Localise pytools cache to each runner

Previously we were sharing a cache between runners ($XDG_CACHE_HOME is
in the home directory) and so different would be clearing it at
different times.

.github/workflows/build-mac.yml

@@ -26,6 +26,7 @@ jobs:
       FIREDRAKE_CI_TESTS: 1  # needed to symlink the checked out branch into the venv
       OMP_NUM_THREADS: 1
       OPENBLAS_NUM_THREADS: 1
+      XDG_CACHE_HOME: ${{ github.workspace }}/.cache
     steps:
       - name: Add homebrew to PATH
         # https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/workflow-commands-for-github-actions#adding-a-system-path
@@ -35,7 +36,7 @@ jobs:
         if: ${{ always() }}
         run: |
           cd ..
-          rm -rf firedrake_venv
+          rm -rf firedrake_venv "$XDG_CACHE_HOME"
       - name: Install Python
         run: brew install python python-setuptools
       - name: Build Firedrake
@@ -58,4 +59,4 @@ jobs:
         if: ${{ always() }}
         run: |
           cd ..
-          rm -rf firedrake_venv
+          rm -rf firedrake_venv "$XDG_CACHE_HOME"

.github/workflows/build.yml

@@ -47,13 +47,14 @@ jobs:
       OPENBLAS_NUM_THREADS: 1
       COMPLEX: ${{ matrix.complex }}
       RDMAV_FORK_SAFE: 1
+      XDG_CACHE_HOME: ${{ github.workspace }}/.cache
     steps:
       - uses: actions/checkout@v4
       - name: Cleanup
         if: ${{ always() }}
         run: |
           cd ..
-          rm -rf firedrake_venv
+          rm -rf firedrake_venv "$XDG_CACHE_HOME"
       - name: Build Firedrake
         run: |
           cd ..
@@ -134,7 +135,7 @@ jobs:
         if: ${{ always() }}
         run: |
           cd ..
-          rm -rf firedrake_venv
+          rm -rf firedrake_venv "$XDG_CACHE_HOME"
   docker_tag:
     name: "Set the Docker release tag"
     runs-on: [self-hosted, Linux]

.github/workflows/pip-mac.yml

@@ -25,6 +25,7 @@ jobs:
     env:
       OMP_NUM_THREADS: 1
       OPENBLAS_NUM_THREADS: 1
+      XDG_CACHE_HOME: ${{ github.workspace }}/.cache
     steps:
       - name: Add homebrew to PATH
         # https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/workflow-commands-for-github-actions#adding-a-system-path
@@ -36,7 +37,7 @@ jobs:
       - name: Cleanup (pre)
         if: ${{ always() }}
         run: |
-          rm -rf pip_venv
+          rm -rf pip_venv "$XDG_CACHE_HOME"
           "$(brew --prefix)/bin/python3" -m pip cache purge
 
       - name: Create a virtual environment
@@ -108,5 +109,5 @@ jobs:
       - name: Cleanup (post)
         if: ${{ always() }}
         run: |
-          rm -rf pip_venv
+          rm -rf pip_venv "$XDG_CACHE_HOME"
           "$(brew --prefix)/bin/python3" -m pip cache purge

.github/workflows/pip.yml

@@ -42,10 +42,11 @@ jobs:
       OMP_NUM_THREADS: 1
       OPENBLAS_NUM_THREADS: 1
       RDMAV_FORK_SAFE: 1
+      XDG_CACHE_HOME: ${{ github.workspace }}/.cache
     steps:
       - name: Cleanup
         if: ${{ always() }}
-        run: rm -rf pip_venv
+        run: rm -rf pip_venv "$XDG_CACHE_HOME"
 
       - name: Create a venv
         run: |
@@ -107,4 +108,4 @@ jobs:
       - name: Cleanup
         # Belt and braces: clean up before and after the run.
         if: ${{ always() }}
-        run: rm -rf pip_venv
+        run: rm -rf pip_venv "$XDG_CACHE_HOME"

.github/workflows/pyop2.yml

@@ -20,9 +20,14 @@ jobs:
       PETSC_ARCH: default
       RDMAV_FORK_SAFE: 1
       PYOP2_CI_TESTS: 1
+      XDG_CACHE_HOME: ${{ github.workspace }}/.cache
     timeout-minutes: 60
 
     steps:
+      - name: Pre-run cleanup
+        if: ${{ always() }}
+        run: rm -rf firedrake "$XDG_CACHE_HOME"
+
       - name: Install system dependencies
         shell: bash
         run: |
@@ -91,3 +96,7 @@ jobs:
           mpiexec -n 2 --oversubscribe pytest -m "parallel[2]" --tb=native --timeout=480 --timeout-method=thread -o faulthandler_timeout=540 -v tests/pyop2
           mpiexec -n 3 --oversubscribe pytest -m "parallel[3]" --tb=native --timeout=480 --timeout-method=thread -o faulthandler_timeout=540 -v tests/pyop2
         timeout-minutes: 10
+
+      - name: Post-run cleanup
+        if: ${{ always() }}
+        run: rm -rf firedrake "$XDG_CACHE_HOME"