Quickstart Using Java and Apache Maven

This page shows you how to set up your Google Cloud project, create a Maven project with the Apache Beam SDK, and run an example pipeline on the Dataflow service.

Before you begin

Sign in to your Google Account.
If you don't already have one, sign up for a new account.
In the Google Cloud Console, on the project selector page, select or create a Google Cloud project.

Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

Go to the project selector page
Make sure that billing is enabled for your Cloud project. Learn how to confirm that billing is enabled for your project.
Enable the Cloud Dataflow, Compute Engine, Stackdriver Logging, Cloud Storage, Cloud Storage JSON, BigQuery, Cloud Pub/Sub, Cloud Datastore, and Cloud Resource Manager APIs.
Enable the APIs

Set up authentication:
1. In the Cloud Console, go to the Create service account key page.
  Go to the Create Service Account Key page
2. From the Service account list, select New service account.
3. In the Service account name field, enter a name.
4. From the Role list, select Project > Owner.
  
  Note: The Role field affects which resources your service account can access in your project. You can revoke these roles or grant additional roles later. In production environments, do not grant the Owner, Editor, or Viewer roles. For more information, see Granting, changing, and revoking access to resources.
5. Click Create. A JSON file that contains your key downloads to your computer.
Set the environment variable GOOGLE_APPLICATION_CREDENTIALS to the path of the JSON file that contains your service account key. This variable only applies to your current shell session, so if you open a new session, set the variable again.
Example: Linux or macOS

Replace [PATH] with the path of the JSON file that contains your service account key.
```
export GOOGLE_APPLICATION_CREDENTIALS="[PATH]"
```
For example:
```
export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/service-account-file.json"
```
Example: Windows

Replace [PATH] with the path of the JSON file that contains your service account key.

With PowerShell:
```
$env:GOOGLE_APPLICATION_CREDENTIALS="[PATH]"
```
For example:
```
$env:GOOGLE_APPLICATION_CREDENTIALS="C:\Users\username\Downloads\my-key.json"
```
With command prompt:
```
set GOOGLE_APPLICATION_CREDENTIALS=[PATH]
```
Create a Cloud Storage bucket:
1. In the Cloud Console, go to the Cloud Storage Browser page.
  Go to the Cloud Storage Browser page
2. Click Create bucket.
3. In the Create bucket dialog, specify the following attributes:
  - Name: A unique bucket name. Do not include sensitive information in the bucket name, because the bucket namespace is global and publicly visible.
  - Default storage class: Standard
  - A location where bucket data will be stored.
4. Click Create.
Download and install the Java Development Kit (JDK) version 11 (Note: Dataflow continues to support version 8.) Verify that the JAVA_HOME environment variable is set and points to your JDK installation.
Download and install Apache Maven by following Maven's installation guide for your specific operating system.

Get the WordCount code

The Apache Beam SDK is an open source programming model for data pipelines. You define these pipelines with an Apache Beam program and can choose a runner, such as Dataflow, to execute your pipeline.

Create a Maven project containing the Apache Beam SDK's WordCount examples, using the Maven Archetype Plugin. From a directory on your computer, run the mvn archetype:generate command in your shell or terminal as follows:

$ mvn archetype:generate \
      -DarchetypeGroupId=org.apache.beam \
      -DarchetypeArtifactId=beam-sdks-java-maven-archetypes-examples \
      -DarchetypeVersion=2.27.0 \
      -DgroupId=org.example \
      -DartifactId=word-count-beam \
      -Dversion="0.1" \
      -Dpackage=org.apache.beam.examples \
      -DinteractiveMode=false

After running the command, you should see a new directory called word-count-beam under your current directory. word-count-beam contains a simple pom.xml file and a series of example pipelines that count words in text files.

$ cd word-count-beam/

$ ls
pom.xml	src

$ ls src/main/java/org/apache/beam/examples/
DebuggingWordCount.java	WindowedWordCount.java	common
MinimalWordCount.java	WordCount.java

For a detailed introduction to the Apache Beam concepts used in these examples, see the WordCount Example Walkthrough. The following example executes WordCount.java.

Run WordCount locally

Run WordCount locally by running the following command from your word-count-beam directory:

$ mvn compile exec:java \
      -Dexec.mainClass=org.apache.beam.examples.WordCount \
      -Dexec.args="--output=counts"

The output files have the prefix counts and are written to the word-count-beam directory. They contain unique words from the input text and the number of occurences of each word.

Run WordCount on the Dataflow service

Build and run WordCount on the Dataflow service:

For the --project argument, specify the Project ID for the Google Cloud project you created.
For the --stagingLocation and --output arguments, specify the name of the Cloud Storage bucket you created as part of the path.
For the --region argument, specify a Dataflow regional endpoint.

$ mvn -Pdataflow-runner compile exec:java \
      -Dexec.mainClass=org.apache.beam.examples.WordCount \
      -Dexec.args="--project=<PROJECT_ID> \
      --stagingLocation=gs://<STORAGE_BUCKET>/staging/ \
      --output=gs://<STORAGE_BUCKET>/output \
      --runner=DataflowRunner \
      --region=<REGION>"

Note: Unless specified through the network option, the Dataflow runner runs jobs in the default Virtual Private Cloud network.

View your results

Open the Dataflow Web UI.
Go to the Dataflow Web UI
You should see your wordcount job with a status of Running at first, and then Succeeded:
Open the Cloud Storage Browser in the Google Cloud Console.
Go to the Cloud Storage browser
In your bucket, you should see the output files and staging files that your job created:

Clean up

To avoid incurring charges to your Google Cloud account for the resources used in this quickstart, follow these steps.

In the Cloud Console, go to the Cloud Storage Browser page.
Go to the Cloud Storage Browser page
Click the checkbox for the bucket you want to delete.
To delete the bucket, click Delete .