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#pragma once
#include <memory>
#include <vector>
#include <unordered_map>
#include <Poco/Timestamp.h>
#include <IO/ReadSettings.h>
#include <IO/WriteSettings.h>
#include <IO/ReadBufferFromFileBase.h>
#include <IO/WriteBufferFromFileBase.h>
#include <Disks/DirectoryIterator.h>
#include <Disks/WriteMode.h>
#include <Disks/ObjectStorages/IObjectStorage.h>
#include <Common/ErrorCodes.h>
namespace DB
{
namespace ErrorCodes
{
extern const int NOT_IMPLEMENTED;
}
class IMetadataStorage;
/// Return the result of operation to the caller.
/// It is used in `IDiskObjectStorageOperation::finalize` after metadata transaction executed to make decision on blob removal.
struct UnlinkMetadataFileOperationOutcome
{
UInt32 num_hardlinks = std::numeric_limits<UInt32>::max();
};
using UnlinkMetadataFileOperationOutcomePtr = std::shared_ptr<UnlinkMetadataFileOperationOutcome>;
/// Tries to provide some "transactions" interface, which allow
/// to execute (commit) operations simultaneously. We don't provide
/// any snapshot isolation here, so no read operations in transactions
/// interface. This transaction is more like "batch operation" than real "transaction".
///
/// But for better usability we can get MetadataStorage interface and use some read methods.
class IMetadataTransaction : private boost::noncopyable
{
public:
virtual void commit() = 0;
virtual const IMetadataStorage & getStorageForNonTransactionalReads() const = 0;
/// General purpose methods
/// Write metadata string to file
virtual void writeStringToFile(const std::string & /* path */, const std::string & /* data */)
{
throwNotImplemented();
}
/// Writes the data inline with the metadata
virtual void writeInlineDataToFile(const std::string & /* path */, const std::string & /* data */)
{
throwNotImplemented();
}
virtual void setLastModified(const std::string & /* path */, const Poco::Timestamp & /* timestamp */)
{
throwNotImplemented();
}
virtual bool supportsChmod() const = 0;
virtual void chmod(const String & /* path */, mode_t /* mode */)
{
throwNotImplemented();
}
virtual void setReadOnly(const std::string & /* path */)
{
throwNotImplemented();
}
virtual void unlinkFile(const std::string & /* path */)
{
throwNotImplemented();
}
virtual void createDirectory(const std::string & /* path */)
{
throwNotImplemented();
}
virtual void createDirectoryRecursive(const std::string & /* path */)
{
throwNotImplemented();
}
virtual void removeDirectory(const std::string & /* path */)
{
throwNotImplemented();
}
virtual void removeRecursive(const std::string & /* path */)
{
throwNotImplemented();
}
virtual void createHardLink(const std::string & /* path_from */, const std::string & /* path_to */)
{
throwNotImplemented();
}
virtual void moveFile(const std::string & /* path_from */, const std::string & /* path_to */)
{
throwNotImplemented();
}
virtual void moveDirectory(const std::string & /* path_from */, const std::string & /* path_to */)
{
throwNotImplemented();
}
virtual void replaceFile(const std::string & /* path_from */, const std::string & /* path_to */)
{
throwNotImplemented();
}
/// Metadata related methods
/// Create empty file in metadata storage
virtual void createEmptyMetadataFile(const std::string & path) = 0;
/// Create metadata file on paths with content (blob_name, size_in_bytes)
virtual void createMetadataFile(const std::string & path, const std::string & blob_name, uint64_t size_in_bytes) = 0;
/// Add to new blob to metadata file (way to implement appends)
virtual void addBlobToMetadata(const std::string & /* path */, const std::string & /* blob_name */, uint64_t /* size_in_bytes */)
{
throwNotImplemented();
}
/// Unlink metadata file and do something special if required
/// By default just remove file (unlink file).
virtual UnlinkMetadataFileOperationOutcomePtr unlinkMetadata(const std::string & path)
{
unlinkFile(path);
return nullptr;
}
virtual ~IMetadataTransaction() = default;
private:
[[noreturn]] static void throwNotImplemented()
{
throw Exception(ErrorCodes::NOT_IMPLEMENTED, "Operation is not implemented");
}
};
using MetadataTransactionPtr = std::shared_ptr<IMetadataTransaction>;
/// Metadata storage for remote disks like DiskObjectStorage.
/// Support some subset of Disk operations, allow to read/write only
/// small amounts of data (strings).
class IMetadataStorage : private boost::noncopyable
{
public:
virtual MetadataTransactionPtr createTransaction() = 0;
/// Get metadata root path.
virtual const std::string & getPath() const = 0;
/// ==== General purpose methods. Define properties of object storage file based on metadata files ====
virtual bool exists(const std::string & path) const = 0;
virtual bool isFile(const std::string & path) const = 0;
virtual bool isDirectory(const std::string & path) const = 0;
virtual uint64_t getFileSize(const std::string & path) const = 0;
virtual Poco::Timestamp getLastModified(const std::string & path) const = 0;
virtual time_t getLastChanged(const std::string & /* path */) const
{
throwNotImplemented();
}
virtual bool supportsChmod() const = 0;
virtual bool supportsStat() const = 0;
virtual struct stat stat(const String & /* path */) const
{
throwNotImplemented();
}
virtual std::vector<std::string> listDirectory(const std::string & path) const = 0;
virtual DirectoryIteratorPtr iterateDirectory(const std::string & path) const = 0;
virtual uint32_t getHardlinkCount(const std::string & path) const = 0;
/// Read metadata file to string from path
virtual std::string readFileToString(const std::string & /* path */) const
{
throwNotImplemented();
}
/// Read inline data for file to string from path
virtual std::string readInlineDataToString(const std::string & /* path */) const
{
throwNotImplemented();
}
virtual ~IMetadataStorage() = default;
/// ==== More specific methods. Previous were almost general purpose. ====
/// Read multiple metadata files into strings and return mapping from file_path -> metadata
virtual std::unordered_map<std::string, std::string> getSerializedMetadata(const std::vector<String> & /* file_paths */) const
{
throwNotImplemented();
}
/// Return object information (absolute_path, bytes_size, ...) for metadata path.
/// object_storage_path is absolute.
virtual StoredObjects getStorageObjects(const std::string & path) const = 0;
virtual std::string getObjectStorageRootPath() const = 0;
private:
[[noreturn]] static void throwNotImplemented()
{
throw Exception(ErrorCodes::NOT_IMPLEMENTED, "Operation is not implemented");
}
};
using MetadataStoragePtr = std::shared_ptr<IMetadataStorage>;
}
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