I'm trying to set up a worker role to read and act based on data from Azure sql database.
I set the connection string like this:
public DBEntities(string connectionString) : base(connectionString) {}
Whenever I try to run the worker role localy I get the following error when querying the entities:
System.Data.Entity.Infrastructure.UnintentionalCodeFirstException: 'The context is being used in Code First mode with code that was generated from an EDMX file for either Database First or Model First development.
To query the entities:
using (ctx = new CODDBEntities(_connectionString))
{
var result = ctx.entity.ToList().FindAll();
}
What am I doing wrong?
It seems that you're specifying the Database Initialization Strategies.
Try the Following:
public CODDBEntities()
{
Database.SetInitializer<CODDBEntities>(null);//Disable initializer
}
more info in here: http://www.entityframeworktutorial.net/code-first/database-initialization-strategy-in-code-first.aspx
Finnaly I got it. Using this article I understood that I was using the wrong connection string type. I needed to use the one starting like - metadata=res://*/..." while I just coiped the default connection string from the Azure portal.
Related
I have looked through various posts related to this problem, but none provide an answer. I created a .Net 5.0 app that accesses an Azure SQL DB using EF 6.4.4 which works with .Net standard libraries. I modified the EF by adding a function that creates the connection string from appsettings.json since .Net 5 apps don't use a web.config file. This also works well in Azure with the configuration settings in an app service.
The connection string looks like this:
metadata=res://*/EF.myDB.csdl|res://*/EF.myDB.ssdl|res://*/EF.myDB.msl;provider=System.Data.SqlClient;provider connection string='Data Source=tcp:mydb.database.windows.net,1433;Initial Catalog=myDB;Integrated Security=False;Persist Security Info=False;User ID=myuserid#mydb;Password="password";MultipleActiveResultSets=True;Connect Timeout=120;Encrypt=True;TrustServerCertificate=True'
I also have a deployment pipeline that will deploy the code after a check-in instead of using the Visual Studio publish feature, but the pipeline deployed code has the same problem.
When I first created the app and published it to the app service, it worked. Recently I updated the app with no changes to the EF connection. Now I get the "Invalid Object name when I reference any table in the model. If I run the same code locally and connect to the Azure SQL DB, the DB is accessed as expected. This problem only occurs when running in the Azure app service. Note that there are no connection strings configured for the app service since the EF string is built from the config settings. I saw this post, but I don't think it applies:
Local works. Azure give error: Invalid object name 'dbo.AspNetUsers'. Why?
even though the problem is the same. I have also read various posts about the format of the EF connection string. Since my model is database first, (and the connection used to work), I'm confident the string has the correct format. I don't think the problem is in the code since it works when running locally with a connection to the Azure SQL DB. It must have something to do with the Azure app service configuration, but I'm not sure what to look for at this point. Unfortunately I don't have a copy of the code and publish files that did work to compare to, but it the pipeline build doesn't work either and that it how the code would normally be deployed. Thanks for any insight you might have!
UPDATE
metadata=res://*/EF.myDB.csdl|res://*/EF.myDB.ssdl|res://*/EF.myDB.msl;provider=System.Data.SqlClient;provider connection string='Data Source=tcp:yourdbsqlserver.database.windows.net,1433;Initial Catalog=yourdb;Persist Security Info=False;User ID=userid;Password=your_password;MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30'
When the troubleshooting problem is not on the string, our easiest way is to use vs2019 to re-use the generated string.
Your connection string should be like below.
<connectionStrings>
<add name="SchoolDBEntities" connectionString="metadata=res://*/SchoolDB.csdl|res://*/SchoolDB.ssdl|res://*/SchoolDB.msl;provider=System.Data.SqlClient;provider connection string="data source=.\sqlexpress;initial catalog=SchoolDB;integrated security=True;multipleactiveresultsets=True;application name=EntityFramework"" providerName="System.Data.EntityClient"/>
</connectionStrings>
For more details, you can refer my answer in the post and the tutorial.
1. Timeout period elasped prior to obtaining a connection from the pool - Entity Framework
2. Entity Framework Tutorial
The problem was one of my config settings in Azure. The catalog parameter was missing. A simple fix, but the error message was misleading, so I thought I would note that here in case anyone else gets the same "Invalid object name" message when referencing an Azure SQL DB with EF. It would have been more helpful if the message was "catalog name invalid" or "unable to connect to database".
For those who are curious about building an EF connection string, here is example code:
public string BuildEFConnectionString(SqlConnectionStringModel sqlModel, EntityConnectionStringModel entityModel)
{
SqlConnectionStringBuilder sqlString = new SqlConnectionStringBuilder()
{
DataSource = sqlModel.DataSource,
InitialCatalog = sqlModel.InitialCatalog,
PersistSecurityInfo = sqlModel.PersistSecurityInfo,
UserID = sqlModel.UserID, // Blank if using Windows authentication
Password = sqlModel.Password, // Blank if using Windows authentication
MultipleActiveResultSets = sqlModel.MultipleActiveResultSets,
Encrypt = sqlModel.Encrypt,
TrustServerCertificate = sqlModel.TrustServerCertificate,
IntegratedSecurity = sqlModel.IntegratedSecurity,
ConnectTimeout = sqlModel.ConnectTimeout
};
//Build an Entity Framework connection string
EntityConnectionStringBuilder entityString = new EntityConnectionStringBuilder()
{
Provider = entityModel.Provider, // "System.Data.SqlClient",
Metadata = entityModel.Metadata,
ProviderConnectionString = sqlString.ToString()
};
return entityString.ConnectionString;
}
Given what I have learned, the properties should be validated before the string is returned. If the string is created this way, all of the connection string properties can be added to the config settings in the app service. I used the options pattern to get them at runtime. Thanks to everyone for your suggestions.
