Configuring the Rate Limiters.

cmd/api/main.go

@@ -28,17 +28,23 @@ For now, the only configuration settings will be the network port that we want t
 and the name of the current operating environment for the application (development, staging, production, etc.)
 We'll read in the configuration settings from command-line flags when the application starts.
 */
-// Add a db struct field to hold the configuration settings for our database connection pool. For now, this only holds the DSN, which we will read in from a command-line flag.
-// Add maxOpenConns, maxIdleConns and maxIdleTime fields to hold the configuration settings for the connection pool
 type config struct {
 	port int
 	env  string
-	db   struct {
-		dsn          string
+	// Add a db struct field to hold the configuration settings for our database connection pool. For now, this only holds the DSN, which we will read in from a command-line flag.
+	db struct {
+		dsn string
+		// Add maxOpenConns, maxIdleConns and maxIdleTime fields to hold the configuration settings for the connection pool
 		maxOpenConns int
 		maxIdleConns int
 		maxIdleTime  time.Duration
 	}
+	// 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
+	}
 }
 
 // application struct hold the dependencies for our HTTP handlers, helpers, and middleware.
@@ -68,6 +74,11 @@ func main() {
 	flag.IntVar(&cfg.db.maxIdleConns, "db-max-idle-conns", 25, "PostgreSQL max idle connections")
 	flag.DurationVar(&cfg.db.maxIdleTime, "db-max-idle-time", 15*time.Minute, "PostgreSQL max connection idle time")
 
+	// Create command line flags to read the setting values into the config struct. Notice taht 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()
 
 	// Initialize a new structured logger which writes log entries to standard out stream.