Same chart saved at different times has different digest #8212
Description
After investigating this issue, I have tracked it down to a change that was made in release v.3.0.3. Here is a demonstration and a way you can reproduce:
export HELM_EXPERIMENTAL_OCI=1
curl -s https://get.helm.sh/helm-v3.0.3-linux-amd64.tar.gz | tar xzvf - -C /tmp/
rm -rf "${HOME}/.cache/helm/registry"
/tmp/linux-amd64/helm create /tmp/mychart
/tmp/linux-amd64/helm chart save /tmp/mychart first:latest
sleep 1
/tmp/linux-amd64/helm chart save /tmp/mychart second:latest
The output is like so:
$ /tmp/linux-amd64/helm chart save /tmp/mychart first:latest
ref: first:latest
digest: 470a1e836bbef03577c15cf44c80f6d17fd3f9a953beba4789ff4fe081a9e3fa
...
$ /tmp/linux-amd64/helm chart save /tmp/mychart second:latest
ref: second:latest
digest: 9b0f939702799c192221d8bb1baffbfca0ec006a4144fbae27d828746a804717
...
This is a result of the timestamp being included in pkg/chartutil/save.go:
func writeToTar(out *tar.Writer, name string, body []byte) error {
// TODO: Do we need to create dummy parent directory names if none exist?
h := &tar.Header{
Name: name,
Mode: 0644,
Size: int64(len(body)),
ModTime: time.Now(), // <-------- this line was added in release 3.0.3
}
if err := out.WriteHeader(h); err != nil {
return err
}
_, err := out.Write(body)
return err
}The timestamp was added as a fix to #4158, so that archives created with helm package would bear the correct timestamp. However, this breaks the correct functioning of helm chart save, which should produce identical digests for identical content. I am preparing a PR to resolve this issue, which will leave the functionality for helm package in tact while fixing it for helm chart save.
helm version
version.BuildInfo{Version:"v3.1.1", GitCommit:"afe70585407b420d0097d07b21c47dc511525ac8", GitTreeState:"clean", GoVersion:"go1.13.8"}
kubectl version
Client Version: version.Info{Major:"1", Minor:"16", GitVersion:"v1.16.3", GitCommit:"b3cbbae08ec52a7fc73d334838e18d17e8512749", GitTreeState:"clean", BuildDate:"2019-11-13T11:23:11Z", GoVersion:"go1.12.12", Compiler:"gc", Platform:"linux/amd64"}
error: You must be logged in to the server (the server has asked for the client to provide credentials)
Cloud provider is irrelevant in this case