The Google Cloud Pub/Sub sink connector pulls data from Pulsar topics and persists data to Google Cloud Pub/Sub topics.

How to get

This section describes how to build the Google Cloud Pub/Sub sink connector.

Work with Function Worker

You can get the Google Cloud Pub/Sub sink connector using one of the following methods if you use Pulsar Function Worker to run connectors in a cluster.

Download the NAR package from the download page.
Build it from the source code.

To build the Google Cloud Pub/Sub sink connector from the source code, follow these steps.

Clone the source code to your machine.

git clone https://github.com/streamnative/pulsar-io-google-pubsub

Build the connector in the pulsar-io-google-pubsub directory.
```
mvn clean install -DskipTests
```
After the connector is successfully built, a NAR package is generated under the target directory.
```
ls target
pulsar-io-google-pubsub-2.8.4.2.nar
```

Work with Function Mesh

You can pull the Google Cloud Pub/Sub sink connector Docker image from the Docker Hub if you use Function Mesh to run the connector.

How to configure

Before using the Google Cloud Pub/Sub sink connector, you need to configure it. This table lists the properties and the descriptions.

Name	Type	Required	Default	Description
`pubsubEndpoint`	String	false	"" (empty string)	The Google Cloud Pub/Sub end-point URL.
`pubsubCredential`	String	false	"" (empty string)	The credential (JSON string) for accessing the Google Cloud.
`pubsubProjectId`	String	true	"" (empty string)	The Google Cloud project ID.
`pubsubTopicId`	String	true	" " (empty string)	The topic ID. It is used to read messages from or write messages to Google Cloud Pub/Sub topics.
`pubsubSchemaId`	String	false	"" (empty string)	The schema ID. You must set the schema ID when creating a schema for Google Cloud Pub/Sub topics.
`pubsubSchemaType`	String	false	"" (empty string)	The schema type. You must set the schema type when creating a schema for Google Cloud Pub/Sub topics. Currently, only the AVRO format is supported.
`pubsubSchemaEncoding`	String	false	"" (empty string)	The encoding of the schema. You must set the schema encoding when creating a schema for Google Cloud Pub/Sub topics. Currently, only the JSON format is supported.
`pubsubSchemaDefinition`	String	false	"" (empty string)	The definition of the schema. It is used to create a schema to or parse messages from Google Cloud Pub/Sub topics.

Note

The provided Google Cloud credentials must have permissions to access Google Cloud resources. To use the Google Cloud Pub/Sub sink connector, ensure the Google Cloud credentials have the following permissions to Google Cloud Pub/Sub API:

projects.topics.create
projects.topics.get
projects.topics.publish For more information about Google Cloud Pub/Sub API permissions, see Google Cloud Pub/Sub API permissions: Access control.

Work with Function Worker

You can create a configuration file (JSON or YAML) to set the properties if you use Pulsar Function Worker to run connectors in a cluster.

Example

JSON

 {
     "tenant": "public",
     "namespace": "default",
     "name": "google-pubsub-sink",
     "inputs": [
       "test-google-pubsub-pulsar"
     ],
     "archive": "connectors/pulsar-io-google-pubsub-2.8.4.2.nar",
     "parallelism": 1,
     "configs": {
       "pubsubCredential": "SECRETS",
       "pubsubProjectId": "pulsar-io-google-pubsub",
       "pubsubTopicId": "test-google-pubsub-sink"
   }
 }

YAML

tenant: public
namespace: default
name: google-pubsub-sink
inputs:
  - test-google-pubsub-pulsar
archive: connectors/pulsar-io-google-pubsub-2.8.4.2.nar
parallelism: 1
configs:
  pubsubCredential: 'SECRETS'
  pubsubProjectId: pulsar-io-google-pubsub
  pubsubTopicId: test-google-pubsub-sink

Work with Function Mesh

You can create a CustomResourceDefinitions (CRD) to create a Google Cloud Pub/Sub sink connector. Using CRD makes Function Mesh naturally integrate with the Kubernetes ecosystem. For more information about Pulsar sink CRD configurations, see sink CRD configurations.

