Function fetchThroughCache

src/launcher/fetcher.cpp:406–447

Returns the resulting file or in case of extraction the destination directory (for logging).

// Returns the resulting file or in case of extraction the destination
// directory (for logging).
static Try<string> fetchThroughCache(
    const FetcherInfo::Item& item,
    const Option<string>& cacheDirectory,
    const string& sandboxDirectory,
    const Option<string>& frameworksHome,
    const Option<Duration>& stallTimeout)
{
  if (cacheDirectory.isNone() || cacheDirectory->empty()) {
    return Error("Cache directory not specified");
  }

  if (!item.has_cache_filename() || item.cache_filename().empty()) {
    // This should never happen if this program is used by the Mesos
    // slave and could then be a CHECK. But other uses are possible.
    return Error("No cache file name for: " + item.uri().value());
  }

  CHECK_NE(FetcherInfo::Item::BYPASS_CACHE, item.action())
    << "Unexpected fetcher action selector";

  CHECK(os::exists(cacheDirectory.get()))
    << "Fetcher cache directory was expected to exist but was not found";

  if (item.action() == FetcherInfo::Item::DOWNLOAD_AND_CACHE) {
    const string cachePath =
      path::join(cacheDirectory.get(), item.cache_filename());

    if (!os::exists(cachePath)) {
      Try<string> downloaded = download(
          item.uri().value(),
          cachePath,
          frameworksHome,
          stallTimeout);

      if (downloaded.isError()) {
        return Error(downloaded.error());
      }
    }
  }

  return fetchFromCache(item, cacheDirectory.get(), sandboxDirectory);
}


// Returns the resulting file or in case of extraction the destination