Adds the database driver and opens database pool

Adds the new -dsn flag so that the user can pass any database into the
program.

Adds a new function that wraps sql.Open() to create the connection pool,
and pings it to ensure it is alive.

1 files changed, 36 insertions, 4 deletions

diff --git a/cmd/web/main.go b/cmd/web/main.go
index a4082fd..b767275 100644
--- a/cmd/web/main.go
+++ b/cmd/web/main.go
@@ -1,11 +1,13 @@
 package main
 
 import (
+	"database/sql"
 	"flag"
-	"log"
 	"log/slog"
 	"net/http"
 	"os"
+
+	_ "github.com/go-sql-driver/mysql"
 )
 
 type application struct {
@@ -14,17 +16,47 @@ type application struct {
 
 func main() {
 	addr := flag.String("addr", ":4000", "HTTP network port")
-	// dsn := flag.String("dsn", "web:dedpassword:/ded?parseTime=true", "MySQL data source name")
+	dsn := flag.String("dsn", "web:dedpassword@/ded?parseTime=true", "MySQL data source name")
 	flag.Parse()
 
 	logger := slog.New(slog.NewTextHandler(os.Stdout, nil))
+
+	// Database connection
+	db, err := openDB(*dsn)
+	if err != nil {
+		logger.Error(err.Error())
+		os.Exit(1)
+	}
+
+	defer db.Close()
+
 	app := &application{
 		logger: logger,
 	}
+
 	// mux := http.NewServeMux()
 	// mux.HandleFunc("/", home)
 	// log.Print("starting server on :4000")
 	logger.Info("starting server", "addr", *addr)
-	err := http.ListenAndServe(*addr, app.routes())
-	log.Fatal(err)
+	err = http.ListenAndServe(*addr, app.routes())
+	logger.Error(err.Error())
+	os.Exit(1)
+}
+
+// openDB wraps sql.Open() and returns a sql.DB connection pool
+// for a given DSN.
+func openDB(dsn string) (*sql.DB, error) {
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		return nil, err
+	}
+
+	err = db.Ping()
+	if err != nil {
+		db.Close()
+		return nil, err
+	}
+
+	return db, nil
+
 }