EtlBox.Classic 1.9.1

ETLBox.Classic

This is a fully open-source (MIT) fork from original ETLBox library. Starting version 2.0 the author of the original library decided to close the source and commercialize the newer branch. ETLBox.Classic is aiming at keeping original 1.x branch up to date with .Net and DB libraries.

Documentation note

Please note, that most of the documentation below is not updated and may contain broken links. Documentation PRs are most welcome. If you use this library, please consider updating some of its documentation.

What is ETLBox

A lightweight ETL (extract, transform, load) library and data integration toolbox for .NET. Source and destination components let you read and write data from the most common databases and file types. Transformations allow you to you harmonize, filter, aggregate, validate and clean your data.

Create your own tailor-made data flow with your .NET language of choice. ETLBox is written in C# and offers full support for .NET Core.

Why ETLBox

ETLBox is a comprehensive C# class library that is able to manage your whole ETL or ELT. You can use it to create your own dataflow pipelines programmatically in .NET, e.g. with C#. Besides a big set of dataflow components it comes which some control flow task that let you easily manage your database or simple execute Sql code without any boilerplate code. It also offers extended logging capabilites based on NLog to monitor and anlayze your ETL job runs.

ETLBox is a fully functional alternative to other ETL tools like Sql Server Integrations Services (SSIS). Creating your ETL processes programatically has some advantages:

Build ETL in .NET: Code your ETL with your favorite .NET language fitting your team’s skills and that is coming with a mature toolset.

Runs everywhere: ETLBox runs on Linux, macOS, and Windows. It is written in the current .NET Standard and successfully tested with the latest versions of .NET Core & .NET.

Run locally: Develop and test your ETL code locally on your desktop using your existing development & debugging tools.

Process In-Memory: ETLBox comes with dataflow components that allow in-memory processing which is much faster than storing data on disk and processing later.

Manage Change: Track you changes with git (or other source controls), code review your etl logic, and use your existing CI/CD processes.

Data integration: While supporting different databases, flat files and web services, you can use ETLBox as a foundation for your custom made Data Integregation platform.

Made for big data: ETLBox relies on Microsoft's TPL.Dataflow library and was designed to work with big amounts of data.

Data Flow and Control Flow

ETLBox is split into two main components: Data Flow and Control Flow Tasks. The Data Flow part offers the core ETL components. The tasks in the Control Flow allow you to manage your databases with a simple syntax. Both components come with customizable logging functionalities.

Data Flow overview

ETLBox comes with a set of Data Flow component to construct your own ETL pipeline . You can connect with different sources (e.g. a Csv file), add some transformations to manipulate that data on-the-fly (e.g. calculating a sum or combining two columns) and then store the changed data in a connected destination (e.g. a database table).

To create your own data flow , you basically follow three steps:

• First you define your dataflow components (sources, optionally transformations and destinations)
• link these components together
• tell your source to start reading the data and wait for the destination to finish

Now the source will start reading and post its data into the components connected to its output. As soon as a connected component retrieves any data in its input, the component will start with processing the data and then send it further down the line to its connected components. The dataflow will finish when all data from the source(s) are read, processed by the transformations and received in the destination(s).

Transformations are not always needed - you can directly connect a source to a destination. Normally, each source has one output, each destination one input and each transformation at least one input and one or more outputs.

Of course, all data is processed asynchronously by the components. Each compoment has its own set of buffers, so while the source is still reading data, the transformations can already process it and the destinations can start writing the processed information into their target. So in an optimal flow only the current row needed for processing is stored in memory. Depending on the processing speed of your components, the buffer of each component can store additional rows to optimize throughput.

Data Flow example

It's easy to create your own data flow pipeline. This example data flow will read data from a MySql database, modify a value and then store the modified data in a Sql Server table and a csv file, depending on a filter expression.

Step 1 is to create a source, the transformations and destinations:

var sourceCon = new MySqlConnectionManager("Server=10.37.128.2;Database=ETLBox_ControlFlow;Uid=etlbox;Pwd=etlboxpassword;");
var destCon = new SqlConnectionManager("Data Source=.;Integrated Security=SSPI;Initial Catalog=ETLBox;");

DbSource<MySimpleRow> source = new DbSource<MySimpleRow>(sourceCon, "SourceTable");
RowTransformation<MySimpleRow, MySimpleRow> rowTrans = new RowTransformation<MySimpleRow, MySimpleRow>(
    row => {  
        row.Value += 1;
        return row;
    });
Multicast<MySimpleRow> multicast = new Multicast<MySimpleRow>();
DbDestination<MySimpleRow> sqlDest = new DbDestination<MySimpleRow>(destCon, "DestinationTable");
CsvDestination<MySimpleRow> csvDest = new CsvDestination<MySimpleRow>("example.csv");

