Function registerDatabaseHDFS

src/Databases/DatabaseHDFS.cpp:244–274

void registerDatabaseHDFS(DatabaseFactory & factory);
void registerDatabaseHDFS(DatabaseFactory & factory)
{
    auto create_fn = [](const DatabaseFactory::Arguments & args)
    {
        auto * engine_define = args.create_query.storage;
        const ASTFunction * engine = engine_define->engine;
        const String & engine_name = engine_define->engine->name;

        /// If source_url is empty, then table name must contain full url
        std::string source_url;

        if (engine->arguments && !engine->arguments->children.empty())
        {
            if (engine->arguments->children.size() != 1)
                throw Exception(ErrorCodes::BAD_ARGUMENTS, "HDFS database requires at most 1 argument: source_url");

            const auto & arguments = engine->arguments->children;
            source_url = safeGetLiteralValue<String>(arguments[0], engine_name);
        }

        return std::make_shared<DatabaseHDFS>(args.database_name, source_url, args.context);
    };
    factory.registerDatabase("HDFS", create_fn, {
        .supports_arguments = true,
        .is_external = true,
        .source_access_type = AccessTypeObjects::Source::HDFS,
    }, Documentation{
        .description = "A read-only database that exposes files in HDFS as tables.",
        .syntax = "ENGINE = HDFS([hdfs_host_and_root_path])",
        .related = {"S3", "Filesystem"}});
}
} // DB

#endif