When building a docker image using `dockertools.buildLayeredImage`, the
resulting image layers are passed to `jq` through the command line. When
building an image with too many layers this would exceed the maximum
command line argument length.
Hence, we store the list of layers in the Nix store and pass them to
`jq` as a file argument using `--slurpfile`.
Fixes#140908.
Fixes#186752. This adds buildVMMemorySize (defaults to 512 MiB) to
buildImage, which is passed to vm.runInLinuxVM. This is needed for
larger base images, which may otherwise cause container build failures
due to OOM in the VM.
This is useful for a use-case we have with a Nix-based CI system that
specifies things like deploy steps as passthru attributes[0].
Previously the only way to do this would have been to concatenate
attributes onto the resulting derivation, but passing them in and
actually treating them as proper passthru attributes is cleaner.
[0]: https://cs.tvl.fyi/depot@f7d7da6aceb407b719cf4683a75878fd3aca319e/-/blob/nix/buildkite/default.nix?L222-226
Apparently, a non-existent nsswitch.conf causes a very misleading host
resolution, differing from the defaults people are used to.
According to
https://github.com/golang/go/issues/22846#issuecomment-346377144, glibc
says the default is "dns [!UNAVAIL=return] files".
This means, `/etc/hosts` isn't really honored, causing all sorts of
unexpected behaviour.
Let's prevent this, and first ask `/etc/hosts` before querying DNS, like
we do on NixOS too.
skopeo 1.4.x doesn't accept --src-tls-verify as a flag to the *program*,
only as a flag to copy; we must pass it after the "copy" verb, or it
will fail with:
> FATA[0000] unknown flag: --src-tls-verify
skopeo will disable the progress bar if it detects that stdout isn't a
TTY - in order to make it think that stdout _isn't_ a TTY and therefore
avoid it printing a lot of "…" on separate lines, we pipe the output
through cat.
This changes the output from:
…
…
…
…
…
…
to the eminently more useful and less spammy:
Getting image source signatures
Copying blob sha256:[snip]
Copying blob sha256:[snip]
Copying blob sha256:[snip]
Copying config sha256:[snip]
Writing manifest to image destination
Storing signatures
For https://github.com/NixOS/nixpkgs/pull/125211 I tried to test
the fetcher with
nix-build -A dockerTools.examples.nixFromDockerHub --option substitute false
But it failed. I haven't figured out the cause, but the outputs
match, so it's probably the hashing method (flat/recursive) that
changed at some point. (The names did match.)
