Merge pull request #938 from mysql-net/server-redirection

Add Azure server redirection.

Author: bgrainger

src/MySqlConnector/Core/ConnectionSettings.cs

@@ -150,6 +150,8 @@ public ConnectionSettings(MySqlConnectionStringBuilder csb)
 			static int ToSigned(uint value) => value >= int.MaxValue ? int.MaxValue : (int) value;
 		}
 
+		public ConnectionSettings CloneWith(string host, int port, string userId, bool isRedirected) => new ConnectionSettings(this, host, port, userId, isRedirected);
+
 		private static MySqlGuidFormat GetEffectiveGuidFormat(MySqlGuidFormat guidFormat, bool oldGuids)
 		{
 			switch (guidFormat)
@@ -240,6 +242,7 @@ private static MySqlGuidFormat GetEffectiveGuidFormat(MySqlGuidFormat guidFormat
 		public bool UseXaTransactions { get; }
 
 		public byte[]? ConnectionAttributes { get; set; }
+		public bool IsRedirected { get; }
 
 		// Helper Functions
 		int? m_connectionTimeoutMilliseconds;
@@ -265,6 +268,66 @@ public int ConnectionTimeoutMilliseconds
 			}
 		}
 
+		private ConnectionSettings(ConnectionSettings other, string host, int port, string userId, bool isRedirected)
+		{
+			ConnectionStringBuilder = other.ConnectionStringBuilder;
+			ConnectionString = other.ConnectionString;
+
+			ConnectionProtocol = MySqlConnectionProtocol.Sockets;
+			HostNames = new[] { host };
+			LoadBalance = other.LoadBalance;
+			Port = port;
+			PipeName = other.PipeName;
+
+			UserID = userId;
+			Password = other.Password;
+			Database = other.Database;
+
+			SslMode = other.SslMode;
+			CertificateFile = other.CertificateFile;
+			CertificatePassword = other.CertificatePassword;
+			SslCertificateFile = other.SslCertificateFile;
+			SslKeyFile = other.SslKeyFile;
+			CACertificateFile = other.CACertificateFile;
+			CertificateStoreLocation = other.CertificateStoreLocation;
+			CertificateThumbprint = other.CertificateThumbprint;
+
+			Pooling = other.Pooling;
+			ConnectionLifeTime = other.ConnectionLifeTime;
+			ConnectionReset = other.ConnectionReset;
+			ConnectionIdlePingTime = other.ConnectionIdlePingTime;
+			ConnectionIdleTimeout = other.ConnectionIdleTimeout;
+			MinimumPoolSize = other.MinimumPoolSize;
+			MaximumPoolSize = other.MaximumPoolSize;
+
+			AllowLoadLocalInfile = other.AllowLoadLocalInfile;
+			AllowPublicKeyRetrieval = other.AllowPublicKeyRetrieval;
+			AllowUserVariables = other.AllowUserVariables;
+			AllowZeroDateTime = other.AllowZeroDateTime;
+			ApplicationName = other.ApplicationName;
+			AutoEnlist = other.AutoEnlist;
+			ConnectionTimeout = other.ConnectionTimeout;
+			ConvertZeroDateTime = other.ConvertZeroDateTime;
+			DateTimeKind = other.DateTimeKind;
+			DefaultCommandTimeout = other.DefaultCommandTimeout;
+			ForceSynchronous = other.ForceSynchronous;
+			IgnoreCommandTransaction = other.IgnoreCommandTransaction;
+			IgnorePrepare = other.IgnorePrepare;
+			InteractiveSession = other.InteractiveSession;
+			GuidFormat = other.GuidFormat;
+			Keepalive = other.Keepalive;
+			NoBackslashEscapes = other.NoBackslashEscapes;
+			PersistSecurityInfo = other.PersistSecurityInfo;
+			ServerRsaPublicKeyFile = other.ServerRsaPublicKeyFile;
+			ServerSPN = other.ServerSPN;
+			TreatTinyAsBoolean = other.TreatTinyAsBoolean;
+			UseAffectedRows = other.UseAffectedRows;
+			UseCompression = other.UseCompression;
+			UseXaTransactions = other.UseXaTransactions;
+
+			IsRedirected = isRedirected;
+		}
+
 		static readonly string[] s_localhostPipeServer = { "." };
 	}
 }

src/MySqlConnector/Core/ServerSession.cs

@@ -350,6 +350,7 @@ public async Task ConnectAsync(ConnectionSettings cs, int startTickCount, ILoadB
 					m_state = State.Connecting;
 				}
 
