discard.go RawHistoryFolder

1package recovery
2
3import (
4	"context"
5	"errors"
6	"fmt"
7)
8
9var (
10	ErrRecoveryRecordNotFound = errors.New("recovery: session not found")
11	ErrSessionNotBroken       = errors.New("recovery: session is not broken")
12)
13
14// Discard throws away a broken session's persisted state and replaces it with a
15// fresh incarnation. It is retry-idempotent, not crash-resumable: a crash
16// leaves either the old record (rerun discard) or a new record plus an orphan
17// directory that background garbage collection removes.
18func (c *Coordinator) Discard(ctx context.Context, name string) error {
19	if c == nil || c.catalogue == nil || c.repository == nil || c.locks == nil || c.random == nil {
20		return errors.New("recovery: incomplete discard dependencies")
21	}
22	if err := ctx.Err(); err != nil {
23		return err
24	}
25	c.mutationMu.Lock()
26	defer c.mutationMu.Unlock()
27	unlock := c.locks.Lock([]string{name})
28	defer unlock()
29
30	record, ok, err := c.catalogue.Record(name)
31	if err != nil {
32		return err
33	}
34	if !ok {
35		return fmt.Errorf("discard %q: %w", name, ErrRecoveryRecordNotFound)
36	}
37	if record.Committed == nil {
38		return nil
39	}
40	if record.DegradedReason == "" {
41		return ErrSessionNotBroken
42	}
43
44	_, _, err = c.replaceIncarnationLocked(ctx, record, false, "discard")
45	return err
46}