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readability

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This commit is contained in:
Shannon
2020-07-08 15:07:12 +10:00
parent 7590161858
commit b80dc8f34b
1 changed files with 102 additions and 90 deletions
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192
src/Umbraco.Core/Runtime/SqlMainDomLock.cs
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@@ -201,7 +201,6 @@ namespace Umbraco.Core.Runtime
return Task.Run(() =>
{
using var db = _dbFactory.CreateDatabase();
var watch = new Stopwatch();
@@ -212,103 +211,116 @@ namespace Umbraco.Core.Runtime
// local testing shows the actual query to be executed from client/server is approx 300ms but would change depending on environment/IO
Thread.Sleep(1000);
using (var transaction = db.GetTransaction(IsolationLevel.ReadCommitted))
{
try
{
// get a read lock
_sqlServerSyntax.ReadLock(db, Constants.Locks.MainDom);
// the row
var mainDomRows = db.Fetch<KeyValueDto>("SELECT * FROM umbracoKeyValue WHERE [key] = @key", new { key = MainDomKey });
if (mainDomRows.Count == 0 || mainDomRows[0].Value == updatedTempId)
{
// the other main dom has updated our record
// Or the other maindom shutdown super fast and just deleted the record
// which indicates that we
// can acquire it and it has shutdown.
_sqlServerSyntax.WriteLock(db, Constants.Locks.MainDom);
// so now we update the row with our appdomain id
InsertLockRecord(_lockId, db);
_logger.Debug<SqlMainDomLock>("Acquired with ID {LockId}", _lockId);
return true;
}
else if (mainDomRows.Count == 1 && !mainDomRows[0].Value.StartsWith(tempId))
{
// in this case, the prefixed ID is different which means
// another new AppDomain has come online and is wanting to take over. In that case, we will not
// acquire.
_logger.Debug<SqlMainDomLock>("Cannot acquire, another booting application detected.");
return false;
}
}
catch (Exception ex)
{
if (IsLockTimeoutException(ex as SqlException))
{
_logger.Error<SqlMainDomLock>(ex, "Sql timeout occurred, waiting for existing MainDom is canceled.");
_errorDuringAcquiring = true;
return false;
}
// unexpected
_logger.Error<SqlMainDomLock>(ex, "Unexpected error, waiting for existing MainDom is canceled.");
_errorDuringAcquiring = true;
return false;
}
finally
{
transaction.Complete();
}
}
var acquired = TryAcquire(db, tempId, updatedTempId);
if (acquired.HasValue)
return acquired.Value;
if (watch.ElapsedMilliseconds >= millisecondsTimeout)
{
// if the timeout has elapsed, it either means that the other main dom is taking too long to shutdown,
// or it could mean that the previous appdomain was terminated and didn't clear out the main dom SQL row
// and it's just been left as an orphan row.
// There's really know way of knowing unless we are constantly updating the row for the current maindom
// which isn't ideal.
// So... we're going to 'just' take over, if the writelock works then we'll assume we're ok
_logger.Debug<SqlMainDomLock>("Timeout elapsed, assuming orphan row, acquiring MainDom.");
using var transaction = db.GetTransaction(IsolationLevel.ReadCommitted);
try
{
_sqlServerSyntax.WriteLock(db, Constants.Locks.MainDom);
// so now we update the row with our appdomain id
InsertLockRecord(_lockId, db);
_logger.Debug<SqlMainDomLock>("Acquired with ID {LockId}", _lockId);
return true;
}
catch (Exception ex)
{
if (IsLockTimeoutException(ex as SqlException))
{
// something is wrong, we cannot acquire, not much we can do
_logger.Error<SqlMainDomLock>(ex, "Sql timeout occurred, could not forcibly acquire MainDom.");
_errorDuringAcquiring = true;
return false;
}
_logger.Error<SqlMainDomLock>(ex, "Unexpected error, could not forcibly acquire MainDom.");
_errorDuringAcquiring = true;
return false;
}
finally
{
transaction.Complete();
}
return AcquireWhenMaxWaitTimeElapsed(db);
}
}
}, _cancellationTokenSource.Token);
}
private bool? TryAcquire(IUmbracoDatabase db, string tempId, string updatedTempId)
{
using var transaction = db.GetTransaction(IsolationLevel.ReadCommitted);
try
{
// get a read lock
_sqlServerSyntax.ReadLock(db, Constants.Locks.MainDom);
// the row
var mainDomRows = db.Fetch<KeyValueDto>("SELECT * FROM umbracoKeyValue WHERE [key] = @key", new { key = MainDomKey });
if (mainDomRows.Count == 0 || mainDomRows[0].Value == updatedTempId)
{
// the other main dom has updated our record
// Or the other maindom shutdown super fast and just deleted the record
// which indicates that we
// can acquire it and it has shutdown.
_sqlServerSyntax.WriteLock(db, Constants.Locks.MainDom);
// so now we update the row with our appdomain id
InsertLockRecord(_lockId, db);
_logger.Debug<SqlMainDomLock>("Acquired with ID {LockId}", _lockId);
return true;
}
else if (mainDomRows.Count == 1 && !mainDomRows[0].Value.StartsWith(tempId))
{
// in this case, the prefixed ID is different which means
// another new AppDomain has come online and is wanting to take over. In that case, we will not
// acquire.
_logger.Debug<SqlMainDomLock>("Cannot acquire, another booting application detected.");
return false;
}
}
catch (Exception ex)
{
if (IsLockTimeoutException(ex as SqlException))
{
_logger.Error<SqlMainDomLock>(ex, "Sql timeout occurred, waiting for existing MainDom is canceled.");
_errorDuringAcquiring = true;
return false;
}
// unexpected
_logger.Error<SqlMainDomLock>(ex, "Unexpected error, waiting for existing MainDom is canceled.");
_errorDuringAcquiring = true;
return false;
}
finally
{
transaction.Complete();
}
return null; // continue
}
private bool AcquireWhenMaxWaitTimeElapsed(IUmbracoDatabase db)
{
// if the timeout has elapsed, it either means that the other main dom is taking too long to shutdown,
// or it could mean that the previous appdomain was terminated and didn't clear out the main dom SQL row
// and it's just been left as an orphan row.
// There's really know way of knowing unless we are constantly updating the row for the current maindom
// which isn't ideal.
// So... we're going to 'just' take over, if the writelock works then we'll assume we're ok
_logger.Debug<SqlMainDomLock>("Timeout elapsed, assuming orphan row, acquiring MainDom.");
using var transaction = db.GetTransaction(IsolationLevel.ReadCommitted);
try
{
_sqlServerSyntax.WriteLock(db, Constants.Locks.MainDom);
// so now we update the row with our appdomain id
InsertLockRecord(_lockId, db);
_logger.Debug<SqlMainDomLock>("Acquired with ID {LockId}", _lockId);
return true;
}
catch (Exception ex)
{
if (IsLockTimeoutException(ex as SqlException))
{
// something is wrong, we cannot acquire, not much we can do
_logger.Error<SqlMainDomLock>(ex, "Sql timeout occurred, could not forcibly acquire MainDom.");
_errorDuringAcquiring = true;
return false;
}
_logger.Error<SqlMainDomLock>(ex, "Unexpected error, could not forcibly acquire MainDom.");
_errorDuringAcquiring = true;
return false;
}
finally
{
transaction.Complete();
}
}
/// <summary>
/// Inserts or updates the key/value row
/// </summary>