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|
package model
import (
"database/sql"
"log"
_ "github.com/mattn/go-sqlite3"
"xengineering.eu/ceres/model/migrations"
)
var db *sql.DB
func ConnectDatabase(path string) {
var err error
db, err = sql.Open("sqlite3", path)
if err != nil {
log.Fatal(err)
}
err = db.Ping()
if err != nil {
log.Fatal(err)
}
}
func Transaction(f func(*sql.Tx) error) error {
tx, err := 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 isDatabaseEmpty(tx *sql.Tx) bool {
cmd := `SELECT COUNT(*) FROM sqlite_master WHERE type='table'`
rows, err := tx.Query(cmd)
if err != nil {
log.Fatal(err)
}
defer rows.Close()
if !rows.Next() {
log.Fatalf("No rows on request of database table number")
}
var number int
err = rows.Scan(&number)
if err != nil {
log.Fatalf("Failed to scan number of database tables to integer")
}
return number == 0
}
func setupMinimalDatabase(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 getDatabaseVersion(tx *sql.Tx) string {
rows, err := tx.Query(`SELECT value FROM metadata WHERE key='version';`)
if err != nil {
log.Fatal(err)
}
defer rows.Close()
if !rows.Next() {
log.Fatalf("No rows on request of database version")
}
var version string
err = rows.Scan(&version)
if err != nil {
log.Fatalf("Failed to scan database version to string")
}
return version
}
func MigrateDatabase(execVersion string) {
err := Transaction(func(tx *sql.Tx) error {
if isDatabaseEmpty(tx) {
log.Println("Starting with empty database")
err := setupMinimalDatabase(tx, execVersion)
if err != nil {
log.Fatalf("Failed to setup minimal database schema: %v", err)
}
log.Println("Executing initial migration")
err = migrations.Migration001(tx)
if err != nil {
return err
}
}
dbVersion := getDatabaseVersion(tx)
if dbVersion != execVersion {
log.Fatalf(
"Database version '%s' does not match executable version '%s'",
dbVersion,
execVersion,
)
}
return nil
})
if err != nil {
log.Fatalf("Fatal: Database migration failed")
}
}
func InjectExampleRecipes() {
err := 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 DisconnectDatabase() {
var err error = db.Close()
if err != nil {
log.Printf("Failed to close database: %v\n", err)
} else {
log.Println("Closed database")
}
}
|
