status-mobile/nix/README.md

# Description

This folder contains configuration for [Nix](https://nixos.org/), a purely functional package manager used by the Status app for its build process.

## Configuration

The main config file is [`nix/nix.conf`](/nix/nix.conf) and its main purpose is defining the [binary caches](https://nixos.org/nix/manual/#ch-basic-package-mgmt) which allow download of packages to avoid having to compile them yourself locally.

__NOTE:__ If you are in Asia you might want to add the `https://nix-cache-cn.status.im/` to be first in order of `substituters`. Removing `cache.nixos.org` could also help.

## Build arguments

We leverage the standard nixpkgs `config` argument for our own parameterization of the builds (e.g. to pass a build number or build type).

Here is a sample structure of the `config` attribute set:

```nix
config = {
  status-im = {
    build-type = "pr";       # Build type (influences which .env file gets used for feature flags)
    build-number = 9999;     # Used for versionCode and CFBundleVersion in Android and iOS respectively
    android = {
      gradle-opts = "";      # Gradle options passed for Android builds
      keystore-path = "";    # Path to keystore for signing the APK
      abi-split = false;     # If APKs should be split based on architectures
      abi-include = "x86";   # Android architectures to build for
    };
    status-go = {
      src-override = "$HOME/my/source/status-go"; # local source override
    };
  };
};
```

## Shell

In order to access an interactive Nix shell a user should run `make shell`.

The Nix shell is started in this repo via the [`nix/scripts/shell.sh`](/nix/scripts/shell.sh) script, which is a wrapper around the `nix-shell` command and is intended for use with our main [`Makefile`](/Makefile). This allows for an implicit use of `nix-shell` as the default shell in the `Makefile`.

Normally the shell starts without any specific target platform, if you want to change that you should export the `TARGET` env variable with appropriate value:

```bash
make shell TARGET=android
```

This way your shell and all other nix commands should run in a setup that is tailored towards Android development.

For valid values you can check the [`nix/shells.nix`](/nix/shells.nix) file.

## Using a local status-go repository

If you need to use a locally checked-out status-go repository, you can achieve that by defining the `STATUS_GO_SRC_OVERRIDE`
environment variable:

```sh
export STATUS_GO_SRC_OVERRIDE=$GOPATH/src/github.com/status-im/status-go
make release-android
```

## Known Issues

See [`KNOWN_ISSUES.md`](./KNOWN_ISSUES.md).