The `docker load` command supports loading tarballs that contain
multiple docker images with their respective image names and tags. This
enables distributing these images as a single file which simplifies the
release of software when an application requires multiple services to
run.
However, pkgs.dockerTools only create tarballs with a single docker
image and there exists is no mechanism in nixpkgs to combine the created
tarballs. This commit implements merging of tarballs in a way that is
compatible with `docker load`.
Since 03eaa48 added perl.withPackages, there is a canonical way to
create a perl interpreter from a list of libraries, for use in script
shebangs or generic build inputs. This method is declarative (what we
are doing is clear), produces short shebangs[1] and needs not to wrap
existing scripts.
Unfortunately there are a few exceptions that I've found:
1. Scripts that are calling perl with the -T switch. This makes perl
ignore PERL5LIB, which is what perl.withPackages is using to inform
the interpreter of the library paths.
2. Perl packages that depends on libraries in their own path. This
is not possible because perl.withPackages works at build time. The
workaround is to add `-I $out/${perl.libPrefix}` to the shebang.
In all other cases I propose to switch to perl.withPackages.
[1]: https://lwn.net/Articles/779997/
Without this fix, I can no longer build anything with releaseTools.nixBuild {}. A job typically fails with:
$ nix-build release.nix -A build.basic.x86_64-linux --show-trace
error: while evaluating the attribute 'lib' of the derivation 'libnixxml-0.1pre1234' at /home/sander/teststuff/nixpkgs/pkgs/build-support/release/nix-build.nix:89:5:
cannot coerce a set to a string, at /home/sander/teststuff/nixpkgs/pkgs/build-support/release/nix-build.nix:89:5
This is caused by the fact that `lib' is propagated as a parameter, which is a function. Functions cannot be converted to strings.
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.
The check for including the C++ standard library headers was nested inside the
check for linking with the C++ standard library. As a result, the `-nostdlib`
flag incorrectly implied `-nostdinc++`, which made it virtually impossible to
partially link C++ objects.
runCommandWith receives an attribute set with options which previously
were positional arguments of runCommand' and a buildCommand. This
allows for overriding the used stdenv freely (so stuff like
llvmPackages.stdenv can be used). Additionally the possibility to change
arguments passed to stdenv.mkDerivation is made more explicit via the
derivationArgs argument.
Previously it was awkward to use the runCommand-variants with
passAsFile as a double definition of passAsFile would potentially
break runCommand: passAsFile would overwrite the previous definition,
defeating the purpose of setting it in runCommand in the first place.
This is now fixed by concatenating the [ "buildCommand" ] list with
one the one from env, if present.
Adjust buildEnv where passAsFile = null; was passed in some cases,
breaking evaluation since it'd evaluate to [ "buildCommand" ] ++ null.
