Add actions/cache/check action

check/README.md

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+# Check action
+
+The check action checks if a cache entry exists without actually downloading it.
+
+## Inputs
+
+* `path` - A list of files, directories, and wildcard patterns to cache and restore. See [`@actions/glob`](https://github.com/actions/toolkit/tree/main/packages/glob) for supported patterns.
+* `key` - String used while saving cache for restoring the cache
+* `restore-keys` - An ordered list of prefix-matched keys to use for restoring stale cache if no cache hit occurred for key.
+* `fail-on-cache-miss` - Fail the workflow if cache entry is not found. Default: false
+
+## Outputs
+
+* `cache-hit` - A boolean value to indicate an exact match was found for the key. 
+* `cache-primary-key` - Cache primary key passed in the input to use in subsequent steps of the workflow.
+* `cache-matched-key` -  Key of the cache that was restored, it could either be the primary key on cache-hit or a partial/complete match of one of the restore keys.
+
+> **Note**
+`cache-hit` will be set to `true` only when cache hit occurs for the exact `key` match. For a partial key match via `restore-keys` or a cache miss, it will be set to `false`.
+
+## Use cases
+
+As this is a newly introduced action to give users more control in their workflows, below are some use cases where one can use this action.
+
+### Skip downloading cache if entry exists
+
+Sometimes it's useful to separate build and test jobs. In that case it's not necessary
+to restore the cache in the first job if an entry already exists.
+
+#### Step 1 - Build artifact only if cache doesn't exist 
+
+```yaml
+build:
+  steps:
+    - uses: actions/checkout@v3
+    
+    - users: actions/cache/check@v3
+      id: cache-check
+      with:
+        path: path/to/dependencies
+        key: ${{ runner.os }}-${{ hashFiles('**/lockfiles') }}
+    
+    - name: Build
+      if: steps.cache-check.outputs.cache-hit != 'true'
+      run: /build.sh
+      
+    - uses: actions/cache/save@v3
+      if: steps.cache-check.outputs.cache-hit != 'true'
+      with:
+        path: path/to/dependencies
+        key: ${{ runner.os }}-${{ hashFiles('**/lockfiles') }}
+```
+
+#### Step 2 - Restore the built artifact from cache using the same key and path
+
+```yaml
+test:
+  needs: build
+  matrix:
+    key: [1, 2, 3]
+  steps:
+    - uses: actions/checkout@v3
+
+    - uses: actions/cache/restore@v3
+      with:
+        path: path/to/dependencies
+        fail-on-cache-miss: true
+        key: ${{ runner.os }}-${{ hashFiles('**/lockfiles') }}
+
+    - name: Test
+      run: /test.sh -key ${{ matrix.key }}
+```

check/action.yml

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+name: 'Check Cache'
+description: 'Check if cache artifact exists without downloading it'
+author: 'GitHub'
+inputs:
+  path:
+    description: 'A list of files, directories, and wildcard patterns to restore'
+    required: true
+  key:
+    description: 'An explicit key for restoring the cache'
+    required: true
+  restore-keys:
+    description: 'An ordered list of keys to use for restoring stale cache if no cache hit occurred for key. Note `cache-hit` returns false in this case.'
+    required: false
+  enableCrossOsArchive:
+    description: 'An optional boolean when enabled, allows windows runners to restore caches that were saved on other platforms'
+    default: 'false'
+    required: false
+  fail-on-cache-miss:
+    description: 'Fail the workflow if cache entry is not found'
+    default: 'false'
+    required: false
+outputs:
+  cache-hit:
+    description: 'A boolean value to indicate an exact match was found for the primary key'
+  cache-primary-key:
+    description: 'A resolved cache key for which cache match was attempted'
+  cache-matched-key:
+    description: 'Key of the cache that was found, it could either be the primary key on cache-hit or a partial/complete match of one of the restore keys'
+runs:
+  using: 'node16'
+  main: '../dist/check-only/index.js'
+branding:
+  icon: 'archive'
+  color: 'gray-dark'