
-	app.logger = makeZapLogger(app.config.logLevel)
+	// if debug logging, make real debug logger
+	app.debugLogger = log.New(os.Stdout, "debug: ", 0)
 
 	// deal with config err (after logger re-init)
 	if err != nil {
@@ -49,7 +53,7 @@ func Start(args []string) {
 
 		if errors.Is(err, ff.ErrHelp) {
 			// help explicitly requested
-			app.logger.Info("\n\n", ffhelp.Command(app.cmd))
+			app.stdLogger.Printf("\n%s\n", ffhelp.Command(app.cmd))
 
 		} else if errors.Is(err, ff.ErrDuplicateFlag) ||
 			errors.Is(err, ff.ErrUnknownFlag) ||
@@ -57,13 +61,13 @@ func Start(args []string) {
 			errors.Is(err, ErrExtraArgs) {
 			// other error that suggests user needs to see help
 			exitCode = 1
-			app.logger.Error(err)
-			app.logger.Info("\n\n", ffhelp.Command(app.cmd))
+			app.errLogger.Print(err)
+			app.stdLogger.Printf("\n%s\n", ffhelp.Command(app.cmd))
 
 		} else {
 			// any other error
 			exitCode = 1
-			app.logger.Error(err)
+			app.errLogger.Print(err)
 		}
 
 		os.Exit(exitCode)
@@ -74,9 +78,14 @@ func Start(args []string) {
 	err = app.cmd.Run(context.Background())
 	if err != nil {
 		exitCode = 1
-		app.logger.Error(err)
+		app.errLogger.Print(err)
+
+		// if extra args, show help
+		if errors.Is(err, ErrExtraArgs) {
+			app.stdLogger.Printf("\n%s\n", ffhelp.Command(app.cmd))
+		}
 	}
 
-	app.logger.Info("apc-p15-tool done")
+	app.stdLogger.Print("apc-p15-tool done")
 	os.Exit(exitCode)
 }