homework-jianmu/docs/examples/python/tmq_websocket_example.py

151 lines
4.4 KiB
Python

#!/usr/bin/python3
import taosws
def prepareMeta():
conn = None
try:
conn = taosws.connect(user="root",
password="taosdata",
host="localhost",
port=6041)
db = "power"
# create database
rowsAffected = conn.execute(f"CREATE DATABASE IF NOT EXISTS {db}")
assert rowsAffected == 0
# change database.
rowsAffected = conn.execute(f"USE {db}")
assert rowsAffected == 0
# create super table
rowsAffected = conn.execute(
"CREATE TABLE IF NOT EXISTS `meters` (`ts` TIMESTAMP, `current` FLOAT, `voltage` INT, `phase` FLOAT) TAGS (`groupid` INT, `location` BINARY(16))"
)
assert rowsAffected == 0
# create table
rowsAffected = conn.execute(
"CREATE TABLE IF NOT EXISTS `d0` USING `meters` (groupid, location) TAGS(0, 'Los Angles')")
assert rowsAffected == 0
sql = """
INSERT INTO
power.d1001 USING power.meters (groupid, location) TAGS(2, 'California.SanFrancisco')
VALUES (NOW + 1a, 10.30000, 219, 0.31000)
(NOW + 2a, 12.60000, 218, 0.33000) (NOW + 3a, 12.30000, 221, 0.31000)
power.d1002 USING power.meters (groupid, location) TAGS(3, 'California.SanFrancisco')
VALUES (NOW + 1a, 10.30000, 218, 0.25000)
"""
affectedRows = conn.execute(sql)
print(f"inserted into {affectedRows} rows to power.meters successfully.")
except Exception as err:
print(f"Failed to prepareMeta {err}")
raise err
finally:
if conn:
conn.close()
# ANCHOR: create_consumer
def create_consumer():
try:
consumer = taosws.Consumer(conf={
"td.connect.websocket.scheme": "ws",
"group.id": "group1",
"client.id": "1",
"auto.offset.reset": "latest",
"td.connect.ip": "localhost",
"td.connect.port": "6041",
"enable.auto.commit": "true",
"auto.commit.interval.ms": "1000",
})
return consumer;
except Exception as err:
print(f"Failed to create websocket consumer, err:{err}");
raise err
# ANCHOR_END: create_consumer
def seek_offset(consumer):
# ANCHOR: assignment
try:
assignments = consumer.assignment()
for assignment in assignments:
topic = assignment.topic()
print(f"topic: {topic}")
for assign in assignment.assignments():
print(
f"vg_id: {assign.vg_id()}, offset: {assign.offset()}, begin: {assign.begin()}, end: {assign.end()}")
consumer.seek(topic, assign.vg_id(), assign.begin())
print("assignment seek to beginning successfully");
except Exception as err:
print(f"seek example failed; err:{err}")
raise err
# ANCHOR_END: assignment
# ANCHOR: subscribe
def subscribe(consumer):
try:
consumer.subscribe(["topic_meters"])
print("subscribe topics successfully")
for i in range(5):
records = consumer.poll(timeout=1.0)
if records:
for block in records:
for row in block:
print(row)
except Exception as err:
print(f"Failed to poll data, err:{err}")
raise err
# ANCHOR_END: subscribe
# ANCHOR: commit_offset
def commit_offset(consumer):
try:
for i in range(5):
records = consumer.poll(timeout=1.0)
if records:
for block in records:
for row in block:
print(row)
consumer.commit(records)
except Exception as err:
print(f"Failed to poll data, err:{err}")
raise err
# ANCHOR_END: commit_offset
#
# ANCHOR: unsubscribe
def unsubscribe(consumer):
try:
consumer.unsubscribe()
except Exception as err:
print("Failed to unsubscribe consumer. err:{err}")
# ANCHOR_END: unsubscribe
if __name__ == "__main__":
consumer = None
try:
prepareMeta()
consumer = create_consumer()
subscribe(consumer)
seek_offset(consumer)
commit_offset(consumer)
unsubscribe(consumer)
except Exception as err:
print(f"Failed to stmt consumer. err:{err}")
finally:
if consumer:
consumer.close()