setup slog inside cmd with debug and json flag

cmd/showbridge/main.go

@@ -25,6 +25,17 @@ func main() {
 			&cli.StringFlag{
 				Name:  "config",
 				Value: "./config.yaml",
+				Usage: "path to config file",
+			},
+			&cli.BoolFlag{
+				Name:  "debug",
+				Value: false,
+				Usage: "set log level to DEBUG",
+			},
+			&cli.BoolFlag{
+				Name:  "json",
+				Value: false,
+				Usage: "log using JSON",
 			},
 		},
 		Action: func(ctx context.Context, c *cli.Command) error {
@@ -37,13 +48,37 @@ func main() {
 			if err != nil {
 				return err
 			}
+
+			logLevel := slog.LevelInfo
+
+			if c.Bool("debug") {
+				logLevel = slog.LevelDebug
+			}
+
+			logHandlerOptions := &slog.HandlerOptions{
+				Level: logLevel,
+			}
+
+			logOutput := os.Stderr
+
+			var logHandler slog.Handler = slog.NewTextHandler(logOutput, logHandlerOptions)
+
+			if c.Bool("json") {
+				logHandler = slog.NewJSONHandler(logOutput, logHandlerOptions)
+			}
+
+			logger := slog.New(logHandler)
+
+			slog.SetDefault(logger)
+
 			router, moduleErrors, routeErrors := showbridge.NewRouter(ctx, config)
+
 			for _, moduleError := range moduleErrors {
-				slog.Error("problem initializing module", "index", moduleError.Index, "error", moduleError.Error)
+				logger.Error("problem initializing module", "index", moduleError.Index, "error", moduleError.Error)
 			}
 
 			for _, routeError := range routeErrors {
-				slog.Error("problem initializing route", "index", routeError.Index, "error", routeError.Error)
+				logger.Error("problem initializing route", "index", routeError.Index, "error", routeError.Error)
 			}
 			router.Run()
 			return nil

router.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"log/slog"
-	"os"
 	"sync"
 
 	"github.com/jwetzell/showbridge-go/internal/config"
@@ -18,16 +17,10 @@ type Router struct {
 	ModuleInstances []module.Module
 	RouteInstances  []route.Route
 	moduleWait      sync.WaitGroup
+	logger          *slog.Logger
 }
 
 func NewRouter(ctx context.Context, config config.Config) (*Router, []module.ModuleError, []route.RouteError) {
-	logger := slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{
-		Level: slog.LevelInfo,
-	}))
-
-	slog.SetDefault(logger)
-
-	slog.Debug("creating router")
 
 	routerContext, cancel := context.WithCancel(ctx)
 	router := Router{
@@ -35,8 +28,11 @@ func NewRouter(ctx context.Context, config config.Config) (*Router, []module.Mod
 		contextCancel:   cancel,
 		ModuleInstances: []module.Module{},
 		RouteInstances:  []route.Route{},
+		logger:          slog.Default().With("component", "router"),
 	}
 
+	router.logger.Debug("creating router")
+
 	var moduleErrors []module.ModuleError
 
 	for moduleIndex, moduleDecl := range config.Modules {
@@ -110,20 +106,20 @@ func NewRouter(ctx context.Context, config config.Config) (*Router, []module.Mod
 }
 
 func (r *Router) Run() {
-	slog.Info("running router")
+	r.logger.Info("running router")
 	for _, moduleInstance := range r.ModuleInstances {
 		r.moduleWait.Add(1)
 		go func() {
 			err := moduleInstance.Run()
 			if err != nil {
-				slog.Error("error encountered running module", "id", moduleInstance.Id(), "error", err)
+				r.logger.Error("error encountered running module", "error", err)
 			}
 			r.moduleWait.Done()
 		}()
 	}
 	<-r.Context.Done()
 	r.moduleWait.Wait()
-	slog.Info("router done")
+	r.logger.Info("router done")
 }
 
 func (r *Router) Stop() {
@@ -143,7 +139,7 @@ func (r *Router) HandleInput(sourceId string, payload any) []route.RouteIOError
 					Index: routeIndex,
 					Error: err,
 				})
-				slog.Error("router unable to route input", "route", routeIndex, "source", sourceId, "error", err)
+				r.logger.Error("router unable to route input", "route", routeIndex, "source", sourceId, "error", err)
 			}
 		}
 	}