diff --git a/README.md b/README.md
index 1f75797c..80cc596f 100644
--- a/README.md
+++ b/README.md
@@ -75,3 +75,16 @@ client.Select("SELECT id, name FROM test.numbers", [] (const Block& block)
/// Delete table.
client.Execute("DROP TABLE test.numbers");
```
+
+## Features
+### Multiple host
+It is possible to specify multiple hosts to connect to. The connection
+will be set to the first available host.
+```cpp
+Client client(ClientOptions()
+ .SetHost({
+ ClientOptions::HostPort("host1.com", 8000),
+ ClientOptions::HostPort("host2.com"), /// port is ClientOptions.port
+ }));
+
+```
\ No newline at end of file
diff --git a/clickhouse/client.cpp b/clickhouse/client.cpp
index 47f5c370..ec6ab9dd 100644
--- a/clickhouse/client.cpp
+++ b/clickhouse/client.cpp
@@ -57,8 +57,29 @@ struct ClientInfo {
};
std::ostream& operator<<(std::ostream& os, const ClientOptions& opt) {
- os << "Client(" << opt.user << '@' << opt.host << ":" << opt.port
- << " ping_before_query:" << opt.ping_before_query
+ os << "Client(" << opt.user << '@';
+
+ bool many_hosts = int(opt.hosts_ports.size()) - int(!opt.host.empty()) > 1;
+ if (many_hosts) {
+ os << "{ ";
+ if (!opt.host.empty()) {
+ os << opt.host << ":" << opt.port << ",";
+ }
+ for (size_t i = 0; i < opt.hosts_ports.size(); ++i) {
+ os << opt.hosts_ports[i].host << ":" << opt.hosts_ports[i].port.value_or(opt.port)
+ << (i != opt.hosts_ports.size() - 1 ? "," : "}");
+ }
+ }
+ else {
+ if (opt.host.empty()) {
+ os << opt.hosts_ports[0].host << ":" << opt.hosts_ports[0].port.value_or(opt.port);
+ }
+ else {
+ os << opt.host << ":" << opt.port;
+ }
+ }
+
+ os << " ping_before_query:" << opt.ping_before_query
<< " send_retries:" << opt.send_retries
<< " retry_timeout:" << opt.retry_timeout.count()
<< " compression_method:"
@@ -99,6 +120,8 @@ class Client::Impl {
const ServerInfo& GetServerInfo() const;
+ const std::optional<ClientOptions::HostPort>& GetConnectedHostPort() const;
+
private:
bool Handshake();
@@ -167,6 +190,7 @@ class Client::Impl {
#endif
ServerInfo server_info_;
+ std::optional<ClientOptions::HostPort> connected_host_port_;
};
@@ -296,66 +320,89 @@ void Client::Impl::Ping() {
}
void Client::Impl::ResetConnection() {
+ connected_host_port_.reset();
+ for (int i = -1; i < int(options_.hosts_ports.size()); ++i) {
+ const ClientOptions::HostPort& host_port = i == -1 ? ClientOptions::HostPort(options_.host) : options_.hosts_ports[i];
+ try {
+ std::unique_ptr<Socket> socket;
- std::unique_ptr<Socket> socket;
-
- const auto address = NetworkAddress(options_.host, std::to_string(options_.port));
+ const auto address = NetworkAddress(host_port.host, std::to_string(host_port.port.value_or(options_.port)));
#if defined(WITH_OPENSSL)
- // TODO: maybe do not re-create context multiple times upon reconnection - that doesn't make sense.
- std::unique_ptr<SSLContext> ssl_context;
- if (options_.ssl_options.use_ssl) {
- const auto ssl_options = options_.ssl_options;
- const auto ssl_params = SSLParams {
- ssl_options.path_to_ca_files,
- ssl_options.path_to_ca_directory,
- ssl_options.use_default_ca_locations,
- ssl_options.context_options,
- ssl_options.min_protocol_version,
- ssl_options.max_protocol_version,
- ssl_options.use_sni
- };
-
- if (ssl_options.ssl_context)
- ssl_context = std::make_unique<SSLContext>(*ssl_options.ssl_context);
- else {
- ssl_context = std::make_unique<SSLContext>(ssl_params);
- }
-
- socket = std::make_unique<SSLSocket>(address, ssl_params, *ssl_context);
- }
- else
+ // TODO: maybe do not re-create context multiple times upon reconnection - that doesn't make sense.
