Create a many-layered Docker Image.
Implements much less than buildImage:
- Doesn't support specific uids/gids
- Doesn't support runninng commands after building
- Doesn't require qemu
- Doesn't create mutable copies of the files in the path
- Doesn't support parent images
If you want those feature, I recommend using buildLayeredImage as an
input to buildImage.
Notably, it does support:
- Caching low level, common paths based on a graph traversial
algorithm, see referencesByPopularity in
0a80233487993256e811f566b1c80a40394c03d6
- Configurable number of layers. If you're not using AUFS or not
extending the image, you can specify a larger number of layers at
build time:
pkgs.dockerTools.buildLayeredImage {
name = "hello";
maxLayers = 128;
config.Cmd = [ "${pkgs.gitFull}/bin/git" ];
};
- Parallelized creation of the layers, improving build speed.
- The contents of the image includes the closure of the configuration,
so you don't have to specify paths in contents and config.
With buildImage, paths referred to by the config were not included
automatically in the image. Thus, if you wanted to call Git, you
had to specify it twice:
pkgs.dockerTools.buildImage {
name = "hello";
contents = [ pkgs.gitFull ];
config.Cmd = [ "${pkgs.gitFull}/bin/git" ];
};
buildLayeredImage on the other hand includes the runtime closure of
the config when calculating the contents of the image:
pkgs.dockerTools.buildImage {
name = "hello";
config.Cmd = [ "${pkgs.gitFull}/bin/git" ];
};
Minor Problems
- If any of the store paths change, every layer will be rebuilt in
the nix-build. However, beacuse the layers are bit-for-bit
reproducable, when these images are loaded in to Docker they will
match existing layers and not be imported or uploaded twice.
Common Questions
- Aren't Docker layers ordered?
No. People who have used a Dockerfile before assume Docker's
Layers are inherently ordered. However, this is not true -- Docker
layers are content-addressable and are not explicitly layered until
they are composed in to an Image.
- What happens if I have more than maxLayers of store paths?
The first (maxLayers-2) most "popular" paths will have their own
individual layers, then layer #(maxLayers-1) will contain all the
remaining "unpopular" paths, and finally layer #(maxLayers) will
contain the Image configuration.
(cherry picked from commit 4fe9006190)
(cherry picked from commit d1e46df24b)
The `name` arg of `vim_configurable.customize` does not only determine
the package name, but also the name of the command/ executable to be
called.
In my opinion this is not documented properly and finding that out took
me several hours.
Hydra passes the full revision in to the input, which we pass through.
If we don't get this ,we try to get it from other sources, or default to
master which should have the definition in a close-ish location.
All published docs should have theURL resolve properly, only local
hackers will have the link break.
(cherry picked from commit 5daee73ce4)
Covers assert functions and about half of the attrsets functions.
Some internal consistency around IDs could be improved.
(cherry picked from commit f835f77e02)
The `overrideScope` bound by `makeScope` (via special `callPackage`)
took an override in the form `super: self { … }`. But this is
dangerously close to the `self: super { … }` form used by *everything*
else, even other definitions of `overrideScope`! Since that
implementation did not even share any code either until I changed it
recently in 3cf43547f4, this inconsistency
is almost certainly an oversight and not intentional.
Unfortunately, just as the inconstency is hard to debug if one just
assumes the conventional order, any sudden fix would break existing
overrides in the same hard-to-debug way. So instead of changing the
definition a new `overrideScope'` with the conventional order is added,
and old `overrideScope` deprecated with a warning saying to use
`overrideScope'` instead. That will hopefully get people to stop using
`overrideScope`, freeing our hand to change or remove it in the future.
For technical reasons, we cannot easily add a warning to top-level
definitions, so 2a6e4ae49a and
e51f736076 reverted the deprecation. But
we can still remove mention of the would-be deprecated definitions to
steer people towards using the preferred alternatives.
(cherry picked from commit e39a73cc55)
This aims to make the `weechat` package even more configurable. It
allows to specify scripts and commands using the `configure` function
inside a `weechat.override` expression.
The package can be configured like this:
```
with import <nixpkgs> { };
weechat.override {
plugins = { availablePlugins, ... }: {
plugins = builtins.attrValues availablePlugins;
init = ''
/set foo bar
/server add freenode chat.freenode.org
'';
scripts = [ "/path/to/script.py" ];
};
}
```
All commands are passed to `weechat --run-command "/set foo bar;/server ..."`.
The `plugins' attribute is not necessarily required anymore, if it's
sufficient to add `init' commands, the `plugins' will be
`builtins.attrValues availablePlugins' by default.
Additionally the result contains `weechat` and `weechat-headless`
(introduced in WeeChat 2.1) now.
(cherry picked from commit a8efe61412)
Because dates are an impurity, by default buildImage will use a static
date of one second past the UNIX Epoch. This can be a bit frustrating
when listing docker images in the CLI:
$ docker image list
REPOSITORY TAG IMAGE ID CREATED SIZE
hello latest 08c791c7846e 48 years ago 25.2MB
If you want to trade the purity for a better user experience, you can
set created to now.
pkgs.dockerTools.buildImage {
name = "hello";
tag = "latest";
created = "now";
contents = pkgs.hello;
config.Cmd = [ "/bin/hello" ];
}
and now the Docker CLI will display a reasonable date and sort the
images as expected:
$ docker image list
REPOSITORY TAG IMAGE ID CREATED SIZE
hello latest de2bf4786de6 About a minute ago 25.2MB
(cherry picked from commit a32d7e0c74)
I don't know when we can/should remove them, but this at least gets
people to stop using them. The preferred alternatives also date back to
17.09 so writing forward-compatable code without extra conditions is
easy.
Beginning with these as they are the least controversial.
