Add a buildkit-cache workspace for preserving the buildkit cache between builds.

task/buildkit-rootless-daemonless/0.1/buildkit-rootless-daemonless.yaml

@@ -22,6 +22,10 @@ spec:
       description: Includes credentials for the docker image registry.
       optional: true
       mountPath: /home/user/.docker
+    - name: buildkit-cache
+      description: For preserving buildkit type=cache mounts between builds.
+      optional: true
+      mountPath: /home/user/.local/share/buildkit
   params:
     - name: OUTPUT
       type: string
@@ -57,13 +61,23 @@ spec:
       description: Full URL to the docker image.
       type: array
   volumes:
-    - name: buildkitd
-      emptyDir: {}
     - name: buildkitd-toml
       emptyDir: {}
     - name: metadata-out
       emptyDir: {}
   steps:
+    - name: setup-cache-ownership
+      image: $(params.BUILDER_IMAGE)
+      workingDir: "$(workspaces.source.path)"
+      script: |
+        #!/usr/bin/env sh
+        set -euo pipefail
+        chown 1000:1000 /home/user/.local/share/buildkit
+        chmod 0777 /home/user/.local/share/buildkit
+      securityContext:
+        runAsNonRoot: false
+        runAsUser: 0
+        runAsGroup: 0
     - name: write-config
       image: $(params.BUILDER_IMAGE)
       workingDir: "$(workspaces.source.path)"
@@ -87,8 +101,6 @@ spec:
         EOF
         chmod +x /home/user/.config/buildkit/entrypoint.sh
       volumeMounts:
-        - name: buildkitd
-          mountPath: /home/user/.local/share/buildkit
         - name: buildkitd-toml
           mountPath: /home/user/.config/buildkit
       securityContext:
@@ -112,8 +124,6 @@ spec:
         - /home/user/.metadata/build.json
         - $(params.EXTRA_ARGS)
       volumeMounts:
-        - name: buildkitd
-          mountPath: /home/user/.local/share/buildkit
         - name: buildkitd-toml
           mountPath: /home/user/.config/buildkit
           readOnly: true