allow non-gzip layers

[tofay]

I'm exploring using zstd layers in rpmoci: to do that I'd like to create a Layer with a different media type and then use OciDir::push_layer

[ariel-miculas]

I'm wondering whether we should use a Descriptor instead of a Blob and MediaType in the Layer struct.

[tofay]

I'm wondering whether we should use a Descriptor instead of a Blob and MediaType in the Layer struct.

Makes sense. I'm also wondering why the Layer fields are public at all.

[cgwalters]

Makes sense. I'm also wondering why the Layer fields are public at all.

Versus having getters? I'm in favor, though let's just start a list of things to change in the next server bump...I don't have a big appetite for another semver just for that.

[cgwalters]

Ah yeah what we had before was clearly suboptimal.

Hmm maybe for consistency it's GzipLayerWriter that sets the mime type explicitly too? I guess yeah that gets to wanting to have an explicit descriptor.

Short of some server-breaking changes this looks sane to me.

[tofay]

Short of some server-breaking changes this looks sane to me.

This change is semver breaking (https://doc.rust-lang.org/cargo/reference/semver.html#struct-add-public-field-when-no-private).

[cgwalters]

This change is semver breaking (https://doc.rust-lang.org/cargo/reference/semver.html#struct-add-public-field-when-no-private).

Technically...yes, but IMO practically no one is using struct literals for this.

Anyways I am also OK to just bump server and make other changes too, though we should also I think try to "settle down" after hopefully just one more bump for a while hopefully.

[ariel-miculas]

I do have some stuff lined up besides #22, basically to implement this function in ocidir-rs