homework-jianmu/docs/examples/node/websocketexample/tmq_example.js

121 lines
3.9 KiB
JavaScript

const taos = require("@tdengine/websocket");
// ANCHOR: create_consumer
const db = 'power';
const stable = 'meters';
const url = 'ws://localhost:6041';
const topic = 'topic_meters'
const topics = [topic];
const groupId = "group1";
const clientId = "client1";
async function createConsumer() {
let groupId = "group1";
let clientId = "client1";
let configMap = new Map([
[taos.TMQConstants.GROUP_ID, groupId],
[taos.TMQConstants.CLIENT_ID, clientId],
[taos.TMQConstants.CONNECT_USER, "root"],
[taos.TMQConstants.CONNECT_PASS, "taosdata"],
[taos.TMQConstants.AUTO_OFFSET_RESET, "latest"],
[taos.TMQConstants.WS_URL, url],
[taos.TMQConstants.ENABLE_AUTO_COMMIT, 'true'],
[taos.TMQConstants.AUTO_COMMIT_INTERVAL_MS, '1000']
]);
try {
conn = await taos.tmqConnect(configMap);
console.log(`Create consumer successfully, host: ${url}, groupId: ${groupId}, clientId: ${clientId}`)
return conn;
} catch (err) {
console.error(`Failed to create websocket consumer, topic: ${topic}, groupId: ${groupId}, clientId: ${clientId}, ErrCode: ${err.code}, ErrMessage: ${err.message}`);
throw err;
}
}
// ANCHOR_END: create_consumer
async function prepare() {
let conf = new taos.WSConfig('ws://localhost:6041');
conf.setUser('root');
conf.setPwd('taosdata');
const createDB = `CREATE DATABASE IF NOT EXISTS ${db}`;
const createStable = `CREATE STABLE IF NOT EXISTS ${db}.${stable} (ts timestamp, current float, voltage int, phase float) TAGS (location binary(64), groupId int);`;
let wsSql = await taos.sqlConnect(conf);
await wsSql.exec(createDB);
await wsSql.exec(createStable);
let createTopic = `CREATE TOPIC IF NOT EXISTS ${topics[0]} AS SELECT * FROM ${db}.${stable}`;
await wsSql.exec(createTopic);
await wsSql.close();
}
const delay = function(ms) {
return new Promise(function(resolve) {
setTimeout(resolve, ms);
});
};
async function insert() {
let conf = new taos.WSConfig('ws://localhost:6041');
conf.setUser('root');
conf.setPwd('taosdata');
conf.setDb('power');
let wsSql = await taos.sqlConnect(conf);
for (let i = 0; i < 50; i++) {
await wsSql.exec(`INSERT INTO d1001 USING ${stable} (location, groupId) TAGS ("California.SanFrancisco", 3) VALUES (NOW, ${10 + i}, ${200 + i}, ${0.32 + i})`);
await delay(100);
}
await wsSql.close();
}
async function subscribe(consumer) {
// ANCHOR: commit
try {
await consumer.subscribe(['topic_meters']);
for (let i = 0; i < 50; i++) {
let res = await consumer.poll(100);
for (let [key, value] of res) {
// Add your data processing logic here
console.log(`data: ${key} ${value}`);
}
await consumer.commit();
console.log("Commit offset manually successfully.");
}
} catch (err) {
console.error(`Failed to poll data, topic: ${topic}, groupId: ${groupId}, clientId: ${clientId}, ErrCode: ${err.code}, ErrMessage: ${err.message}`);
throw err;
}
// ANCHOR_END: commit
}
async function test() {
// ANCHOR: unsubscribe
let consumer = null;
try {
await prepare();
consumer = await createConsumer();
const allPromises = [];
allPromises.push(subscribe(consumer));
allPromises.push(insert());
await Promise.all(allPromises);
await consumer.unsubscribe();
console.log("Consumer unsubscribed successfully.");
}
catch (err) {
console.error(`Failed to unsubscribe consumer, topic: ${topic}, groupId: ${groupId}, clientId: ${clientId}, ErrCode: ${err.code}, ErrMessage: ${err.message}`);
throw err;
}
finally {
if (consumer) {
await consumer.close();
console.log("Consumer closed successfully.");
}
taos.destroy();
}
// ANCHOR_END: unsubscribe
}
test()