134 lines
4.1 KiB
Go
134 lines
4.1 KiB
Go
package database
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import (
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"errors"
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"fmt"
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"time"
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"gorm.io/gorm"
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)
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const CurrentSchemaVersion int64 = 1
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const baselineSchemaChecksum = "sha256:open-ai-canvas-schema-v1-20260830"
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const postgresSchemaMigrationLockID int64 = 73123910420260830
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type SchemaStatus struct {
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Current int64 `json:"current"`
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Expected int64 `json:"expected"`
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Ready bool `json:"ready"`
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}
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type schemaMigration struct {
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Version int64 `gorm:"primaryKey"`
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Name string `gorm:"size:160;not null"`
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Checksum string `gorm:"size:96;not null"`
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AppliedAt time.Time `gorm:"not null"`
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}
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func (schemaMigration) TableName() string { return "schema_migrations" }
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type migration struct {
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version int64
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name string
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checksum string
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apply func(*gorm.DB) error
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}
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var schemaMigrations = []migration{
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{version: 1, name: "baseline_gorm_schema", checksum: baselineSchemaChecksum, apply: migrateSchemaV1},
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}
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func MigrateSchema(db *gorm.DB) error {
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return db.Transaction(func(tx *gorm.DB) error {
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if tx.Dialector.Name() == "postgres" {
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if err := tx.Exec("SELECT pg_advisory_xact_lock(?)", postgresSchemaMigrationLockID).Error; err != nil {
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return fmt.Errorf("获取数据库迁移锁：%w", err)
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}
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}
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if err := tx.AutoMigrate(&schemaMigration{}); err != nil {
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return fmt.Errorf("初始化数据库迁移记录：%w", err)
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}
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for _, item := range schemaMigrations {
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var applied schemaMigration
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err := tx.First(&applied, "version = ?", item.version).Error
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if err == nil {
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if err := validateMigrationRecord(applied, item); err != nil {
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return err
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}
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continue
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}
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if !errors.Is(err, gorm.ErrRecordNotFound) {
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return fmt.Errorf("读取数据库迁移 %d：%w", item.version, err)
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}
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if err := item.apply(tx); err != nil {
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return fmt.Errorf("执行数据库迁移 %d（%s）：%w", item.version, item.name, err)
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}
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record := schemaMigration{Version: item.version, Name: item.name, Checksum: item.checksum, AppliedAt: time.Now().UTC()}
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if err := tx.Create(&record).Error; err != nil {
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return fmt.Errorf("记录数据库迁移 %d：%w", item.version, err)
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}
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}
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return RequireSchemaVersion(tx)
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})
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}
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func ReadSchemaStatus(db *gorm.DB) (SchemaStatus, error) {
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status := SchemaStatus{Expected: CurrentSchemaVersion}
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if !db.Migrator().HasTable(&schemaMigration{}) {
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return status, nil
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}
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if err := db.Model(&schemaMigration{}).Select("COALESCE(MAX(version), 0)").Scan(&status.Current).Error; err != nil {
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return status, fmt.Errorf("读取数据库结构版本：%w", err)
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}
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if status.Current != status.Expected {
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return status, nil
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}
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if err := validateMigrationRecords(db); err != nil {
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return status, err
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}
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status.Ready = true
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return status, nil
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}
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func validateMigrationRecords(db *gorm.DB) error {
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for _, item := range schemaMigrations {
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var applied schemaMigration
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if err := db.First(&applied, "version = ?", item.version).Error; err != nil {
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if errors.Is(err, gorm.ErrRecordNotFound) {
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return fmt.Errorf("数据库缺少迁移记录 %d（%s）", item.version, item.name)
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}
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return fmt.Errorf("读取数据库迁移 %d：%w", item.version, err)
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}
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if err := validateMigrationRecord(applied, item); err != nil {
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return err
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}
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}
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return nil
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}
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func validateMigrationRecord(applied schemaMigration, expected migration) error {
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if applied.Name != expected.name {
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return fmt.Errorf("数据库迁移 %d 名称不一致：记录为 %s，程序期望 %s", expected.version, applied.Name, expected.name)
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}
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if applied.Checksum != expected.checksum {
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return fmt.Errorf("数据库迁移 %d 校验和不一致：记录为 %s，程序期望 %s", expected.version, applied.Checksum, expected.checksum)
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}
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return nil
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}
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func RequireSchemaVersion(db *gorm.DB) error {
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status, err := ReadSchemaStatus(db)
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if err != nil {
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return err
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}
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if status.Current < status.Expected {
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return fmt.Errorf("数据库结构版本过旧：当前 %d，程序要求 %d，请先执行 migrate-schema up", status.Current, status.Expected)
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}
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if status.Current > status.Expected {
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return fmt.Errorf("数据库结构版本 %d 高于程序支持的 %d，拒绝使用旧程序连接新数据库", status.Current, status.Expected)
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}
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return nil
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}
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