nix-health[^1] is a program that checks the health of your Nix install. Furthermore, individual projects can configure their own health checks in their flake.nix. For example, the nammayatri project checks that the cachix cache is in use.
| Check | Configurable in flake.nix? |
| --- | --- |
| Flakes are enabled | - |
| Nix version is not too old | Yes |
| Nix runs natively (no rosetta)[^2] | Yes |
| Builds use multiple cores (max-jobs) | Yes |
| Nix Caches in use | Yes |
| $USER is in trusted-users | - |
| Direnv: installed and activated | Yes |
| Min RAM / Disk space | Yes |
Note that some checks are considered non-essential. For eg., the disk space check looks for 1TB+ disk space, but if the user is on a laptop with 256GB SSD, the check will report a warning instead of failing. This can also be configured in per-project basis from flake.nix (see below).
nix-health is still in development. To run the development version,
bash
nix run "github:juspay/nix-browser#nix-health"
To run nix-health along with health check configuration specified in a project flake, pass that flake as an argument. For eg., to run nix-health with additional checks from the nammayatri project, run:
```bash
nix run "github:juspay/nix-browser#nix-health" github:nammayatri/nammayatri ```
flake.nix {#conf}To add project specific health checks or configure health checks, add the following flake output:
nix
{
outputs = inputs: {
nix-health.default = {
# Add configuration here
caches.required = [ "https://ourproject.cachix.org" ];
};
};
}
To see all available configuration options, run nix-health --dump-schema. This will dump the schema of the configuration in JSON format. Convert that to a Nix attrset to see what can be added under the nix-health.default attrset of your flake.
sh-session
$ nix-health --dump-schema > schema.json
$ nix eval --impure --expr 'builtins.fromJSON (builtins.readFile ./schema.json)' | nix run nixpkgs#alejandra -- --quiet
{
caches = {required = ["https://cache.nixos.org/"];};
direnv = {
enable = true;
required = false;
};
flake-enabled = {};
max-jobs = {};
nix-version = {min-required = "2.13.0";};
rosetta = {
enable = true;
required = true;
};
system = {
enable = true;
min_disk_space = "1024.0 GB";
min_ram = null;
required = false;
};
trusted-users = {};
}