Let’s write a Synchronization Framework in C#
Ok in the last post we defined the conceptual parts of a synchronization framework, now let’s create the code that represents those parts
Delta
https://github.com/egarim/SyncFramework/blob/main/src/BIT.Data.Sync/IDelta.cs
/// <summary>
/// Represents a transaction made to the database
/// </summary>
public interface IDelta
{
double Epoch { get; set; }
/// <summary>
/// Who created the delta
/// </summary>
string Identity { get; set; }
/// <summary>
/// The unique identifier of the delta
/// </summary>
Guid Index { get; }
/// <summary>
/// The database transaction(s) that represents this delta
/// </summary>
byte[] Operation { get; set; }
}
Epoch: The date when the operation happened
Identity: Who created the delta
Index: A sortable GUID
Operation: The database transaction(s) that represents this delta
Delta Processor
https://github.com/egarim/SyncFramework/blob/main/src/src/BIT.Data.Sync/IDeltaProcessor.cs
public interface IDeltaProcessor
{
/// <summary>
/// Extracts the content of an IEnumerable of deltas and process it on the current data object
/// </summary>
/// <param name="deltas">an IEnumerable of deltas</param>
/// <param name="cancellationToken">Cancellation token</param>
/// <returns>An empty task</returns>
Task ProcessDeltasAsync(IEnumerable<IDelta> deltas, CancellationToken cancellationToken);
}
As you can see the delta processor is really simple, it only contains one method that is in charge of getting the content of a group of deltas and process those differences in the current data object
Delta Store
https://github.com/egarim/SyncFramework/blob/main/src/src/BIT.Data.Sync/IDeltaStore.cs
public interface IDeltaStore
{
string Identity { get; }
void SetIdentity(string Identity);
/// <summary>
/// Saves the IEnumerable<IDelta> of deltas in the current store
/// </summary>
/// <param name="deltas">The IEnumerable<IDelta> to be saved</param>
/// <param name="cancellationToken">A cancellation token</param>
/// <returns>An empty task</returns>
Task SaveDeltasAsync(IEnumerable<IDelta> deltas, CancellationToken cancellationToken);
/// <summary>
/// Gets an IEnumerable<IDelta> of deltas generated by other nodes with indeces greater than the start index
/// </summary>
/// <param name="startindex">The start index</param>
/// <param name="myIdentity">The identity of the current node </param>
/// <param name="cancellationToken">a Cancellation token</param>
/// <returns>An IEnumerable with deltas generated by other nodes</returns>
Task<IEnumerable<IDelta>> GetDeltasFromOtherNodes(Guid startindex, string myIdentity, CancellationToken cancellationToken);
/// <summary>
/// Get all deltas in the store with an index greater than the start index
/// </summary>
/// <param name="startindex">The start index</param>
/// <param name="cancellationToken">a cancellation token</param>
/// <returns>An IEnumerable of deltas</returns>
Task<IEnumerable<IDelta>> GetDeltasAsync(Guid startindex, CancellationToken cancellationToken);
/// <summary>
/// Gets the count of deltas with indeces greater that the start index
/// </summary>
/// <param name="startindex">The start index</param>
/// <param name="cancellationToken">A cancellation token</param>
/// <returns>The count</returns>
Task<int> GetDeltaCountAsync(Guid startindex, CancellationToken cancellationToken);
/// <summary>
/// Gets the index of the last delta process by this data object
/// </summary>
/// <param name="cancellationToken"> cancellation token</param>
/// <returns>The index of the last delta process by this data object</returns>
Task<Guid> GetLastProcessedDeltaAsync(CancellationToken cancellationToken);
/// <summary>
/// Sets the index of the last delta process by this data object
/// </summary>
/// <param name="Index">The index to be saved</param>
/// <param name="cancellationToken">A cancellation token</param>
/// <returns>An empty task</returns>
Task SetLastProcessedDeltaAsync(Guid Index, CancellationToken cancellationToken);
/// <summary>
/// Gets the index of the last delta pushed to the server node
/// </summary>
/// <param name="cancellationToken">A cancellation token</param>
/// <returns>the index of the last delta pushed to the server node</returns>
Task<Guid> GetLastPushedDeltaAsync(CancellationToken cancellationToken);
/// <summary>
/// Sets the index of the last delta pushed to the server node
/// </summary>
/// <param name="Index">The index to be saved</param>
/// <param name="cancellationToken">A cancellation token</param>
/// <returns>An empty task</returns>
Task SetLastPushedDeltaAsync(Guid Index, CancellationToken cancellationToken);
/// <summary>
/// Delete all deltas in the store
/// </summary>
/// <param name="cancellationToken">A cancellation token</param>
/// <returns>An empty task</returns>
Task PurgeDeltasAsync(CancellationToken cancellationToken);
}
SaveDeltasAsync :Saves the IEnumerable<IDelta> of deltas in the current store
GetDeltasFromOtherNodes: Gets an IEnumerable<IDelta> of deltas generated by other nodes with indices greater than the start index
GetDeltasAsync: Get all deltas in the store with an index greater than the start index
GetDeltaCountAsync: Gets the count of deltas with indices greater than the start index
GetLastProcessedDeltaAsync: Gets the index of the last delta process by this data object
SetLastProcessedDeltaAsync: Sets the index of the last delta process by this data object
GetLastPushedDeltaAsync: Gets the index of the last delta pushed to the server node
SetLastPushedDeltaAsync(Guid Index, CancellationToken cancellationToken): Sets the index of the last delta pushed to the server node
PurgeDeltasAsync: Delete all deltas in the store
That’s all for this post in the next post we will define the bases classes that implement the interfaces described above
