use Cachix in GitHub Action

Author: peterbecich

.github/workflows/nix-shell.yml

@@ -13,33 +13,16 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/[email protected]
-    # https://github.com/cachix/install-nix-action/issues/56
-    - run: |
-        sudo mkdir -p /nix/store
-        sudo chmod -R 777 /nix
-
-    - name: Cache nix env take N+1
-      uses: actions/[email protected]
-      with:
-        path: /nix/store
-          # See https://github.com/actions/cache/pull/726
-          # /nix/store/**
-          # Missing something?
-          # /nix/var/nix/*/*
-          # /nix/var/nix/db/*
-          # /nix/var/nix/db/*/**
-          # !/nix/var/nix/daemon-socket/socket
-          # !/nix/var/nix/userpool/*
-          # !/nix/var/nix/gc.lock
-          # !/nix/var/nix/db/big-lock
-          # !/nix/var/nix/db/reserved
-        key: ${{ runner.os }}-nix-store-${{ hashFiles('/nix/store/**') }}
-        restore-keys: ${{ runner.os }}-nix-store-
-
     - uses: cachix/install-nix-action@v16
       with:
         nix_path: nixpkgs=channel:nixos-21.11
         extra_nix_config: |
           trusted-public-keys = hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
           substituters = https://hydra.iohk.io https://cache.nixos.org/
+    - uses: cachix/cachix-action@v10
+      with:
+        # https://nix.dev/tutorials/continuous-integration-github-actions#setting-up-github-actions
+        # name: mycache ## TODO should this be set to name of Cachix account?
+        signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'
+        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
     - run: nix-shell --pure --run "cabal update && cabal build all --enable-tests"