Add the information about osbuid artifact to the target result.
Specifically the name of the osbuild pipeline which was exported for the
specific target, and the filename of the exported file.
This will later enable embedding this information in Koji build metadata
to make it easy to reproduce the image build using the attached
manifest.
The filename of the image as produced by osbuild for a given export is
currently set in each target options type in the `Filename` struct
member. However, the value is not really specific to any target type,
but to the specific export used for the target. For this reason move the
value form target type options to the `Target` struct inside a new
struct `OsbuildArtifact` under the name`ExportFilename`.
The backward compatibility with older implementations of the composer
and workers is kept on the JSON (Un)mashaling level, where the JSON
object is always a super-set of the old and new way of providing the
export filename in the Target.
This commit adds and implements org.osbuild.azure.image target.
Let's talk about the already implemented org.osbuild.azure target firstly:
The purpose of this target is to authenticate using the Azure Storage
credentials and upload the image file as a Page Blob. Page Blob is basically
an object in storage and it cannot be directly used to launch a VM. To achieve
that, you need to define an actual Azure Image with the Page Blob attached.
For the cloud API, we would like to create an actual Azure Image that is
immediately available for new VMs. The new target accomplishes it.
To achieve this, it must use a different authentication method: Azure OAuth.
The other important difference is that currently, the credentials are stored
on the worker and not in target options. This should lead to better security
because we don't send the credentials over network. In the future, we would
like to have credential-less setup using workers in Azure with the right
IAM policies applied but this requires more investigation and is not
implemented in this commit.
Signed-off-by: Ondřej Budai <ondrej@budai.cz>