forked from go-jet/jet
/
mysql_generator.go
118 lines (96 loc) · 2.97 KB
/
mysql_generator.go
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package mysql
import (
"database/sql"
"errors"
"fmt"
"strings"
"github.com/ag5/jet/v2/generator/metadata"
"github.com/ag5/jet/v2/generator/template"
"github.com/ag5/jet/v2/mysql"
mysqldr "github.com/go-sql-driver/mysql"
)
const mysqlMaxConns = 10
// DBConnection contains MySQL connection details
type DBConnection struct {
Host string
Port int
User string
Password string
Params string
DBName string
}
// Generate generates jet files at destination dir from database connection details
func Generate(destDir string, dbConn DBConnection, generatorTemplate ...template.Template) error {
connectionString := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s", dbConn.User, dbConn.Password, dbConn.Host, dbConn.Port, dbConn.DBName)
if dbConn.Params != "" {
connectionString += "?" + dbConn.Params
}
db, err := openConnection(connectionString)
if err != nil {
return fmt.Errorf("failed to open db connection: %w", err)
}
defer db.Close()
err = generate(db, dbConn.DBName, destDir, generatorTemplate...)
if err != nil {
return err
}
return nil
}
// GenerateDSN opens connection via DSN string and does everything what Generate does.
func GenerateDSN(dsn, destDir string, templates ...template.Template) error {
// Special case for go mysql driver. It does not understand schema,
// so we need to trim it before passing to generator
// https://github.com/go-sql-driver/mysql#dsn-data-source-name
idx := strings.Index(dsn, "://")
if idx != -1 {
dsn = dsn[idx+len("://"):]
}
cfg, err := mysqldr.ParseDSN(dsn)
if err != nil {
return fmt.Errorf("failed to parse DSN: %w", err)
}
if cfg.DBName == "" {
return errors.New("database name is required")
}
db, err := openConnection(dsn)
if err != nil {
return fmt.Errorf("failed to open db connection: %w", err)
}
defer db.Close()
err = generate(db, cfg.DBName, destDir, templates...)
if err != nil {
return fmt.Errorf("failed to generate: %w", err)
}
return nil
}
func openConnection(connectionString string) (*sql.DB, error) {
fmt.Println("Connecting to MySQL database...")
db, err := sql.Open("mysql", connectionString)
if err != nil {
return nil, fmt.Errorf("failed to open mysql connection: %w", err)
}
db.SetMaxOpenConns(mysqlMaxConns)
db.SetMaxIdleConns(mysqlMaxConns)
err = db.Ping()
if err != nil {
return nil, fmt.Errorf("failed to ping database: %w", err)
}
return db, nil
}
func generate(db *sql.DB, dbName, destDir string, templates ...template.Template) error {
fmt.Println("Retrieving database information...")
// No schemas in MySQL
schemaMetaData, err := metadata.GetSchema(db, &mySqlQuerySet{}, dbName)
if err != nil {
return fmt.Errorf("failed to get '%s' database metadata: %w", dbName, err)
}
genTemplate := template.Default(mysql.Dialect)
if len(templates) > 0 {
genTemplate = templates[0]
}
err = template.ProcessSchema(destDir, schemaMetaData, genTemplate)
if err != nil {
return fmt.Errorf("failed to process '%s' database: %w", schemaMetaData.Name, err)
}
return nil
}