public UpdateSessionTransaction ReplaceUpdateDomain(UpdateSessionStatus status)
{
var updateDomainEntity = status.UpdateDomainEntity;
updateDomainEntity.UpdateDomain = _updateDomain;
_batchOperation.Add(TableOperation.Replace(updateDomainEntity));
return(this);
}
public async Task <bool> TryStartUpdateSession(string appId)
{
Trace.TraceInformation(
$"Instance {_instanceId} will attempt to start update session for " +
$"ApplicationId = {appId}, UpdateDomain = {_instanceUpdateDomain}");
UpdateSessionTransaction transaction = new UpdateSessionTransaction(_clusterId, _instanceId, _instanceUpdateDomain, appId);
UpdateSessionStatus updateSessionStatus = await _updateSessionTable.FetchUpdateSessionStatus(_clusterId, appId);
if (updateSessionStatus.UpdateDomainEntity == null ||
updateSessionStatus.UpdateDomainEntity.UpdateDomain == _instanceUpdateDomain)
{
if (updateSessionStatus.UpdateDomainEntity == null)
{
transaction.InsertUpdateDomain();
}
transaction.MarkInstanceListAsModified();
}
else if (!updateSessionStatus.InstancesEntities.Any()) // no instance in the current update domain is updating
{
// set a new update domain (if no other instance beats us to it)
transaction.ReplaceUpdateDomain(updateSessionStatus); // will fail if current update domain changes
transaction.FailIfInstanceListModified(updateSessionStatus); // will fail if instance list changes
}
else
{
return(false);
}
// enlist the current instance (this will succeed even if the active update domain is different but we
// won't start the update session, see below)
transaction.InsertOrReplaceInstance();
if (await _updateSessionTable.TryExecuteTransaction(transaction))
{
// handle the case where an instance enlisted itself after the update domain has changed,
string updateDomain = await _updateSessionTable.GetActiveUpdateDomain(_clusterId, appId);
if (updateDomain != _instanceUpdateDomain)
{
// Note that deleting this row is optional because it will filtered out anyway when list of instances
// of the active update domain is loaded (as a result, it's not an issue if this fails).
// We delete it anyway to keep the table clean.
await _updateSessionTable.DeleteInstanceEntity(_clusterId, _instanceId, appId);
return(false);
}
Trace.TraceInformation(
$"Instance {_instanceId} successfully started the update session for " +
$"ApplicationId = {appId}, UpdateDomain = {_instanceUpdateDomain}");
return(true);
}
return(false);
}
public UpdateSessionTransaction FailIfInstanceListModified(UpdateSessionStatus status)
{
_batchOperation.Add(TableOperation.Replace(status.ModifiedEntity));
return(this);
}
