95 lines
2.5 KiB
Go
95 lines
2.5 KiB
Go
package bolt
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import (
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"time"
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bolt "github.com/coreos/bbolt"
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)
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// SchemaVersionBucket stores ids of completed migrations
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var SchemaVersionBucket = []byte("SchemaVersions")
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// IsMigrationComplete checks for the presence of a particular migration id
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func IsMigrationComplete(db *bolt.DB, id string) (bool, error) {
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complete := false
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if err := db.View(func(tx *bolt.Tx) error {
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migration := tx.Bucket(SchemaVersionBucket).Get([]byte(id))
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if migration != nil {
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complete = true
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}
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return nil
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}); err != nil {
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return true, err
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}
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return complete, nil
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}
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// MarkMigrationAsComplete adds the migration id to the schema bucket
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func MarkMigrationAsComplete(db *bolt.DB, id string) error {
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if err := db.Update(func(tx *bolt.Tx) error {
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now := time.Now().UTC().Format(time.RFC3339)
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return tx.Bucket(SchemaVersionBucket).Put([]byte(id), []byte(now))
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}); err != nil {
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return err
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}
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return nil
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}
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// Migration defines a database state/schema transition
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// ID: After the migration is run, this id is stored in the database.
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// We don't want to run a state transition twice
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// Up: The forward-transition function. After a version upgrade, a number
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// of these will run on database startup in order to bring a user's
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// schema in line with struct definitions in the new version.
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// Down: The backward-transition function. We don't expect these to be
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// run on a user's database -- if the user needs to rollback
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// to a previous version, it will be easier for them to replace
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// their current database with one of their backups. The primary
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// purpose of a Down() function is to help contributors move across
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// development branches that have different schema definitions.
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type Migration struct {
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ID string
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Up func(db *bolt.DB) error
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Down func(db *bolt.DB) error
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}
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// Migrate runs one migration's Up() function, if it has not already been run
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func (m Migration) Migrate(client *Client) error {
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complete, err := IsMigrationComplete(client.db, m.ID)
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if err != nil {
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return err
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}
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if complete {
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return nil
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}
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if client.logger != nil {
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client.logger.Info("Running migration ", m.ID, "")
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}
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if err = m.Up(client.db); err != nil {
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return err
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}
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return MarkMigrationAsComplete(client.db, m.ID)
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}
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// MigrateAll iterates through all known migrations and runs them in order
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func MigrateAll(client *Client) error {
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for _, m := range migrations {
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err := m.Migrate(client)
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if 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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var migrations = []Migration{
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changeIntervalToDuration,
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}
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