You can define a CRD file (YAML) to set the properties as below.

apiVersion: compute.functionmesh.io/v1alpha1
kind: Sink
metadata:
  name: google-pubsub-sink-sample
spec:
  image: streamnative/pulsar-io-google-pubsub:2.8.4.2
  className: org.apache.pulsar.ecosystem.io.pubsub.PubsubSink
  replicas: 1
  maxReplicas: 1
  input:
    topics: 
      - persistent://public/default/destination
  sinkConfig:
    pubsubCredential: 'SECRETS'
    pubsubProjectId: pulsar-io-google-pubsub
    pubsubTopicId: test-google-pubsub-sink
  pulsar:
    pulsarConfig: "test-pulsar-sink-config"
  resources:
    limits:
    cpu: "0.2"
    memory: 1.1G
    requests:
    cpu: "0.1"
    memory: 1G
  java:
    jar: connectors/pulsar-io-google-pubsub-2.8.4.2.nar
  clusterName: test-pulsar
  autoAck: true

How to use

You can use the Google Cloud Pub/Sub sink connector with Function Worker or Function Mesh.

Work with Function Worker

You can use the Google Cloud Pub/Sub sink connector as a non built-in connector or a built-in connector.

If you already have a Pulsar cluster, you can use the Google Cloud Pub/Sub sink connector as a non built-in connector directly.

This example shows how to create a Google Cloud Pub/Sub sink connector on a Pulsar cluster using the pulsar-admin sinks create command.

PULSAR_HOME/bin/pulsar-admin sinks create \
--sink-config-file <google-pubsub-sink-config.yaml>

Work with Function Mesh

This example describes how to create a Google Cloud Pub/Sub sink connector for a Kuberbetes cluster using Function Mesh.

Prerequisites

Create and connect to a Kubernetes cluster.
Create a Pulsar cluster in the Kubernetes cluster.
Install the Function Mesh Operator and CRD into the Kubernetes cluster.
Prepare Google Cloud PubSub service. For details, see Getting Started with Google Cloud Pub/Sub.

Step

Define the Google Cloud Pub/Sub sink connector with a YAML file and save it as sink-sample.yaml.

This example shows how to publish the Google Cloud Pub/Sub sink connector to Function Mesh with a Docker image.

apiVersion: compute.functionmesh.io/v1alpha1
kind: Sink
metadata:
  name: google-pubsub-sink-sample
spec:
  image: streamnative/pulsar-io-google-pubsub:2.8.4.2
  className: org.apache.pulsar.ecosystem.io.pubsub.PubsubSink
  replicas: 1
  maxReplicas: 1
  input:
    topics: 
      - persistent://public/default/destination
    typeClassName: “[B”
  sinkConfig:
    pubsubCredential: 'SECRETS'
    pubsubProjectId: pulsar-io-google-pubsub
    pubsubTopicId: test-google-pubsub-sink
  pulsar:
    pulsarConfig: "test-pulsar-sink-config"
  resources:
    limits:
      cpu: "0.2"
      memory: 1.1G
    requests:
      cpu: "0.1"
      memory: 1G
  java:
    jar: connectors/pulsar-io-google-pubsub-2.8.4.2.nar
  clusterName: test-pulsar
  autoAck: true

Apply the YAML file to create the Google Cloud Pub/Sub sink connector.

Input

kubectl apply -f <path-to-sink-sample.yaml>

Output

sink.compute.functionmesh.io/google-pubsub-sink-sample created

Check whether the Google Cloud Pub/Sub sink connector is created successfully.
Input
```
kubectl get all
```
Output
```
NAME                                         READY   STATUS      RESTARTS   AGE
pod/google-pubsub-sink-sample-0               1/1    Running     0          77s
```
After that, you can produce and consume messages using the Google Cloud Pub/Sub sink connector between Pulsar and Google Cloud Pub/Sub.