Update documentation for save and restore

save/README.md

@@ -1,6 +1,6 @@
-# Save action
+# Save Action with Google Cloud Storage Support
 
-The save action saves a cache. It works similarly to the `cache` action except that it doesn't first do a restore. This action provides granular ability to save a cache without having to restore it, or to do a save at any stage of the workflow job -- not only in post phase.
+The save action saves a cache to Google Cloud Storage (GCS) with fallback to GitHub's cache backend. This action provides the granular ability to save a cache without first having to restore it, or to save a cache at any stage of the workflow job—not only in the post phase.
 
 ## Documentation
 
@@ -9,6 +9,30 @@ The save action saves a cache. It works similarly to the `cache` action except t
 * `key` - An explicit key for a cache entry. See [creating a cache key](../README.md#creating-a-cache-key).
 * `path` - A list of files, directories, and wildcard patterns to cache. See [`@actions/glob`](https://github.com/actions/toolkit/tree/main/packages/glob) for supported patterns.
 * `upload-chunk-size` - The chunk size used to split up large files during upload, in bytes
+* `gcs-bucket` - Google Cloud Storage bucket name to use for caching. When provided, GCS will be used as the cache backend.
+* `gcs-path-prefix` - Optional prefix path within the GCS bucket for cache files. Default: `github-cache`
+
+### GCS Authentication
+
+This action uses [Application Default Credentials (ADC)](https://cloud.google.com/docs/authentication/application-default-credentials) to authenticate with Google Cloud. The recommended approach is to use the official Google Cloud auth action before using this action:
+
+```yaml
+- uses: google-github-actions/auth@v2
+  with:
+    # Using Service Account Key JSON (less secure)
+    credentials_json: ${{ secrets.GCP_CREDENTIALS }}
+    
+    # Alternatively, use Workload Identity Federation (more secure)
+    # workload_identity_provider: ${{ secrets.WIF_PROVIDER }}
+    # service_account: ${{ secrets.WIF_SERVICE_ACCOUNT }}
+```
+
+For Workload Identity Federation, your workflow will need these permissions:
+```yaml
+permissions:
+  contents: 'read'
+  id-token: 'write' # Required for workload identity federation
+```
 
 ### Outputs
 
@@ -31,11 +55,12 @@ steps:
   - name: Build artifacts
     run: /build.sh
 
-  - uses: actions/cache/save@v4
+  - uses: danySam/gcs-cache/save@v1
     id: cache
     with:
       path: path/to/dependencies
       key: ${{ runner.os }}-${{ hashFiles('**/lockfiles') }}
+      gcs-bucket: my-github-cache-bucket # Optional: Use GCS for caching
 ```
 
 ### Re-evaluate cache key while saving
@@ -47,15 +72,16 @@ Let's say we have a restore step that computes a key at runtime.
 #### Restore a cache
 
 ```yaml
-uses: actions/cache/restore@v4
+uses: danySam/gcs-cache/restore@v1
 id: restore-cache
 with:
     key: cache-${{ hashFiles('**/lockfiles') }}
+    gcs-bucket: my-github-cache-bucket
 ```
 
 #### Case 1 - Where a user would want to reuse the key as it is
 ```yaml
-uses: actions/cache/save@v4
+uses: danySam/gcs-cache/save@v1
 with:
     key: ${{ steps.restore-cache.outputs.cache-primary-key }}
 ```
@@ -63,16 +89,17 @@ with:
 #### Case 2 - Where the user would want to re-evaluate the key
 
 ```yaml
-uses: actions/cache/save@v4
+uses: danySam/gcs-cache/save@v1
 with:
     key: npm-cache-${{hashfiles(package-lock.json)}}
+    gcs-bucket: my-github-cache-bucket
 ```
 
 ### Always save cache
 
 There are instances where some flaky test cases would fail the entire workflow and users would get frustrated because the builds would run for hours and the cache couldn't be saved as the workflow failed in between.
-For such use-cases, users now have the ability to use the `actions/cache/save` action to save the cache by using an [`always()`](https://docs.github.com/actions/writing-workflows/choosing-what-your-workflow-does/expressions#always) condition.
-This way the cache will always be saved if generated, or a warning will be generated that nothing is found on the cache path. Users can also use the `if` condition to only execute the `actions/cache/save` action depending on the output of previous steps. This way they get more control of when to save the cache.
+For such use-cases, users now have the ability to use the `danySam/gcs-cache/save` action to save the cache by using an [`always()`](https://docs.github.com/actions/writing-workflows/choosing-what-your-workflow-does/expressions#always) condition.
+This way the cache will always be saved if generated, or a warning will be generated that nothing is found on the cache path. Users can also use the `if` condition to only execute the `danySam/gcs-cache/save` action depending on the output of previous steps. This way they get more control of when to save the cache.
 
 To avoid saving a cache that already exists, the `cache-hit` output from a restore step should be checked.
 
@@ -95,19 +122,20 @@ jobs:
 
     - name: Restore cached Prime Numbers
       id: cache-prime-numbers-restore
-      uses: actions/cache/restore@v4
+      uses: danySam/gcs-cache/restore@v1
       with:
         key: ${{ runner.os }}-prime-numbers
         path: |
           path/to/dependencies
           some/other/dependencies
+        gcs-bucket: my-github-cache-bucket
 
     # Intermediate workflow steps
 
     - name: Always Save Prime Numbers
       id: cache-prime-numbers-save
       if: always() && steps.cache-prime-numbers-restore.outputs.cache-hit != 'true'
-      uses: actions/cache/save@v4
+      uses: danySam/gcs-cache/save@v1
       with:
         key: ${{ steps.cache-prime-numbers-restore.outputs.cache-primary-key }}
         path: |