feat: rate limiter, users table, validation, servers split up, graceful quit, user functions

projects/greenlight/cmd/api/main.go

@@ -4,9 +4,6 @@ import (
 	"context"
 	"database/sql"
 	"flag"
-	"fmt"
-	"log"
-	"net/http"
 	"os"
 	"time"
 
@@ -34,6 +31,13 @@ type config struct {
 		maxOpenConns int
 		maxIdleConns int
 		maxIdleTime  string
+	} // Add a new limiter struct containing fields for the requests-per-second and burst
+	// values, and a boolean field which we can use to enable/disable rate limiting
+	// altogether.
+	limiter struct {
+		rps     float64
+		burst   int
+		enabled bool
 	}
 }
 
@@ -70,6 +74,12 @@ func main() {
 	flag.IntVar(&cfg.db.maxIdleConns, "db-max-idle-conns", 25, "PostgreSQL max idle connections")
 	flag.StringVar(&cfg.db.maxIdleTime, "db-max-idle-time", "15m", "PostgreSQL max connection idle time")
 
+	// Create command line flags to read the setting values into the config struct.
+	// Notice that we use true as the default for the 'enabled' setting?
+	flag.Float64Var(&cfg.limiter.rps, "limiter-rps", 2, "Rate limiter maximum requests per second")
+	flag.IntVar(&cfg.limiter.burst, "limiter-burst", 4, "Rate limiter maximum burst")
+	flag.BoolVar(&cfg.limiter.enabled, "limiter-enabled", true, "Enable rate limiter")
+
 	flag.Parse()
 
 	// Call the openDB() helper function (see below) to create the connection pool,
@@ -97,22 +107,10 @@ func main() {
 		models: data.NewModels(db),
 	}
 
-	// Use the httprouter instance returned by app.routes() as the server handler.
-	srv := &http.Server{
-		Addr:         fmt.Sprintf(":%d", cfg.port),
-		Handler:      app.routes(),
-		IdleTimeout:  time.Minute,
-		ErrorLog:     log.New(logger, "", 0),
-		ReadTimeout:  10 * time.Second,
-		WriteTimeout: 30 * time.Second,
+	err = app.serve()
+	if err != nil {
+		logger.PrintFatal(err, nil)
 	}
-
-	logger.PrintInfo("starting server", map[string]string{
-		"addr": srv.Addr,
-		"env":  cfg.env,
-	})
-	err = srv.ListenAndServe()
-	logger.PrintFatal(err, nil)
 }
 
 func openDB(cfg config) (*sql.DB, error) {