nix: move nix-purge code to nix/scripts/purge.sh

Signed-off-by: Jakub Sokołowski <jakub@status.im>

Makefile

@@ -41,15 +41,11 @@ export REACT_SERVER_PORT ?= 5001
 export NIX_CONF_DIR = $(PWD)/nix
 # Defines which variables will be kept for Nix pure shell, use semicolon as divider
 export _NIX_KEEP ?= TMPDIR,BUILD_ENV,STATUS_GO_SRC_OVERRIDE,NIMBUS_SRC_OVERRIDE
-export _NIX_ROOT = /nix
 # legacy TARGET_OS variable support
 ifdef TARGET_OS
 export TARGET ?= $(TARGET_OS)
 endif
 
-# Useful for checking if we are on NixOS
-OS_NAME := $(shell [ -f /etc/os-release ] && awk -F= '/^NAME/{print $2}' /etc/os-release)
-
 # Useful for Andoird release builds
 TMP_BUILD_NUMBER := $(shell ./scripts/version/gen_build_no.sh | cut -c1-10)
 
@@ -57,7 +53,6 @@ TMP_BUILD_NUMBER := $(shell ./scripts/version/gen_build_no.sh | cut -c1-10)
 UNAME_S := $(shell uname -s)
 ifeq ($(UNAME_S),Darwin)
 export NIX_IGNORE_SYMLINK_STORE=1
-export _NIX_ROOT = /opt/nix
 endif
 
 #----------------
@@ -78,19 +73,17 @@ else
 	@echo "${YELLOW}Nix shell is already active$(RESET)"
 endif
 
+nix-gc: export TARGET := default
 nix-gc: ##@nix Garbage collect all packages older than 20 days from /nix/store
 	nix-collect-garbage --delete-old --delete-older-than 20d
 
+nix-clean: export TARGET := default
 nix-clean: ##@nix Remove all status-react build artifacts from /nix/store
 	nix/scripts/clean.sh
 
 nix-purge: SHELL := /bin/sh
-nix-purge: ##@nix Completely remove the complete Nix setup
+nix-purge: ##@nix Completely remove Nix setup, including /nix directory
-ifeq ($(OS_NAME), NixOS)
+	nix/scripts/purge.sh
-	$(error $(RED)You should not purge Nix files on NixOS!$(RESET))
-else
-	sudo rm -rf $(_NIX_ROOT)/* ~/.nix-profile ~/.nix-defexpr ~/.nix-channels ~/.cache/nix ~/.status .nix-gcroots
-endif
 
 nix-add-gcroots: export TARGET := default
 nix-add-gcroots: ##@nix Add Nix GC roots to avoid status-react expressions being garbage collected

nix/scripts/purge.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+set -e
+
+GIT_ROOT=$(cd "${BASH_SOURCE%/*}" && git rev-parse --show-toplevel)
+source "${GIT_ROOT}/scripts/colors.sh"
+
+# Purging /nix on NixOS would be disasterous
+if [[ -f "/etc/os-release" ]]; then
+    OS_NAME=$(awk -F= '/^NAME/{print $2}' /etc/os-release)
+    if [[ "$OS_NAME" == "NixOS" ]]; then
+        echo -e "${RED}You should not purge Nix files on NixOS!${RST}" >&2
+        exit
+    fi
+fi
+
+NIX_ROOT="/nix"
+if [[ $(uname -s) == "Darwin" ]]; then
+    # Special case due to read-only root on MacOS Catalina
+    NIX_ROOT="/opt/nix"
+fi
+
+sudo rm -rf ${NIX_ROOT}/* ~/.nix-profile ~/.nix-defexpr ~/.nix-channels ~/.cache/nix ~/.status .nix-gcroots
+echo -e "${GRN}Purged all Nix files from your system.${RST}" >&2

nix/scripts/setup.sh

@@ -15,14 +15,14 @@ function install_nix() {
   if [ $? -eq 0 ]; then
     echo -e "${GRN}The Nix package manager was successfully installed.${RST}"
   else
-    echo -e "${RED}Failed to install Nix package manager!${RST}" > /dev/stderr
+    echo -e "${RED}Failed to install Nix package manager!${RST}" >&2
-    echo "Please see: https://nixos.org/nix/manual/#chap-installation" > /dev/stderr
+    echo "Please see: https://nixos.org/nix/manual/#chap-installation" >&2
     exit 1
   fi
 }
 
 if [[ ! -x "$(command -v git)" ]]; then
-  echo -e "${RED}The 'curl' utility is required for Nix installation.${RST}" > /dev/stderr
+  echo -e "${RED}The 'curl' utility is required for Nix installation.${RST}" >&2
   exit 1
 fi