For images running on Kubernetes, there is no guarantee on how duplicate
environment variables in the image config will be handled. This seems
to be different from Docker, where the last environment variable value
is consistently selected.
The current code for `streamLayeredImage` was exploiting that assumption
to easily propagate environment variables from the base image, leaving
duplicates unchecked. It should rather resolve these duplicates to
ensure consistent behavior on Docker and Kubernetes.
It is now possible to pass a `fromImage` to `buildLayeredImage` and
`streamLayeredImage`, similar to what `buildImage` currently supports.
This will prepend the layers of the given base image to the resulting
image, while ensuring that at most `maxLayers` are used. It will also
ensure that environment variables from the base image are propagated
to the final image.
When using `buildLayeredImage`, it is not possible to specify an image
name of the form `<registry>/my/image`, although it is a valid name.
This is due to derivations under `buildLayeredImage` using that image
name as their derivation name, but slashes are not permitted in that
context.
A while ago, #13099 fixed that exact same problem in `buildImage` by
using `baseNameOf name` in derivation names instead of `name`. This
change does the same thing for `buildLayeredImage`.
Previously the Docker daemon was started by systemd socket activation.
Thus, the Docker test waited for the sockets.target unit.
But when the docker module was changed to start the Docker daemon at
boot instead of by socket activation, the test was left untouched.
With the Docker 20.10 update this lead to a timing issue, where the
docker command is run before the Docker daemon has started and hangs.
Fixes #109416
Docker (via containerd) and the the OCI Image Configuration imply and
suggest, respectfully, that the architecture set in images matches those
of GOARCH in the Go Language document.
This changeset updates the implimentation of getArch in dockerTools to
return GOARCH values, to satisfy Docker.
Fixes: #106695
The image tag can be specified or generated from the output hash.
Previously, a generated tag could be recovered from the evaluated
image with some string operations.
However, with the introduction of streamLayeredImage, it's not
feasible to compute the generated tag yourself.
With this change, the imageTag attribute is set unconditionally,
for the buildImage, buildLayeredImage, streamLayeredImage functions.
This is useful when buildLayeredImage is called in a generic way
that should allow simple (base) images to be built, which may not
reference any store paths.
Docker images used to be, essentially, a linked list of layers. Each
layer would have a tarball and a json document pointing to its parent,
and the image pointed to the top layer:
imageA ----> layerA
|
v
layerB
|
v
layerC
The current image spec changed this format to where the Image defined
the order and set of layers:
imageA ---> layerA
|--> layerB
`--> layerC
For backwards compatibility, docker produces images which follow both
specs: layers point to parents, and images also point to the entire
list:
imageA ---> layerA
| |
| v
|--> layerB
| |
| v
`--> layerC
This is nice for tooling which supported the older version and never
updated to support the newer format.
Our `buildImage` code only supported the old version, so in order for
`buildImage` to properly generate an image based on another image
with `fromImage`, the parent image's layers must fully support the old
mechanism.
This is not a problem in general, but is a problem with
`buildLayeredImage`.
`buildLayeredImage` creates images with newer image spec, because
individual store paths don't have a guaranteed parent layer. Including
a specific parent ID in the layer's json makes the output less likely
to cache hit when published or pulled.
This means until now, `buildLayeredImage` could not be the input to
`buildImage`.
The changes in this PR change `buildImage` to only use the layer's
manifest when locating parent IDs. This does break buildImage on
extremely old Docker images, though I do wonder how many of these
exist.
This work has been sponsored by Target.