+serverRedirection:
 				// TLS negotiation should automatically fall back to the best version supported by client and server. However,
 				// Windows Schannel clients will fail to connect to a yaSSL-based MySQL Server if TLS 1.2 is requested and
 				// have to use only TLS 1.1: https://github.com/mysql-net/MySqlConnector/pull/101
@@ -465,7 +466,51 @@ public async Task ConnectAsync(ConnectionSettings cs, int startTickCount, ILoadB
 					payload = await SwitchAuthenticationAsync(cs, payload, ioBehavior, cancellationToken).ConfigureAwait(false);
 				}
 
-				OkPayload.Create(payload.Span, SupportsDeprecateEof, SupportsSessionTrack);
+				var ok = OkPayload.Create(payload.Span, SupportsDeprecateEof, SupportsSessionTrack);
+				if (ok.StatusInfo is not null && ok.StatusInfo.StartsWith("Location: mysql://", StringComparison.Ordinal))
+				{
+					// server redirection string has the format "Location: mysql://{host}:{port}/user={userId}[&ttl={ttl}]"
+					m_logArguments[1] = ok.StatusInfo;
+					Log.Info("Session{0} has server redirection header {1}", m_logArguments);
+
+					if (cs.IsRedirected)
+					{
+						Log.Info("Session{0} is already redirected; ignoring it.", m_logArguments);
+					}
+					else
+					{
+						var hostIndex = 18;
+						var colonIndex = ok.StatusInfo.IndexOf(':', hostIndex);
+						if (colonIndex != -1)
+						{
+							var host = ok.StatusInfo.Substring(hostIndex, colonIndex - hostIndex);
+							var portIndex = colonIndex + 1;
+							var userIndex = ok.StatusInfo.IndexOf("/user=", StringComparison.Ordinal);
+							if (userIndex != -1)
+							{
+								if (int.TryParse(ok.StatusInfo.Substring(portIndex, userIndex - portIndex), out var port))
+								{
+									var ampersandIndex = ok.StatusInfo.IndexOf('&', userIndex);
+									var userId = ampersandIndex == -1 ? ok.StatusInfo.Substring(userIndex + 6) : ok.StatusInfo.Substring(userIndex + 6, ampersandIndex - userIndex - 6);
+									Log.Info("Session{0} found server redirection Host={1}; Port={2}; User={3}", m_logArguments[0], host, port, userId);
+
+									if (host != cs.HostNames![0] || port != cs.Port || userId != cs.UserID)
+									{
+										Log.Info("Session{0} closing existing connection", m_logArguments);
+										await SendAsync(QuitPayload.Instance, ioBehavior, cancellationToken).ConfigureAwait(false);
+										Log.Info("Session{0} opening new connection to Host={1}; Port={2}; User={3}", m_logArguments[0], host, port, userId);
+										cs = cs.CloneWith(host, port, userId, isRedirected: true);
+										goto serverRedirection;
+									}
+									else
+									{
+										Log.Info("Session{0} is already connected to this server; ignoring redirection", m_logArguments);
+									}
+								}
+							}
+						}
+					}
+				}
 
 				if (m_useCompression)
 					m_payloadHandler = new CompressedPayloadHandler(m_payloadHandler.ByteHandler);
@@ -1420,6 +1465,7 @@ private bool ShouldGetRealServerDetails(ConnectionSettings cs)
 			if (cs.ConnectionProtocol == MySqlConnectionProtocol.Sockets && cs.HostNames!.Count == 1)
 			{
 				return cs.HostNames[0].EndsWith(".mysql.database.azure.com", StringComparison.OrdinalIgnoreCase) ||
+					cs.HostNames[0].EndsWith(".database.windows.net", StringComparison.OrdinalIgnoreCase) ||
 					cs.HostNames[0].EndsWith(".mysql.database.chinacloudapi.cn", StringComparison.OrdinalIgnoreCase);
 			}
 

