TableStorage.Abstractions

Repository wrapper for Azure Table Storage in C# using the Azure.Data.Tables libraries and supporting .NET Standard 2.0 and tested in .NET Framework 4.8 and .NET 6.0

Introduction

Working with Azure Table Storage has been interesting and very different from working with SQL Server which I have done for many years. After reading a number of articles about it and using it I realised a generic wrapper would be useful to aid unit testing and so this is the result of that realisation.

I referenced a number of articles on Table Storage most of which are quite old now but still valid. Suggestions from these articles have been included in this library.

https://blogs.msdn.microsoft.com/windowsazurestorage/2010/06/25/nagles-algorithm-is-not-friendly-towards-small-requests/

https://azure.microsoft.com/en-gb/blog/managing-concurrency-in-microsoft-azure-storage-2/

https://docs.microsoft.com/en-us/azure/storage/storage-table-design-guide

https://docs.particular.net/nservicebus/azure-storage-persistence/performance-tuning

http://robertgreiner.com/2012/06/why-is-azure-table-storage-so-slow/

Configuration

Optimisations are controlled by the Table Storage Options Class. The defaults are applied as below if not overridden:

public class TableStorageOptions
{
    public bool UseNagleAlgorithm { get; set; } = false;

    public bool Expect100Continue { get; set; } = false;

    public int ConnectionLimit { get; set; } = 10;

    public int Retries { get; set; } = 3;

    public double RetryWaitTimeInSeconds { get; set; } = 1;

    public bool EnsureTableExists { get; set; } = true;
}

Example entity:

NOTE: Azure.Data.Tables requires inheritance from the interface as the base class TableEntity is a sealed class.

public class TestTableEntity : ITableEntity
{
    public string PartitionKey { get; set; }
    public string RowKey { get; set; }
    public DateTimeOffset? Timestamp { get; set; }
    public ETag ETag { get; set; }

    public int Age { get; set; }
    public string Email { get; set; }

    public TestTableEntity() {}

    public TestTableEntity(string name, string surname)
    {
        PartitionKey = surname;
        RowKey = name;
    }
}

The library also includes a factory class to make it easier when using dependency injection with multiple tables. This can create a table store with the default TableStorageOptions which is used when not specified, or override the options depending on your needs.

public class TestTableStorageClient
{
    private ITableStore<MyStuff> _store;

    public TestTableStorageClient(ITableStoreFactory factory)
    {
        _store = factory.CreateTableStore<MyStuff>("MyTable", "UseDevelopmentStorage=true");
    }
}

Support for other credentials other than connection string are also included i.e. TokenCredential, AzureSasCredential and TableSharedKeyCredential

Override TableStorageOptions when using the factory creation

public class TestTableStorageClient
{
    private ITableStore<MyStuff> _store;

    public TestTableStorageClient(ITableStoreFactory factory)
    {
        var options = new TableStorageOptions
        {
            UseNagleAlgorithm = true,
            ConnectionLimit = 100,
            EnsureTableExists = false
        };

        _store = factory.CreateTableStore<MyStuff>("MyTable", "UseDevelopmentStorage=true", options);
    }
}

Override TableStorageOptions when using the store creation

public class TestTableStorageClient
{
    private ITableStore<MyStuff> _store;

    public TestTableStorageClient()
    {
        var options = new TableStorageOptions
        {
            UseNagleAlgorithm = true,
            ConnectionLimit = 100,
            EnsureTableExists = false
        };

        _store = new TableStore<MyStuff>("MyTable", "UseDevelopmentStorage=true", options);
    }
}

Insert Records

Example Insert of a record

var tableStorage = new TableStore<TestTableEntity>("MyTable", "UseDevelopmentStorage=true");
var entity = new TestTableEntity("John", "Smith") { Age = 21, Email = "john.smith@something.com" };

await tableStorage.InsertAsync(entity);

// Get the entries by the row key
var result = tableStorage.GetByRowKey("John").ToList();

Inserting multiple entries into table storage requires each entry to have the same partition key for a batch. This implementation in the wrapper does this job for you so that you can just pass a list of entities.

Example Insert of multiple records

var tableStorage = new TableStore<TestTableEntity>("MyTable", "UseDevelopmentStorage=true");
var entries = new List<TestTableEntity>
{
    new TestTableEntity("John", "Smith") {Age = 21, Email = "john.smith@something.com"},
    new TestTableEntity("Jane", "Smith") {Age = 28, Email = "jane.smith@something.com"},
    new TestTableEntity("Bill", "Smith") { Age = 38, Email = "bill.smith@another.com"},
    new TestTableEntity("Fred", "Jones") {Age = 32, Email = "fred.jones@somewhere.com"},
    new TestTableEntity("Bill", "Jones") {Age = 45, Email = "bill.jones@somewhere.com"},
    new TestTableEntity("Bill", "King") {Age = 45, Email = "bill.king@email.com"},
    new TestTableEntity("Fred", "Bloggs") { Age = 32, Email = "fred.bloggs@email.com" }
};

await tableStorage.InsertAsync(entries);

