Function create

src/uri/fetcher.cpp:37–77

namespace fetcher {

Try<Owned<Fetcher>> create(const Option<Flags>& _flags)
{
  // Use the default flags if not specified.
  Flags flags;
  if (_flags.isSome()) {
    flags = _flags.get();
  }

  // Load built-in plugins.
  typedef lambda::function<Try<Owned<Fetcher::Plugin>>()> Creator;

  hashmap<string, Creator> creators = {
    {CurlFetcherPlugin::NAME,
       [flags]() { return CurlFetcherPlugin::create(flags); }},
    {CopyFetcherPlugin::NAME,
       [flags]() { return CopyFetcherPlugin::create(flags); }},
    {HadoopFetcherPlugin::NAME,
       [flags]() { return HadoopFetcherPlugin::create(flags); }},
#ifndef __WINDOWS__
    {DockerFetcherPlugin::NAME,
       [flags]() { return DockerFetcherPlugin::create(flags); }},
#endif // __WINDOWS__
  };

  vector<Owned<Fetcher::Plugin>> plugins;

  foreachpair (const string& name, const Creator& creator, creators) {
    Try<Owned<Fetcher::Plugin>> plugin = creator();
    if (plugin.isError()) {
      // NOTE: We skip the plugin if it cannot be created, instead of
      // returning an Error so that we can still use other plugins.
      LOG(INFO) << "Skipping URI fetcher plugin " << "'" << name << "' "
                << "as it could not be created: " << plugin.error();
      continue;
    }

    plugins.push_back(plugin.get());
  }

  return Owned<Fetcher>(new Fetcher(plugins));
}

} // namespace fetcher {