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#pragma once
///
/// @file yt/cpp/mapreduce/interface/io.h
///
/// Header containing client interface for reading and writing tables and files.
#include "fwd.h"
#include "client_method_options.h"
#include "common.h"
#include "format.h"
#include "node.h"
#include "mpl.h"
#include "skiff_row.h"
#include <google/protobuf/message.h>
#include <util/stream/input.h>
#include <util/stream/output.h>
#include <util/generic/yexception.h>
#include <util/generic/maybe.h>
namespace NYT {
////////////////////////////////////////////////////////////////////////////////
///
/// @brief "Marker" type to use for several protobuf types in @ref NYT::TTableReader.
///
/// @tparam Ts Possible types of rows to be read.
template<class... TProtoRowTypes>
class TProtoOneOf
{
public:
static_assert(
(TIsBaseOf<::google::protobuf::Message, TProtoRowTypes>::Value && ...),
"Template parameters can only be protobuf types");
TProtoOneOf() = delete;
};
///
/// @brief "Marker" type to use for several skiff row types in @ref NYT::TTableReader.
///
/// @tparam Ts Possible types of rows to be read.
template<class... TSkiffRowTypes>
class TSkiffRowOneOf
{
public:
static_assert(
(TIsSkiffRow<TSkiffRowTypes>::value && ...),
"Template parameters can only be SkiffRow types");
TSkiffRowOneOf() = delete;
};
////////////////////////////////////////////////////////////////////////////////
/// @cond Doxygen_Suppress
namespace NDetail {
////////////////////////////////////////////////////////////////////////////////
template <class TTuple>
struct TProtoOneOfFromTuple;
template <class... Ts>
struct TProtoOneOfFromTuple<std::tuple<Ts...>>
{
using TType = TProtoOneOf<Ts...>;
};
template <class... Ts>
struct TProtoOneOfUnique
{
using TTuple = typename TUniqueTypes<std::tuple<>, std::tuple<Ts...>>::TType;
using TType = typename TProtoOneOfFromTuple<TTuple>::TType;
};
////////////////////////////////////////////////////////////////////////////////
} // namespace NDetail
/// @endcond
////////////////////////////////////////////////////////////////////////////////
struct INodeReaderImpl;
struct IYaMRReaderImpl;
struct IProtoReaderImpl;
struct ISkiffRowReaderImpl;
struct INodeWriterImpl;
struct IYaMRWriterImpl;
struct IProtoWriterImpl;
////////////////////////////////////////////////////////////////////////////////
/// Class of exceptions connected to reading or writing tables or files.
class TIOException
: public yexception
{ };
///////////////////////////////////////////////////////////////////////////////
/// Interface representing YT file reader.
class IFileReader
: public TThrRefBase
, public IInputStream
{ };
/// Interface representing YT file writer.
class IFileWriter
: public TThrRefBase
, public IOutputStream
{
public:
virtual size_t GetBufferMemoryUsage() const
{
return 0;
}
};
////////////////////////////////////////////////////////////////////////////////
/// Low-level interface to read YT table with retries.
class TRawTableReader
: public TThrRefBase
, public IInputStream
{
public:
/// @brief Retry table read starting from the specified `rangeIndex` and `rowIndex`.
///
/// @param rangeIndex Index of first range to read
/// @param rowIndex Index of first row to read; if `rowIndex == Nothing` entire request will be retried.
///
/// @return `true` on successful request retry, `false` if no retry attempts are left (then `Retry()` shouldn't be called any more).
///
/// `rowIndex` must be inside the range with index `rangeIndex` if the latter is specified.
///
/// After successful retry the user should reset `rangeIndex` / `rowIndex` values and read new ones
/// from the stream.
virtual bool Retry(
const TMaybe<ui32>& rangeIndex,
const TMaybe<ui64>& rowIndex,
const std::exception_ptr& error) = 0;
/// Resets retry attempt count to the initial value (then `Retry()` can be called again).
virtual void ResetRetries() = 0;
/// @brief May the input stream contain table ranges?
///
/// In the case when it is `true` the `TRawTableReader` user is responsible
/// to track active range index in order to pass it to Retry().
virtual bool HasRangeIndices() const = 0;
};
/// @brief Low-level interface to write YT table.
///
/// Retries must be handled by implementation.
class TRawTableWriter
: public TThrRefBase
, public IOutputStream
{
public:
/// @brief Call this method after complete row representation is written to the stream.
