fix: cache dir

setup-db/README.md

@@ -4,6 +4,8 @@ A reusable Gitea Action that sets up the Trivy vulnerability database, restoring
 
 The action runs Trivy inside **Docker** with a restricted container configuration so the Trivy runtime is isolated from the host while the database is downloaded into your cache directory.
 
+The default **`cache-dir`** is under **`${{ github.workspace }}`** so the path is visible to the Docker daemon when jobs run inside a container (bind-mounting e.g. `/tmp/...` often fails because that path does not exist on the Docker host).
+
 **Note:** This action only prepares the vulnerability database. If you run Trivy on the runner host for scans (for example `trivy fs .`), install Trivy separately (e.g. with a `setup-trivy` action or your own step).
 
 ## Usage
@@ -38,9 +40,9 @@ jobs:
 
 ## Inputs
 
-| Input            | Description                                                                 | Required | Default |
-| ---------------- | --------------------------------------------------------------------------- | -------- | ------- |
-| `cache-dir`      | Path to the Trivy cache directory                                           | No       | `${{ runner.temp }}/trivy` |
-| `trivy-version`  | Docker image reference for Trivy (digest pin recommended)                   | No       | Pinned `ghcr.io/aquasecurity/trivy` image in `action.yaml` |
+| Input           | Description                                               | Required | Default                                                    |
+| --------------- | --------------------------------------------------------- | -------- | ---------------------------------------------------------- |
+| `cache-dir`     | Path to the Trivy cache directory                         | No       | `${{ github.workspace }}/.trivy-cache`                     |
+| `trivy-version` | Docker image reference for Trivy (digest pin recommended) | No       | Pinned `ghcr.io/aquasecurity/trivy` image in `action.yaml` |
 
 **`trivy-version` is optional.** If you omit it, the action uses the default image (version and digest) from `action.yaml`. Set it only when you need a different Trivy image or your own digest pin.

setup-db/action.yaml

@@ -7,9 +7,9 @@ branding:
 
 inputs:
   cache-dir:
-    description: "Path to the Trivy cache directory (default: ${{runner.temp}}/trivy)"
+    description: "Path to the Trivy cache directory (default: under the workspace so Docker bind mounts work on containerized runners)"
     required: false
-    default: "${{ runner.temp }}/trivy"
+    default: "${{ github.workspace }}/.trivy-cache"
   trivy-version:
     description: "Trivy docker image version to use (full image reference including digest is recommended)"
     required: false
@@ -23,6 +23,9 @@ outputs:
 runs:
   using: "composite"
   steps:
+    - name: Ensure cache directory exists
+      shell: bash
+      run: mkdir -p "${{ inputs.cache-dir }}"
     - id: current-date
       shell: bash
       run: |