ci: Try caching in the nix build

.gitea/workflows/deploy.sh

@@ -8,15 +8,13 @@ on:
     - '*.*.*'
 jobs:
   build-deploy-ubuntu:
-    env:
-      RUNNER_TOOL_CACHE: /toolcache
     # Is it a risk to Ouroboros this?
     # Really want this to be able to run on ubuntu but it is a slow run.
     runs-on: ubuntu-latest
     # runs-on: nix-runner
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0 # Fetch all history for tags
       - name: Install Nix
@@ -58,22 +56,36 @@ jobs:
         run: |
           nix develop -c bash scripts/deploy.sh
   nix-check:
-    env:
-      RUNNER_TOOL_CACHE: /toolcache
     runs-on: nix-runner
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0 # Fetch all history for tags
+      - name: "Cache Nix store"
+        uses: actions/cache@v4
+        id: nix-cache
+        with:
+          path: /tmp/nixcache
+          key: nix-${{ runner.os }}-nix-builder-image-${{ hashFiles('**/package.json', 'package-lock.json', '**/*.nix', '**/flake.lock', '.npmrc', '.eleventy.js') }}
+          restore-keys: |
+            nix-${{ runner.os }}-nix-builder-image
       - name: Setup Attic Cache
         uses: ryanccn/attic-action@3354ae812cb672e1381be4c7914204c44db53866
         with:
           endpoint: ${{ secrets.ATTIC_ENDPOINT }}
           cache: ${{ secrets.ATTIC_CACHE }}
           token: ${{ secrets.ATTIC_TOKEN }}
+      - name: "Import Nix store cache"
+        continue-on-error: true
+        # if: "steps.nix-cache.outputs.cache-hit == 'true'"
+        run: bash scripts/restore_cache.sh
       - name: Build container
         run: nix build .#act-runner-image
       - name: Check Nix flake
         run: nix flake check
         id: flake-check
+      - name: "Export Nix store cache"
+        if: always()
+        # if: "steps.nix-cache.outputs.cache-hit != 'true'"
+        run: bash scripts/populate_cache.sh

scripts/populate_cache.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+set -Eeuox pipefail
+
+CACHE_PATH=${CACHE_PATH:-"/tmp/nixcache"}
+
+banner() {
+  echo "========================================================"
+  echo "  $*"
+  echo "========================================================"
+}
+
+banner "List what we start with"
+
+nix-store --query --requisites --include-outputs "$(nix eval .\#devShells.x86_64-linux.default.drvPath --raw)" >dependencies.txt
+nix-store --query --requisites --include-outputs "$(nix eval .\#packages.x86_64-linux.default.drvPath --raw)" >>dependencies.txt
+# nix-store --query --requisites --include-outputs "$(nix eval .\#checks.x86_64-linux.formatting.drvPath --raw)" >>dependencies.txt
+# nix-store --query --requisites --include-outputs "$(nix eval .\#checks.x86_64-linux.test-check.drvPath --raw)" >>dependencies.txt
+nix-store --query --requisites --include-outputs "$(nix eval .\#formatter.x86_64-linux.drvPath --raw)" >>dependencies.txt
+
+sort -o dependencies.txt -u dependencies.txt
+
+banner "list obtained paths to cache"
+
+wc -l dependencies.txt
+
+banner "filter out our matches"
+
+echo "Using filter"
+cat scripts/populate_cache_exclude_patterns.txt
+
+grep -vf scripts/populate_cache_exclude_patterns.txt dependencies.txt >filtered_dependencies.txt
+
+echo "Count our filtered"
+wc -l filtered_dependencies.txt
+
+xargs <filtered_dependencies.txt -r nix copy --to "file://${CACHE_PATH}" --no-substitute
+
+banner "done with populating cache"

scripts/restore_cache.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+set -Eeuo pipefail
+
+CACHE_PATH=${CACHE_PATH:-"/tmp/nixcache"}
+
+banner() {
+  echo "========================================================"
+  echo "  $*"
+  echo "========================================================"
+}
+
+# banner "List what we start with"
+# ls -alh "${CACHE_PATH}"
+
+banner "Copy time"
+nix copy --from "file://${CACHE_PATH}" --no-check-sigs --all