src/MySqlConnector/Protocol/Payloads/OkPayload.cs

@@ -11,6 +11,7 @@ internal sealed class OkPayload
 		public ulong LastInsertId { get; }
 		public ServerStatus ServerStatus { get; }
 		public int WarningCount { get; }
+		public string? StatusInfo { get; }
 		public string? NewSchema { get; }
 
 		public const byte Signature = 0x00;
@@ -36,12 +37,13 @@ public static OkPayload Create(ReadOnlySpan<byte> span, bool deprecateEof, bool
 			var serverStatus = (ServerStatus) reader.ReadUInt16();
 			var warningCount = (int) reader.ReadUInt16();
 			string? newSchema = null;
+			ReadOnlySpan<byte> statusBytes;
 
 			if (clientSessionTrack)
 			{
 				if (reader.BytesRemaining > 0)
 				{
-					reader.ReadLengthEncodedByteString(); // human-readable info
+					statusBytes = reader.ReadLengthEncodedByteString(); // human-readable info
 
 					if ((serverStatus & ServerStatus.SessionStateChanged) == ServerStatus.SessionStateChanged && reader.BytesRemaining > 0)
 					{
@@ -65,33 +67,46 @@ public static OkPayload Create(ReadOnlySpan<byte> span, bool deprecateEof, bool
 						}
 					}
 				}
+				else
+				{
+					statusBytes = default;
+				}
 			}
 			else
 			{
-				// ignore "string<EOF> info" human-readable string
+				// read EOF-terminated string
+				statusBytes = reader.ReadByteString(reader.BytesRemaining);
+
+				// try to detect if it was actually a length-prefixed string (up to 250 bytes); some servers send
+				// a length-prefixed status string even when CLIENT_SESSION_TRACK is not specified
+				if (statusBytes.Length != 0 && statusBytes[0] == statusBytes.Length - 1)
+					statusBytes = statusBytes.Slice(1);
 			}
 
-			if (affectedRowCount == 0 && lastInsertId == 0 && warningCount == 0 && newSchema is null)
+			var statusInfo = statusBytes.Length == 0 ? null : Encoding.UTF8.GetString(statusBytes);
+
+			if (affectedRowCount == 0 && lastInsertId == 0 && warningCount == 0 && statusInfo is null && newSchema is null)
 			{
 				if (serverStatus == ServerStatus.AutoCommit)
 					return s_autoCommitOk;
 				if (serverStatus == (ServerStatus.AutoCommit | ServerStatus.SessionStateChanged))
 					return s_autoCommitSessionStateChangedOk;
 			}
 
-			return new OkPayload(affectedRowCount, lastInsertId, serverStatus, warningCount, newSchema);
+			return new OkPayload(affectedRowCount, lastInsertId, serverStatus, warningCount, statusInfo, newSchema);
 		}
 
-		private OkPayload(int affectedRowCount, ulong lastInsertId, ServerStatus serverStatus, int warningCount, string? newSchema)
+		private OkPayload(int affectedRowCount, ulong lastInsertId, ServerStatus serverStatus, int warningCount, string? statusInfo, string? newSchema)
 		{
 			AffectedRowCount = affectedRowCount;
 			LastInsertId = lastInsertId;
 			ServerStatus = serverStatus;
 			WarningCount = warningCount;
+			StatusInfo = statusInfo;
 			NewSchema = newSchema;
 		}
 
-		static readonly OkPayload s_autoCommitOk = new(0, 0, ServerStatus.AutoCommit, 0, null);
-		static readonly OkPayload s_autoCommitSessionStateChangedOk = new(0, 0, ServerStatus.AutoCommit | ServerStatus.SessionStateChanged, 0, null);
+		static readonly OkPayload s_autoCommitOk = new(0, 0, ServerStatus.AutoCommit, 0, null, null);
+		static readonly OkPayload s_autoCommitSessionStateChangedOk = new(0, 0, ServerStatus.AutoCommit | ServerStatus.SessionStateChanged, 0, null, null);
 	}
 }