Building Flink from Source
- Build Flink
- Build PyFlink
  - Prerequisites
  - Installation
Dependency Shading
Scala Versions
Encrypted File Systems

Building Flink from Source

This page covers how to build Flink 1.12.0 from sources.

Build Flink
Build PyFlink
Dependency Shading
Scala Versions
Encrypted File Systems

Build Flink

In order to build Flink you need the source code. Either download the source of a release or clone the git repository.

In addition you need Maven 3 and a JDK (Java Development Kit). Flink requires at least Java 8 to build.

NOTE: Maven 3.3.x can build Flink, but will not properly shade away certain dependencies. Maven 3.2.5 creates the libraries properly. To build unit tests use Java 8u51 or above to prevent failures in unit tests that use the PowerMock runner.

To clone from git, enter:

git clone https://github.com/apache/flink

The simplest way of building Flink is by running:

mvn clean install -DskipTests

This instructs Maven (mvn) to first remove all existing builds (clean) and then create a new Flink binary (install).

To speed up the build you can skip tests, QA plugins, and JavaDocs:

mvn clean install -DskipTests -Dfast

Build PyFlink

Prerequisites

Building Flink

If you want to build a PyFlink package that can be used for pip installation, you need to build the Flink project first, as described in Build Flink.

Python version(3.5, 3.6, 3.7 or 3.8) is required

 $ python --version
 # the version printed here must be 3.5, 3.6, 3.7 or 3.8

Build PyFlink with Cython extension support (optional)

To build PyFlink with Cython extension support, you’ll need a C compiler. It’s a little different on how to install the C compiler on different operating systems:
- Linux Linux operating systems usually come with GCC pre-installed. Otherwise, you need to install it manually. For example, you can install it with command sudo apt-get install build-essential On Ubuntu or Debian.
- Mac OS X To install GCC on Mac OS X, you need to download and install “Command Line Tools for Xcode”, which is available in Apple’s developer page.
You also need to install the dependencies with following command:
```
 $ python -m pip install -r flink-python/dev/dev-requirements.txt
```

Installation

Then go to the root directory of flink source code and run this command to build the sdist package and wheel package:

cd flink-python; python setup.py sdist bdist_wheel

The sdist and wheel packages will be found under ./flink-python/dist/. Either of them could be used for pip installation, such as:

python -m pip install dist/*.tar.gz

Dependency Shading

Flink shades away some of the libraries it uses, in order to avoid version clashes with user programs that use different versions of these libraries. Among the shaded libraries are Google Guava, Asm, Apache Curator, Apache HTTP Components, Netty, and others.

The dependency shading mechanism was recently changed in Maven and requires users to build Flink slightly differently, depending on their Maven version:

Maven 3.1.x and 3.2.x It is sufficient to call mvn clean install -DskipTests in the root directory of Flink code base.

Maven 3.3.x The build has to be done in two steps: First in the base directory, then in the distribution project:

mvn clean install -DskipTests
cd flink-dist
mvn clean install

Note: To check your Maven version, run mvn --version.

Scala Versions

Info Users that purely use the Java APIs and libraries can ignore this section.

Flink has APIs, libraries, and runtime modules written in Scala. Users of the Scala API and libraries may have to match the Scala version of Flink with the Scala version of their projects (because Scala is not strictly backwards compatible).

Since version 1.7 Flink builds with Scala version 2.11 (default) and 2.12.

To build FLink against Scala 2.12, issue the following command:

mvn clean install -DskipTests -Dscala-2.12

Encrypted File Systems

If your home directory is encrypted you might encounter a java.io.IOException: File name too long exception. Some encrypted file systems, like encfs used by Ubuntu, do not allow long filenames, which is the cause of this error.

The workaround is to add:

<args>
    <arg>-Xmax-classfile-name</arg>
    <arg>128</arg>
</args>

in the compiler configuration of the pom.xml file of the module causing the error. For example, if the error appears in the flink-yarn module, the above code should be added under the <configuration> tag of scala-maven-plugin. See this issue for more information.