model: Refactor public API of DB

This commit makes not externally needed methods private and adds error
return values since something like log.Fatal() should be called outside
this package since it is control-flow-related.

2 files changed, 31 insertions, 25 deletions

diff --git a/main.go b/main.go
index 1d7d3e1..55425e4 100644
--- a/main.go
+++ b/main.go
@@ -34,15 +34,29 @@ func main() {
 	}
 	log.Printf("Storage directory: %s\n", storage.Path)
 
-	db := model.OpenDB(filepath.Join(storage.Path, "ceres.sqlite3"))
-	defer db.Close()
-	err := db.Migrate()
+	db, err := model.OpenDB(filepath.Join(storage.Path, "ceres.sqlite3"))
+	if err != nil {
+		log.Fatalf("Failed to open database: %v", err)
+	}
+	defer func() {
+		err := db.Close()
+		if err != nil {
+			log.Println("Failed to close database")
+		} else {
+			log.Println("Closed database")
+		}
+	}()
+
+	err = db.Migrate()
 	if err != nil {
 		log.Fatal(err)
 	}
 
 	if flags.examples {
-		db.CreateExamples()
+		err := db.CreateExamples()
+		if err != nil {
+			log.Fatalf("Failed to insert example recipes: %v", err)
+		}
 		log.Println("Created example recipes")
 	}
 
diff --git a/model/database.go b/model/database.go
index 84ed497..f3fb607 100644
--- a/model/database.go
+++ b/model/database.go
@@ -11,18 +11,18 @@ import (
 
 type DB sql.DB
 
-func OpenDB(path string) *DB {
+func OpenDB(path string) (*DB, error) {
 	db, err := sql.Open("sqlite3", path)
 	if err != nil {
-		log.Fatal(err)
+		return nil, fmt.Errorf("Failed to open SQLite3 database: %w", err)
 	}
 
 	err = db.Ping()
 	if err != nil {
-		log.Fatal(err)
+		return nil, fmt.Errorf("Failed to ping SQLite3 database: %w", err)
 	}
 
-	return (*DB)(db)
+	return (*DB)(db), nil
 }
 
 func (db *DB) Transaction(f func(*sql.Tx) error) error {
@@ -46,7 +46,7 @@ func (db *DB) Transaction(f func(*sql.Tx) error) error {
 	return tx.Commit()
 }
 
-func (db *DB) IsEmpty(tx *sql.Tx) (bool, error) {
+func (db *DB) isEmpty(tx *sql.Tx) (bool, error) {
 	cmd := `SELECT COUNT(*) FROM sqlite_master WHERE type='table'`
 	rows, err := tx.Query(cmd)
 	if err != nil {
@@ -67,8 +67,8 @@ func (db *DB) IsEmpty(tx *sql.Tx) (bool, error) {
 	return number == 0, nil
 }
 
-func (db *DB) SchemaVersion(tx *sql.Tx) (int, error) {
-	empty, err := db.IsEmpty(tx)
+func (db *DB) schemaVersion(tx *sql.Tx) (int, error) {
+	empty, err := db.isEmpty(tx)
 	if err != nil {
 		return 0, fmt.Errorf("Failed to check if DB is empty: %w", err)
 	}
@@ -142,7 +142,7 @@ func (db *DB) Migrate() error {
 		var version int
 		for index, migration := range migrations {
 			var err error
-			version, err = db.SchemaVersion(tx)
+			version, err = db.schemaVersion(tx)
 			if err != nil {
 				return fmt.Errorf("Failed to get DB schema version: %w", err)
 			}
@@ -155,7 +155,7 @@ func (db *DB) Migrate() error {
 				}
 			}
 		}
-		version, err := db.SchemaVersion(tx)
+		version, err := db.schemaVersion(tx)
 		if err != nil {
 			return fmt.Errorf("Failed to get DB schema version: %w", err)
 		}
@@ -168,8 +168,8 @@ func (db *DB) Migrate() error {
 	})
 }
 
-func (db *DB) CreateExamples() {
-	err := db.Transaction(func(tx *sql.Tx) error {
+func (db *DB) CreateExamples() error {
+	return db.Transaction(func(tx *sql.Tx) error {
 		recipes := RecipeTestData()
 
 		for _, recipe := range recipes {
@@ -181,16 +181,8 @@ func (db *DB) CreateExamples() {
 
 		return nil
 	})
-	if err != nil {
-		log.Fatalf("Failed to inject example recipes: %v", err)
-	}
 }
 
-func (db *DB) Close() {
-	err := (*sql.DB)(db).Close()
-	if err != nil {
-		log.Printf("Failed to close database: %v\n", err)
-	} else {
-		log.Println("Closed database")
-	}
+func (db *DB) Close() error {
+	return (*sql.DB)(db).Close()
 }