I have an azure function that runs off of a queue trigger. The repository has method to grab the connection string from the ConnectionStrings collection.
return System.Configuration.ConfigurationManager.ConnectionStrings["MyDataBase"].ToString();
This works great for the most part but I see intermittently that this returns a null exception error.
Is there a way I can make this more robust?
Do azure functions sometimes fail to get the settings?
Should I store the setting in a different section?
I also want to say that this runs thousands of times a day but I see this popup about a 100 times.
Runtime version: 1.0.12299.0
Are you reading the configuration for every function call? You should consider reading it once (e.g. using a Lazy<string> and static) and reusing it for all function invocations.
Maybe there is a concurrency issue when multiple threads access the code. Putting a lock around the code could help as well. ConfigurationManager.ConnectionStrings should be tread-safe, but maybe it isn't in the V1 runtime.
A similar problem was posted here, but this concerned app settings and not connection strings. I don't think using CloudConfigurationManager should be the correct solution.
You can also try putting the connection string into the app settings, unless you are using Entity Framework.
Connection strings should only be used with a function app if you are using entity framework. For other scenarios use App Settings. Click to learn more.
(via Azure Portal)
Not sure if this applies to the V1 runtime as well.
The solution was to add a private static string for the connection string. Then only read from the configuration if it fails. I then added a retry that paused half a second. This basically removed this from happening.
private static string connectionString = String.Empty;
private string getConnectionString(int retryCount)
{
if (String.IsNullOrEmpty(connectionString))
{
if (System.Configuration.ConfigurationManager.ConnectionStrings["MyEntity"] != null)
{
connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["MyEntity"].ToString();
}
else
{
if (retryCount > 2)
{
throw new Exception("Failed to Get Connection String From Application Settings");
}
retryCount++;
getConnectionString(retryCount);
}
}
return connectionString;
}
I don't know if this perfect but it works. I went from seeing this exception 30 times a day to none.
Is there anywhere to report bugs/ request features in ServiceStack?
While using ServiceStack, my ServiceStack.ServiceInterface.Service object was throwing this error:
ExecuteReader requires an open and available Connection. The connection's current state is closed.
The Service class includes a Db property (used in examples), which is a IDbConnection - db connections are not thread safe.
I'm interested to know why this non thread safe method of access a database is included in the Service class. It's no good for servicing multiple web service requests.
Service.cs will try to resolve an IDbConnectionFactory that will create a new IDbConnection for you, so there isn't a thread safety issue here.
If you'd like to handle it differently, you can override it.
private IDbConnection db;
public virtual IDbConnection Db
{
get { return db ?? (db = TryResolve<IDbConnectionFactory>().OpenDbConnection()); }
}
Source:
https://github.com/ServiceStack/ServiceStack/blob/ada0f43012610dc9ee9ae863e77dfa36b7abea28/src/ServiceStack/Service.cs#L68
Edit:
Maybe it's not clear that OrmLiteConnectionFactories automatically create a new connection in conjunction with an OpenDbConnection call, but they do:
Source:
https://github.com/ServiceStack/ServiceStack.OrmLite/blob/db40347532a14441eba32e575bcf07f3b2f45cef/src/ServiceStack.OrmLite/OrmLiteConnectionFactory.cs#L72
I have an ASP.NET app being developed for Windows Azure. It's been deemed necessary that we use sharding for the DB to improve write times since the app is very write heavy but the data is easily isolated. However, I need to keep track of a few central variables across all instances, and I'm not sure the best place to store that info. What are my options?
Requirements:
Must be durable, can survive instance reboots
Must be synchronized. It's incredibly important to avoid conflicting updates or at least throw an exception in such cases, rather than overwriting values or failing silently.
Must be reasonably fast (2000+ read/writes per second
I thought about writing a separate component to run on a worker role that simply reads/writes the values in memory and flushes them to disk every so often, but I figure there's got to be something already written for that purpose that I can appropriate in Windows Azure.
I think what I'm looking for is a system like Apache ZooKeeper, but I dont' want to have to deal with installing the JRE during the worker role startup and all that jazz.
