protected T RunInExecutionWrapper <T>(Func <T> run)
{
// We wrap this so it will repeat the whole test if there is a timeout or
// we lose connectivity in the cloud.
var executionStrategy = new SqlAzureExecutionStrategy();
SqlAzureDbConfiguration.SuspendExecutionStrategy = true;
return(executionStrategy.Execute(run));
}
public static IEnumerable <T> QueryResiliently <T>(string sql, dynamic param = null, CommandType?commandType = null)
{
IEnumerable <T> result = null;
var executionStrategy = new SqlAzureExecutionStrategy();
executionStrategy.Execute(() =>
{
using (var connection = GetOpenConnection())
{
// QueryAsync is marked async in the source code, but is not in metadata. +https://code.google.com/p/dapper-dot-net/source/browse/Dapper+NET45/SqlMapperAsync.cs
result = SqlMapper.Query <T>(connection, sql, param: param, transaction: null, commandTimeout: null, commandType: commandType);
}
});
return(result);
}
/// <summary>
/// Strip the beginning of the exception message which contains the name of the stored procedure and the argument values. We do not disclose the values to the client.
/// 20150724 AF. We strip the prefix in Runnymede.Website.Utils.CustomExceptionResult
/// </summary>
/// <param name="ex"></param>
/// <returns></returns>
//public static Exception StripException(SqlException ex)
//{
// var index = ex.Message.IndexOf("::"); // The magic separator used within stored procedures.
// return (index > 0) ? new Exception(ex.Message.Substring(index + 2).Trim(), ex) : ex;
//}
public static int ExecuteResiliently(string sql, dynamic param = null, CommandType?commandType = null)
{
int rowsAffected = 0;
var executionStrategy = new SqlAzureExecutionStrategy();
executionStrategy.Execute(() =>
{
using (var connection = GetOpenConnection())
{
// Outside-initiated user transactions are not supported. See Limitations with Retrying Execution Strategies (EF6 onwards) +http://msdn.microsoft.com/en-us/data/dn307226
// +http://entityframework.codeplex.com/wikipage?title=Connection+Resiliency+Spec
// To find a workaround, search for SqlAzureExecutionStrategy in the project code.
rowsAffected = SqlMapper.Execute(connection, sql, param: param, transaction: null, commandTimeout: null, commandType: commandType);
}
});
return(rowsAffected);
}
public override T BuildAndPersist(IRepository repository = null)
{
if (repository == null)
{
var executionStrategy = new SqlAzureExecutionStrategy();
SqlAzureDbConfiguration.SuspendExecutionStrategy = true;
var entity = executionStrategy.Execute(() => base.BuildAndPersist(null));
SqlAzureDbConfiguration.SuspendExecutionStrategy = false;
return(entity);
}
return(base.BuildAndPersist(repository));
}
/// <summary>
///
/// Suspend Retry Execution Strategy handling method:
/// Encapsulate the wrapping db user transaction and final context.SaveChanges() code in this method.
/// Don't leak the SuspendRetryExecutionStrategy setting change.
///
/// </summary>
/// <param name="db">The db context that will be for all enclosed within a transaction database update operations</param>
/// <param name="dbOperationsAction">The delegate with any entity updates operations performed using the db context</param>
public static void TransactWithRetryStrategy(ApplicationDbContext db, Action dbOperationsAction)
{
try {
ConnRetryConf.SuspendRetryExecutionStrategy = true;
var executionStrategy = new SqlAzureExecutionStrategy(2, TimeSpan.FromSeconds(10));
executionStrategy
.Execute(() => {
using (var dbContextTransaction =
db.Database.BeginTransaction(IsolationLevel.Serializable))
{
dbOperationsAction();
db.SaveChanges();
dbContextTransaction.Commit();
}
});
// Don't leak suspend setting
} finally {
ConnRetryConf.SuspendRetryExecutionStrategy = false;
}
}
/// <summary>
/// Saves all changes made in this context to the underlying database
/// </summary>
/// <param name="context">The DB context</param>
/// <returns>The number of objects written to the underlying database</returns>
private int SaveChanges
(
DbContext context
)
{
Validate.IsNotNull(context);
var success = false;
var preEventQueue = GenerateEventQueue(true);
var postEventQueue = GenerateEventQueue();
var aggregates = GetPendingAggregates();
var rows = default(int);
ProcessEventQueue
(
preEventQueue,
true
);
var executionStrategy = new SqlAzureExecutionStrategy();
AzureEfConfiguration.SuspendExecutionStrategy = true;
executionStrategy.Execute
(
() =>
{
using (var transaction = context.Database.BeginTransaction())
{
try
{
rows = context.SaveChanges();
transaction.Commit();
success = true;
}
catch (Exception ex)
{
transaction.Rollback();
if (ex is DBConcurrencyException ||
ex is OptimisticConcurrencyException)
{
// NOTE:
// For concurrency exceptions we want to ensure the
// entities are not cached in the context so we can
// stop the same error being raised indefinitely.
