通过消费组（ConsumerGroup）消费日志有显著优点，您无需关注日志服务的实现细节和消费者之间的负载均衡、Failover等，只需要专注于业务逻辑即可。本文通过Python代码介绍如何使用消费组消费日志。
工作流程
一个Logstore中包含多个Shard，通过消费组消费数据就是将Shard分配给一个消费组下面的消费者，分配方式遵循以下原则。
在一个消费组中，一个Shard只会分配到一个消费者。
在一个消费组中，一个消费者可以被分配多个Shard。
新的消费者加入消费组后，这个消费组下面的Shard从属关系会调整，以实现消费的负载均衡，但是仍遵循上述分配原则。
说明
通过消费组消费，程序发生故障时，会默认保存Checkpoint。在程序故障恢复时，能够从断点处继续消费，从而保证数据不会被重复消费。
前提条件
已开通日志服务。更多信息，请参见开通日志服务。
已创建RAM用户并完成授权。具体操作，请参见创建RAM用户并完成授权。
已配置环境变量ALIBABA_CLOUD_ACCESS_KEY_ID和ALIBABA_CLOUD_ACCESS_KEY_SECRET。具体操作，请参见在Linux、macOS和Windows系统配置环境变量。
重要阿里云账号的AccessKey拥有所有API的访问权限，建议您使用RAM用户的AccessKey进行API访问或日常运维。
强烈建议不要把AccessKey ID和AccessKey Secret保存到工程代码里，否则可能导致AccessKey泄露，威胁您账号下所有资源的安全。
已安装日志服务Python SDK。具体操作，请参见安装Python SDK。
已创建Project。具体操作，请参见创建项目Project。
注意事项
本示例以华东1（杭州）的公网Endpoint为例，其公网Endpoint为https://cn-hangzhou.log.aliyuncs.com。如果您通过与Project同地域的其他阿里云产品访问日志服务，请使用内网Endpointhttps://cn-hangzhou-intranet.log.aliyuncs.com。关于日志服务支持的地域与Endpoint的对应关系，请参见服务入口。
代码示例
以下代码用于创建Logstore、为Logstore写入日志、创建消费组并消费日志。
import os
import time
from aliyun.log.consumer import *
from aliyun.log import *
from threading import RLock
class SampleConsumer(ConsumerProcessorBase):
shard_id = -1
last_check_time = 0
log_results = []
lock = RLock()
def initialize(self, shard):
self.shard_id = shard
def process(self, log_groups, check_point_tracker):
for log_group in log_groups.LogGroups:
items = []
for log in log_group.Logs:
item = dict()
item['time'] = log.Time
for content in log.Contents:
item[content.Key] = content.Value
items.append(item)
log_items = dict()
log_items['topic'] = log_group.Topic
log_items['source'] = log_group.Source
log_items['logs'] = items
with SampleConsumer.lock:
SampleConsumer.log_results.append(log_items)
print(log_items)
current_time = time.time()
if current_time - self.last_check_time > 3:
try:
self.last_check_time = current_time
check_point_tracker.save_check_point(True)
except Exception:
import traceback
traceback.print_exc()
else:
try:
check_point_tracker.save_check_point(False)
except Exception:
import traceback
traceback.print_exc()
# None means succesful process
# if need to roll-back to previous checkpoint，return check_point_tracker.get_check_point()
return None
def shutdown(self, check_point_tracker):
try:
check_point_tracker.save_check_point(True)
except Exception:
import traceback
traceback.print_exc()
test_item_count = 20
# 为Logstore写入日志。
def _prepare_data(client, project, logstore):
topic = 'python-ide-test'
source = ''
for i in range(0, test_item_count):
logitemList = [] # LogItem list
contents = [
('user', 'magic_user_' + str(i)),
('avg', 'magic_age_' + str(i))
]
logItem = LogItem()
logItem.set_time(int(time.time()))
logItem.set_contents(contents)
logitemList.append(logItem)
# 将日志写入Logstore。
request = PutLogsRequest(project, logstore, topic, source, logitemList)
response = client.put_logs(request)
print("successfully put logs in logstore")
def sleep_until(seconds, exit_condition=None, expect_error=False):
if not exit_condition:
time.sleep(seconds)
return
s = time.time()
while time.time() - s < seconds:
try:
if exit_condition():
break
except Exception:
if expect_error:
continue
time.sleep(1)
def sample_consumer_group():
# 日志服务的服务接入点。此处以杭州为例，其它地域请根据实际情况填写。
endpoint = os.environ.get('ALIYUN_LOG_SAMPLE_ENDPOINT', 'cn-hangzhou.log.aliyuncs.com')
# 本示例从环境变量中获取AccessKey ID和AccessKey Secret。
accessKeyId = os.environ.get('ALIBABA_CLOUD_ACCESS_KEY_ID', '')
accessKey = os.environ.get('ALIBABA_CLOUD_ACCESS_KEY_SECRET', '')
# Project名称。本示例中，SDK不会创建Project，您需要在运行代码前创建该Project。
project = os.environ.get('ALIYUN_LOG_SAMPLE_PROJECT', 'ali-test-project-python')
# Logstore名称。本示例中，SDK会自动创建该Logstore，您无需提前创建该Logstore。
logstore = 'ali-test-logstore'
# 消费组名称。您无需提前创建，SDK会自动创建该消费组。
consumer_group = 'consumer-group-1'
consumer_name1 = "consumer-group-1-A"
consumer_name2 = "consumer-group-1-B"
token = ""
if not logstore:
logstore = 'consumer_group_test_' + str(time.time()).replace('.', '_')
assert endpoint and accessKeyId and accessKey and project, ValueError("endpoint/access_id/key and "
"project cannot be empty")
