infoverload commented on a change in pull request #18353: URL: https://github.com/apache/flink/pull/18353#discussion_r798691818
########## File path: docs/content/docs/dev/configuration/maven.md ########## @@ -0,0 +1,175 @@ +--- +title: "Using Maven" +weight: 2 +type: docs +--- +<!-- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +# How to use Maven to configure your project + +You will likely need a build tool to configure your Flink project. This guide will show you how to +do so with [Maven](https://maven.apache.org), an open-source build automation tool developed by the +Apache Group that enables you to build, publish, and deploy projects. You can use it to manage the +entire lifecycle of your software project. + +## Requirements + +- Maven 3.0.4 (or higher) +- Java 8.x + +## Importing the project into your IDE + +Once the project folder and files have been created, we recommend that you import this project into +your IDE for developing and testing. + +IntelliJ IDEA supports Maven projects out-of-the-box. Eclipse offers the [m2e plugin](http://www.eclipse.org/m2e/) +to [import Maven projects](http://books.sonatype.com/m2eclipse-book/reference/creating-sect-importing-projects.html#fig-creating-import). + +**Note**: The default JVM heap size for Java may be too small for Flink and you have to manually increase it. +In Eclipse, choose `Run Configurations -> Arguments` and write into the `VM Arguments` box: `-Xmx800m`. +In IntelliJ IDEA recommended way to change JVM options is from the `Help | Edit Custom VM Options` menu. +See [this article](https://intellij-support.jetbrains.com/hc/en-us/articles/206544869-Configuring-JVM-options-and-platform-properties) for details. + +**Note on IntelliJ:** To make the applications run within IntelliJ IDEA, it is necessary to tick the +`Include dependencies with "Provided" scope` box in the run configuration. If this option is not available +(possibly due to using an older IntelliJ IDEA version), then a workaround is to create a test that +calls the application's `main()` method. + +## Building the project + +If you want to build/package your project, navigate to your project directory and run the +'`mvn clean package`' command. You will find a JAR file that contains your application (plus connectors +and libraries that you may have added as dependencies to the application) here:`target/<artifact-id>-<version>.jar`. + +__Note:__ If you used a different class than `DataStreamJob` as the application's main class / entry point, +we recommend you change the `mainClass` setting in the `pom.xml` file accordingly so that Flink +can run the application from the JAR file without additionally specifying the main class. + +## Adding dependencies to the project + +Open the `pom.xml` file in your profile directory and add the dependency in between +the `dependencies` tab. + +For example, you can add the Kafka connector as a dependency like this: + +```xml +<dependencies> + + <dependency> + <groupId>org.apache.flink</groupId> + <artifactId>flink-connector-kafka</artifactId> + <version>{{< version >}}</version> + </dependency> + +</dependencies> +``` + +Then execute `mvn install` on the command line. + +Projects created from the `Java Project Template`, the `Scala Project Template`, or Gradle are configured +to automatically include the application dependencies into the application JAR when you run `mvn clean package`. +For projects that are not set up from those templates, we recommend adding the Maven Shade Plugin to +build the application jar with all required dependencies. + +**Important:** Note that all these core API dependencies should have their scope set to [*provided*](https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#dependency-scope). This means that +they are needed to compile against, but that they should not be packaged into the project's resulting +application JAR file. If not set to *provided*, the best case scenario is that the resulting JAR +becomes excessively large, because it also contains all Flink core dependencies. The worst case scenario +is that the Flink core dependencies that are added to the application's JAR file clash with some of +your own dependency versions (which is normally avoided through inverted classloading). + +To correctly package the dependencies into the application JAR, the Flink API dependencies must +be set to the *compile* scope. + +## Packaging the application + +Depending on your use case, you may need to package your Flink application in different ways before it +gets deployed to a Flink environment. + +If you want to create a JAR for a Flink Job and use only Flink dependencies without any third-party +dependencies (i.e. using the filesystem connector with JSON format), you do not need to create an +uber/fat JAR or shade any dependencies. + +If you want to create a JAR for a Flink Job and use external dependencies not built into the Flink +distribution, you can either add them to the classpath of the distribution or shade them into your +uber/fat application JAR. + +With the generated uber/fat JAR, you can submit it to a local or remote cluster with: + +```sh +bin/flink run -c org.example.MyJob myFatJar.jar +``` + +To learn more about how to deploy Flink jobs, check out the [deployment guide]({{< ref "docs/deployment/cli" >}}). + +## Template for creating an uber/fat JAR with dependencies + +To build an application JAR that contains all dependencies required for declared connectors and libraries, +you can use the following shade plugin definition: + +```xml Review comment: After some discussion, I think we can improve it after the PR. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
