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Kafka Plugin for Godspeed

Kafka is a versatile messaging system designed to securely transfer data between various systems. Its functionality can be tailored through configuration, allowing it to serve as a reliable conduit for real-time event tracking or even function as a replicated distributed database. While it's often colloquially labeled as a queue, it's more precisely described as a hybrid system that combines characteristics and trade-offs from both queue and database systems.

Steps to use kafka plugin in godspeed​

Install Kafka Plugin​

godspeed plugin add @godspeedsystems/plugins-kafka-as-datasource-as-eventsource

After installation, you will find auto-generated files in your project related to the plugin at src/datasources/types/kafka.ts and src/datasources/kafka.yamland src/eventsources/types/kafka.ts and src/datasources/kafka.yaml.

Use as Datasource (Producer)​

1. Update configuration file based on your requirements in src/datasources/kafka.yaml file.

src/datasources/kafka.yaml
type: kafka 
clientId: "kafka_proj"
brokers: ["kafka:9092"]

2. In the event, we establish an HTTP endpoint that accepts parameters such as the topic name and message content. When this endpoint is invoked, it triggers the datasource.kafka.producer function. This function, in turn, takes the provided topic name and message as input arguments and performs the task of publishing the message to the specified Kafka topic.

src/events/kafka_pub.yaml
# event for Publish
'http.post./kafka-pub':
  fn: kafka-publish
  body:
    content:
      application/json:
        schema:
          type: object
          properties:
            message:
              type: string
          required: ['message']
  responses:
    200:
      content:
        application/json:
          schema:
            type: object
            properties:
              name:
                type: string

3. In workflow we need to mension datasource.kafka.producer as function fn to produce data.

src/functions/kafka-publish.yaml
id: kafka-publish
summary: kafka publish message
tasks:
    - id: publish
      fn: datasource.kafka.producer
      args:
        topic: "publish-producer1"
        message: <% inputs.body.message%>

Use as EventSource (Consumer)​

1. Update configuration file based on your requirements in src/eventsources/kafka.yaml.

src/eventsources/kafka.yaml
type: kafka
groupId: "kafka_proj"

2. To use Consumer we need to follow the below event key format.

src/events/kafka_pub.yaml
kafka.{Topic}.{GroupId}:

The consumer event is triggered whenever a new message arrives on the specified topic. Upon triggering, it retrieves the incoming message and forwards it to the kafka_consume function. Inside this function, the incoming message is processed, and the result is then returned.

src/events/kafka_pub.yaml
# event for consume data from Topic
kafka.publish-producer1.kafka_proj: // event key
  id: kafka__consumer
  fn: kafka_consume
  body:
    description: The body of the query
    content:
      application/json: 
        schema:
          type: string

3. kafka workflow for consumer

# function for consume data
id: kafka-consumer
summary: consumer
tasks:
    - id: set_consumer
      fn: com.gs.return
      args: <% inputs %>

Project Structure:​

After implementing Kafka plugin, your project structure will look like this:

.
├── src
│   ├── datasources
│   │   ├── types
│   │   │    └── kafka.ts                    # Custom datasource logic
│   │   └── kafka.yaml                       # Datasource configuration
│   ├── events
│   │   ├── kafka_publish_event.yaml         # Event to trigger the Kafka publish
│   │   └── kafka_consumer_event.yaml        # Event to trigger the Kafka consume
│   ├── eventsources
│   │   └── kafka.yaml                       # Eventsource configuration
│   └── functions
│       ├── kafka-publish.yaml               # Workflow to publish message
│       └── kafka-consume.yaml               # Workflow to consume message

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