forked from lix-project/lix
99 lines
3.2 KiB
Markdown
99 lines
3.2 KiB
Markdown
R""(
|
|
|
|
# Description
|
|
|
|
`nix registry` provides subcommands for managing *flake
|
|
registries*. Flake registries are a convenience feature that allows
|
|
you to refer to flakes using symbolic identifiers such as `nixpkgs`,
|
|
rather than full URLs such as `git://github.com/NixOS/nixpkgs`. You
|
|
can use these identifiers on the command line (e.g. when you do `nix
|
|
run nixpkgs#hello`) or in flake input specifications in `flake.nix`
|
|
files. The latter are automatically resolved to full URLs and recorded
|
|
in the flake's `flake.lock` file.
|
|
|
|
In addition, the flake registry allows you to redirect arbitrary flake
|
|
references (e.g. `github:NixOS/patchelf`) to another location, such as
|
|
a local fork.
|
|
|
|
There are multiple registries. These are, in order from lowest to
|
|
highest precedence:
|
|
|
|
* The global registry, which is a file downloaded from the URL
|
|
specified by the setting `flake-registry`. It is cached locally and
|
|
updated automatically when it's older than `tarball-ttl`
|
|
seconds. The default global registry is kept in [a GitHub
|
|
repository](https://github.com/NixOS/flake-registry).
|
|
|
|
* The system registry, which is shared by all users. The default
|
|
location is `/etc/nix/registry.json`. On NixOS, the system registry
|
|
can be specified using the NixOS option `nix.registry`.
|
|
|
|
* The user registry `~/.config/nix/registry.json`. This registry can
|
|
be modified by commands such as `nix flake pin`.
|
|
|
|
* Overrides specified on the command line using the option
|
|
`--override-flake`.
|
|
|
|
# Registry format
|
|
|
|
A registry is a JSON file with the following format:
|
|
|
|
```json
|
|
{
|
|
"version": 2,
|
|
"flakes": [
|
|
{
|
|
"from": {
|
|
"type": "indirect",
|
|
"id": "nixpkgs"
|
|
},
|
|
"to": {
|
|
"type": "github",
|
|
"owner": "NixOS",
|
|
"repo": "nixpkgs"
|
|
}
|
|
},
|
|
...
|
|
]
|
|
}
|
|
```
|
|
|
|
That is, it contains a list of objects with attributes `from` and
|
|
`to`, both of which contain a flake reference in attribute
|
|
representation. (For example, `{"type": "indirect", "id": "nixpkgs"}`
|
|
is the attribute representation of `nixpkgs`, while `{"type":
|
|
"github", "owner": "NixOS", "repo": "nixpkgs"}` is the attribute
|
|
representation of `github:NixOS/nixpkgs`.)
|
|
|
|
Given some flake reference *R*, a registry entry is used if its
|
|
`from` flake reference *matches* *R*. *R* is then replaced by the
|
|
*unification* of the `to` flake reference with *R*.
|
|
|
|
# Matching
|
|
|
|
The `from` flake reference in a registry entry *matches* some flake
|
|
reference *R* if the attributes in `from` are the same as the
|
|
attributes in `R`. For example:
|
|
|
|
* `nixpkgs` matches with `nixpkgs`.
|
|
|
|
* `nixpkgs` matches with `nixpkgs/nixos-20.09`.
|
|
|
|
* `nixpkgs/nixos-20.09` does not match with `nixpkgs`.
|
|
|
|
* `nixpkgs` does not match with `git://github.com/NixOS/patchelf`.
|
|
|
|
# Unification
|
|
|
|
The `to` flake reference in a registry entry is *unified* with some flake
|
|
reference *R* by taking `to` and applying the `rev` and `ref`
|
|
attributes from *R*, if specified. For example:
|
|
|
|
* `github:NixOS/nixpkgs` unified with `nixpkgs` produces `github:NixOS/nixpkgs`.
|
|
|
|
* `github:NixOS/nixpkgs` unified with `nixpkgs/nixos-20.09` produces `github:NixOS/nixpkgs/nixos-20.09`.
|
|
|
|
* `github:NixOS/nixpkgs/master` unified with `nixpkgs/nixos-20.09` produces `github:NixOS/nixpkgs/nixos-20.09`.
|
|
|
|
)""
|