lk-dispatch

Canonical way to dispatch events to kinesis in the lk-architecture.

Usage

import {Kinesis} from "aws-sdk";
import getDispatch from "lk-dispatch";

const kinesis = new Kinesis();

const dispatch = getDispatch({
    kinesisClient: kinesis,
    kinesisStream: "entrypoint",
    producerId: "server@hostname"
});

const eventType = "eventType";
const eventData = {
    key: "value"
};
const eventOptions = {
    sourceUserId: "userId",
    partitionKey: "partitionKey"
};
dispatch(eventType, eventData, eventOptions)
    .then(event => {
        console.log(`Event ${event.id} inserted in kinesis`);
    });

Events in the lk-architecture

An event in the lk-architecture is a json object which conforms to the following json schema:

{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "type": "object",
    "properties": {
        "id": {
            "type": "string"
        },
        "type": {
            "type": "string"
        },
        "timestamp": {
            "type": "string",
            "format": "date-time"
        },
        "data": {
            "type": "object"
        },
        "source": {
            "type": "object",
            "properties": {
                "kinesisPartitionKey": {
                    "type": "string"
                },
                "producerId": {
                    "type": "string"
                },
                "producerId": {
                    "type": "string"
                }
            }
        }
    }
}

Example event:

const event = {
    id: "f47ac10b-58cc-4372-a567-0e02b2c3d479",
    type: "eventType",
    data: {/* whatever */},
    timestamp: "2016-01-01T00:00:00.000Z",
    source: {
        userId: "userId",
        producerId: "producerId",
        kinesisPartitionKey: "kinesisPartitionKey"
    }
};

Api

getDispatch(options)

Get the dispatch function.

Params

• options:
  • kinesisClient: AWS.Kinesis instance
  • kinesisStream: name of the kinesis stream where events will be published
  • producerId: a token to identify where events come from (will end up in event.source.producerId)

Return value

The dispatch function.

dispatch(type, data, options)

The dispatch function, publishes event to the configured kinesis stream.

Params

• type: the type of the event
• data: the data of the event
• options (optional):
  • sourceUserId (optional): the id of the user which triggered the operation that generated the event
  • partitionKey (optional): kinesis stream partition where to publish the event

Return value

A Promise that will be resolved with the published event when said event has been successfully published to kinesis.