chore: added readme with usage and kafka installation guide for easy usage

Signed-off-by: Femi <[email protected]>

Author: FemiOfficial

examples/kafka-ex/README.md

@@ -0,0 +1,58 @@
+# Kafka Example
+
+## Summary
+This is an example on how to use the cloudevents javascript sdk with Kafka in NodeJs.
+
+
+## Description 
+A simple cli application sending user input as a cloudevent message through a kafka producer to a topic. And eventually, the cloudevent message is handled and deserialized correctly by a consumer within a consumer group subscribed to the same topic.
+
+## Dependencies
+- NodeJS (>18)
+- Kafka running locally or remotely
+
+## Local Kafka Setup with Docker
+
+#### Option 1:  Run Zookeeper and Kafka Dccker Images sequentially with these commands 
+
+```bash
+docker run -d \
+  --name zookeeper \
+  -e ZOOKEEPER_CLIENT_PORT=2181 \
+  -e ZOOKEEPER_TICK_TIME=2000 \
+  confluentinc/cp-zookeeper:7.3.2
+
+```
+```bash
+docker run -d \
+  --name kafka \
+  -p 9092:9092 \
+  -e KAFKA_BROKER_ID=1 \
+  -e KAFKA_ZOOKEEPER_CONNECT=localhost:2181 \
+  -e KAFKA_ADVERTISED_LISTENERS=PLAINTEXT://localhost:9092 \
+  -e KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR=1 \
+  -e KAFKA_GROUP_INITIAL_REBALANCE_DELAY_MS=0 \
+  --link zookeeper:zookeeper \
+  confluentinc/cp-kafka:7.3.2
+
+```
+
+#### Option 2: Run both images using the docker compose file
+
+```bash
+  cd ${directory of the docker compose file}
+
+  docker compose up -d
+```
+
+## Then, run the producer (cli) and consumer
+
+#### To Start the Producer
+```bash
+npm run start:producer
+```
+
+#### To Start the Consumer
+```bash
+npm run start:consumer ${groupId}
+```

examples/kafka-ex/docker-compose.yml

@@ -0,0 +1,23 @@
+---
+version: '3'
+services:
+  zookeeper:
+    image: confluentinc/cp-zookeeper:7.3.2
+    container_name: zookeeper
+    environment:
+      ZOOKEEPER_CLIENT_PORT: 2181
+      ZOOKEEPER_TICK_TIME: 2000
+
+  kafka:
+    image: confluentinc/cp-kafka:7.3.2
+    container_name: kafka
+    depends_on:
+      - zookeeper
+    ports:
+      - "9092:9092"
+    environment:
+      KAFKA_BROKER_ID: 1
+      KAFKA_ZOOKEEPER_CONNECT: 'zookeeper:2181'
+      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://localhost:9092
+      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
+      KAFKA_GROUP_INITIAL_REBALANCE_DELAY_MS: 0

examples/kafka-ex/src/consumer.ts

@@ -1,4 +1,5 @@
 /* eslint-disable */
+
 import { Headers, Kafka, Message } from "cloudevents";
 import kafka from "./client";
 
@@ -21,10 +22,10 @@ const groupId = process.argv[2];
       });
 
       try {
-        let newHeaders: Headers = {};
+        const newHeaders: Headers = {};
         Object.keys(message.headers as Headers).forEach((key) => {
           // this is needed here because the headers are buffer values
-          // when it gets to the consumer which is invalid for the
+          // when it gets to the consumer and the buffer headers are not valid for the
           // toEvent api from cloudevents, so this converts each key value to a string
           // as expected by the toEvent api
           newHeaders[key] = message!.headers![key]?.toString() ?? "";

examples/kafka-ex/src/producer.ts

@@ -1,4 +1,5 @@
 /* eslint-disable */
+
 import { CloudEvent, Kafka } from "cloudevents";
 import readline from "readline";
 import kafka from "./client";
@@ -12,7 +13,7 @@ const rl = readline.createInterface({
   const producer = kafka.producer();
   await producer.connect();
 
-  rl.setPrompt("> ");
+  rl.setPrompt("Enter message > ");
   rl.prompt();
   rl.on("line", async (line) => {
     const event = new CloudEvent({