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'); conf.setDb('power'); 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); for (let i = 0; i < 10; i++) { await wsSql.exec(`INSERT INTO d1001 USING ${stable} (location, groupId) TAGS ("California.SanFrancisco", 3) VALUES (NOW, ${10 + i}, ${200 + i}, ${0.32 + i})`); } 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() await subscribe(consumer) 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}`); } finally { if (consumer) { await consumer.close(); console.log("Consumer closed successfully."); } taos.destroy(); } // ANCHOR_END: unsubscribe } test()