80 lines
3.1 KiB
Markdown
80 lines
3.1 KiB
Markdown
# Nix development and build environment
|
|
|
|
With Nix it's possible to quickly and reliably recreate the full environments
|
|
for developing, testing and building PostgREST.
|
|
|
|
## Getting started with Nix
|
|
|
|
You'll need to [get Nix](https://nixos.org/download.html). The installer will
|
|
create your Nix store in the `/nix/` directory, where all build artifacts and
|
|
their dependencies will be stored. It will also link the Nix executables like
|
|
`nix-env`, `nix-build` and `nix-shell` into your PATH. Nix will manage all
|
|
other PostgREST dependencies from here on out. To clean up older build
|
|
artifacts from the `/nix/store`, you can run `nix-collect-garbage`.
|
|
|
|
## Building PostgREST
|
|
|
|
To build PostgREST from your local checkout of the repository, run:
|
|
|
|
```bash
|
|
nix-build --attr postgrest
|
|
|
|
```
|
|
|
|
This will create a `result` directory that contains the PostgREST binary at
|
|
`result/bin/postgrest`. The `--attr` parameter (or short: `-A`) tells Nix to
|
|
build the `postgrest` attribute from the Nix expression it finds in our
|
|
`default.nix` (see below for details). Nix will take care of getting the right
|
|
GHC version and all the build dependencies.
|
|
|
|
## Developing
|
|
|
|
A development environment for PostgREST is available with `nix-shell`. The
|
|
following command will put you into a new shell that has GHC and Cabal on the
|
|
PATH:
|
|
|
|
```bash
|
|
nix-shell
|
|
|
|
```
|
|
|
|
Within `nix-shell`, you can run Cabal commands as usual. You can also run
|
|
stack with the `--nix` option, which causes stack to pick up the non-Haskell
|
|
dependencies from the same pinned Nixpkgs version that the Nix builds use.
|
|
|
|
## Tour
|
|
|
|
The following is not required for working on PostgREST with Nix, but it will
|
|
give you some more background and details on how it works.
|
|
|
|
### `default.nix`
|
|
|
|
[`default.nix`](../default.nix) is our 'respository expression' that pulls all
|
|
the pieces that we define with Nix together. It returns a set (like a dict in
|
|
other programming languages), where each attribute is a derivation that Nix
|
|
knows how to build, like the `postgrest` attribute from earlier.
|
|
|
|
Internally, our `default.nix` uses the `pkgs.callPackage` function to import
|
|
the modules that we defined in the `nix` directory. It automatically passes the
|
|
arguments those modules require if they are available in `pkgs` (this means
|
|
that `pkgs` is defined in terms of itself, better not to think too much about
|
|
that).
|
|
|
|
We also use `default.nix` to load our pinned version of the `nixpkgs`
|
|
repository. This set of packages will always be the same, independently from
|
|
where or when you use it. The pinned version can be upgraded with the small
|
|
`nixpkgs-upgrade` utility. Running `nixpkgs-upgrade > nix/nixpkgs-version.nix`
|
|
in `nix-shell` will upgrade the pinned version to the latest `nixpkgs-unstable`
|
|
version.
|
|
|
|
### `shell.nix`
|
|
|
|
[`shell.nix`](../shell.nix) defines an environment in which PostgREST can be
|
|
built and developed. It extends the build enviroment from our `postgrest`
|
|
attribute with useful utilities that will be put on the PATH in `nix-shell`.
|
|
|
|
### `nix/overlays`
|
|
|
|
Our overlays to the Nix package set are defined here. They allow us to tweak our
|
|
`pkgs` in `default.nix` by adding new packages or overriding existing ones.
|