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https://github.com/setl-framework/setl

A simple Spark-powered ETL framework that just works ๐Ÿบ
https://github.com/setl-framework/setl

big-data data-analysis data-engineering data-science data-transformation dataset etl etl-pipeline framework machine-learning modularization pipeline scala setl spark

Last synced: 25 days ago
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A simple Spark-powered ETL framework that just works ๐Ÿบ

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README

        

![logo](docs/img/logo_setl.png)
----------

[![build](https://github.com/SETL-Framework/setl/workflows/build/badge.svg?branch=master)](https://github.com/SETL-Framework/setl/actions)
[![codecov](https://codecov.io/gh/SETL-Framework/setl/branch/master/graph/badge.svg)](https://codecov.io/gh/SETL-Framework/setl)
[![Maven Central](https://img.shields.io/maven-central/v/io.github.setl-framework/setl_2.11.svg?label=Maven%20Central&color=blue)](https://mvnrepository.com/artifact/io.github.setl-framework/setl)
[![javadoc](https://javadoc.io/badge2/io.github.setl-framework/setl_2.12/javadoc.svg)](https://javadoc.io/doc/io.github.setl-framework/setl_2.12)
[![documentation](https://img.shields.io/badge/docs-passing-1f425f.svg)](https://setl-framework.github.io/setl/)

If youโ€™re a **data scientist** or **data engineer**, this might sound familiar while working on an **ETL** project:

- Switching between multiple projects is a hassle
- Debugging othersโ€™ code is a nightmare
- Spending a lot of time solving non-business-related issues

**SETL** (pronounced "settle") is a Scala ETL framework powered by [Apache Spark](https://spark.apache.org/) that helps you structure your Spark ETL projects, modularize your data transformation logic and speed up your development.

## Use SETL

### In a new project

You can start working by cloning [this template project](https://github.com/SETL-Framework/setl-template).

### In an existing project

```xml

io.github.setl-framework
setl_2.12
1.0.0-RC2

```

To use the SNAPSHOT version, add Sonatype snapshot repository to your `pom.xml`
```xml


ossrh-snapshots
https://s01.oss.sonatype.org/content/repositories/snapshots/


io.github.setl-framework
setl_2.12
1.0.0-SNAPSHOT

```

## Quick Start

### Basic concept

With SETL, an ETL application could be represented by a `Pipeline`. A `Pipeline` contains multiple `Stages`. In each stage, we could find one or several `Factories`.

The class `Factory[T]` is an abstraction of a data transformation that will produce an object of type `T`. It has 4 methods (*read*, *process*, *write* and *get*) that should be implemented by the developer.

The class `SparkRepository[T]` is a data access layer abstraction. It could be used to read/write a `Dataset[T]` from/to a datastore. It should be defined in a configuration file. You can have as many SparkRepositories as you want.

The entry point of a SETL project is the object `io.github.setl.Setl`, which will handle the pipeline and spark repository instantiation.

### Show me some code

You can find the following tutorial code in [the starter template of SETL](https://github.com/SETL-Framework/setl-template). Go and clone it :)

Here we show a simple example of creating and saving a **Dataset[TestObject]**. The case class **TestObject** is defined as follows:

```scala
case class TestObject(partition1: Int, partition2: String, clustering1: String, value: Long)
```

#### Context initialization

Suppose that we want to save our output into `src/main/resources/test_csv`. We can create a configuration file **local.conf** in `src/main/resources` with the following content that defines the target datastore to save our dataset:

```txt
testObjectRepository {
storage = "CSV"
path = "src/main/resources/test_csv"
inferSchema = "true"
delimiter = ";"
header = "true"
saveMode = "Append"
}
```

In our `App.scala` file, we build `Setl` and register this data store:
```scala
val setl: Setl = Setl.builder()
.withDefaultConfigLoader()
.getOrCreate()

// Register a SparkRepository to context
setl.setSparkRepository[TestObject]("testObjectRepository")

