func readFiles()

in step5/src/server/main.go [173:231]

• 52 lines of code
• 10 McCabe index (conditional complexity)

func readFiles(ctx context.Context, bucketName, prefix string) ([]string, error) {
	type resp struct {
		s   string
		err error
	}

	// step4: add an extra span
	span := trace.SpanFromContext(ctx)
	span.SetName("server.readFiles")
	span.SetAttributes(attribute.Key("bucketname").String(bucketName))
	defer span.End()
	// step4: end add span

	client, err := storage.NewClient(ctx, option.WithoutAuthentication())
	if err != nil {
		return []string{}, fmt.Errorf("failed to create storage client: %s", err)
	}
	defer client.Close()

	bucket := client.Bucket(bucketName)

	var paths []string
	it := bucket.Objects(ctx, &storage.Query{Prefix: bucketPrefix})
	for {
		attrs, err := it.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return []string{}, fmt.Errorf("failed to iterate over files in %s starting with %s: %v", bucketName, prefix, err)
		}
		if attrs.Name != "" {
			paths = append(paths, attrs.Name)
		}
	}

	resps := make(chan resp)
	for _, path := range paths {
		go func(path string) {
			obj := bucket.Object(path)
			r, err := obj.NewReader(ctx)
			if err != nil {
				resps <- resp{"", err}
			}
			defer r.Close()
			data, err := ioutil.ReadAll(r)
			resps <- resp{string(data), err}
		}(path)
	}
	ret := make([]string, len(paths))
	for i := 0; i < len(paths); i++ {
		r := <-resps
		if r.err != nil {
			err = r.err
		}
		ret[i] = r.s
	}
	return ret, err
}