audit.go

package app

// AuditLog is the audit log used by the audit hook.
type AuditLog struct {
	ID      *int           `json:"id,omitempty"`
	Changes map[string]any `json:"changes,omitempty"`
}

func getID(m ent.Mutation) *int {
	if idr, ok := m.(interface{ ID() (int, bool) }); ok {
		if id, found := idr.ID(); found {
			return &id
		}
	}
	return nil
}

// AuditRecorder is a recorder of audits events.
type AuditRecorder interface {
	RegisterAuditLog(ctx context.Context, userID int, event string, data any) error
}

// skipTables is a list of tables that we should avoid creating audit events.
var skipTables = []string{
	ent.TypeAudit,
	ent.TypeUserSession,
	ent.TypeStatefulAction,
	ent.TypeIdempotency,
	ent.TypeChannelSubscriptionMessage,
	ent.TypeFingerprint,
}

// auditHook is the audit hook used for most of the events.
func (tt *TT) auditHook() ent.Hook {
	shouldSkip := func(name string) bool {
		for _, n := range skipTables {
			if strings.EqualFold(n, name) {
				return true
			}
		}
		return false
	}

	return func(next ent.Mutator) ent.Mutator {
		return ent.MutateFunc(func(ctx context.Context, m ent.Mutation) (ent.Value, error) {
			if shouldSkip(m.Type()) {
				return next.Mutate(ctx, m)
			}

			recordID := getID(m)

			// we run the mutation first.
			val, err := next.Mutate(ctx, m)
			if err != nil {
				return nil, err
			}

			// maybe we are creating a record, check
			// if we have a record id again
			if recordID == nil {
				recordID = getID(m)
			}

			var userID *int
			uID, found := httputil.UserIDFromContext(ctx)
			if found {
				userID = &uID
			}

			al := AuditLog{
				ID:      recordID,
				Changes: map[string]any{},
			}

			if !m.Op().Is(ent.OpDelete | ent.OpDeleteOne) {
				for _, f := range m.Fields() {
					v, _ := m.Field(f)
					al.Changes[f] = v
				}
			}

			event := fmt.Sprintf("%s%s", m.Type(), m.Op().String())
			err = tt.RegisterAuditLog(ctx, userID, event, al)
			if err != nil {
				// in case of an error, we log the information to leave an audit trail.
				applog.LogCtx(ctx).Err(err).
					Interface("audit_log", al).
					Str("event", event).
					Interface("user_id", userID).
					Msg("error saving an audit log")
				return nil, err
			}

			return val, nil
		})
	}
}