Replace in-memory database with SQLite

api.go

@@ -1,24 +1,66 @@
 package api
 
 import (
+	"database/sql"
 	"net/http"
 
 	"github.com/gin-gonic/gin"
+	_ "github.com/mattn/go-sqlite3"
 )
 
 // album represents data about a record album.
 type album struct {
-	ID     string  `json:"id"`
+	ID     int64   `json:"id"`
 	Title  string  `json:"title"`
 	Artist string  `json:"artist"`
 	Price  float64 `json:"price"`
 }
 
-// albums slice to seed record album data.
-var albums = []album{
-	{ID: "1", Title: "Blue Train", Artist: "John Coltrane", Price: 56.99},
-	{ID: "2", Title: "Jeru", Artist: "Gerry Mulligan", Price: 17.99},
-	{ID: "3", Title: "Sarah Vaughan and Clifford Brown", Artist: "Sarah Vaughan", Price: 39.99},
+var db *sql.DB
+
+func initDB() error {
+	var err error
+	db, err = sql.Open("sqlite3", "./albums.db")
+	if err != nil {
+		return err
+	}
+
+	createTableSQL := `CREATE TABLE IF NOT EXISTS albums (
+		id INTEGER PRIMARY KEY AUTOINCREMENT,
+		title TEXT NOT NULL,
+		artist TEXT NOT NULL,
+		price REAL NOT NULL
+	);`
+
+	_, err = db.Exec(createTableSQL)
+	if err != nil {
+		return err
+	}
+
+	// Check if table is empty and seed with initial data
+	var count int
+	err = db.QueryRow("SELECT COUNT(*) FROM albums").Scan(&count)
+	if err != nil {
+		return err
+	}
+
+	if count == 0 {
+		seedData := []album{
+			{Title: "Blue Train", Artist: "John Coltrane", Price: 56.99},
+			{Title: "Jeru", Artist: "Gerry Mulligan", Price: 17.99},
+			{Title: "Sarah Vaughan and Clifford Brown", Artist: "Sarah Vaughan", Price: 39.99},
+		}
+
+		for _, a := range seedData {
+			_, err = db.Exec("INSERT INTO albums (title, artist, price) VALUES (?, ?, ?)",
+				a.Title, a.Artist, a.Price)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
 }
 
 // setupRouter configures and returns the Gin router with all routes
@@ -32,12 +74,35 @@ func setupRouter() *gin.Engine {
 }
 
 func main() {
+	if err := initDB(); err != nil {
+		panic(err)
+	}
+	defer db.Close()
+
 	router := setupRouter()
 	router.Run("localhost:8080")
 }
 
 // getAlbums responds with the list of all albums as JSON.
 func getAlbums(c *gin.Context) {
+	rows, err := db.Query("SELECT id, title, artist, price FROM albums")
+	if err != nil {
+		c.IndentedJSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	defer rows.Close()
+
+	var albums []album
+	for rows.Next() {
+		var a album
+		err := rows.Scan(&a.ID, &a.Title, &a.Artist, &a.Price)
+		if err != nil {
+			c.IndentedJSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+		albums = append(albums, a)
+	}
+
 	c.IndentedJSON(http.StatusOK, albums)
 }
 
@@ -51,8 +116,22 @@ func postAlbums(c *gin.Context) {
 		return
 	}
 
-	// Add the new album to the slice.
-	albums = append(albums, newAlbum)
+	// Insert the new album into the database and get the generated ID.
+	result, err := db.Exec("INSERT INTO albums (title, artist, price) VALUES (?, ?, ?)",
+		newAlbum.Title, newAlbum.Artist, newAlbum.Price)
+	if err != nil {
+		c.IndentedJSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Get the auto-generated ID
+	id, err := result.LastInsertId()
+	if err != nil {
+		c.IndentedJSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	newAlbum.ID = id
+
 	c.IndentedJSON(http.StatusCreated, newAlbum)
 }
 
@@ -61,13 +140,17 @@ func postAlbums(c *gin.Context) {
 func getAlbumByID(c *gin.Context) {
 	id := c.Param("id")
 
-	// Loop through the list of albums, looking for
-	// an album whose ID value matches the parameter.
-	for _, a := range albums {
-		if a.ID == id {
-			c.IndentedJSON(http.StatusOK, a)
-			return
-		}
+	var a album
+	err := db.QueryRow("SELECT id, title, artist, price FROM albums WHERE id = ?", id).
+		Scan(&a.ID, &a.Title, &a.Artist, &a.Price)
+
+	if err == sql.ErrNoRows {
+		c.IndentedJSON(http.StatusNotFound, gin.H{"message": "album not found"})
+		return
+	} else if err != nil {
+		c.IndentedJSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
 	}
-	c.IndentedJSON(http.StatusNotFound, gin.H{"message": "album not found"})
+
+	c.IndentedJSON(http.StatusOK, a)
 }

api_test.go

@@ -25,7 +25,6 @@ func BenchmarkGetAlbumByIDNotFound(b *testing.B) {
 
 func BenchmarkPostAlbumsValid(b *testing.B) {
 	newAlbum := album{
-		ID:     "4",
 		Title:  "Kind of Blue",
 		Artist: "Miles Davis",
 		Price:  29.99,
@@ -37,7 +36,7 @@ func BenchmarkPostAlbumsValid(b *testing.B) {
 }
 
 func BenchmarkPostAlbumsInvalidJSON(b *testing.B) {
-	invalidJSON := `{"id": "5", "title": "Invalid Album", "artist": "Test Artist", "price": "invalid_price"}`
+	invalidJSON := `{"title": "Invalid Album", "artist": "Test Artist", "price": "invalid_price"}`
 	req, _ := http.NewRequest("POST", "/albums", strings.NewReader(invalidJSON))
 	req.Header.Set("Content-Type", "application/json")
 	benchmarkRequest(b, req)

benchmark_utils.go

@@ -31,6 +31,14 @@ func setupBenchmarkRouter() *gin.Engine {
 	gin.SetMode(gin.ReleaseMode)
 	// Discard all output during benchmarks to only preserve benchmark output
 	gin.DefaultWriter = io.Discard
+
+	// Initialize database if not already initialized
+	if db == nil {
+		if err := initDB(); err != nil {
+			panic(err)
+		}
+	}
+
 	return setupRouter()
 }
 

go.mod

@@ -23,6 +23,7 @@ require (
 	github.com/klauspost/cpuid/v2 v2.2.7 // indirect
 	github.com/leodido/go-urn v1.4.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/mattn/go-sqlite3 v1.14.32 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.2 // indirect

go.sum

@@ -38,6 +38,8 @@ github.com/leodido/go-urn v1.4.0 h1:WT9HwE9SGECu3lg4d/dIA+jxlljEa1/ffXKmRjqdmIQ=
 github.com/leodido/go-urn v1.4.0/go.mod h1:bvxc+MVxLKB4z00jd1z+Dvzr47oO32F/QSNjSBOlFxI=
 github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
 github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/mattn/go-sqlite3 v1.14.32 h1:JD12Ag3oLy1zQA+BNn74xRgaBbdhbNIDYvQUEuuErjs=
+github.com/mattn/go-sqlite3 v1.14.32/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd h1:TRLaZ9cD/w8PVh93nsPXa1VrQ6jlwL5oN8l14QlcNfg=
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=