# 创建Logstore。
client = LogClient(endpoint, accessKeyId, accessKey, token)
ret = client.create_logstore(project, logstore, 2, 4)
print("successfully create logstore")
time.sleep(60)
SampleConsumer.log_results = []
try:
# 为Logstore写入日志。
_prepare_data(client, project, logstore)
# 在消费组中创建2个消费者消费数据。
option1 = LogHubConfig(endpoint, accessKeyId, accessKey, project, logstore, consumer_group,
consumer_name1, cursor_position=CursorPosition.BEGIN_CURSOR, heartbeat_interval=6,
data_fetch_interval=1)
option2 = LogHubConfig(endpoint, accessKeyId, accessKey, project, logstore, consumer_group,
consumer_name2, cursor_position=CursorPosition.BEGIN_CURSOR, heartbeat_interval=6,
data_fetch_interval=1)
print("*** start to consume data...")
client_worker1 = ConsumerWorker(SampleConsumer, consumer_option=option1)
client_worker1.start()
client_worker2 = ConsumerWorker(SampleConsumer, consumer_option=option2)
client_worker2.start()
sleep_until(300, lambda: len(SampleConsumer.log_results) >= test_item_count)
print("*** consumer group status ***")
ret = client.list_consumer_group(project, logstore)
print("successfully list consumergroup")
for c in ret.get_consumer_groups():
ret = client.get_check_point_fixed(project, logstore, c.get_consumer_group_name())
print("successfully get checkpoint fixed")
print("*** stopping workers")
client_worker1.shutdown()
client_worker2.shutdown()
finally:
# clean-up
# ret = client.delete_logstore(project, logstore)
ret = client.list_logstore(project, logstore)
print("successfully list logstore")
# validate
ret = str(SampleConsumer.log_results)
print("*** get content:")
print(ret)
assert 'magic_user_0' in ret and 'magic_age_0' in ret \
and 'magic_user_' + str(test_item_count-1) in ret \
and 'magic_age_' + str(test_item_count-1) in ret
if __name__ == '__main__':
sample_consumer_group()预期结果如下：
successfully create logstore
successfully put logs in logstore
successfully put logs in logstore
successfully put logs in logstore
successfully put logs in logstore
successfully put logs in logstore
......
*** start to consume data...
{'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123452, 'user': 'magic_user_0', 'avg': 'magic_age_0'}]}
{'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123453, 'user': 'magic_user_1', 'avg': 'magic_age_1'}]}
{'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123453, 'user': 'magic_user_3', 'avg': 'magic_age_3'}]}
{'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123453, 'user': 'magic_user_5', 'avg': 'magic_age_5'}]}
{'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123453, 'user': 'magic_user_6', 'avg': 'magic_age_6'}]}
......
*** consumer group status ***
successfully list consumergroup
successfully get checkpoint fixed
*** stopping workers
successfully list logstore
*** get content:
[{'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123452, 'user': 'magic_user_0', 'avg': 'magic_age_0'}]}, {'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123453, 'user': 'magic_user_1', 'avg': 'magic_age_1'}]}, {'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123453, 'user': 'magic_user_3', 'avg': 'magic_age_3'}]}, {'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123453, 'user': 'magic_user_5', 'avg': 'magic_age_5'}]}, {'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123453, 'user': 'magic_user_6', 'avg': 'magic_age_6'}]}, {'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123453, 'user': 'magic_user_8', 'avg': 'magic_age_8'}]}, {'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123453, 'user': 'magic_user_9', 'avg': 'magic_age_9'}]}, {'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123453, 'user': 'magic_user_2', 'avg': 'magic_age_2'}]}, {'topic': 'python-ide-test', 'source': '47.100.XX.XX', 'logs': [{'time': 1672123453, 'user': 'magic_user_11', 'avg': 'magic_age_11'}]}, ......}]相关文档
阿里云OpenAPI开发者门户提供调试、SDK、示例和配套文档。通过OpenAPI，您无需手动封装请求和签名操作，就可以快速对日志服务API进行调试。更多信息，请参见OpenAPI开发者门户。
为满足越来越多的自动化日志服务配置需求，日志服务提供命令行工具CLI（Command Line Interface）。更多信息，请参见日志服务命令行工具CLI。
更多示例代码，请参见Aliyun Log Python SDK on GitHub。