ch19.2

cmd/api/main.go

@@ -3,8 +3,10 @@ package main
 import (
 	"context"
 	"database/sql"
+	"expvar"
 	"flag"
 	"os"
+	"runtime"
 	"strings"
 	"sync"
 	"time"
@@ -114,6 +116,20 @@ func main() {
 
 	logger.PrintInfo("database connection pool established", nil)
 
+	expvar.NewString("version").Set(version)
+
+	expvar.Publish("goroutines", expvar.Func(func() any {
+		return runtime.NumGoroutine()
+	}))
+
+	expvar.Publish("database", expvar.Func(func() any {
+		return db.Stats()
+	}))
+
+	expvar.Publish("timestamp", expvar.Func(func() any {
+		return time.Now().Unix()
+	}))
+
 	app := &application{
 		config: cfg,
 		logger: logger,

cmd/api/routes.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"expvar"
 	"net/http"
 
 	"github.com/julienschmidt/httprouter"
@@ -25,5 +26,7 @@ func (app *application) routes() http.Handler {
 
 	router.HandlerFunc(http.MethodPost, "/v1/tokens/authentication", app.createAuthenticationTokenHandler)
 
+	router.Handler(http.MethodGet, "/debug/vars", expvar.Handler())
+
 	return app.recoverPanic(app.enableCORS(app.rateLimit(app.authenticate(router))))
 }