cache-apt-pkgs-action/restore_pkgs.sh

#!/bin/bash

# Fail on any error.
set -e

# Debug mode for diagnosing issues.
# Setup first before other operations.
debug="${4}"
test ${debug} == "true" && set -x

# Include library.
script_dir="$(dirname -- "$(realpath -- "${0}")")"
source "${script_dir}/lib.sh"

# Directory that holds the cached packages.
cache_dir="${1}"

# Root directory to untar the cached packages to.
# Typically filesystem root '/' but can be changed for testing.
cache_restore_root="${2}"
test -d ${cache_restore_root} || mkdir ${cache_restore_root}

# Cache and execute post install scripts on restore.
execute_install_scripts="${3}"

cache_filepaths="$(ls -1 "${cache_dir}" | sort)"
log "Found $(echo ${cache_filepaths} | wc -w) files in the cache."
for cache_filepath in ${cache_filepaths}; do
  log "- "$(basename ${cache_filepath})""
done

log_empty_line

log "Reading from main requested packages manifest..."
for logline in $(cat "${cache_dir}/manifest_main.log" | tr ',' '\n' ); do
  log "- $(echo "${logline}" | tr ':' ' ')"
done
log "done"

log_empty_line

# Only search for archived results. Manifest and cache key also live here.
cached_filepaths=$(ls -1 "${cache_dir}"/*.tar 2>/dev/null | sort)
cached_filecount=$(echo ${cached_filepaths} | wc -w)

log "Restoring ${cached_filecount} packages from cache..."
for cached_filepath in ${cached_filepaths}; do

  log "- $(basename "${cached_filepath}") restoring..."
  sudo tar -xf "${cached_filepath}" -C "${cache_restore_root}" > /dev/null
  log "  done"

  # Execute install scripts if available.
  if test ${execute_install_scripts} == "true"; then
    # May have to add more handling for extracting pre-install script before extracting all files.
    # Keeping it simple for now.
    execute_install_script "${cache_restore_root}" "${cached_filepath}" preinst install
    execute_install_script "${cache_restore_root}" "${cached_filepath}" postinst configure
  fi
done
log "done"

log_empty_line

# Register packages with dpkg so they appear as installed.
# The tar extraction restores dpkg info files (list, md5sums, etc.) but the
# main status database (/var/lib/dpkg/status) also needs updating.
dpkg_status_dir="${cache_dir}"
status_files=$(ls -1 "${dpkg_status_dir}"/*.dpkg-status 2>/dev/null || true)
if test -n "${status_files}"; then
  log "Registering restored packages with dpkg..."
  dpkg_status_path="${cache_restore_root}var/lib/dpkg/status"
  for status_file in ${status_files}; do
    pkg_name=$(grep '^Package:' "${status_file}" | head -1 | sed 's/^Package: //')
    cached_ver=$(grep '^Version:' "${status_file}" | head -1 | sed 's/^Version: //')
    cached_arch=$(grep '^Architecture:' "${status_file}" | head -1 | sed 's/^Architecture: //')

    # Build architecture-qualified name for dpkg queries.
    dpkg_query_name="${pkg_name}"
    if [ -n "${cached_arch}" ] && [ "${cached_arch}" != "all" ]; then
      dpkg_query_name="${pkg_name}:${cached_arch}"
    fi

    if dpkg -s "${dpkg_query_name}" > /dev/null 2>&1; then
      existing_status=$(dpkg -s "${dpkg_query_name}" 2>/dev/null | grep '^Status:' | head -1)
      existing_ver=$(dpkg -s "${dpkg_query_name}" 2>/dev/null | grep '^Version:' | head -1 | sed 's/^Version: //')

      if echo "${existing_status}" | grep -q 'install ok installed'; then
        if [ "${existing_ver}" = "${cached_ver}" ]; then
          log "- ${dpkg_query_name} already at version ${cached_ver}, skipping."
          continue
        fi
        # Package is installed at a different version (was upgraded during
        # the original install).  Remove the old dpkg status entry so we can
        # replace it with the cached (upgraded) version.
        log "- ${dpkg_query_name} updating from ${existing_ver} to ${cached_ver}..."
        sudo python3 -c "
import sys
pkg, arch, path = sys.argv[1], sys.argv[2], sys.argv[3]
with open(path, 'r') as f:
    content = f.read()
entries = content.split('\n\n')
kept = []
for entry in entries:
    if not entry.strip():
        continue
    lines = entry.strip().split('\n')
    match_pkg = any(l == 'Package: ' + pkg for l in lines)
    match_arch = any(l == 'Architecture: ' + arch for l in lines)
    if match_pkg and match_arch:
        continue
    kept.append(entry.strip())
with open(path, 'w') as f:
    f.write('\n\n'.join(kept))
    if kept:
        f.write('\n\n')
" "${pkg_name}" "${cached_arch}" "${dpkg_status_path}"
      fi
    fi

    # Append the status entry (with blank line separator) to the dpkg database.
    echo "" | sudo tee -a "${dpkg_status_path}" > /dev/null
    cat "${status_file}" | sudo tee -a "${dpkg_status_path}" > /dev/null
    log "- ${dpkg_query_name} registered."
  done
  log "done"
fi