Edit: Based on the suggestion below, I'm trying to use Azure Table Storage using the following code:
var context = table.ServiceClient.GetTableServiceContext();
var item = context.CreateQuery<OfferDataItemTableEntity>(table.Name)
.Where(x => x.PartitionKey == Name).FirstOrDefault();
if (item == null)
{
item = new OfferDataItemTableEntity(Name);
context.AddObject(table.Name, item);
}
if (item.Allocated < Quantity)
{
allocated = ++item.Allocated;
context.UpdateObject(item);
context.SaveChanges();
return true;
}
However, the context.UpdateObject(item) call fails with The context is not currently tracking the entity. Doesn't querying the context for the item initially add it to the context tracking mechanism?
Have you looked into SQL Azure Federations? It seems like exactly what you're looking for:
sharding for SQL Azure.
Here are a few links to read:
http://msdn.microsoft.com/en-us/library/windowsazure/hh597452.aspx
http://convective.wordpress.com/2012/03/05/introduction-to-sql-azure-federations/
http://searchcloudapplications.techtarget.com/tip/Tips-for-deploying-SQL-Azure-Federations
What you need is Table Storage since it matches all your requirements:
Durable: Yes, Table Storage is part of a Storage Account, which isn't related to a specific Cloud Service or instance.
Synchronized: Yes, Table Storage is part of a Storage Account, which isn't related to a specific Cloud Service or instance.
It's incredibly important to avoid conflicting updates: Yes, this is possible with the use of ETags
Reasonably fast? Very fast, up to 20,000 entities/messages/blobs per second
Update:
Here is some sample code that uses the new storage SDK (2.0):
var storageAccount = CloudStorageAccount.DevelopmentStorageAccount;
var table = storageAccount.CreateCloudTableClient()
.GetTableReference("Records");
table.CreateIfNotExists();
// Add item.
table.Execute(TableOperation.Insert(new MyEntity() { PartitionKey = "", RowKey ="123456", Customer = "Sandrino" }));
var user1record = table.Execute(TableOperation.Retrieve<MyEntity>("", "123456")).Result as MyEntity;
var user2record = table.Execute(TableOperation.Retrieve<MyEntity>("", "123456")).Result as MyEntity;
user1record.Customer = "Steve";
table.Execute(TableOperation.Replace(user1record));
user2record.Customer = "John";
table.Execute(TableOperation.Replace(user2record));
First it adds the item 123456.
Then I'm simulating 2 users getting that same record (imagine they both opened a page displaying the record).
User 1 is fast and updates the item. This works.
User 2 still had the window open. This means he's working on an old version of the item. He updates the old item and tries to save it. This causes the following exception (this is possible because the SDK matches the ETag):
The remote server returned an error: (412) Precondition Failed.
I ended up with a hybrid cache / table storage solution. All instances track the variable via Azure caching, while the first instance spins up a timer that saves the value to table storage once per second. On startup, the cache variable is initialized with the value saved to table storage, if available.
I am using quartz.net as a scheduler in a Microsoft Azure Web Role. I can get Quartz.net to work just fine if I use the RamDataStore. However, I want to break this into two components: the first will allow scheduling of jobs through a web interface and the second will execute the jobs through a worker role. To have this distributed processing, I will need to use an ADOJobStore.
Everything works fine with the RamDataStore but it breaks when I try to switch over to the ADOJobStore. So this leads me to believe that there is something in my properties that I'm missing. I am using Azure SQL database and while this is similar to SQL Server, there are some gotchas that sometimes cause problems.
I am using Quartz.net 2.0 (from nuGet) in VS2010, the database is Azure SQL.
When I call .GetScheduler(), I get the following exception:
{"JobStore type 'Quartz.Impl.AdoJobStore.JobStoreTX' props could not
be configured."}
with the details:
{"Could not parse property 'default.connectionString' into correct
data type: No writable property 'Default.connectionString' found"}
My connection code (including programatically set properties):
NameValueCollection properties = new NameValueCollection();
properties["quartz.scheduler.instanceName"] = "SchedulingServer";
properties["quartz.threadPool.type"] = "Quartz.Simpl.ZeroSizeThreadPool, Quartz";
properties["quartz.jobStore.type"] = "Quartz.Impl.AdoJobStore.JobStoreTX, Quartz";
properties["quartz.jobStore.tablePrefix"] = "QRTZ_";
properties["quartz.jobStore.clustered"] = "false";
properties["quartz.jobStore.driverDelegateType"] = "Quartz.Impl.AdoJobStore.SqlServerDelegate, Quartz";
properties["quartz.jobStore.dataSource"] = "default";
properties["quartz.jobStore.default.connectionString"] = "Server=tcp:serverName.database.windows.net;Database=scheduler;User ID=scheduler#serverName;Password=***;Trusted_Connection=False;Encrypt=True;";
properties["quartz.jobStore.default.provider"] = "SqlServer-20";
properties["quartz.jobStore.useProperties"] = "true";
ISchedulerFactory sf = new StdSchedulerFactory(properties);
_scheduler = sf.GetScheduler();
Any help or suggestions would be appreciated.
You have small but subtle error in your data source property naming, it should read:
properties["quartz.dataSource.default.connectionString"] = "Server=tcp:serverName.database.windows.net;Database=scheduler;User ID=scheduler#serverName;Password=***;Trusted_Connection=False;Encrypt=True;";
Also there is a property connectionStringName if you want to use the connection string section of configuration file.