```

#### Implementation of Factory

We will create our `Dataset[TestObject]` inside a `Factory[Dataset[TestObject]]`. A `Factory[A]` will always produce an object of type `A`, and it contains 4 abstract methods that you need to implement:
- read
- process
- write
- get

```scala
class MyFactory() extends Factory[Dataset[TestObject]] with HasSparkSession {

import spark.implicits._

// A repository is needed for writing data. It will be delivered by the pipeline
@Delivery
private[this] val repo = SparkRepository[TestObject]

private[this] var output = spark.emptyDataset[TestObject]

override def read(): MyFactory.this.type = {
// in our demo we don't need to read any data
this
}

override def process(): MyFactory.this.type = {
output = Seq(
TestObject(1, "a", "A", 1L),
TestObject(2, "b", "B", 2L)
).toDS()
this
}

override def write(): MyFactory.this.type = {
repo.save(output) // use the repository to save the output
this
}

override def get(): Dataset[TestObject] = output

}
```

#### Define the pipeline

To execute the factory, we should add it into a pipeline.

When we call `setl.newPipeline()`, **Setl** will instantiate a new **Pipeline** and configure all the registered repositories as inputs of the pipeline. Then we can call `addStage` to add our factory into the pipeline.

```scala
val pipeline = setl
.newPipeline()
.addStage[MyFactory]()
```

#### Run our pipeline

```scala
pipeline.describe().run()
```
The dataset will be saved into `src/main/resources/test_csv`

#### What's more?

As our `MyFactory` produces a `Dataset[TestObject]`, it can be used by other factories of the same pipeline.

```scala
class AnotherFactory extends Factory[String] with HasSparkSession {

import spark.implicits._

@Delivery
private[this] val outputOfMyFactory = spark.emptyDataset[TestObject]

override def read(): AnotherFactory.this.type = this

override def process(): AnotherFactory.this.type = this

override def write(): AnotherFactory.this.type = {
outputOfMyFactory.show()
this
}

override def get(): String = "output"
}
```

Add this factory into the pipeline:

```scala
pipeline.addStage[AnotherFactory]()
```

### Custom Connector

You can implement you own data source connector by implementing the `ConnectorInterface`

```scala
class CustomConnector extends ConnectorInterface with CanDrop {
override def setConf(conf: Conf): Unit = null

override def read(): DataFrame = {
import spark.implicits._
Seq(1, 2, 3).toDF("id")
}

override def write(t: DataFrame, suffix: Option[String]): Unit = logDebug("Write with suffix")

override def write(t: DataFrame): Unit = logDebug("Write")

/**
* Drop the entire table.
*/
override def drop(): Unit = logDebug("drop")
}
```

To use it, just set the storage to **OTHER** and provide the class reference of your connector:

```txt
myConnector {
storage = "OTHER"
class = "com.example.CustomConnector" // class reference of your connector
}
```

### Generate pipeline diagram

You can generate a [Mermaid diagram](https://mermaid-js.github.io/mermaid/#/) by doing:
```scala
pipeline.showDiagram()
```