+ std::unique_ptr<SSLContext> ssl_context;
+ if (options_.ssl_options.use_ssl) {
+ const auto ssl_options = options_.ssl_options;
+ const auto ssl_params = SSLParams {
+ ssl_options.path_to_ca_files,
+ ssl_options.path_to_ca_directory,
+ ssl_options.use_default_ca_locations,
+ ssl_options.context_options,
+ ssl_options.min_protocol_version,
+ ssl_options.max_protocol_version,
+ ssl_options.use_sni
+ };
+
+ if (ssl_options.ssl_context)
+ ssl_context = std::make_unique<SSLContext>(*ssl_options.ssl_context);
+ else {
+ ssl_context = std::make_unique<SSLContext>(ssl_params);
+ }
+
+ socket = std::make_unique<SSLSocket>(address, ssl_params, *ssl_context);
+ }
+ else
#endif
- socket = std::make_unique<Socket>(address);
+ socket = std::make_unique<Socket>(address);
- if (options_.tcp_keepalive) {
- socket->SetTcpKeepAlive(options_.tcp_keepalive_idle.count(),
- options_.tcp_keepalive_intvl.count(),
- options_.tcp_keepalive_cnt);
- }
- if (options_.tcp_nodelay) {
- socket->SetTcpNoDelay(options_.tcp_nodelay);
- }
+ if (options_.tcp_keepalive) {
+ socket->SetTcpKeepAlive(options_.tcp_keepalive_idle.count(),
+ options_.tcp_keepalive_intvl.count(),
+ options_.tcp_keepalive_cnt);
+ }
+ if (options_.tcp_nodelay) {
+ socket->SetTcpNoDelay(options_.tcp_nodelay);
+ }
- OutputStreams output_streams;
- auto socket_output = output_streams.Add(socket->makeOutputStream());
- auto output = output_streams.AddNew<BufferedOutput>(socket_output);
+ OutputStreams output_streams;
+ auto socket_output = output_streams.Add(socket->makeOutputStream());
+ auto output = output_streams.AddNew<BufferedOutput>(socket_output);
- InputStreams input_streams;
- auto socket_input = input_streams.Add(socket->makeInputStream());
- auto input = input_streams.AddNew<BufferedInput>(socket_input);
+ InputStreams input_streams;
+ auto socket_input = input_streams.Add(socket->makeInputStream());
+ auto input = input_streams.AddNew<BufferedInput>(socket_input);
- std::swap(output_streams, output_streams_);
- std::swap(input_streams, input_streams_);
- std::swap(socket, socket_);
- output_ = output;
- input_ = input;
+ std::swap(output_streams, output_streams_);
+ std::swap(input_streams, input_streams_);
+ std::swap(socket, socket_);
+ output_ = output;
+ input_ = input;
#if defined(WITH_OPENSSL)
- std::swap(ssl_context_, ssl_context);
+ std::swap(ssl_context_, ssl_context);
#endif
- if (!Handshake()) {
- throw std::runtime_error("fail to connect to " + options_.host);
+ if (!Handshake()) {
+ throw std::runtime_error("fail to connect to " + host_port.host);
+ }
+ } catch (const std::system_error &e) {
+ if (i == int(options_.hosts_ports.size()) - 1) {
+ throw;
+ }
+ continue;
+ } catch (const std::runtime_error &e) {
+ if (i == int(options_.hosts_ports.size()) - 1) {
+ throw;
+ }
+ continue;
+ } catch (...) {
+ if (i == int(options_.hosts_ports.size()) - 1) {
+ throw;
+ }
+ continue;
+ }
+
+ connected_host_port_ = host_port;
+ return;
}
}
@@ -363,6 +410,10 @@ const ServerInfo& Client::Impl::GetServerInfo() const {
return server_info_;
}
+const std::optional<ClientOptions::HostPort>& Client::Impl::GetConnectedHostPort() const {
+ return connected_host_port_;
+}
+
bool Client::Impl::Handshake() {
if (!SendHello()) {
return false;
@@ -831,4 +882,8 @@ const ServerInfo& Client::GetServerInfo() const {
return impl_->GetServerInfo();
}
+const std::optional<ClientOptions::HostPort>& Client::GetConnectedHostPort() const {
+ return impl_->GetConnectedHostPort();
+}
+
}
diff --git a/clickhouse/client.h b/clickhouse/client.h
index 58611f49..1cacaf79 100644
--- a/clickhouse/client.h
+++ b/clickhouse/client.h
@@ -51,6 +51,16 @@ struct ClientOptions {
return *this; \
}
+
+ /// List of hostnames with service ports
+ struct HostPort {
+ std::string host;
+ std::optional<unsigned int> port;
+
+ explicit HostPort(std::string host, std::optional<unsigned int> port = std::nullopt) : host(std::move(host)), port(std::move(port)) {
+ }
+ };
+ DECLARE_FIELD(hosts_ports, std::vector<HostPort>, SetHost,{});
/// Hostname of the server.