InsertOrReplace

Example of Insert or Replace of a record

var tableStorage = new TableStore<TestTableEntity>("MyTable", "UseDevelopmentStorage=true");
var entity = new TestTableEntity("John", "Smith") { Age = 21, Email = "john.smith@something.com" };

await tableStorage.InsertOrReplaceAsync(entity);

Update Records

Example of Updating a record

var tableStorage = new TableStore<TestTableEntity>("MyTable", "UseDevelopmentStorage=true");

// Get the current record
var entity = await tableStorage.GetRecordAsync("Smith", "John");

// Update properties
entity.Age = 22;

await tableStorage.UpdateAsync(entity);

Delete Records

Example of deleting a record

var tableStorage = new TableStore<TestTableEntity>("MyTable", "UseDevelopmentStorage=true");

// Get the current record
var entity = await tableStorage.GetRecordAsync("Smith", "John");

await tableStorage.DeleteAsync(entity);

Example of deleting all records for a partition

var tableStorage = new TableStore<TestTableEntity>("MyTable", "UseDevelopmentStorage=true");

await tableStorage.DeleteByPartitionAsync("Smith");

Example of deleting all records in all partitions

var tableStorage = new TableStore<TestTableEntity>("MyTable", "UseDevelopmentStorage=true");

await tableStorage.DeleteAllAsync();

Filter Records

Table Storage does not really have generic way of filtering data as yet. So there are some methods to help with that. NOTE: The filtering works by getting all records so on large datasets this will be slow. Testing showed ~1.3 seconds for 10,000 records Testing when paged by 100 ~0.0300 seconds for 10,000 records returning 100 records

var tableStorage = new TableStore<TestTableEntity>("MyTable", "UseDevelopmentStorage=true");
var results = tableStorage.GetRecordsByFilter(x => x.Age > 21 && x.Age < 25);

And with basic paging starting at 0 and returning 100 NOTE: The start is number of records e.g. 20, 100 would start at record 20 and then return a maxiumum of 100 after that

var tableStorage = new TableStore<TestTableEntity>("MyTable", "UseDevelopmentStorage=true");
var results = tableStorage.GetRecordsByFilter(x => x.Age > 21 && x.Age < 25, 0, 100);

There is also the consideration of using Reactive Extensions (RX - http://reactivex.io/) to observe the results from a get all records call or a get filtered records.

var tableStorage = new TableStore<TestTableEntity>("MyTable", "UseDevelopmentStorage=true");
var theObserver = tableStorage.GetAllRecordsObservable();
theObserver.Where(x => x.Age > 21 && x.Age < 25).Take(100).Subscribe(x =>
{
   // Do something with the table entry
});

or

var tableStorage = new TableStore<TestTableEntity>("MyTable", "UseDevelopmentStorage=true");
var theObserver = tableStorage.GetRecordsByFilterObservable(x => x.Age > 21 && x.Age < 25, 0, 100);
theObserver.Subscribe(x =>
{
   // Do something with the table entry
});

Heterogeneous Tables

As Table storage is a schema-less store there are times when you are dealing with multiple entity types in a single table. https://docs.microsoft.com/en-us/azure/cosmos-db/table-storage-design-guide#work-with-heterogeneous-entity-types

This library has some additional support for those times.

When creating a TableStore if no generic type is supplied then it creates a dynamic store. This allows the basic methods, Insert, Update, GetRecord, etc. to specify the generic type on the method call. Getting all records now returns a list of DynamicTableEntity but you can still get by partition key using a generic type.

var tableStorage = new TableStoreDynamic("MyTable", "UseDevelopmentStorage=true");
var entity = new TestTableEntity("John", "Smith") { Age = 21, Email = "john.smith@something.com" };
var otherEntity = new AnotherTableEntity("52a54878-b4b3-45bd-bc5b-3822989b460f", "MyProduct") { Name = "Product", Url = "https://someendpoint" };

await tableStorage.InsertAsync<TestTableEntity>(entity);
await tableStorage.InsertAsync<AnotherTableEntity>(otherEntity);

var employee = await GetRecordAsync<TestTableEntity>("Smith", "John");
var productEntity = await GetRecordAsync<otherEntity>("MyProduct", "52a54878-b4b3-45bd-bc5b-3822989b460f");

NOTE: Currently only the basic methods are supported for this type of table, there are no filter/search methods.

Useful Reading

https://docs.microsoft.com/en-gb/azure/storage/storage-dotnet-how-to-use-tables http://www.introtorx.com/content/v1.0.10621.0/01_WhyRx.html

Notes

Most methods have a synchronous and asynchronous version.

The unit tests rely on using Azurite Emulator which is now bundled with Visual Studio 2022 details can be found on Microsoft Docs for other installations including Visual Studio Code and Docker.