homework-jianmu/docs/examples/go/demo/consumerws/main.go

116 lines
2.8 KiB
Go

package main
import (
"database/sql"
"fmt"
"os"
"time"
"github.com/taosdata/driver-go/v3/common"
tmqcommon "github.com/taosdata/driver-go/v3/common/tmq"
_ "github.com/taosdata/driver-go/v3/taosRestful"
"github.com/taosdata/driver-go/v3/ws/tmq"
)
func main() {
db, err := sql.Open("taosRestful", "root:taosdata@http(localhost:6041)/")
if err != nil {
panic(err)
}
defer db.Close()
_, err = db.Exec("create database if not exists power WAL_RETENTION_PERIOD 86400")
if err != nil {
panic(err)
}
_, err = db.Exec("CREATE STABLE IF NOT EXISTS power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))")
if err != nil {
panic(err)
}
_, err = db.Exec("create table if not exists power.d001 using power.meters tags(1,'location')")
if err != nil {
panic(err)
}
// ANCHOR: create_topic
_, err = db.Exec("CREATE TOPIC IF NOT EXISTS topic_meters AS SELECT ts, current, voltage, phase, groupid, location FROM power.meters")
if err != nil {
panic(err)
}
// ANCHOR_END: create_topic
// ANCHOR: create_consumer
consumer, err := tmq.NewConsumer(&tmqcommon.ConfigMap{
"ws.url": "ws://127.0.0.1:6041",
"ws.message.channelLen": uint(0),
"ws.message.timeout": common.DefaultMessageTimeout,
"ws.message.writeWait": common.DefaultWriteWait,
"td.connect.user": "root",
"td.connect.pass": "taosdata",
"group.id": "example",
"client.id": "example_consumer",
"auto.offset.reset": "latest",
})
if err != nil {
panic(err)
}
// ANCHOR_END: create_consumer
// ANCHOR: poll_data
go func() {
for {
_, err = db.Exec("insert into power.d001 values (now, 1.1, 220, 0.1)")
if err != nil {
panic(err)
}
time.Sleep(time.Millisecond * 100)
}
}()
err = consumer.Subscribe("topic_meters", nil)
if err != nil {
panic(err)
}
for i := 0; i < 5; i++ {
ev := consumer.Poll(500)
if ev != nil {
switch e := ev.(type) {
case *tmqcommon.DataMessage:
fmt.Printf("get message:%v\n", e)
case tmqcommon.Error:
fmt.Fprintf(os.Stderr, "%% Error: %v: %v\n", e.Code(), e)
panic(e)
}
consumer.Commit()
}
}
// ANCHOR_END: poll_data
// ANCHOR: consumer_seek
partitions, err := consumer.Assignment()
if err != nil {
panic(err)
}
for i := 0; i < len(partitions); i++ {
fmt.Println(partitions[i])
err = consumer.Seek(tmqcommon.TopicPartition{
Topic: partitions[i].Topic,
Partition: partitions[i].Partition,
Offset: 0,
}, 0)
if err != nil {
panic(err)
}
}
partitions, err = consumer.Assignment()
if err != nil {
panic(err)
}
// ANCHOR_END: consumer_seek
for i := 0; i < len(partitions); i++ {
fmt.Println(partitions[i])
}
// ANCHOR: consumer_close
err = consumer.Close()
if err != nil {
panic(err)
}
// ANCHOR_END: consumer_close
}