///
/// When this method is called `TRowTableWriter` can check its buffer
/// and if it is full send data to YT.
/// @note `TRawTableWriter` never sends partial records to YT (due to retries).
virtual void NotifyRowEnd() = 0;
/// @brief Try to abort writing process as soon as possible (makes sense for multi-threaded writers).
///
/// By default it does nothing, but implementations are welcome to override this method.
virtual void Abort()
{ }
virtual size_t GetBufferMemoryUsage() const
{
return 0;
}
};
/// @brief Interface to deal with multiple raw output streams.
class IProxyOutput
{
public:
virtual ~IProxyOutput()
{ }
/// Get amount of managed streams.
virtual size_t GetStreamCount() const = 0;
/// Get stream corresponding to the specified table index.
virtual IOutputStream* GetStream(size_t tableIndex) const = 0;
/// This handler must be called right after the next row has been written.
virtual void OnRowFinished(size_t tableIndex) = 0;
/// @brief Try to abort writing process as soon as possible (makes sense for multi-threaded writers).
///
/// By default it does nothing, but implementations are welcome to override this method.
virtual void Abort()
{ }
virtual size_t GetBufferMemoryUsage() const
{
return 0;
}
};
////////////////////////////////////////////////////////////////////////////////
/// @brief Class template to read typed rows from YT tables.
///
/// @tparam T Row type.
///
/// Correct usage of this class usually looks like
/// ```
/// for (const auto& cursor : *reader) {
/// const auto& row = cursor.GetRow();
/// ...
/// }
/// ```
/// or, more verbosely,
/// ```
/// for (; reader->IsValid(); reader->Next()) {
/// const auto& row = reader->GetRow();
/// ...
/// }
/// ```
///
/// @note Actual (partial) specializations of this template may look a bit different,
/// e.g. @ref NYT::TTableReader::GetRow, @ref NYT::TTableReader::MoveRow may be method templates.
template <class T, class>
class TTableReader
: public TThrRefBase
{
public:
/// Get current row.
const T& GetRow() const;
/// Extract current row; further calls to `GetRow` and `MoveRow` will fail.
T MoveRow();
/// Extract current row to `result`; further calls to `GetRow` and `MoveRow` will fail.
void MoveRow(T* result);
/// Check whether all the rows were read.
bool IsValid() const;
/// Move the cursor to the next row.
void Next();
/// Get table index of the current row.
ui32 GetTableIndex() const;
/// Get range index of the current row (zero if it is unknown or read request contains no ranges)
ui32 GetRangeIndex() const;
/// Get current row index (zero if it unknown).
ui64 GetRowIndex() const;
/// Get current tablet index (for ordered dynamic tables).
i64 GetTabletIndex() const;
/// Returns `true` if job consumed all the input and `false` otherwise.
bool IsEndOfStream() const;
/// Returns `true` if job raw input stream was closed and `false` otherwise.
bool IsRawReaderExhausted() const;
};
/// @brief Iterator for use in range-based-for.
///
/// @note Idiomatic usage:
/// ```
/// for (const auto& cursor : *reader) {
/// const auto& row = cursor.GetRow();
/// ...
/// }
/// ```
template <class T>
class TTableReaderIterator
{
public:
/// Construct iterator from table reader (can be `nullptr`).
explicit TTableReaderIterator<T>(TTableReader<T>* reader)
{
if (reader && reader->IsValid()) {
Reader_ = reader;
} else {
Reader_ = nullptr;
}
}
/// Equality operator.
bool operator==(const TTableReaderIterator& it) const
{
return Reader_ == it.Reader_;
}
/// Dereference operator.
TTableReader<T>& operator*()
{
return *Reader_;
}
/// Const dereference operator.
const TTableReader<T>& operator*() const
{
return *Reader_;
}
/// Preincrement operator.
TTableReaderIterator& operator++()
{
Reader_->Next();
if (!Reader_->IsValid()) {
Reader_ = nullptr;
}
return *this;
}
private:
TTableReader<T>* Reader_;
};
/// @brief Function to facilitate range-based-for for @ref NYT::TTableReader.
///
/// @see @ref NYT::TTableReaderIterator
template <class T>
TTableReaderIterator<T> begin(TTableReader<T>& reader)
{
return TTableReaderIterator<T>(&reader);
}
/// @brief Function to facilitate range-based-for for @ref NYT::TTableReader.
