ClickHouse/dbms/src/Core/ExternalTable.cpp

181 lines
6.1 KiB
C++

#include <boost/program_options.hpp>
#include <boost/algorithm/string.hpp>
#include <DataStreams/AsynchronousBlockInputStream.h>
#include <DataTypes/DataTypeFactory.h>
#include <Interpreters/Context.h>
#include <IO/copyData.h>
#include <IO/ReadBufferFromIStream.h>
#include <IO/ReadBufferFromFile.h>
#include <IO/LimitReadBuffer.h>
#include <Storages/StorageMemory.h>
#include <Poco/Net/MessageHeader.h>
#include <Core/ExternalTable.h>
namespace DB
{
namespace ErrorCodes
{
extern const int BAD_ARGUMENTS;
}
ExternalTableData BaseExternalTable::getData(const Context & context)
{
initReadBuffer();
initSampleBlock();
auto input = context.getInputFormat(format, *read_buffer, sample_block, DEFAULT_BLOCK_SIZE);
return std::make_pair(std::make_shared<AsynchronousBlockInputStream>(input), name);
}
void BaseExternalTable::clean()
{
name = "";
file = "";
format = "";
structure.clear();
sample_block = Block();
read_buffer.reset();
}
/// Function for debugging information output
void BaseExternalTable::write()
{
std::cerr << "file " << file << std::endl;
std::cerr << "name " << name << std::endl;
std::cerr << "format " << format << std::endl;
std::cerr << "structure: \n";
for (size_t i = 0; i < structure.size(); ++i)
std::cerr << "\t" << structure[i].first << " " << structure[i].second << std::endl;
}
std::vector<std::string> BaseExternalTable::split(const std::string & s, const std::string & d)
{
std::vector<std::string> res;
boost::split(res, s, boost::algorithm::is_any_of(d), boost::algorithm::token_compress_on);
return res;
}
void BaseExternalTable::parseStructureFromStructureField(const std::string & argument)
{
std::vector<std::string> vals = split(argument, " ,");
if (vals.size() & 1)
throw Exception("Odd number of attributes in section structure", ErrorCodes::BAD_ARGUMENTS);
for (size_t i = 0; i < vals.size(); i += 2)
structure.emplace_back(vals[i], vals[i + 1]);
}
void BaseExternalTable::parseStructureFromTypesField(const std::string & argument)
{
std::vector<std::string> vals = split(argument, " ,");
for (size_t i = 0; i < vals.size(); ++i)
structure.emplace_back("_" + toString(i + 1), vals[i]);
}
void BaseExternalTable::initSampleBlock()
{
const DataTypeFactory & data_type_factory = DataTypeFactory::instance();
for (size_t i = 0; i < structure.size(); ++i)
{
ColumnWithTypeAndName column;
column.name = structure[i].first;
column.type = data_type_factory.get(structure[i].second);
column.column = column.type->createColumn();
sample_block.insert(std::move(column));
}
}
void ExternalTable::initReadBuffer()
{
if (file == "-")
read_buffer = std::make_unique<ReadBufferFromFileDescriptor>(STDIN_FILENO);
else
read_buffer = std::make_unique<ReadBufferFromFile>(file);
}
ExternalTable::ExternalTable(const boost::program_options::variables_map & external_options)
{
if (external_options.count("file"))
file = external_options["file"].as<std::string>();
else
throw Exception("--file field have not been provided for external table", ErrorCodes::BAD_ARGUMENTS);
if (external_options.count("name"))
name = external_options["name"].as<std::string>();
else
throw Exception("--name field have not been provided for external table", ErrorCodes::BAD_ARGUMENTS);
if (external_options.count("format"))
format = external_options["format"].as<std::string>();
else
throw Exception("--format field have not been provided for external table", ErrorCodes::BAD_ARGUMENTS);
if (external_options.count("structure"))
parseStructureFromStructureField(external_options["structure"].as<std::string>());
else if (external_options.count("types"))
parseStructureFromTypesField(external_options["types"].as<std::string>());
else
throw Exception("Neither --structure nor --types have not been provided for external table", ErrorCodes::BAD_ARGUMENTS);
}
void ExternalTablesHandler::handlePart(const Poco::Net::MessageHeader & header, std::istream & stream)
{
const Settings & settings = context.getSettingsRef();
/// The buffer is initialized here, not in the virtual function initReadBuffer
read_buffer_impl = std::make_unique<ReadBufferFromIStream>(stream);
if (settings.http_max_multipart_form_data_size)
read_buffer = std::make_unique<LimitReadBuffer>(
*read_buffer_impl, settings.http_max_multipart_form_data_size,
true, "the maximum size of multipart/form-data. This limit can be tuned by 'http_max_multipart_form_data_size' setting");
else
read_buffer = std::move(read_buffer_impl);
/// Retrieve a collection of parameters from MessageHeader
Poco::Net::NameValueCollection content;
std::string label;
Poco::Net::MessageHeader::splitParameters(header.get("Content-Disposition"), label, content);
/// Get parameters
name = content.get("name", "_data");
format = params.get(name + "_format", "TabSeparated");
if (params.has(name + "_structure"))
parseStructureFromStructureField(params.get(name + "_structure"));
else if (params.has(name + "_types"))
parseStructureFromTypesField(params.get(name + "_types"));
else
throw Exception("Neither structure nor types have not been provided for external table " + name + ". Use fields " + name + "_structure or " + name + "_types to do so.", ErrorCodes::BAD_ARGUMENTS);
ExternalTableData data = getData(context);
/// Create table
NamesAndTypesList columns = sample_block.getNamesAndTypesList();
StoragePtr storage = StorageMemory::create("_external", data.second, ColumnsDescription{columns});
storage->startup();
context.addExternalTable(data.second, storage);
BlockOutputStreamPtr output = storage->write(ASTPtr(), context);
/// Write data
data.first->readPrefix();
output->writePrefix();
while (Block block = data.first->read())
output->write(block);
data.first->readSuffix();
output->writeSuffix();
/// We are ready to receive the next file, for this we clear all the information received
clean();
}
}