arttor/helmify

package decoder

import (
    "errors"
    "io"

    "github.com/sirupsen/logrus"
    "k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
    "k8s.io/apimachinery/pkg/runtime"
    "k8s.io/apimachinery/pkg/runtime/serializer/yaml"
    yamlutil "k8s.io/apimachinery/pkg/util/yaml"
)

const (
    yamlDecoderBufferSize          = 100
    decoderResultChannelBufferSize = 1
)

// Decode - reads bytes stream of k8s yaml manifests and decodes it to k8s unstructured objects.
// Non-blocking function. Sends results into buffered channel. Closes channel on io.EOF.
func Decode(stop <-chan struct{}, reader io.Reader) <-chan *unstructured.Unstructured {
    decoder := yamlutil.NewYAMLOrJSONDecoder(reader, yamlDecoderBufferSize)
    res := make(chan *unstructured.Unstructured, decoderResultChannelBufferSize)
    go func() {
        defer close(res)
        logrus.Debug("Start processing...")
        for {
            select {
            case <-stop:
                logrus.Debug("Exiting: received stop signal")
                return
            default:
            }
            var rawObj runtime.RawExtension
            err := decoder.Decode(&rawObj)
            if errors.Is(err, io.EOF) {
                logrus.Debug("EOF received. Finishing input objects decoding.")
                return
            }
            if err != nil {
                logrus.WithError(err).Error("unable to decode yaml from input")
                continue
            }
            obj, _, err := yaml.NewDecodingSerializer(unstructured.UnstructuredJSONScheme).Decode(rawObj.Raw, nil, nil)
            if err != nil {
                logrus.WithError(err).Error("unable to decode yaml")
                continue
            }
            unstructuredMap, err := runtime.DefaultUnstructuredConverter.ToUnstructured(obj)
            if err != nil {
                logrus.WithError(err).Error("unable to map yaml to k8s unstructured")
                continue
            }
            object := &unstructured.Unstructured{Object: unstructuredMap}
            logrus.WithFields(logrus.Fields{
                "ApiVersion": object.GetAPIVersion(),
                "Kind":       object.GetKind(),
                "Name":       object.GetName(),
            }).Debug("decoded")
            res <- object
        }
    }()
    return res
}