func()

in internal/cloudsql/instance.go [358:463]

• 86 lines of code
• 6 McCabe index (conditional complexity)

func (i *RefreshAheadCache) scheduleRefresh(d time.Duration) *refreshOperation {
	r := &refreshOperation{}
	r.ready = make(chan struct{})
	r.timer = time.AfterFunc(d, func() {
		// instance has been closed, don't schedule anything
		if err := i.ctx.Err(); err != nil {
			i.logger.Debugf(
				context.Background(),
				"[%v] Instance is closed, stopping refresh operations",
				i.connName.String(),
			)
			r.err = err
			close(r.ready)
			return
		}
		i.logger.Debugf(
			context.Background(),
			"[%v] Connection info refresh operation started",
			i.connName.String(),
		)

		ctx, cancel := context.WithTimeout(i.ctx, i.refreshTimeout)
		defer cancel()

		// avoid refreshing too often to try not to tax the SQL Admin
		// API quotas
		err := i.l.Wait(ctx)
		if err != nil {
			r.err = errtype.NewDialError(
				"context was canceled or expired before refresh completed",
				i.connName.String(),
				nil,
			)
		} else {
			var useIAMAuthN bool
			i.mu.Lock()
			useIAMAuthN = i.useIAMAuthNDial
			i.mu.Unlock()
			r.result, r.err = i.r.ConnectionInfo(
				ctx, i.connName, useIAMAuthN,
			)
		}
		switch r.err {
		case nil:
			i.logger.Debugf(
				ctx,
				"[%v] Connection info refresh operation complete",
				i.connName.String(),
			)
			i.logger.Debugf(
				ctx,
				"[%v] Current certificate expiration = %v",
				i.connName.String(),
				r.result.Expiration.UTC().Format(time.RFC3339),
			)
		default:
			i.logger.Debugf(
				ctx,
				"[%v] Connection info refresh operation failed, err = %v",
				i.connName.String(),
				r.err,
			)
		}

		close(r.ready)

		// Once the refresh is complete, update "current" with working
		// refreshOperation and schedule a new refresh
		i.mu.Lock()
		defer i.mu.Unlock()

		// if failed, scheduled the next refresh immediately
		if r.err != nil {
			i.logger.Debugf(
				ctx,
				"[%v] Connection info refresh operation scheduled immediately",
				i.connName.String(),
			)
			i.next = i.scheduleRefresh(0)
			// If the latest refreshOperation is bad, avoid replacing the
			// used refreshOperation while it's still valid and potentially
			// able to provide successful connections. TODO: This
			// means that errors while the current refreshOperation is still
			// valid are suppressed. We should try to surface
			// errors in a more meaningful way.
			if !i.cur.isValid() {
				i.cur = r
			}
			return
		}

		// Update the current results, and schedule the next refresh in
		// the future
		i.cur = r
		t := refreshDuration(time.Now(), i.cur.result.Expiration)
		i.logger.Debugf(
			ctx,
			"[%v] Connection info refresh operation scheduled at %v (now + %v)",
			i.connName.String(),
			time.Now().Add(t).UTC().Format(time.RFC3339),
			t.Round(time.Minute),
		)
		i.next = i.scheduleRefresh(t)
	})
	return r
}