feat: sql, migrations, sql postgress db setup, movie model

projects/greenlight/cmd/api/main.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/joho/godotenv"
 	_ "github.com/lib/pq"
+	"greenlight.debuggingjon.dev/internal/data"
 )
 
 // Declare a string containing the application version number. Later in the book we'll
@@ -28,7 +29,10 @@ type config struct {
 	port int
 	env  string
 	db   struct {
-		dsn string
+		dsn          string
+		maxOpenConns int
+		maxIdleConns int
+		maxIdleTime  string
 	}
 }
 
@@ -38,6 +42,7 @@ type config struct {
 type application struct {
 	config config
 	logger *log.Logger
+	models data.Models
 }
 
 func main() {
@@ -54,7 +59,12 @@ func main() {
 	flag.StringVar(&cfg.env, "env", "development", "Environment (development|staging|production)")
 	// Read the DSN value from the db-dsn command-line flag into the config struct. We
 	// default to using our development DSN if no flag is provided.
-	flag.StringVar(&cfg.db.dsn, "db-dsn", dsn, "PostgreSQL DSN (From DATABASE_DSN in .env)")
+	flag.StringVar(&cfg.db.dsn, "db-dsn", dsn, "PostgreSQL DSN (Default from DATABASE_DSN in .env)")
+	// Read the connection pool settings from command-line flags into the config struct.
+	// Notice the default values that we're using?
+	flag.IntVar(&cfg.db.maxOpenConns, "db-max-open-conns", 25, "PostgreSQL max open connections")
+	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")
 
 	flag.Parse()
 
@@ -80,6 +90,7 @@ func main() {
 	app := &application{
 		config: cfg,
 		logger: logger,
+		models: data.NewModels(db),
 	}
 
 	// Use the httprouter instance returned by app.routes() as the server handler.
@@ -97,26 +108,36 @@ func main() {
 }
 
 func openDB(cfg config) (*sql.DB, error) {
-	// Use sql.Open() to create an empty connection pool, using the DSN from the config
-	// struct.
 	db, err := sql.Open("postgres", cfg.db.dsn)
 	if err != nil {
 		return nil, err
 	}
 
-	// Create a context with a 5-second timeout deadline.
+	// Set the maximum number of open (in-use + idle) connections in the pool. Note that
+	// passing a value less than or equal to 0 will mean there is no limit.
+	db.SetMaxOpenConns(cfg.db.maxOpenConns)
+
+	// Set the maximum number of idle connections in the pool. Again, passing a value
+	// less than or equal to 0 will mean there is no limit.
+	db.SetMaxIdleConns(cfg.db.maxIdleConns)
+
+	// Use the time.ParseDuration() function to convert the idle timeout duration string
+	// to a time.Duration type.
+	duration, err := time.ParseDuration(cfg.db.maxIdleTime)
+	if err != nil {
+		return nil, err
+	}
+
+	// Set the maximum idle timeout.
+	db.SetConnMaxIdleTime(duration)
+
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
 
-	// Use PingContext() to establish a new connection to the database, passing in the
-	// context we created above as a parameter. If the connection couldn't be
-	// established successfully within the 5 second deadline, then this will return an
-	// error.
 	err = db.PingContext(ctx)
 	if err != nil {
 		return nil, err
 	}
 
-	// Return the sql.DB connection pool.
 	return db, nil
 }