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443 lines (376 loc) · 14.3 KB
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//
class MiniKafkaClient
{
constructor()
{
this.ws = null;
this.reconnectAttempts = 0;
}
async connect() {
return new Promise((resolve, reject) => {
this.ws = new WebSocket('ws://localhost:8765');
this.ws. => {
this.reconnectAttempts = 0;
resolve();
};
this.ws. => {
if (e.code === 1011) {
reject(new Error("Backend unavailable"));
} else {
this.attemptReconnect();
}
};
this.ws. => {
reject(error);
};
});
}
attemptReconnect() {
if (this.reconnectAttempts++ < 3) {
setTimeout(() => this.connect(), 1000 * this.reconnectAttempts);
}
}
async produce(topic, value) {
if (!this.ws || this.ws.readyState !== WebSocket.OPEN) {
throw new Error("WebSocket is not connected");
}
const message = {
action: "produce",
topic: topic,
value: value
};
this.ws.send(JSON.stringify(message));
}
disconnect() {
if (this.socket) {
this.socket.close();
this.socket = null;
this.connected = false;
}
}
sendCommand(command) {
return new Promise((resolve, reject) => {
if (!this.connected || !this.socket) {
reject(new Error("Not connected to broker"));
return;
}
const messageId = Date.now().toString();
const messageWithId = { ...command, messageId };
const handleResponse = (event) => {
try {
const response = JSON.parse(event.data);
if (response.messageId === messageId) {
this.socket.removeEventListener('message', handleResponse);
if (response.status === "error") {
reject(new Error(response.message));
} else {
resolve(response);
}
}
} catch (e) {
console.error("Error processing response:", e);
}
};
this.socket.addEventListener('message', handleResponse);
this.socket.send(JSON.stringify(messageWithId));
});
}
createTopic(name, partitions = 1) {
return this.sendCommand({
action: "create_topic",
topic: name,
partitions: partitions
});
}
listTopics() {
return this.sendCommand({
action: "list_topics"
});
}
produce(topic, value, key = null) {
return this.sendCommand({
action: "produce",
topic: topic,
value: value,
key: key
});
}
consume(topic, partition = 0, offset = 0, maxMessages = 100) {
return this.sendCommand({
action: "consume",
topic: topic,
partition: partition,
offset: offset,
max_messages: maxMessages
});
}
subscribe(topic, partition = 0, callback) {
const callbackKey = `${topic}:${partition}`;
this.subscriptionCallbacks[callbackKey] = callback;
return this.sendCommand({
action: "subscribe",
topic: topic,
partition: partition
});
}
getMetrics() {
return this.sendCommand({
action: "get_metrics"
});
}
}
// UI Application
class KafkaWebClient {
constructor() {
this.client = null;
this.currentSubscription = null;
this.initElements();
this.setupEventListeners();
this.updateConnectionStatus(false);
}
initElements() {
this.elements = {
brokerUrl: document.getElementById('broker-url'),
connectBtn: document.getElementById('connect-btn'),
connectionStatus: document.getElementById('connection-status'),
newTopic: document.getElementById('new-topic'),
partitions: document.getElementById('partitions'),
createTopicBtn: document.getElementById('create-topic-btn'),
topicsList: document.getElementById('topics-list'),
produceTopic: document.getElementById('produce-topic'),
messageKey: document.getElementById('message-key'),
messageValue: document.getElementById('message-value'),
produceBtn: document.getElementById('produce-btn'),
produceResult: document.getElementById('produce-result'),
consumeTopic: document.getElementById('consume-topic'),
partition: document.getElementById('partition'),
offset: document.getElementById('offset'),
consumeBtn: document.getElementById('consume-btn'),
subscribeBtn: document.getElementById('subscribe-btn'),
messagesList: document.getElementById('messages-list')
};
}
setupEventListeners() {
this.elements.connectBtn.addEventListener('click', () => this.toggleConnection());
this.elements.createTopicBtn.addEventListener('click', () => this.createTopic());
this.elements.produceBtn.addEventListener('click', () => this.produceMessage());
this.elements.consumeBtn.addEventListener('click', () => this.consumeMessages());
this.elements.subscribeBtn.addEventListener('click', () => this.toggleSubscription());
// Replace DOMSubtreeModified with MutationObserver
const topicsObserver = new MutationObserver((mutations) => {
this.populateTopicDropdowns();
});
topicsObserver.observe(this.elements.topicsList, {
childList: true, // Observe direct children additions/removals
subtree: true, // Observe all descendants
characterData: false // Don't observe text changes
});
// Store observer for potential disconnection later
this.topicsObserver = topicsObserver;
}
async toggleConnection() {
if (this.client && this.client.connected) {
this.client.disconnect();
this.updateConnectionStatus(false);
this.elements.connectBtn.textContent = "Connect";
} else {
try {
const brokerUrl = this.elements.brokerUrl.value;
this.client = new MiniKafkaClient(brokerUrl);
await this.client.connect();
this.updateConnectionStatus(true);
this.elements.connectBtn.textContent = "Disconnect";
this.loadTopics();
} catch (error) {
this.showError(`Connection failed: ${error.message}`);
this.updateConnectionStatus(false);
}
}
}
updateConnectionStatus(connected) {
const statusElement = this.elements.connectionStatus;
