ClickHouse/dbms/src/Interpreters/InterserverIOHandler.h

156 lines
4.2 KiB
C++

#pragma once
#include <IO/ReadBuffer.h>
#include <IO/WriteBuffer.h>
#include <IO/ReadBufferFromString.h>
#include <IO/ReadHelpers.h>
#include <IO/WriteBufferFromString.h>
#include <IO/WriteHelpers.h>
#include <Common/ActionBlocker.h>
#include <Core/Types.h>
#include <map>
#include <atomic>
#include <utility>
#include <Poco/Net/HTMLForm.h>
namespace Poco { namespace Net { class HTTPServerResponse; } }
namespace DB
{
namespace ErrorCodes
{
extern const int DUPLICATE_INTERSERVER_IO_ENDPOINT;
extern const int NO_SUCH_INTERSERVER_IO_ENDPOINT;
}
/** Location of the service.
*/
struct InterserverIOEndpointLocation
{
public:
InterserverIOEndpointLocation(const std::string & name_, const std::string & host_, UInt16 port_)
: name(name_), host(host_), port(port_)
{
}
/// Creates a location based on its serialized representation.
InterserverIOEndpointLocation(const std::string & serialized_location)
{
ReadBufferFromString buf(serialized_location);
readBinary(name, buf);
readBinary(host, buf);
readBinary(port, buf);
assertEOF(buf);
}
/// Serializes the location.
std::string toString() const
{
WriteBufferFromOwnString buf;
writeBinary(name, buf);
writeBinary(host, buf);
writeBinary(port, buf);
return buf.str();
}
public:
std::string name;
std::string host;
UInt16 port;
};
/** Query processor from other servers.
*/
class InterserverIOEndpoint
{
public:
virtual std::string getId(const std::string & path) const = 0;
virtual void processQuery(const Poco::Net::HTMLForm & params, ReadBuffer & body, WriteBuffer & out, Poco::Net::HTTPServerResponse & response) = 0;
virtual ~InterserverIOEndpoint() {}
/// You need to stop the data transfer if blocker is activated.
ActionBlocker blocker;
};
using InterserverIOEndpointPtr = std::shared_ptr<InterserverIOEndpoint>;
/** Here you can register a service that processes requests from other servers.
* Used to transfer chunks in ReplicatedMergeTree.
*/
class InterserverIOHandler
{
public:
void addEndpoint(const String & name, InterserverIOEndpointPtr endpoint)
{
std::lock_guard<std::mutex> lock(mutex);
bool inserted = endpoint_map.try_emplace(name, std::move(endpoint)).second;
if (!inserted)
throw Exception("Duplicate interserver IO endpoint: " + name, ErrorCodes::DUPLICATE_INTERSERVER_IO_ENDPOINT);
}
void removeEndpoint(const String & name)
{
std::lock_guard<std::mutex> lock(mutex);
if (!endpoint_map.erase(name))
throw Exception("No interserver IO endpoint named " + name, ErrorCodes::NO_SUCH_INTERSERVER_IO_ENDPOINT);
}
InterserverIOEndpointPtr getEndpoint(const String & name)
try
{
std::lock_guard<std::mutex> lock(mutex);
return endpoint_map.at(name);
}
catch (...)
{
throw Exception("No interserver IO endpoint named " + name, ErrorCodes::NO_SUCH_INTERSERVER_IO_ENDPOINT);
}
private:
using EndpointMap = std::map<String, InterserverIOEndpointPtr>;
EndpointMap endpoint_map;
std::mutex mutex;
};
/// In the constructor calls `addEndpoint`, in the destructor - `removeEndpoint`.
class InterserverIOEndpointHolder
{
public:
InterserverIOEndpointHolder(const String & name_, InterserverIOEndpointPtr endpoint_, InterserverIOHandler & handler_)
: name(name_), endpoint(std::move(endpoint_)), handler(handler_)
{
handler.addEndpoint(name, endpoint);
}
InterserverIOEndpointPtr getEndpoint()
{
return endpoint;
}
~InterserverIOEndpointHolder()
try
{
handler.removeEndpoint(name);
/// After destroying the object, `endpoint` can still live, since its ownership is acquired during the processing of the request,
/// see InterserverIOHTTPHandler.cpp
}
catch (...)
{
tryLogCurrentException("~InterserverIOEndpointHolder");
}
ActionBlocker & getBlocker() { return endpoint->blocker; }
private:
String name;
InterserverIOEndpointPtr endpoint;
InterserverIOHandler & handler;
};
using InterserverIOEndpointHolderPtr = std::shared_ptr<InterserverIOEndpointHolder>;
}