Now we link these elements together.

source.LinkTo(trans);
rowTrans.LinkTo(multicast);
multicast.LinkTo(sqlDest, row => row.FilterValue > 0);
multicast.LinkTo(csvDest, row => row.FilterValue < 0);

Finally, start the dataflow at the source and wait for the destinations to rececive all data (and the completion message from the source).

source.Execute();
sqlDest.Wait();
csvDest.Wait();

Data integration

The heart of an ETL framework is it's ability to integrate with other systems. The following table shows which types of sources and destination are supported out-of-the box with the current version of ETLBox. You can always integrate any other system not listed here by using a CustomSource or CustomDestination - though you have to write the integration code yourself.

You can choose between different sources and destination components. DbSource and DbDestination will connect to the most used databases (e.g. Sql Server, Postgres, MySql, SQLite). CsvSource, CsvDestination give you support for flat files - based on CSVHelper. ExcelSource allows you to read data from an excel sheet. JsonSource, JsonDestination, XmlSource and XmlDestination let you read and write json from files or web service request. MemorySource, MemoryDestinatiation as well as CustomSource and CustomDestination will give you a lot flexibility to read or write data directly from memory or to create your own custom made source or destination component.

Transformations

ETLBox has 3 type of transformations: Non-blocking, partially blocking and blocking transformations. Non-blocking transformations will only store the row that is currently processed in memory (plus some more in the buffer to optimize throughput and performance). Partially blocking transformations will load some data in the memory before they process data row-by-row. Blocking transformations will wait until all data has arrived at the component before it starts processing all records subsequently.

The following table is an overview of the most common transformations in ETLBox:

Designed for big data

ETLBox was designed for performance and is able to deal with big amounts of data. All destinations do support Bulk or Batch operations. By default, every component comes with an input and/or output buffer. You can design your data flow that only batches or your data is stored in memory, which are kept in different buffers for every component to increase throughput. All operations can be execute asynchrounously, so that your processing will run only within separate threads.

Control Flow - overview

Control Flow Tasks gives you control over your database: They allow you to create or delete databases, tables, procedures, schemas or other objects in your database. With these tasks you also can truncate your tables, count rows or execute any sql you like. Anything you can script in sql can be done here - but with only one line of easy-to-read C# code. This improves the readability of your code a lot, and gives you more time to focus on your business logic.

Code tells - here is some example code, without writing the whole "boilerplate" code by ADO.NET.

var conn = new SqlConnectionManager("Server=10.37.128.2;Database=ETLBox_ControlFlow;Uid=etlbox;Pwd=etlboxpassword;");
//Execute some Sql
SqlTask.ExecuteNonQuery(conn, "Do some sql",$@"EXEC myProc");
//Count rows
int count = RowCountTask.Count(conn, "demo.table1").Value;
//Create a table (works on all databases)
CreateTableTask.Create(conn, "Table1", new List<TableColumn>() {
    new TableColumn(name:"key",dataType:"INT",allowNulls:false,isPrimaryKey:true, isIdentity:true),
    new TableColumn(name:"value", dataType:"NVARCHAR(100)",allowNulls:true)
});

Logging

By default, ETLBox uses and extends NLog. ETLBox already comes with NLog as dependency - so you don't need to include additional packages from nuget. In order to have the logging activating, you just have to set up a nlog configuration called nlog.config, and create a target and a logger rule. After adding this, you will already get logging output for all tasks and components in ETLBox. Read more about logging here.

Getting ETLBox

You can use ETLBox within any .NET or .NET core project that supports .NET Standard 2.0. (Basically all latest versions of .NET)

Variant 1: Nuget

ETLBox is available on nuget. Just add the package to your project via your nuget package manager.

Variant 2: Download the sources

Clone the repository:

git clone https://github.com/rpsft/etlbox.git

Then, open the downloaded solution file ETLBox.sln with Visual Studio 2019 or higher. Now you can build the solution, and use it as a reference in other projects.

Going further

ETLBox is open source. Feel free to make changes or to fix bugs. Every particiation in this open source project is appreciated.

To dig deeper into it, have a look at the test projects. There is a test for (almost) everything that you can do with ETLBox.

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See the ETLBox Project website for introductional articles and a complete API documentation. Enjoy!

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