REFACTOR: Create Single Connection For App Lifetime

cms/internal/services/db.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"database/sql"
 	"fmt"
+	"log"
 	"thamanyah/cms/v2/internal/db"
 	"time"
 )
@@ -31,17 +32,21 @@ type DBClient interface {
 }
 
 type DBConcrete struct {
-	ConnectionString string
+	SQLDB *sql.DB
+}
+
+func CreateConcreteDbClient(connectionString string) DBConcrete {
+	sqlDB, err := sql.Open("postgres", connectionString)
+	if err != nil {
+		panic(fmt.Errorf("db: cannot open connection: %w", err))
+	}
+	return DBConcrete{
+		SQLDB: sqlDB,
+	}
 }
 
 func (svc DBConcrete) CreateVideo(ctx context.Context, v Video) (Video, error) {
-	sqlDB, err := sql.Open("postgres", svc.ConnectionString)
+	tx, err := svc.SQLDB.BeginTx(ctx, nil)
-	if err != nil {
-		return Video{}, err
-	}
-	defer sqlDB.Close()
-
-	tx, err := sqlDB.BeginTx(ctx, nil)
 	if err != nil {
 		return Video{}, err
 	}
@@ -75,13 +80,7 @@ func (svc DBConcrete) CreateVideo(ctx context.Context, v Video) (Video, error) {
 }
 
 func (svc DBConcrete) ListCategories(ctx context.Context) ([]string, error) {
-	sqlDB, err := sql.Open("postgres", svc.ConnectionString)
+	rows, err := svc.SQLDB.QueryContext(ctx, `SELECT name FROM categories ORDER BY name`)
-	if err != nil {
-		return nil, err
-	}
-	defer sqlDB.Close()
-
-	rows, err := sqlDB.QueryContext(ctx, `SELECT name FROM categories ORDER BY name`)
 	if err != nil {
 		return nil, err
 	}
@@ -99,26 +98,20 @@ func (svc DBConcrete) ListCategories(ctx context.Context) ([]string, error) {
 }
 
 func (svc DBConcrete) Migrate() {
-	sqlDB, err := sql.Open("postgres", svc.ConnectionString)
+	if err := db.Migrate(svc.SQLDB); err != nil {
-	if err != nil {
-		panic(fmt.Errorf("failed to open db connection: %w", err))
-	}
-	if err := db.Migrate(sqlDB); err != nil {
 		panic(err)
 	}
-	sqlDB.Close()
 }
 
-// AssertSuccessfulConnection verifies the database is reachable, mirroring
+func (svc DBConcrete) CloseConnection() {
-// S3Concrete's boot-time check — panics rather than let the service come up broken.
+	err := svc.SQLDB.Close()
-func (svc DBConcrete) AssertSuccessfulConnection(ctx context.Context) {
-	sqlDB, err := sql.Open("postgres", svc.ConnectionString)
 	if err != nil {
-		panic(fmt.Errorf("db: cannot open connection: %w", err))
+		log.Fatalf("Error Closing DB Connection: %s", err)
 	}
-	defer sqlDB.Close()
+}
 
-	if err := sqlDB.PingContext(ctx); err != nil {
+func (svc DBConcrete) AssertSuccessfulConnection(ctx context.Context) {
+	if err := svc.SQLDB.PingContext(ctx); err != nil {
 		panic(fmt.Errorf("db: cannot connect: %w", err))
 	}
 }

cms/main.go

@@ -24,7 +24,8 @@ func main() {
 }
 
 func runMigrate() {
-	concreteDBClient := &services.DBConcrete{ConnectionString: requireDBConnectionString()}
+	concreteDBClient := services.CreateConcreteDbClient(requireDBConnectionString())
+	defer concreteDBClient.CloseConnection()
 	concreteDBClient.Migrate()
 	log.Println("migrations applied successfully")
 }
@@ -70,7 +71,8 @@ func runServer() {
 		OutputBucket:       mediaConvertOutputBucket,
 	}
 
-	concreteDBClient := &services.DBConcrete{ConnectionString: requireDBConnectionString()}
+	concreteDBClient := services.CreateConcreteDbClient(requireDBConnectionString())
+	defer concreteDBClient.CloseConnection()
 	concreteDBClient.AssertSuccessfulConnection(context.Background())
 	services.DB = concreteDBClient