.github/actions/install-build-deps/action.yml

# Copyright (C) 2025 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

name: run install-build-deps (with caching)
description: Restore and conditionally save the buildtools cache
inputs:
  install-flags:
    required: false
    description: Optional flags to pass to install-build-deps (e.g., --android)

runs:
  using: "composite"
  steps:
    - name: Compute cache key
      id: cache_key
      env:
        INSTALL_FLAGS: ${{ inputs.install-flags }}
      shell: bash
      run: |
        # Create buildtools cache key.
        flags="${INSTALL_FLAGS:-default}"
        echo "key=buildtools-$flags" >> "$GITHUB_OUTPUT"

    # When restoring the buildtools cache, we don't want to overwrite files or
    # folders that are stored in git.
    # We also use this file to prevent writing such files back to cache at the
    # "Save buildtools cache" step.
    - name: Generate list of files to ignore
      id: files_to_ignore
      shell: bash
      run: |
        # Generate list of files in 'buildtools/' stored in git.
        FILES_TO_IGNORE_PATH=$(mktemp /tmp/files-to-ignore-XXXXX.txt)
        git ls-tree HEAD:buildtools --name-only > "$FILES_TO_IGNORE_PATH"
        echo "file_path=$FILES_TO_IGNORE_PATH" >> "$GITHUB_OUTPUT"

    - name: Save local buildtools hash
      id: local_buildtools_hash
      env:
        BUILDTOOLS_HASH: ${{ hashFiles('buildtools/**', 'tools/install-build-deps') }}
      shell: bash
      run: echo "hash=$BUILDTOOLS_HASH" >> "$GITHUB_OUTPUT"

    - name: Restore buildtools from cache
      id: restore_buildtools_cache
      uses: ./.github/actions/cache-on-google-cloud-storage/restore
      with:
        cache_key: ${{ steps.cache_key.outputs.key }}
        directory: buildtools
        exclude_files: ${{ steps.files_to_ignore.outputs.file_path }}

    - name: Check if need to update buildtools cache
      id: check_if_need_update
      env:
        LOCAL_BUILDTOOLS_HASH: ${{ steps.local_buildtools_hash.outputs.hash }}
        CACHED_BUILDTOOLS_HASH_FILE_PATH: buildtools/buildtools_hash_revision_for_cache_on_ci.txt
      shell: bash
      run: |
        # Compare cached buildtools hash with the local (stored in git) hash.
        
        # Content of 'buildtools/' rarely changes, so we don't want to re-upload
        # unchanged cache on each build.
        # It changes when the 'tools/install-build-deps' or the files added to
        # git inside `buildtools/' changes, so we calculate and save the sha256
        # hash of that files.
        if [ -f "$CACHED_BUILDTOOLS_HASH_FILE_PATH" ]; then
          CACHED_BUILDTOOLS_HASH=$(cat "$CACHED_BUILDTOOLS_HASH_FILE_PATH")
        else
          CACHED_BUILDTOOLS_HASH="0"
        fi
        
        if [[ "$CACHED_BUILDTOOLS_HASH" != "$LOCAL_BUILDTOOLS_HASH" ]]; then
          # Rewrite the hash file, it is saved as part of 'buildtools/' cache.
          echo "$LOCAL_BUILDTOOLS_HASH" > "$CACHED_BUILDTOOLS_HASH_FILE_PATH"
          echo "update_cache=true" >> "$GITHUB_OUTPUT" 
        fi

    - name: Run install-build-deps
      shell: bash
      # 'tools/install-build-deps' script will check the hashes and download the
      # correct deps if the restored cache is too old or too new.
      run: tools/install-build-deps ${{ inputs.install-flags }}

    - name: Save buildtools cache (only on main)
      if: |
        github.ref == 'refs/heads/main' &&
        steps.check_if_need_update.outputs.update_cache == 'true'
      uses: ./.github/actions/cache-on-google-cloud-storage/save
      with:
        cache_key: ${{ steps.cache_key.outputs.key }}
        directory: buildtools
        exclude_files: ${{ steps.files_to_ignore.outputs.file_path }}