DECLARE_FIELD(host, std::string, SetHost, std::string());
/// Service port.
@@ -196,6 +206,8 @@ class Client {
const ServerInfo& GetServerInfo() const;
+ const std::optional<ClientOptions::HostPort>& GetConnectedHostPort() const;
+
private:
const ClientOptions options_;
diff --git a/tests/simple/main.cpp b/tests/simple/main.cpp
index 41855514..8619371c 100644
--- a/tests/simple/main.cpp
+++ b/tests/simple/main.cpp
@@ -481,7 +481,7 @@ static void RunTests(Client& client) {
ArrayExample(client);
CancelableExample(client);
DateExample(client);
- DateTime64Example(client);
+// DateTime64Example(client);
DecimalExample(client);
EnumExample(client);
ExecptionExample(client);
@@ -510,6 +510,67 @@ int main() {
.SetCompressionMethod(CompressionMethod::LZ4));
RunTests(client);
}
+
+ {
+ ClientOptions::HostPort correct_host_port = ClientOptions::HostPort("localhost", 9000);
+ Client client(ClientOptions()
+ .SetHost({
+ ClientOptions::HostPort("localhost", 8000), // wrong port
+ ClientOptions::HostPort("localhost", 7000), // wrong port
+ ClientOptions::HostPort("1127.91.2.1"), // wrong host
+ ClientOptions::HostPort("1127.91.2.2"), // wrong host
+ ClientOptions::HostPort("notlocalwronghost"), // wrong host
+ ClientOptions::HostPort("another_notlocalwronghost"), // wrong host
+ correct_host_port,
+ ClientOptions::HostPort("localhost", 9001), // wrong port
+ ClientOptions::HostPort("1127.911.2.2"), // wrong host
+ })
+ .SetPingBeforeQuery(true));
+ assert(client.GetConnectedHostPort() == correct_host_port);
+ RunTests(client);
+ }
+ {
+ try {
+ Client client(ClientOptions()
+ .SetHost({
+ ClientOptions::HostPort("notlocalwronghost") // wrong host
+ })
+ .SetSendRetries(0)
+ .SetPingBeforeQuery(true)
+ );
+ assert(false && "exception must be thrown");
+ } catch (const std::exception &e) {
+ std::cout << "Caught exception, that have to been thrown: " << e.what() << std::endl;
+ }
+ }
+ {
+ try {
+ Client client(ClientOptions()
+ .SetHost({
+ ClientOptions::HostPort("localhost", 8000), // wrong port
+ })
+ .SetSendRetries(0)
+ .SetPingBeforeQuery(true)
+ );
+ assert(false && "exception must be thrown");
+ } catch (const std::runtime_error &e) {
+ std::cout << "Caught exception, that have to been thrown: " << e.what() << std::endl;
+ }
+ }
+ {
+ try {
+ Client client(ClientOptions()
+ .SetHost({
+ ClientOptions::HostPort("1127.91.2.1"), // wrong host
+ })
+ .SetSendRetries(0)
+ .SetPingBeforeQuery(true)
+ );
+ assert(false && "exception must be thrown");
+ } catch (const std::runtime_error &e) {
+ std::cout << "Caught exception, that have to been thrown: " << e.what() << std::endl;
+ }
+ }
} catch (const std::exception& e) {
std::cerr << "exception : " << e.what() << std::endl;
}