RefreshAll();
}
throw;
}
}
}
);
AzureEfConfiguration.SuspendExecutionStrategy = false;
if (success)
{
foreach (var aggregate in aggregates)
{
aggregate.UnpublishedEvents.Clear();
}
ProcessEventQueue(postEventQueue);
}
return(rows);
}
private async Task <ApplicationUser> InternalSignup(SignupBindingModel model, ExternalLoginInfo loginInfo, string extId)
{
string email = null;
string name = null;
string password = null;
// ExternalLoginInfo comes from an external authentication provider, i.e. Facebook or Google.
if (loginInfo != null)
{
email = loginInfo.Email;
name = loginInfo.ExternalIdentity.Name;
}
// SignupBindingModel comes filled out manually by the user. Override values from the external service with the manually entered values.
if (model != null)
{
email = model.Email;
name = model.Name;
password = model.Password;
}
if ((String.IsNullOrEmpty(password) && loginInfo == null))
{
throw new ArgumentNullException();
}
var user = new ApplicationUser
{
UserName = email,
Email = email,
};
var displayName = CoalesceDisplayName(name);
// The internal Connection Resiliency strategy does not work with user-initiated transactions.
// The workaround is described in "Limitations with Retrying Execution Strategies" +http://msdn.microsoft.com/en-us/data/dn307226.aspx
AppDbConfiguration.SuspendExecutionStrategy = true; // try-finally is not needed. The value is stored per request.
var executionStrategy = new SqlAzureExecutionStrategy();
await executionStrategy.Execute(
async() =>
{
/* We do not use this.userManager within the Connection Resiliency block.
* The DbContext should be constructed within the code block to be retried. This ensures that we are starting with a clean state for each retry.
*/
using (var dbContext = new ApplicationDbContext())
using (var userStore = new CustomUserStore(dbContext))
using (var userManager = new ApplicationUserManager(userStore))
{
// Reuse the original validators.
userManager.UserValidator = this.userManager.UserValidator;
userManager.PasswordValidator = this.userManager.PasswordValidator;
/* dbo.appGetNewUserId() generates random Ids and tests them against dbo.aspnetUsers until it finds a vacant one.
* Yes, fragmentation in the table increases (it would be somewhat anyway due to editing), bad splits on insert ( but not every time after a page has initially been split in halves).
* I believe that after the initial page split many next inserts and edits cause a next split not soon.
* So the only harm is about 1/4 extra space (not doubled, because we continue filling pages randomly up until the default fillfactor.)
* But the space havily depends on what users put in nvarchars anyway, so to worry about the space is pointless.
* Clustered index seeks shouldn't be affected. Splits affect only leaf B-tree pages, branch pages have default fillfactor less than 100% always.
* The benefit is we get rid of ExtId nchar(12) in many denormalized tables.
* Just to remind, the initial idea behind the original ExtId was to prevent a bad guy from guessing sequecial Ids and download all avatars (avatars are accessable directly as Blobs).
* So we sent the true Id to the client plus a separate ExtId for avatar URL and we stored it denormalized in many places.
* Now ExtId is just a pre-signup cookie value not used anywhere else.
*/
user.Id = await dbContext.Database.SqlQuery <int>("select dbo.appGetNewUserId();").SingleAsync();
using (var transaction = dbContext.Database.BeginTransaction())
{
// First phase. Create an ASP.NET Identity user in dbo.aspnetUsers
var identityResult = String.IsNullOrWhiteSpace(password)
? await userManager.CreateAsync(user)
: await userManager.CreateAsync(user, password);
if (identityResult.Succeeded)
{
// Second phase. dbo.appUsers. Postpone the creation of the money account until it is really used.
await dbContext.Database.ExecuteSqlCommandAsync(
"insert dbo.appUsers (Id, DisplayName, ExtId) values (@p0, @p1, @p2);",
user.Id, displayName, extId);
/* The UserManager checks the existence of the username in another connection.
* So in the case of an external authorisation (Google, Facebook) AddLoginAsync() does not see the username created by CreateAsync() in our transaction.
* Using IsolationLevel.ReadUncommitted for our transaction would not help since the UserManager reads with ReadCommitted.
* So we are forced to commit prematurely.
*/
transaction.Commit();
}
else
{
transaction.Rollback();
}
if (identityResult.Succeeded && loginInfo != null)
{
identityResult = await userManager.AddLoginAsync(user.Id, loginInfo.Login);
}
if (!identityResult.Succeeded)
{
// A hack to report the error to the caller method. See InspectErrorAfterSignup().
user.Id = 0;
var dummyClaim = new CustomUserClaim
{
ClaimType = ClaimTypes.UserData,
ClaimValue = identityResult.PlainErrorMessage("Signup failed.")
};
user.Claims.Add(dummyClaim);
}
}
}
});
AppDbConfiguration.SuspendExecutionStrategy = false;
return(user);
}