Better GitHub CI caching strategy for golang (k3s-io#9495)

Signed-off-by: Derek Nola <derek.nola@suse.com>

.github/actions/setup-go/actions.yaml

@@ -0,0 +1,27 @@
+name: 'Setup golang with master only caching'
+description: 'A composite action that installs golang, but with a caching strategy that only updates the cache on master branch.'
+runs:
+  using: 'composite'
+  steps:
+    - uses: actions/setup-go@v5
+      with:
+        go-version-file: 'go.mod'  # Just use whatever version is in the go.mod file
+        cache: ${{ github.ref == 'refs/heads/master' }}
+
+    - name: Prepare for go cache
+      if: ${{ github.ref != 'refs/heads/master' }}
+      run: |
+        echo "GO_CACHE=$(go env GOCACHE)" | tee -a "$GITHUB_ENV"
+        echo "GO_MODCACHE=$(go env GOMODCACHE)" | tee -a "$GITHUB_ENV"
+        echo "GO_VERSION=$(go env GOVERSION | tr -d 'go')" | tee -a "$GITHUB_ENV"
+
+    - name: Setup read-only cache
+      if: ${{ github.ref != 'refs/heads/master' }}
+      uses: actions/cache/restore@v4
+      with:
+        path: |
+          ${{ env.GO_MODCACHE }}
+          ${{ env.GO_CACHE }}
+        key: setup-go-${{ runner.os }}-go-${{ env.GO_VERSION }}-${{ hashFiles('go.sum') }}
+        restore-keys: |
+          setup-go-${{ runner.os }}-

.github/workflows/integration.yaml

@@ -46,14 +46,7 @@ jobs:
       with:
         fetch-depth: 1
     - name: Install Go
-      uses: actions/setup-go@v5
-      with: 
-        go-version: '1.21.7'
-        check-latest: true
-        cache: true
-        cache-dependency-path: |
-          **/go.sum
-          **/go.mod
+      uses: .github/actions/setup-go
     - name: "Download k3s binary"
       uses: actions/download-artifact@v3
       with:

.github/workflows/unitcoverage.yaml

@@ -36,10 +36,7 @@ jobs:
       with:
         fetch-depth: 1
     - name: Install Go
-      uses: actions/setup-go@v5
-      with: 
-        go-version-file: go.mod # Just use whatever version is in the go.mod file
-        check-latest: true
+      uses: .github/actions/setup-go
     - name: Run Unit Tests
       run: | 
         go test -coverpkg=./... -coverprofile=coverage.out ./pkg/... -run Unit

.github/workflows/updatecli.yaml

@@ -26,7 +26,7 @@ jobs:
         uses: actions/setup-go@v5
         with:
           go-version: 'stable'
-
+          cache: false
       - name: Delete leftover UpdateCLI branches
         run: |
           gh pr list --search "is:closed is:pr head:updatecli_" --json headRefName --jq ".[].headRefName" | sort -u > closed_prs_branches.txt