///
/// @see @ref NYT::TTableReaderIterator
template <class T>
TTableReaderIterator<T> end(TTableReader<T>&)
{
return TTableReaderIterator<T>(nullptr);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief Class to facilitate reading table rows sorted by key.
///
/// Each reader returned from @ref NYT::TTableRangesReader::GetRange represents
/// a range of rows with the same key.
///
/// @note Idiomatic usage:
/// ```
/// for (; reader->IsValid(); reader->Next()) {
/// auto& rangeReader = reader->GetRange();
/// ...
/// }
/// ```
template <class T, class>
class TTableRangesReader
: public TThrRefBase
{
public:
/// Get reader for rows with the same key.
TTableReader<T>& GetRange();
/// Check whether all rows are read.
bool IsValid() const;
/// Move cursor to the next range.
void Next();
};
////////////////////////////////////////////////////////////////////////////////
/// Class template to write typed rows to YT tables.
template <class T, class>
class TTableWriter
: public TThrRefBase
{
public:
/// @brief Submit a row for writing.
///
/// The row may (and very probably will) *not* be written immediately.
void AddRow(const T& row);
/// Complete writing and check that everything is written successfully.
/// No other data can be written after Finish is called.
void Finish();
size_t GetBufferMemoryUsage() const;
};
////////////////////////////////////////////////////////////////////////////////
/// @brief Type representing YaMR table row.
///
/// @deprecated
struct TYaMRRow
{
/// Key column.
TStringBuf Key;
/// Subkey column.
TStringBuf SubKey;
/// Value column.
TStringBuf Value;
};
////////////////////////////////////////////////////////////////////////////////
/// Interface for creating table and file readers and writer.
class IIOClient
{
public:
virtual ~IIOClient() = default;
/// Create a reader for file at `path`.
virtual IFileReaderPtr CreateFileReader(
const TRichYPath& path,
const TFileReaderOptions& options = TFileReaderOptions()) = 0;
/// Create a writer for file at `path`.
virtual IFileWriterPtr CreateFileWriter(
const TRichYPath& path,
const TFileWriterOptions& options = TFileWriterOptions()) = 0;
/// Create a typed reader for table at `path`.
template <class T>
TTableReaderPtr<T> CreateTableReader(
const TRichYPath& path,
const TTableReaderOptions& options = TTableReaderOptions());
/// Create a typed writer for table at `path`.
template <class T>
TTableWriterPtr<T> CreateTableWriter(
const TRichYPath& path,
const TTableWriterOptions& options = TTableWriterOptions());
/// Create a writer to write protobuf messages with specified descriptor.
virtual TTableWriterPtr<::google::protobuf::Message> CreateTableWriter(
const TRichYPath& path,
const ::google::protobuf::Descriptor& descriptor,
const TTableWriterOptions& options = TTableWriterOptions()) = 0;
/// Create a reader to read a table using specified format.
virtual TRawTableReaderPtr CreateRawReader(
const TRichYPath& path,
const TFormat& format,
const TTableReaderOptions& options = TTableReaderOptions()) = 0;
/// Create a reader to write a table using specified format.
virtual TRawTableWriterPtr CreateRawWriter(
const TRichYPath& path,
const TFormat& format,
const TTableWriterOptions& options = TTableWriterOptions()) = 0;
///
/// @brief Create a reader for [blob table](https://docs.yandex-team.ru/docs/yt/description/storage/blobtables) at `path`.
///
/// @param path Blob table path.
/// @param blobId Key identifying the blob.
/// @param options Optional parameters
///
/// Blob table is a table that stores a number of blobs.
/// Blobs are sliced into parts of the same size (maybe except of last part).
/// Those parts are stored in the separate rows.
///
/// Blob table have constraints on its schema.
/// - There must be columns that identify blob (blob id columns). That columns might be of any type.
/// - There must be a column of `int64` type that identify part inside the blob (this column is called `part index`).