statusElement.textContent = connected ? "Connected" : "Disconnected";
statusElement.className = connected ? "status-connected" : "status-disconnected";
// Enable/disable UI elements based on connection status
const interactiveElements = [
this.elements.createTopicBtn,
this.elements.produceBtn,
this.elements.consumeBtn,
this.elements.subscribeBtn
];
interactiveElements.forEach(el => {
el.disabled = !connected;
});
}
async createTopic() {
const topicName = this.elements.newTopic.value.trim();
const partitions = parseInt(this.elements.partitions.value);
if (!topicName) {
this.showError("Please enter a topic name");
return;
}
try {
await this.client.createTopic(topicName, partitions);
this.elements.newTopic.value = "";
this.showSuccess(`Topic "${topicName}" created successfully`);
this.loadTopics();
} catch (error) {
this.showError(`Failed to create topic: ${error.message}`);
}
}
async loadTopics() {
try {
const response = await this.client.listTopics();
this.displayTopics(response.topics);
} catch (error) {
this.showError(`Failed to load topics: ${error.message}`);
}
}
displayTopics(topics) {
this.elements.topicsList.innerHTML = "";
if (!topics || topics.length === 0) {
this.elements.topicsList.innerHTML = "<li>No topics found</li>";
return;
}
topics.forEach(topic => {
const li = document.createElement('li');
li.innerHTML = `
<strong>${topic.name}</strong>
<span class="topic-meta">Partitions: ${topic.partitions}</span>
`;
this.elements.topicsList.appendChild(li);
});
}
populateTopicDropdowns() {
const topicSelects = [this.elements.produceTopic, this.elements.consumeTopic];
topicSelects.forEach(select => {
const currentValue = select.value;
select.innerHTML = "";
const topics = Array.from(this.elements.topicsList.querySelectorAll('li strong')).map(el => el.textContent);
if (topics.length === 0) {
const option = document.createElement('option');
option.value = "";
option.textContent = "No topics available";
select.appendChild(option);
select.disabled = true;
return;
}
select.disabled = false;
topics.forEach(topic => {
const option = document.createElement('option');
option.value = topic;
option.textContent = topic;
select.appendChild(option);
});
if (topics.includes(currentValue)) {
select.value = currentValue;
}
});
}
async produceMessage() {
const topic = this.elements.produceTopic.value;
const key = this.elements.messageKey.value.trim();
const value = this.elements.messageValue.value.trim();
if (!topic) {
this.showError("Please select a topic");
return;
}
if (!value) {
this.showError("Please enter a message value");
return;
}
try {
const response = await this.client.produce(topic, value, key || null);
this.showSuccess(`Message produced to ${topic}:${response.partition} at offset ${response.offset}`);
this.elements.messageValue.value = "";
} catch (error) {
this.showError(`Failed to produce message: ${error.message}`);
}
}
async consumeMessages() {
const topic = this.elements.consumeTopic.value;
const partition = parseInt(this.elements.partition.value);
const offset = parseInt(this.elements.offset.value);
if (!topic) {
this.showError("Please select a topic");
return;
}
try {
const response = await this.client.consume(topic, partition, offset);
this.displayMessages(response.messages);
} catch (error) {
this.showError(`Failed to consume messages: ${error.message}`);
}
}
displayMessages(messages) {
this.elements.messagesList.innerHTML = "";
if (!messages || messages.length === 0) {
this.elements.messagesList.innerHTML = "<div class='message-item'>No messages found</div>";
return;
}
messages.forEach(msg => {
const messageDiv = document.createElement('div');
messageDiv.className = "message-item";
messageDiv.innerHTML = `
<div class="message-header">Message at offset ${msg.offset}</div>
<div class="message-meta">
Partition: ${msg.partition} |
Key: ${msg.key || '(none)'} |
${new Date(msg.timestamp).toLocaleString()}
</div>
<div class="message-value">${msg.value}</div>
`;
this.elements.messagesList.appendChild(messageDiv);
});
}
async toggleSubscription() {
if (this.currentSubscription) {
this.unsubscribe();
this.elements.subscribeBtn.textContent = "Subscribe";
} else {
await this.subscribe();
this.elements.subscribeBtn.textContent = "Unsubscribe";
}
}
async subscribe() {
const topic = this.elements.consumeTopic.value;
const partition = parseInt(this.elements.partition.value);
if (!topic) {
this.showError("Please select a topic");
return false;
}
try {
this.currentSubscription = {
topic,
partition,
callback: (message) => {
this.displayMessages([message]);
}
};
await this.client.subscribe(topic, partition, this.currentSubscription.callback);
return true;
} catch (error) {
this.showError(`Failed to subscribe: ${error.message}`);
this.currentSubscription = null;
return false;
}
}
unsubscribe() {
if (this.currentSubscription) {
// In a real implementation, we would send an unsubscribe command to the server
this.currentSubscription = null;
}
}
showSuccess(message) {
this.elements.produceResult.textContent = message;
this.elements.produceResult.className = "success";
}
showError(message) {
this.elements.produceResult.textContent = message;
this.elements.produceResult.className = "error";
}
}
// Initialize the application when the DOM is loaded
document.addEventListener('DOMContentLoaded', () => {
const app = new KafkaWebClient();
});