feat(ci): nix cache for staging and testnet-internal

.github/workflows/nix-cache.yml

@@ -0,0 +1,49 @@
+name: Nix Cache
+
+on:
+  workflow_dispatch:
+  push:
+    # Only build nix cache for branches that need distribution
+    branches: [ "staging", "testnet-internal", "o/nix-ci" ]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  # build & cache project dependencies
+  deps:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v25
+    - uses: cachix/cachix-action@v14
+      with:
+        name: fleek-network
+        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+    - run: nix build .#lightning-deps
+
+  # build & cache node binary
+  node:
+    runs-on: ubuntu-latest
+    needs: deps
+    steps:
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v25
+    - uses: cachix/cachix-action@v14
+      with:
+        name: fleek-network
+        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+    - run: nix build .#lightning-node
+
+  # build & cache services binaries
+  services:
+    runs-on: ubuntu-latest
+    needs: deps
+    steps:
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v25
+    - uses: cachix/cachix-action@v14
+      with:
+        name: fleek-network
+        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+    - run: nix build .#lightning-services

flake.nix

@@ -16,7 +16,6 @@
     };
 
     flake-utils.url = "github:numtide/flake-utils";
-
   };
 
   outputs = { self, nixpkgs, crane, fenix, flake-utils, ... }:
@@ -186,6 +185,9 @@
             name = "lightning-node-full";
             paths = [ lightning-node lightning-services ];
           };
+
+          # Expose for standalone ci step
+          lightning-deps = cargoArtifacts;
         } // lib.optionalAttrs (!pkgs.stdenv.isDarwin) {
           lightning-llvm-coverage = llvmCraneLib.cargoLlvmCov
             (commonArgs // { inherit cargoArtifacts; });