/// - There must be a column of `string` type that stores actual data (this column is called `data column`).
virtual IFileReaderPtr CreateBlobTableReader(
const TYPath& path,
const TKey& blobId,
const TBlobTableReaderOptions& options = TBlobTableReaderOptions()) = 0;
private:
virtual ::TIntrusivePtr<INodeReaderImpl> CreateNodeReader(
const TRichYPath& path, const TTableReaderOptions& options) = 0;
virtual ::TIntrusivePtr<IYaMRReaderImpl> CreateYaMRReader(
const TRichYPath& path, const TTableReaderOptions& options) = 0;
virtual ::TIntrusivePtr<IProtoReaderImpl> CreateProtoReader(
const TRichYPath& path,
const TTableReaderOptions& options,
const ::google::protobuf::Message* prototype) = 0;
virtual ::TIntrusivePtr<ISkiffRowReaderImpl> CreateSkiffRowReader(
const TRichYPath& path,
const TTableReaderOptions& options,
const ISkiffRowSkipperPtr& skipper,
const NSkiff::TSkiffSchemaPtr& schema) = 0;
virtual ::TIntrusivePtr<INodeWriterImpl> CreateNodeWriter(
const TRichYPath& path, const TTableWriterOptions& options) = 0;
virtual ::TIntrusivePtr<IYaMRWriterImpl> CreateYaMRWriter(
const TRichYPath& path, const TTableWriterOptions& options) = 0;
virtual ::TIntrusivePtr<IProtoWriterImpl> CreateProtoWriter(
const TRichYPath& path,
const TTableWriterOptions& options,
const ::google::protobuf::Message* prototype) = 0;
};
////////////////////////////////////////////////////////////////////////////////
///
/// @brief Create a protobuf table reader from a stream.
///
/// @tparam T Protobuf message type to read (must be inherited from `Message`).
///
/// @param stream Input stream in YT protobuf format.
template <typename T>
TTableReaderPtr<T> CreateTableReader(
IInputStream* stream,
const TTableReaderOptions& options = {});
///
/// @brief Create a protobuf multi table reader from a stream.
///
/// @tparam Ts Protobuf message types to read (must be inherited from `Message`).
///
/// @param stream Input stream in YT protobuf format.
template <class... Ts>
TTableReaderPtr<typename NDetail::TProtoOneOfUnique<Ts...>::TType> CreateProtoMultiTableReader(
IInputStream* stream,
const TTableReaderOptions& options = {});
///
/// @brief Create a homogeneous protobuf multi table reader from a stream.
///
/// @tparam T Protobuf message type to read (must be inherited from `Message`).
///
/// @param stream Input stream in YT protobuf format.
/// @param tableCount Number of tables in input stream.
template <class T>
TTableReaderPtr<T> CreateProtoMultiTableReader(
IInputStream* stream,
int tableCount,
const TTableReaderOptions& options = {});
/// Create a @ref NYT::TNode table reader from a stream.
template <>
TTableReaderPtr<TNode> CreateTableReader<TNode>(
IInputStream* stream, const TTableReaderOptions& options);
/// Create a @ref NYT::TYaMRRow table reader from a stream.
template <>
TTableReaderPtr<TYaMRRow> CreateTableReader<TYaMRRow>(
IInputStream* stream, const TTableReaderOptions& options);
namespace NDetail {
/// Create a protobuf table reader from a stream.
::TIntrusivePtr<IProtoReaderImpl> CreateProtoReader(
IInputStream* stream,
const TTableReaderOptions& options,
const ::google::protobuf::Descriptor* descriptor);
/// Create a protobuf table reader from a stream that can contain table switches.
::TIntrusivePtr<IProtoReaderImpl> CreateProtoReader(
IInputStream* stream,
const TTableReaderOptions& options,
TVector<const ::google::protobuf::Descriptor*> descriptors);
} // namespace NDetail
////////////////////////////////////////////////////////////////////////////////
/// Convert generic protobuf table reader to a concrete one (for certain type `T`).
template <typename T>
TTableReaderPtr<T> CreateConcreteProtobufReader(TTableReader<Message>* reader);
/// Convert generic protobuf table reader to a concrete one (for certain type `T`).
template <typename T>
TTableReaderPtr<T> CreateConcreteProtobufReader(const TTableReaderPtr<Message>& reader);
/// Convert a concrete (for certain type `T`) protobuf table reader to a generic one.
template <typename T>
TTableReaderPtr<Message> CreateGenericProtobufReader(TTableReader<T>* reader);
/// Convert a concrete (for certain type `T`) protobuf table reader to a generic one.
template <typename T>
TTableReaderPtr<Message> CreateGenericProtobufReader(const TTableReaderPtr<T>& reader);
////////////////////////////////////////////////////////////////////////////////
} // namespace NYT
#define IO_INL_H_
#include "io-inl.h"
#undef IO_INL_H_
|