You will have some log like this:
```
--------- MERMAID DIAGRAM ---------
classDiagram
class MyFactory {
<>
+SparkRepository[TestObject]
}

class DatasetTestObject {
<>
>partition1: Int
>partition2: String
>clustering1: String
>value: Long
}

DatasetTestObject <|.. MyFactory : Output
class AnotherFactory {
<>
+Dataset[TestObject]
}

class StringFinal {
<>

}

StringFinal <|.. AnotherFactory : Output
class SparkRepositoryTestObjectExternal {
<>

}

AnotherFactory <|-- DatasetTestObject : Input
MyFactory <|-- SparkRepositoryTestObjectExternal : Input

------- END OF MERMAID CODE -------

You can copy the previous code to a markdown viewer that supports Mermaid.

Or you can try the live editor: https://mermaid-js.github.io/mermaid-live-editor/#/edit/eyJjb2RlIjoiY2xhc3NEaWFncmFtXG5jbGFzcyBNeUZhY3Rvcnkge1xuICA8PEZhY3RvcnlbRGF0YXNldFtUZXN0T2JqZWN0XV0-PlxuICArU3BhcmtSZXBvc2l0b3J5W1Rlc3RPYmplY3RdXG59XG5cbmNsYXNzIERhdGFzZXRUZXN0T2JqZWN0IHtcbiAgPDxEYXRhc2V0W1Rlc3RPYmplY3RdPj5cbiAgPnBhcnRpdGlvbjE6IEludFxuICA-cGFydGl0aW9uMjogU3RyaW5nXG4gID5jbHVzdGVyaW5nMTogU3RyaW5nXG4gID52YWx1ZTogTG9uZ1xufVxuXG5EYXRhc2V0VGVzdE9iamVjdCA8fC4uIE15RmFjdG9yeSA6IE91dHB1dFxuY2xhc3MgQW5vdGhlckZhY3Rvcnkge1xuICA8PEZhY3RvcnlbU3RyaW5nXT4-XG4gICtEYXRhc2V0W1Rlc3RPYmplY3RdXG59XG5cbmNsYXNzIFN0cmluZ0ZpbmFsIHtcbiAgPDxTdHJpbmc-PlxuICBcbn1cblxuU3RyaW5nRmluYWwgPHwuLiBBbm90aGVyRmFjdG9yeSA6IE91dHB1dFxuY2xhc3MgU3BhcmtSZXBvc2l0b3J5VGVzdE9iamVjdEV4dGVybmFsIHtcbiAgPDxTcGFya1JlcG9zaXRvcnlbVGVzdE9iamVjdF0-PlxuICBcbn1cblxuQW5vdGhlckZhY3RvcnkgPHwtLSBEYXRhc2V0VGVzdE9iamVjdCA6IElucHV0XG5NeUZhY3RvcnkgPHwtLSBTcGFya1JlcG9zaXRvcnlUZXN0T2JqZWN0RXh0ZXJuYWwgOiBJbnB1dFxuIiwibWVybWFpZCI6eyJ0aGVtZSI6ImRlZmF1bHQifX0=

```

You can either copy the code into a Markdown viewer or just copy the link into your browser ([link](https://mermaid-js.github.io/mermaid-live-editor/#/edit/eyJjb2RlIjoiY2xhc3NEaWFncmFtXG5jbGFzcyBNeUZhY3Rvcnkge1xuICA8PEZhY3RvcnlbRGF0YXNldFtUZXN0T2JqZWN0XV0-PlxuICArU3BhcmtSZXBvc2l0b3J5W1Rlc3RPYmplY3RdXG59XG5cbmNsYXNzIERhdGFzZXRUZXN0T2JqZWN0IHtcbiAgPDxEYXRhc2V0W1Rlc3RPYmplY3RdPj5cbiAgPnBhcnRpdGlvbjE6IEludFxuICA-cGFydGl0aW9uMjogU3RyaW5nXG4gID5jbHVzdGVyaW5nMTogU3RyaW5nXG4gID52YWx1ZTogTG9uZ1xufVxuXG5EYXRhc2V0VGVzdE9iamVjdCA8fC4uIE15RmFjdG9yeSA6IE91dHB1dFxuY2xhc3MgQW5vdGhlckZhY3Rvcnkge1xuICA8PEZhY3RvcnlbU3RyaW5nXT4-XG4gICtEYXRhc2V0W1Rlc3RPYmplY3RdXG59XG5cbmNsYXNzIFN0cmluZ0ZpbmFsIHtcbiAgPDxTdHJpbmc-PlxuICBcbn1cblxuU3RyaW5nRmluYWwgPHwuLiBBbm90aGVyRmFjdG9yeSA6IE91dHB1dFxuY2xhc3MgU3BhcmtSZXBvc2l0b3J5VGVzdE9iamVjdEV4dGVybmFsIHtcbiAgPDxTcGFya1JlcG9zaXRvcnlbVGVzdE9iamVjdF0-PlxuICBcbn1cblxuQW5vdGhlckZhY3RvcnkgPHwtLSBEYXRhc2V0VGVzdE9iamVjdCA6IElucHV0XG5NeUZhY3RvcnkgPHwtLSBTcGFya1JlcG9zaXRvcnlUZXN0T2JqZWN0RXh0ZXJuYWwgOiBJbnB1dFxuIiwibWVybWFpZCI6eyJ0aGVtZSI6ImRlZmF1bHQifX0=)) ๐Ÿป

### App Configuration

The configuration system of SETL allows users to execute their Spark application in different execution environments, by
using environment-specific configurations.

