(d *Daemon).PullImage downloads an OCI image, flattens it into an
ext4 rootfs, and registers the result as a managed banger image.
Flow (internal/daemon/images_pull.go):
1. Parse + validate the OCI ref via go-containerregistry/name.
2. Derive a friendly default name from the ref ("debian-bookworm")
when --name is omitted.
3. Reject if an image with that name already exists.
4. Resolve kernel info via the new shared resolveKernelInputs
helper (refactored out of RegisterImage); ValidateKernelPaths
checks the kernel triple alone.
5. Acquire imageOpsMu, generate a fresh image id, and stage at
<ImagesDir>/<id>.staging.
6. imagepull.Pull → cache layers under OCICacheDir;
imagepull.Flatten → temp rootfs tree under os.TempDir (so the
state filesystem doesn't temporarily double in size).
7. Default size: max(treeSize × 1.25, 1 GiB); --size override
accepted.
8. imagepull.BuildExt4 produces the rootfs.ext4 in the staging dir.
9. imagemgr.StageBootArtifacts stages the kernel/initrd/modules
into the same dir (reused unchanged).
10. Atomic os.Rename(staging, finalDir) publishes the artifact dir.
11. Persist model.Image with Managed=true. Failure at any step
removes the staging dir; failure post-rename removes finalDir.
The pullAndFlatten field on Daemon is the test seam: tests stub it
to write a fixture tree into destDir and skip the real registry.
Refactor: extracted the "kernel-ref vs direct paths" resolution
out of RegisterImage into d.resolveKernelInputs so PullImage and
RegisterImage share one source of truth for that policy. Split
ValidateRegisterPaths into a kernel-only ValidateKernelPaths so
PullImage (which produces the rootfs itself) can validate just
the kernel triple without the rootfs check.
API: ImagePullParams { Ref, Name, KernelPath, InitrdPath,
ModulesDir, KernelRef, SizeBytes }. RPC dispatch case image.pull
mirrors image.register.
Tests cover: happy-path producing a managed image with all four
artifacts present + staging cleaned up, name-collision rejection,
missing-kernel rejection, and staging cleanup on a failed pull.
defaultImageNameFromRef handles tag/digest/no-suffix cases.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Thales Maciel
a8c9983542