返回AWS中的所有警报，而不是仅在Python上使用describe_alarms 50

Question

当使用函数describe_alarms时，如何打印所有警报名称，而不是仅打印50个？

代码，使用Python：

conn = boto.connect_cloudwatch()
alarms = conn.describe_alarms()    
for item in alarms:
    print item.name

谢谢。

Answer 1

默认情况下，它返回50。如果需要更多信息，请设置max_records=value并尝试。

由于底层AWS实现限制，它将返回最多100个警报。不知道现在是不是修好了。

conn.describe_alarms(max_records=100)

有关模块boto.ec2.Cloudwatch中的方法describe_alarms的帮助： Describe_alarms(自我，action_prefix=None，alarm_name_prefix=None，alarm_names=None，max_records=None，state_value=None，next_token=None) 类型max_records: int :param max_records:要检索的最大警报描述数。

Answer 2

尽管我参加聚会有点晚了，但这里是我的解决方案(用Java)。您必须获得下一个令牌，并一直在循环中询问结果，直到没有下一个令牌为止，因此它的行为就像在网站上分页一样。

String nextToken = null;
List<MetricAlarm> metricAlarms = new ArrayList<>();
for (int i = 0; i < 100; i++) {

    DescribeAlarmsRequest describeAlarmsRequest = new DescribeAlarmsRequest();
    describeAlarmsRequest.setNextToken(nextToken);
    describeAlarmsRequest.setMaxRecords(100);

    DescribeAlarmsResult describeAlarmsResult = getClient().describeAlarms(describeAlarmsRequest);
    List<MetricAlarm> metricAlarmsTmp = describeAlarmsResult.getMetricAlarms();
    metricAlarms.addAll(metricAlarmsTmp);
    nextToken = describeAlarmsResult.getNextToken();
    logger.info("nextToken: {}", nextToken);

    if (nextToken == null) {
        break;
    }
}
logger.info("metricAlarms size: {}", metricAlarms.size());

当然，还有改进的余地，例如创建一个while循环而不是for循环。

更新：

在这里，我的精致版本

String nextToken = null;
List<MetricAlarm> metricAlarms = new ArrayList<>();

while (nextToken != null || metricAlarms.size() == 0) {
    DescribeAlarmsRequest describeAlarmsRequest = new DescribeAlarmsRequest().withNextToken(nextToken).withMaxRecords(100); // create the request
    DescribeAlarmsResult describeAlarmsResult = getClient().describeAlarms(describeAlarmsRequest); // get the result
    metricAlarms.addAll(describeAlarmsResult.getMetricAlarms()); // add new alarms to our list
    nextToken = describeAlarmsResult.getNextToken(); // check if we have a nextToken
    if (nextToken == null && cachedMetricAlarms.size() == 0) { // if we have no alarm in AWS we get inside the loop but we would never exit -> intercept that
            break;
        }
}
logger.info("metricAlarms size: {}", metricAlarms.size());

Answer 3

下面是一个完整的示例，说明如何在记录中分页，以确保检索所有记录，而不是受Cloudwatch警报API上的最大记录的限制：

alarmMaxRecords = 10

response = client.describe_alarms(
AlarmNamePrefix=prefix,
MaxRecords=alarmMaxRecords
)

alarmsItems = []
while response:
    alarmsItems += response['MetricAlarms']
    response = client.describe_alarms(AlarmNamePrefix=prefix, MaxRecords=alarmMaxRecords, NextToken=response['NextToken']) if 'NextToken' in response else None

for alarm in alarmsItems:
    # Do something with the alarm
    print(response['MetricAlarms'])

以上将检索10条记录一次，但可以是任何高达100。

或者更简单地使用boto3提供的boto3方法：

import boto3

# Create CloudWatch client
cloudwatch = boto3.client('cloudwatch')

# List alarms of insufficient data through the pagination interface
paginator = cloudwatch.get_paginator('describe_alarms')
for response in paginator.paginate(AlarmNamePrefix=prefix, MaxRecords=alarmMaxRecords):
    # Do something with the alarm
    print(response['MetricAlarms'])