ci: add KOCACHE to speed up ko builds in GitHub Actions

Port KOCACHE optimization from pipelines-as-code to tektoncd/pipeline.
This caches ko layer metadata between workflow runs, avoiding redundant
compression and speeding up builds on cache hits.

Changes:
- ci.yaml: Add KOCACHE to multi-arch-build job
- e2e-matrix.yml: Add KOCACHE to e2e-tests job (with arch in cache key)
- e2e-matrix-extras.yaml: Add KOCACHE to e2e-extras job

Signed-off-by: Vincent Demeester <vdemeest@redhat.com>

Author: vdemeester

.github/workflows/ci.yaml

@@ -151,11 +151,20 @@ jobs:
     needs: [build]
     name: Multi-arch build
     runs-on: ubuntu-latest
+    env:
+      KOCACHE: /tmp/ko-cache
     steps:
     - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8  # v6.0.1
     - uses: actions/setup-go@7a3fe6cf4cb3a834922a1244abfce67bcef6a0c5  # v6.2.0
       with:
         go-version-file: "go.mod"
+    - name: Cache ko build cache
+      uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684  # v4.2.3
+      with:
+        path: /tmp/ko-cache
+        key: ${{ runner.os }}-${{ runner.arch }}-ko-${{ hashFiles('go.sum') }}
+        restore-keys: |
+          ${{ runner.os }}-${{ runner.arch }}-ko-
     - uses: ko-build/setup-ko@d006021bd0c28d1ce33a07e7943d48b079944c8d # v0.9
     - name: ko-resolve
       run: |

.github/workflows/e2e-matrix-extras.yaml

@@ -94,6 +94,7 @@ jobs:
       KO_DOCKER_REPO: registry.local:5000/tekton
       CLUSTER_DOMAIN: c${{ github.run_id }}.local
       ARTIFACTS: ${{ github.workspace }}/artifacts
+      KOCACHE: /tmp/ko-cache
     steps:
     - name: Report tests check
       uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
@@ -116,6 +117,13 @@ jobs:
     - uses: actions/setup-go@7a3fe6cf4cb3a834922a1244abfce67bcef6a0c5  # v6.2.0
       with:
         go-version-file: "go.mod"
+    - name: Cache ko build cache
+      uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684  # v4.2.3
+      with:
+        path: /tmp/ko-cache
+        key: ${{ runner.os }}-${{ runner.arch }}-ko-${{ hashFiles('go.sum') }}
+        restore-keys: |
+          ${{ runner.os }}-${{ runner.arch }}-ko-
     - uses: ko-build/setup-ko@d006021bd0c28d1ce33a07e7943d48b079944c8d # v0.9
 
     - name: Install Dependencies

.github/workflows/e2e-matrix.yml

@@ -50,6 +50,7 @@ jobs:
       KO_DOCKER_REPO: registry.local:5000/tekton
       CLUSTER_DOMAIN: c${{ github.run_id }}.local
       ARTIFACTS: ${{ github.workspace }}/artifacts
+      KOCACHE: /tmp/ko-cache
 
     steps:
     - name: Free disk space
@@ -68,6 +69,13 @@ jobs:
     - uses: actions/setup-go@7a3fe6cf4cb3a834922a1244abfce67bcef6a0c5  # v6.2.0
       with:
         go-version-file: "go.mod"
+    - name: Cache ko build cache
+      uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684  # v4.2.3
+      with:
+        path: /tmp/ko-cache
+        key: ${{ runner.os }}-${{ runner.arch }}-ko-${{ hashFiles('go.sum') }}
+        restore-keys: |
+          ${{ runner.os }}-${{ runner.arch }}-ko-
     - uses: ko-build/setup-ko@d006021bd0c28d1ce33a07e7943d48b079944c8d # v0.9
 
     - name: Install Dependencies