SqlServerExceptionHandlingStrategy.cs

//------------------------------------------------------------------------------
// <copyright file="SqlServerExceptionHandlingStrategy.cs"
//  company="Scott Dorman"
//  library="Cadru">
//    Copyright (C) 2001-2020 Scott Dorman.
// </copyright>
//
// <license>
//    Licensed under the Microsoft Public License (Ms-PL) (the "License");
//    you may not use this file except in compliance with the License.
//    You may obtain a copy of the License at
//
//    http://opensource.org/licenses/Ms-PL.html
//
//    Unless required by applicable law or agreed to in writing, software
//    distributed under the License is distributed on an "AS IS" BASIS,
//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//    See the License for the specific language governing permissions and
//    limitations under the License.
// </license>
//------------------------------------------------------------------------------

using System;
using System.Diagnostics.CodeAnalysis;

using Cadru.Polly.Resources;

using Microsoft.Data.SqlClient;

namespace Cadru.Polly.Data.SqlServer
{
    /// <summary>
    /// Defines a strategy for determining transient SQL Server network
    /// connectivity errors.
    /// </summary>
    public class NetworkConnectivityExceptionHandlingStrategy : IExceptionHandlingStrategy
    {
        /// <inheritdoc/>
        public bool ShouldHandle([NotNull] Exception exception)
        {
            if (exception is SqlException sqlException)
            {
                return sqlException.Number switch
                {
                    // SQL Error Code: 11001 A network-related or
                    // instance-specific error occurred while establishing a
                    // connection to SQL Server. The server was not found or was
                    // not accessible. Verify that the instance name is correct
                    // and that SQL Server is configured to allow remote
                    // connections. (provider: TCP Provider, error: 0 - No such
                    // host is known.)
                    11001 => true,
                    _ => false,
                };
            }

            return false;
        }
    }

    /// <summary>
    /// Defines a strategy for determining SQL Server timeout errors.
    /// </summary>
    public class SqlServerTimeoutExceptionHandlingStrategy : IExceptionHandlingStrategy
    {
        /// <inheritdoc/>
        public bool ShouldHandle([NotNull] Exception exception)
        {
            if (exception is SqlException sqlException)
            {
                foreach (SqlError err in sqlException.Errors)
                {
                    switch (err.Number)
                    {
                        // SQL Error Code: -2
                        case -2:
                            return true;
                    }
                }
            }

            return false;
        }
    }

    /// <summary>
    /// Defines a strategy for determining transient SQL Server errors.
    /// </summary>
    public class SqlServerTransientExceptionHandlingStrategy : IExceptionHandlingStrategy
    {
        /// <inheritdoc/>
        public bool ShouldHandle([NotNull] Exception exception)
        {
            if (exception is SqlException sqlException)
            {
                foreach (SqlError err in sqlException.Errors)
                {
                    switch (err.Number)
                    {
                        // SQL Error Code: 40501 The service is currently busy.
                        // Retry the request after 10 seconds. Code: (reason
                        // code to be decoded).
                        case ThrottlingCondition.ThrottlingErrorNumber:
                            // Decode the reason code from the error message to
                            // determine the grounds for throttling.
                            var condition = ThrottlingCondition.FromError(err);

                            // Attach the decoded values as additional
                            // attributes to the original SQL exception.
                            exception.Data[condition.ThrottlingMode.GetType().Name] = condition.ThrottlingMode.ToString();
                            exception.Data[condition.GetType().Name] = condition;
                            return true;

                        case 0:
                            if ((err.Class == 20 || err.Class == 11) && err.State == 0 && err.Server != null && exception.InnerException == null && String.Equals(err.Message, Strings.SQL_SevereError, StringComparison.CurrentCultureIgnoreCase))
                            {
                                return true;
                            }
                            return false;

