ClickHouse/dbms/include/DB/Dictionaries/ClickHouseDictionarySource.h
2015-02-11 00:14:11 +03:00

136 lines
4.1 KiB
C++

#pragma once
#include <DB/Dictionaries/IDictionarySource.h>
#include <DB/Client/ConnectionPool.h>
#include <DB/DataStreams/RemoteBlockInputStream.h>
#include <DB/Interpreters/executeQuery.h>
#include <DB/Common/isLocalAddress.h>
#include <statdaemons/ext/range.hpp>
#include <Poco/Util/AbstractConfiguration.h>
#include <Poco/Net/NetworkInterface.h>
namespace DB
{
const auto max_connections = 1;
/** Allows loading dictionaries from local or remote ClickHouse instance
* @todo use ConnectionPoolWithFailover
* @todo invent a way to keep track of source modifications
*/
class ClickHouseDictionarySource final : public IDictionarySource
{
public:
ClickHouseDictionarySource(const Poco::Util::AbstractConfiguration & config,
const std::string & config_prefix,
Block & sample_block, Context & context)
: host{config.getString(config_prefix + ".host")},
port(config.getInt(config_prefix + ".port")),
user{config.getString(config_prefix + ".user", "")},
password{config.getString(config_prefix + ".password", "")},
db{config.getString(config_prefix + ".db", "")},
table{config.getString(config_prefix + ".table")},
sample_block{sample_block}, context(context),
is_local{isLocalAddress({ host, port })},
pool{is_local ? nullptr : std::make_unique<ConnectionPool>(
max_connections, host, port, db, user, password, context.getDataTypeFactory(),
"ClickHouseDictionarySource")
},
load_all_query{composeLoadAllQuery(sample_block, table)}
{}
/// copy-constructor is provided in order to support cloneability
ClickHouseDictionarySource(const ClickHouseDictionarySource & other)
: host{other.host}, port{other.port}, user{other.user}, password{other.password},
db{other.db}, table{other.db},
sample_block{other.sample_block}, context(other.context),
is_local{other.is_local},
pool{is_local ? nullptr : std::make_unique<ConnectionPool>(
max_connections, host, port, db, user, password, context.getDataTypeFactory(),
"ClickHouseDictionarySource")},
load_all_query{other.load_all_query}
{}
BlockInputStreamPtr loadAll() override
{
/** Query to local ClickHouse is marked internal in order to avoid
* the necessity of holding process_list_element shared pointer.
*/
if (is_local)
return executeQuery(load_all_query, context, true).in;
return new RemoteBlockInputStream{pool.get(), load_all_query, nullptr};
}
BlockInputStreamPtr loadId(const std::uint64_t id) override
{
throw Exception{
"Method unsupported",
ErrorCodes::NOT_IMPLEMENTED
};
}
BlockInputStreamPtr loadIds(const std::vector<std::uint64_t> ids) override
{
throw Exception{
"Method unsupported",
ErrorCodes::NOT_IMPLEMENTED
};
}
bool isModified() const override { return true; }
bool supportsSelectiveLoad() const override { return true; }
DictionarySourcePtr clone() const override { return std::make_unique<ClickHouseDictionarySource>(*this); }
private:
/// @todo escape table and column names
static std::string composeLoadAllQuery(const Block & block, const std::string & table)
{
std::string query{"SELECT "};
auto first = true;
for (const auto idx : ext::range(0, block.columns()))
{
if (!first)
query += ", ";
query += block.getByPosition(idx).name;
first = false;
}
query += " FROM " + table + ';';
return query;
}
static bool isLocal(const std::string & host, const UInt16 port)
{
const UInt16 clickhouse_port = Poco::Util::Application::instance().config().getInt("tcp_port", 0);
static auto interfaces = Poco::Net::NetworkInterface::list();
if (clickhouse_port == port)
{
return interfaces.end() != std::find_if(interfaces.begin(), interfaces.end(),
[&] (const Poco::Net::NetworkInterface & interface) {
return interface.address() == Poco::Net::IPAddress(host);
});
}
return false;
}
const std::string host;
const UInt16 port;
const std::string user;
const std::string password;
const std::string db;
const std::string table;
Block sample_block;
Context & context;
const bool is_local;
std::unique_ptr<ConnectionPool> pool;
const std::string load_all_query;
};
}