add error to MySQL client connect

src/Core/MySQLClient.cpp

@@ -2,13 +2,10 @@
 
 namespace DB
 {
-using namespace MySQLProtocol;
 using namespace MySQLProtocol::Authentication;
 
 namespace ErrorCodes
 {
-    extern const int NETWORK_ERROR;
-    extern const int SOCKET_TIMEOUT;
     extern const int UNKNOWN_PACKET_FROM_SERVER;
 }
 
@@ -18,36 +15,22 @@ MySQLClient::MySQLClient(const String & host_, UInt16 port_, const String & user
     client_capability_flags = CLIENT_PROTOCOL_41 | CLIENT_PLUGIN_AUTH | CLIENT_SECURE_CONNECTION;
 }
 
-void MySQLClient::connect()
+bool MySQLClient::connect()
 {
-    try
+    if (connected)
-    {
-        if (connected)
-        {
-            close();
-        }
-
-        socket = std::make_unique<Poco::Net::StreamSocket>();
-        address = DNSResolver::instance().resolveAddress(host, port);
-        socket->connect(*address);
-
-        in = std::make_shared<ReadBufferFromPocoSocket>(*socket);
-        out = std::make_shared<WriteBufferFromPocoSocket>(*socket);
-        packet_sender = std::make_shared<PacketSender>(*in, *out, seq);
-        connected = true;
-
-        handshake();
-    }
-    catch (Poco::Net::NetException & e)
     {
         close();
-        throw NetException(e.displayText(), ErrorCodes::NETWORK_ERROR);
-    }
-    catch (Poco::TimeoutException & e)
-    {
-        close();
-        throw NetException(e.displayText(), ErrorCodes::SOCKET_TIMEOUT);
     }
+
+    socket = std::make_unique<Poco::Net::StreamSocket>();
+    address = DNSResolver::instance().resolveAddress(host, port);
+    socket->connect(*address);
+
+    in = std::make_shared<ReadBufferFromPocoSocket>(*socket);
+    out = std::make_shared<WriteBufferFromPocoSocket>(*socket);
+    packet_sender = std::make_shared<PacketSender>(*in, *out, seq);
+    connected = true;
+    return handshake();
 }
 
 void MySQLClient::close()
@@ -61,7 +44,7 @@ void MySQLClient::close()
 }
 
 /// https://dev.mysql.com/doc/internals/en/connection-phase-packets.html
-void MySQLClient::handshake()
+bool MySQLClient::handshake()
 {
     Handshake handshake;
     packet_sender->receivePacket(handshake);
@@ -81,16 +64,19 @@ void MySQLClient::handshake()
 
     PacketResponse packetResponse(handshake.capability_flags);
     packet_sender->receivePacket(packetResponse);
-
+    if (packetResponse.getType() != PACKET_ERR)
-    switch (packetResponse.getType())
     {
-        case PACKET_OK:
+        return true;
-            break;
+    }
-        case PACKET_ERR:
+    else
-            throw Exception(packetResponse.err.error_message, ErrorCodes::UNKNOWN_PACKET_FROM_SERVER);
+    {
-            break;
+        last_error = packetResponse.err.error_message;
-        case PACKET_EOF:
+        return false;
-            break;
     }
 }
+
+String MySQLClient::error()
+{
+    return last_error;
+}
 }

src/Core/MySQLClient.h

@@ -14,14 +14,15 @@
 
 namespace DB
 {
+using namespace MySQLProtocol;
+
 class MySQLClient
 {
 public:
     MySQLClient(const String & host_, UInt16 port_, const String & user_, const String & password_, const String & database_);
-
+    bool connect();
-    void connect();
-
     void close();
+    String error();
 
 private:
     String host;
@@ -32,6 +33,7 @@ private:
 
     bool connected = false;
     UInt32 client_capability_flags = 0;
+    String last_error;
 
     uint8_t seq = 0;
     UInt8 charset_utf8 = 33;
@@ -42,10 +44,8 @@ private:
     std::shared_ptr<WriteBuffer> out;
     std::unique_ptr<Poco::Net::StreamSocket> socket;
     std::optional<Poco::Net::SocketAddress> address;
+    std::shared_ptr<PacketSender> packet_sender;
 
