CI: Cache virtual environments

nedbat · Jul 21, 2023 · 90064b8 · 90064b8
1 parent 7727ac5
commit 90064b8
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diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
@@ -37,6 +37,7 @@ jobs:
         uses: "actions/checkout@v3"
 
       - name: "Set up Python"
+        id: "setup-python"
         uses: "actions/setup-python@v4"
         with:
           # The last listed Python version is the default.
@@ -47,13 +48,26 @@ jobs:
             3.9
             3.10
             3.11
-          cache: pip
-          cache-dependency-path: 'requirements/*.txt'
+
+      - name: "Restore cache"
+        id: "restore-cache"
+        uses: "actions/cache@v3"
+        with:
+          path: |
+            .tox/
+            .venv/
+          key: "cache-python-${{ steps.setup-python.outputs.python-version }}-os-${{ runner.os }}-hash-${{ hashFiles('tox.ini', 'requirements/*.txt') }}"
+
+      - name: "Identify venv path"
+        shell: "bash"
+        run: "echo 'venv-path=${{ runner.os == 'Windows' && '.venv/Scripts' || '.venv/bin' }}' >> $GITHUB_ENV"
 
       - name: "Install dependencies"
+        if: "steps.restore-cache.outputs.cache-hit == false"
         run: |
-          python -m pip install -U setuptools
-          python -m pip install -r requirements/tox.txt
+          python -m venv .venv
+          ${{ env.venv-path }}/python -m pip install -U setuptools
+          ${{ env.venv-path }}/python -m pip install -r requirements/tox.txt
 
       - name: "Install pandoc on Linux"
         # sudo apt-get pandoc: will install a version from 2018!
@@ -74,7 +88,7 @@ jobs:
 
       - name: "Run tox"
         run: |
-          python -m tox -m ci-tests
+          ${{ env.venv-path }}/python -m tox -m ci-tests
 
       - name: "Upload coverage data"
         uses: actions/upload-artifact@v3

diff --git a/changelog.d/20230206_072342_kurtmckee_reduce_ci_usage.rst b/changelog.d/20230206_072342_kurtmckee_reduce_ci_usage.rst
@@ -0,0 +1,12 @@
+Changed
+.......
+
+-   Create and cache a virtual environment in CI, as well as the tox environments.
+
+    With a cache hit, this decreases CI total usage from ~15 minutes to ~10 minutes.
+    It decreases CI duration from ~7 minutes to ~5 minutes.
+
+    The cache keys hash ``requirements/*.txt`` and ``tox.ini``.
+    GitHub caches are branch-specific, but if no cache is found for the current branch,
+    the cache for the ``main`` branch will then be checked.
+    It is anticipated that most branches will therefore have a cache hit.