CopyFile relies on copy.Copy from https://github.com/otiai10/copy which
doesn't handle named pipes copy. Handle it here until
https://github.com/otiai10/copy/issues/47 is fixed.
This causes luet to hang while copying packages that have named pipes in
it.
Also invert compression argument for gzip, it causes slowliness.
Several changes are included:
- Expose ensureDir in helpers, and call it in the Docker client. In
other implementations that was handled by CopyFile behind the scenes,
but that's not the case here
- Create accessor in Artifact to create Artifact objects from files.
This is handy when we have to carry over downloaded package content
into caches when artifacts are already verified
- Fix various issues around the imagePush flag, so now trees are pushed
forcefully each time
- Take into consideration the real artifact name when pushing single
files in the docker image. This behavior should be changed eventually,
because single files which aren't repository packages now are in its
own docker image, but we should have just one that brings the required
metadata alltogether.
Create compiler interface with switchable backends. For now it can resolve and
parse a `build.yaml` which is in the same folder as in `definition.yaml`
Add also tests to cover this and new fixtures
