tPubSubInputAvro properties for Apache Spark Streaming

Define a Google Cloud configuration component

If you are using Dataproc as your Spark cluster, clear this check box.

Otherwise, select this check box to allow the Pub/Sub component to use the Google Cloud configuration information provided by a tGoogleCloudConfiguration component.

Schema and Edit schema

A schema is a row description. It defines the number of fields (columns) to be processed and passed on to the next component. When you create a Spark Job, avoid the reserved word line when naming the fields.

Note that the schema defined here must correspond exactly to the binary Avro schema of the messages received on Pub/Sub. To guarantee this, you can create another Spark Streaming Job to define a given schema using tWriteAvroFields and write the messages with this schema using tPubSubOutput.

Topic name

Enter the name of topic from which you want to consume the messages.

Subscription name

Enter the name of the subscription that needs to consume the specified topic.

If the subscription exists, it must be connected to the given topic; if the subscription does not exist, it is created and connected to the given topic at runtime.

Storage level

From the Storage level drop-down list that is displayed, select how the cached RDDs are stored, such as in memory only or in memory and on disk.

For further information about each of the storage level, see https://spark.apache.org/docs/latest/programming-guide.html#rdd-persistence.

Use hierarchical mode

Select this check box to map the binary (including hierarchical) Avro schema to the flat schema defined in the schema editor of the current component. If the Avro message to be processed is flat, leave this check box clear.

Once selecting it, you need set the following parameter(s):

• Local path to the avro schema: browse to the file which defines the schema of the Avro data to be processed.

• Mapping: create the map between the schema columns of the current component and the data stored in the hierarchical Avro message to be handled. In the Node column, you need to enter the JSON path pointing to the data to be read from the Avro message.

Usage rule

This component is used as a start component and requires an output link.

Spark Connection

This connection is effective on a per-Job basis.

PubSub access permissions

When you use Pub/Sub with a Dataproc cluster, ensure that this cluster has the appropriate permissions to access the Pub/Sub service.

gcloud beta dataproc clusters create CLUSTER_ID \
    --zone europe-west1-b \
    --master-machine-type n1-standard-2 \
    --master-boot-disk-size 50 \
    --num-workers 2 \
    --worker-machine-type n1-standard-2 \
    --worker-boot-disk-size 50 \
    --scopes 'https://www.googleapis.com/auth/cloud-platform' \
    --project PROJECT_ID