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package model
import (
"database/sql"
"fmt"
"log"
_ "github.com/mattn/go-sqlite3"
"xengineering.eu/ceres/model/migrations"
)
type DB sql.DB
func OpenDB(path string) *DB {
db, err := sql.Open("sqlite3", path)
if err != nil {
log.Fatal(err)
}
err = db.Ping()
if err != nil {
log.Fatal(err)
}
return (*DB)(db)
}
func (db *DB) Transaction(f func(*sql.Tx) error) error {
tx, err := (*sql.DB)(db).Begin()
if err != nil {
log.Printf("Failed to start database transaction: %v", err)
return err
}
defer func() {
if tx.Rollback() == nil {
log.Println("Rolled back transaction")
}
}()
err = f(tx)
if err != nil {
log.Printf("Failed transaction: %v", err)
return err
}
return tx.Commit()
}
func (db *DB) IsEmpty(tx *sql.Tx) (bool, error) {
var number int
cmd := `SELECT COUNT(*) FROM sqlite_master WHERE type='table'`
rows, err := tx.Query(cmd)
if err != nil {
return false, fmt.Errorf("Select call failed: %w", err)
}
defer rows.Close()
if !rows.Next() {
return false, fmt.Errorf("Result set is empty")
}
err = rows.Scan(&number)
if err != nil {
return false, fmt.Errorf("Failed to scan numerical value: %w", err)
}
return number == 0, nil
}
func (db *DB) setupMinimal(tx *sql.Tx, execVersion string) error {
cmd := `
CREATE TABLE metadata (
key TEXT PRIMARY KEY,
value TEXT
);
INSERT INTO metadata
(key, value)
VALUES
('version', ?);
`
_, err := tx.Exec(cmd, execVersion)
return err
}
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)
}
if empty {
return 0, nil
}
rows, err := tx.Query(`SELECT value FROM metadata WHERE key='version';`)
if err != nil {
return 0, fmt.Errorf("Select call failed: %w", err)
}
defer rows.Close()
if rows.Next() {
return 1, nil // version field was only present in one schema version
}
return 0, fmt.Errorf("Unknown schema version")
}
func (db *DB) Migrate(execVersion string) error {
return db.Transaction(func(tx *sql.Tx) error {
for {
schema, err := db.SchemaVersion(tx)
if err != nil {
return fmt.Errorf("Failed to get DB schema version: %w", err)
}
switch schema {
case 0:
log.Println("Starting with empty database")
err := db.setupMinimal(tx, execVersion)
if err != nil {
return fmt.Errorf("Failed to setup minimal database schema: %w", err)
}
log.Println("Executing initial migration")
err = migrations.Migration001(tx)
if err != nil {
return err
}
case 1:
return nil
default:
return fmt.Errorf("Cannot migrate database to a matching schema version")
}
}
})
}
func (db *DB) CreateExamples() {
err := db.Transaction(func(tx *sql.Tx) error {
recipes := RecipeTestData()
for _, recipe := range recipes {
err := recipe.Create(tx)
if err != nil {
return err
}
}
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")
}
}
|
