Add the tool code

action.yml

@@ -0,0 +1,50 @@
+name: "CI Storage"
+description: "Quickly stores the content of huge work directory with low percentage of changed files in the storage on a remote host, or loads the content from the storage."
+inputs:
+  action:
+    description: "What to do (store or load)."
+    required: true
+  storage-host:
+    description: "Storage host in the format [user@]host; it must have password-free SSH key access. If not set, uses CI_STORAGE_HOST environment variable. Must not be empty eventually."
+    required: false
+  storage-dir:
+    description: "Storage directory on the remote host. If not set, uses CI_STORAGE_DIR environment variable. If still empty, uses the ci-storage tool default ~/ci-storage."
+    required: false
+  storage-max-age-sec:
+    description: "Remove slots created earlier than this many seconds ago. If not set, uses CI_STORAGE_MAX_AGE_SEC environment variable. If still empty, uses the ci-storage tool default 4 hours."
+    required: false
+  slot-id:
+    description: 'Id of the slot to store to or load from; use "*" to load a random most recent slot. If empty, uses "$GITHUB_RUN_ID-$GITHUB_RUN_ATTEMPT" value.'
+    required: false
+  local-dir:
+    description: 'Local directory path to store from or load to. If not set, uses "." (the current work directory).'
+    required: false
+  exclude:
+    description: "Newline separated exclude pattern(s) for rsync."
+    required: false
+  verbose:
+    description: "If set, prints the list of transferred files."
+    type: boolean
+    required: false
+runs:
+  using: "composite"
+  steps:
+    - name: Run ci-storage ${{ inputs.action }}
+      run: ci-storage \
+        --storage-host="$CI_STORAGE_HOST" \
+        --storage-dir="$CI_STORAGE_DIR" \
+        --storage-max-age-sec="$CI_STORAGE_MAX_AGE_SEC" \
+        --slot-id="$SLOT_ID" \
+        --local-dir="$LOCAL_DIR" \
+        --exclude="$EXCLUDE" \
+        $VERBOSE \
+        "${{ inputs.action }}"
+      shell: bash
+      env:
+        CI_STORAGE_HOST: ${{ inputs.storage-host || env.CI_STORAGE_HOST || "" }}
+        CI_STORAGE_DIR: ${{ inputs.storage-dir || env.CI_STORAGE_DIR || "" }}
+        CI_STORAGE_MAX_AGE_SEC: ${{ inputs.storage-max-age-sec || env.CI_STORAGE_MAX_AGE_SEC || "" }}
+        SLOT_ID: ${{ inputs.slot-id || format("{0}-{1}", env.GITHUB_RUN_ID, env.GITHUB_RUN_ATTEMPT) }}
+        LOCAL_DIR: ${{ inputs.local-dir || "." }}
+        EXCLUDE: ${{ inputs.exclude || "" }}
+        VERBOSE: ${{ inputs.verbose && "--verbose" || "" }}