                        // SQL Error Code: 49920 Cannot process request. Too
                        // many operations in progress for subscription "%ld".
                        // The service is busy processing multiple requests for
                        // this subscription. Requests are currently blocked for
                        // resource optimization. Query sys.dm_operation_status
                        // for operation status. Wait until pending requests are
                        // complete or delete one of your pending requests and
                        // retry your request later.
                        case 49920:
                        // SQL Error Code: 49919 Cannot process create or update
                        // request. Too many create or update operations in
                        // progress for subscription "%ld". The service is busy
                        // processing multiple create or update requests for
                        // your subscription or server. Requests are currently
                        // blocked for resource optimization. Query
                        // sys.dm_operation_status for pending operations. Wait
                        // till pending create or update requests are complete
                        // or delete one of your pending requests and retry your
                        // request later.
                        case 49919:
                        // SQL Error Code: 49918 Cannot process request. Not
                        // enough resources to process request. The service is
                        // currently busy.Please retry the request later.
                        case 49918:
                        // SQL Error Code: 41839 Transaction exceeded the
                        // maximum number of commit dependencies.
                        case 41839:
                        // SQL Error Code: 41325 The current transaction failed
                        // to commit due to a serializable validation failure.
                        case 41325:
                        // SQL Error Code: 41305 The current transaction failed
                        // to commit due to a repeatable read validation failure.
                        case 41305:
                        // SQL Error Code: 41302 The current transaction
                        // attempted to update a record that has been updated
                        // since the transaction started.
                        case 41302:
                        // SQL Error Code: 41301 Dependency failure: a
                        // dependency was taken on another transaction that
                        // later failed to commit.
                        case 41301:
                        // SQL Error Code: 40613 Database XXXX on server YYYY is
                        // not currently available. Please retry the connection
                        // later. If the problem persists, contact customer
                        // support, and provide them the session tracing ID of ZZZZZ.
                        case 40613:
                        // SQL Error Code: 40197 The service has encountered an
                        // error processing your request. Please try again.
                        case 40197:
                        // SQL Error Code: 10936 Resource ID : %d. The request
                        // limit for the elastic pool is %d and has been
                        // reached. See
                        // 'http://go.microsoft.com/fwlink/?LinkId=267637' for assistance.
                        case 10936:
                        // SQL Error Code: 10929 Resource ID: %d. The %s minimum
                        // guarantee is %d, maximum limit is %d and the current
                        // usage for the database is %d. However, the server is
                        // currently too busy to support requests greater than
                        // %d for this database. For more information, see
                        // http://go.microsoft.com/fwlink/?LinkId=267637.
                        // Otherwise, please try again.
                        case 10929:
                        // SQL Error Code: 10928 Resource ID: %d. The %s limit
                        // for the database is %d and has been reached. For more
                        // information, see http://go.microsoft.com/fwlink/?LinkId=267637.
                        case 10928:
                        // SQL Error Code: 10060 A network-related or
                        // instance-specific error occurred while establishing a
                        // connection to SQL Server. The server was not found or
                        // was not accessible. Verify that the instance name is
                        // correct and that SQL Server is configured to allow
                        // remote connections. (provider: TCP Provider, error: 0
                        // - A connection attempt failed because the connected
                        // party did not properly respond after a period of
                        // time, or established connection failed because
                        // connected host has failed to respond.)"
                        case 10060:
                        // SQL Error Code: 10054 A transport-level error has
                        // occurred when sending the request to the server.
                        // (provider: TCP Provider, error: 0 - An existing
                        // connection was forcibly closed by the remote host.)
                        case 10054:
                        // SQL Error Code: 10053 A transport-level error has
                        // occurred when receiving results from the server. An
                        // established connection was aborted by the software in
                        // your host machine.
                        case 10053:
                        // SQL Error Code: 4221 Login to read-secondary failed
                        // due to long wait on
                        // 'HADR_DATABASE_WAIT_FOR_TRANSITION_TO_VERSIONING'.
                        // The replica is not available for login because row
                        // versions are missing for transactions that were
                        // in-flight when the replica was recycled. The issue
                        // can be resolved by rolling back or committing the
                        // active transactions on the primary replica.
                        // Occurrences of this condition can be minimized by
                        // avoiding long write transactions on the primary.
                        case 4221:
                        // SQL Error Code: 4060 Cannot open database "%.*ls"
                        // requested by the login. The login failed.
                        case 4060:
                        // SQL Error Code: 1205 Deadlock
                        case 1205:
                        // SQL Error Code: 233 The client was unable to
                        // establish a connection because of an error during
                        // connection initialization process before login.
                        // Possible causes include the following: the client
                        // tried to connect to an unsupported version of SQL
                        // Server; the server was too busy to accept new
                        // connections; or there was a resource limitation
                        // (insufficient memory or maximum allowed connections)
                        // on the server. (provider: TCP Provider, error: 0 - An
                        // existing connection was forcibly closed by the remote host.)
                        case 233:
                        // SQL Error Code: 121 The semaphore timeout period has expired
                        case 121:
                        // SQL Error Code: 64 A connection was successfully
                        // established with the server, but then an error
                        // occurred during the login process. (provider: TCP
                        // Provider, error: 0 - The specified network name is no
                        // longer available.)
                        case 64:
                        // DBNETLIB Error Code: 20 The instance of SQL Server
                        // you attempted to connect to does not support encryption.
                        case 20:
                            return true;
                    }
                }
            }

            return false;
        }
    }

    /// <summary>
    /// Defines a strategy for determining transient SQL Server transaction errors.
    /// </summary>
    public class SqlServerTransientTransactionExceptionHandlingStrategy : IExceptionHandlingStrategy
    {
        /// <inheritdoc/>
        public bool ShouldHandle([NotNull] Exception exception)
        {
            if (exception is SqlException sqlException)
            {
                foreach (SqlError err in sqlException.Errors)
                {
                    switch (err.Number)
                    {
                        // SQL Error Code: 40549
                        case 40549:
                        // SQL Error Code: 40550
                        case 40550:
                            return true;
                    }
                }
            }

            return false;
        }
    }
}