-    void handshake();
+    bool handshake();
-
-protected:
-    std::shared_ptr<MySQLProtocol::PacketSender> packet_sender;
 };
 }

src/Core/MySQLProtocol.h

@@ -491,49 +491,30 @@ public:
 
     void readPayloadImpl(ReadBuffer & buffer) override
     {
-        /// 1-byte: [0a] protocol version
         buffer.readStrict(reinterpret_cast<char *>(&protocol_version), 1);
-
-        /// string[NUL]: server version
         readNullTerminated(server_version, buffer);
-
-        /// 4-bytes: connection id
         buffer.readStrict(reinterpret_cast<char *>(&connection_id), 4);
 
-        /// 8-bytes: auth-plugin-data-part-1
         auth_plugin_data.resize(AUTH_PLUGIN_DATA_PART_1_LENGTH);
         buffer.readStrict(auth_plugin_data.data(), AUTH_PLUGIN_DATA_PART_1_LENGTH);
 
-        /// 1-byte: [00] filler
         buffer.ignore(1);
-
-        /// 2-bytes: capability flags lower 2-bytes
         buffer.readStrict(reinterpret_cast<char *>(&capability_flags), 2);
-
-        /// 1-byte: character set
         buffer.readStrict(reinterpret_cast<char *>(&character_set), 1);
-
-        /// 2-bytes: status flags(ignored)
         buffer.readStrict(reinterpret_cast<char *>(&status_flags), 2);
-
-        /// 2-bytes: capability flags upper 2-bytes
         buffer.readStrict((reinterpret_cast<char *>(&capability_flags)) + 2, 2);
 
         UInt8 auth_plugin_data_length = 0;
         if (capability_flags & MySQLProtocol::CLIENT_PLUGIN_AUTH)
         {
-            /// 1-byte: length of auth-plugin-data
             buffer.readStrict(reinterpret_cast<char *>(&auth_plugin_data_length), 1);
         }
         else
         {
-            /// 1-byte:  [00]
             buffer.ignore(1);
         }
 
-        /// string[10]     reserved (all [00])
         buffer.ignore(10);
-
         if (capability_flags & MySQLProtocol::CLIENT_SECURE_CONNECTION)
         {
             UInt8 part2_length = (auth_plugin_data_length - AUTH_PLUGIN_DATA_PART_1_LENGTH) > 13
@@ -764,7 +745,7 @@ public:
     String session_state_changes;
     String info;
 
-    OK_Packet(uint32_t capabilities_) : capabilities(capabilities_) { }
+    OK_Packet(uint32_t capabilities_) : header(0x00), capabilities(capabilities_), affected_rows(0), last_insert_id(0), status_flags(0) { }
     OK_Packet(
         uint8_t header_,
         uint32_t capabilities_,
@@ -776,6 +757,7 @@ public:
         : header(header_)
         , capabilities(capabilities_)
         , affected_rows(affected_rows_)
+        , last_insert_id(0)
         , warnings(warnings_)
         , status_flags(status_flags_)
         , session_state_changes(std::move(session_state_changes_))
@@ -814,7 +796,7 @@ public:
     {
         buffer.write(header);
         writeLengthEncodedNumber(affected_rows, buffer);
-        writeLengthEncodedNumber(0, buffer); /// last insert-id
+        writeLengthEncodedNumber(last_insert_id, buffer); /// last insert-id
 
         if (capabilities & CLIENT_PROTOCOL_41)
         {
@@ -859,7 +841,8 @@ public:
             auto len = readLengthEncodedNumber(payload);
             info.resize(len);
             payload.readStrict(info.data(), len);
-            if (status_flags & SERVER_SESSION_STATE_CHANGED) {
+            if (status_flags & SERVER_SESSION_STATE_CHANGED)
+            {
                 len = readLengthEncodedNumber(payload);
                 session_state_changes.resize(len);
                 payload.readStrict(session_state_changes.data(), len);

src/Core/tests/mysql_client.cpp

@@ -1,3 +1,4 @@
+#include <iostream>
 #include <Core/MySQLClient.h>
 
 
@@ -5,9 +6,12 @@ int main(int, char **)
 {
     using namespace DB;
 
-    UInt16 port = 4407;
+    UInt16 port = 9001;
-    String host = "127.0.0.1", user = "mock", password = "mock";
+    String host = "127.0.0.1", user = "default", password = "123";
     MySQLClient client(host, port, user, password, "");
-    client.connect();
+    if (!client.connect())
+    {
+        std::cerr << "Connect Error: " << client.error() << std::endl;
+    }
     return 0;
 }