In `src/main/resources` directory, you should have at least two configuration files named `application.conf`
and `local.conf`
(take a look at this [example](https://github.com/SETL-Framework/setl-template/tree/master/src/main/resources)). These
are what you need if you only want to run your application in one single environment.

You can also create other configurations (for example `dev.conf` and `prod.conf`), in which environment-specific
parameters can be defined.

##### application.conf

This configuration file should contain universal configurations that could be used regardless the execution environment.

##### env.conf (e.g. local.conf, dev.conf)

These files should contain environment-specific parameters. By default, `local.conf` will be used.

##### How to use the configuration

Imagine the case we have two environments, a local development environment and a remote production environment. Our application
needs a repository for saving and loading data. In this use case, let's prepare `application.conf`, `local.conf`, `prod.conf`
and `storage.conf`

```hocon
# application.conf
setl.environment = ${app.environment}
setl.config {
spark.app.name = "my_application"
# and other general spark configurations
}
```

```hocon
# local.conf
include "application.conf"

setl.config {
spark.default.parallelism = "200"
spark.sql.shuffle.partitions = "200"
# and other local spark configurations
}

app.root.dir = "/some/local/path"

include "storage.conf"
```

```hocon
# prod.conf
setl.config {
spark.default.parallelism = "1000"
spark.sql.shuffle.partitions = "1000"
# and other production spark configurations
}

app.root.dir = "/some/remote/path"

include "storage.conf"
```

```hocon
# storage.conf
myRepository {
storage = "CSV"
path = ${app.root.dir} // this path will depend on the execution environment
inferSchema = "true"
delimiter = ";"
header = "true"
saveMode = "Append"
}
```

To compile with local configuration, with maven, just run:
```shell
mvn compile
```

To compile with production configuration, pass the jvm property `app.environment`.
```shell
mvn compile -Dapp.environment=prod
```

Make sure that your resources directory has filtering enabled:
```xml


src/main/resources
true

```

## Dependencies

**SETL** currently supports the following data source. You won't need to provide these libraries in your project (except the JDBC driver):
- All file formats supported by Apache Spark (csv, json, parquet etc)
- Delta
- Excel ([crealytics/spark-excel](https://github.com/crealytics/spark-excel))
- Cassandra ([datastax/spark-cassandra-connector](https://github.com/datastax/spark-cassandra-connector))
- DynamoDB ([audienceproject/spark-dynamodb](https://github.com/audienceproject/spark-dynamodb))
- JDBC (you have to provide the jdbc driver)

To read/write data from/to AWS S3 (or other storage services), you should include the
corresponding hadoop library in your project.

For example
```

org.apache.hadoop
hadoop-aws
2.9.2

```

You should also provide Scala and Spark in your pom file. SETL is tested against the following version of Spark:

| Spark Version | Scala Version | Note |
| ------------- | ------------- | -----------------------------|
| 3.0 | 2.12 | :heavy_check_mark: Ok |
| 2.4 | 2.12 | :heavy_check_mark: Ok |
| 2.4 | 2.11 | :warning: see *known issues* |
| 2.3 | 2.11 | :warning: see *known issues* |

## Known issues

### Spark 2.4 with Scala 2.11

When using `setl_2.11-1.x.x` with Spark 2.4 and Scala 2.11, you may need to include manually these following dependencies to override the default version:
```xml

com.audienceproject
spark-dynamodb_2.11
1.0.4

io.delta
delta-core_2.11
0.7.0

com.datastax.spark
spark-cassandra-connector_2.11
2.5.1

```

### Spark 2.3 with Scala 2.11

- `DynamoDBConnector` doesn't work with Spark version 2.3
- `Compress` annotation can only be used on Struct field or Array of Struct field with Spark 2.3

## Test Coverage

[![coverage.svg](https://codecov.io/gh/SETL-Framework/setl/branch/master/graphs/sunburst.svg)](https://codecov.io/gh/SETL-Framework/setl)

## Documentation

[https://setl-framework.github.io/setl/](https://setl-framework.github.io/setl/)

## Contributing to SETL

[Check our contributing guide](https://github.com/SETL-Framework/setl/blob/master/CONTRIBUTING.md)