func()

in go/pkg/client/cas.go [690:754]

• 64 lines of code
• 12 McCabe index (conditional complexity)

func (c *Client) BatchDownloadBlobs(ctx context.Context, dgs []digest.Digest) (map[digest.Digest][]byte, error) {
	if len(dgs) > int(c.MaxBatchDigests) {
		return nil, fmt.Errorf("batch read of %d total blobs exceeds maximum of %d", len(dgs), c.MaxBatchDigests)
	}
	req := &repb.BatchReadBlobsRequest{InstanceName: c.InstanceName}
	var sz int64
	foundEmpty := false
	for _, dg := range dgs {
		if dg.Size == 0 {
			foundEmpty = true
			continue
		}
		sz += int64(dg.Size)
		req.Digests = append(req.Digests, dg.ToProto())
	}
	if sz > int64(c.MaxBatchSize) {
		return nil, fmt.Errorf("batch read of %d total bytes exceeds maximum of %d", sz, c.MaxBatchSize)
	}
	res := make(map[digest.Digest][]byte)
	if foundEmpty {
		res[digest.Empty] = nil
	}
	opts := c.RPCOpts()
	closure := func() error {
		var resp *repb.BatchReadBlobsResponse
		err := c.CallWithTimeout(ctx, "BatchReadBlobs", func(ctx context.Context) (e error) {
			resp, e = c.cas.BatchReadBlobs(ctx, req, opts...)
			return e
		})
		if err != nil {
			return err
		}

		numErrs, errDg, errMsg := 0, &repb.Digest{}, ""
		var failedDgs []*repb.Digest
		var retriableError error
		allRetriable := true
		for _, r := range resp.Responses {
			st := status.FromProto(r.Status)
			if st.Code() != codes.OK {
				e := st.Err()
				if c.Retrier.ShouldRetry(e) {
					failedDgs = append(failedDgs, r.Digest)
					retriableError = e
				} else {
					allRetriable = false
				}
				numErrs++
				errDg = r.Digest
				errMsg = r.Status.Message
			} else {
				res[digest.NewFromProtoUnvalidated(r.Digest)] = r.Data
			}
		}
		req.Digests = failedDgs
		if numErrs > 0 {
			if allRetriable {
				return retriableError // Retriable errors only, retry the failed digests.
			}
			return fmt.Errorf("downloading blobs as part of a batch resulted in %d failures, including blob %s: %s", numErrs, errDg, errMsg)
		}
		return nil
	}
	return res, c.Retrier.Do(ctx, closure)
}