我将python与boto API一起使用:
- 创建 SNS、SQS 并将 SQS 队列订阅到 SNS。
- 连接到 Cloudwatch,并为"状态检查失败"指标创建警报。
- 使用put_metric_alarm启动警报监控和通知。
我启动了自己的一个 AMI,它将模拟 StatusCheckFailed 条件。如果我转到 AWS console>SQS,我可以看到我收到了警报通知。 我也可以在 AWS 控制台中查看 JSON 格式的内容。
当我使用 python 和 SQS API 时,我可以:
- 查找队列 (
q = sqs.lookup(queue_name)
) - 获取消息 (
msg = q.read()
) - 获取消息正文 (
b = message.get_body_encoded()
) - 或
message.get_body()
结果不可读。
-
例如get_body_encoded
得到一个没有任何分隔符的字符串。TypeNotificationMessageId02a8ce9dc21e55eaaeca83b5258563ffTopicArnarnawssnsuswest21888888879statuscheckalarm17122223479SubjectStatusCheckAlarmbadvmstatusalarminUSWest2MessageAlarmNamebadvmstatusalarmAlarmDescriptionstatuscheckfori50602c5abadvmAWSAccountId11233333333NewStateValueALARMNewStateReasonThresholdCross....`
-
get_body
让你无法阅读编码。
如何获取 JSON 格式的消息正文,例如 AWS 控制台的 SQS 部分中显示的消息正文?
get_body()
的结果返回 JSON 格式的字符串。
重新创建了您的情况,将 SQS 队列订阅到 SNS 主题,然后创建了一个将通知推送到 SNS 主题的警报。然后我触发了一个警报情况并通过 Python 检索结果:
$ python
Python 2.6.9 (unknown, Sep 13 2014, 00:25:11)
[GCC 4.8.2 20140120 (Red Hat 4.8.2-16)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import boto, boto.sqs
>>> from boto.sqs.message import Message
>>> q_conn = boto.sqs.connect_to_region("ap-southeast-2")
>>> q = q_conn.get_queue('bob')
>>> m = q.read(visibility_timeout=15)
>>> m.get_body()
u'{n "Type" : "Notification",n "MessageId" : "adcad528-680b-5b4f-88bd-98432f1bf252",n "TopicArn" : "arn:aws:sns:ap-southeast-2:123412341234:bob-topic",n "Subject" : "ALARM: \"my-alarm-name\" in APAC - Sydney",n "Message" : "{\"AlarmName\":\"my-alarm-name\",\"AlarmDescription\":\"my-alarm-description\",\"AWSAccountId\":\"123412341234\",\"NewStateValue\":\"ALARM\",\"NewStateReason\":\"Threshold Crossed: 1 datapoint (1459.0) was greater than or equal to the threshold (0.0).\",\"StateChangeTime\":\"2015-01-11T00:33:20.013+0000\",\"Region\":\"APAC - Sydney\",\"OldStateValue\":\"INSUFFICIENT_DATA\",\"Trigger\":{\"MetricName\":\"NetworkIn\",\"Namespace\":\"AWS/EC2\",\"Statistic\":\"SUM\",\"Unit\":null,\"Dimensions\":[{\"name\":\"InstanceId\",\"value\":\"i-af41ec91\"}],\"Period\":60,\"EvaluationPeriods\":1,\"ComparisonOperator\":\"GreaterThanOrEqualToThreshold\",\"Threshold\":0.0}}",n "Timestamp" : "2015-01-11T00:33:20.072Z",n "SignatureVersion" : "1",n "Signature" : "(removed)",n "SigningCertURL" : "(removed)",n "UnsubscribeURL" : "https://sns.ap-southeast-2.amazonaws.com/?Action=Unsubscribe&SubscriptionArn=arn:aws:sns:ap-southeast-2:123412341234:bob-topic:9bc1234c-1234-4995-927a-72b752866e5e"n}'
对get_body()
的响应是包含 JSON 的字符串。这可以使用 JSON 库进行解析:
>>> message_string = json.loads(m.get_body())['Message']
>>> message_string
u'{"AlarmName":"my-alarm-name","AlarmDescription":"my-alarm-description","AWSAccountId":"123412341234","NewStateValue":"ALARM","NewStateReason":"Threshold Crossed: 1 datapoint (1459.0) was greater than or equal to the threshold (0.0).","StateChangeTime":"2015-01-11T00:33:20.013+0000","Region":"APAC - Sydney","OldStateValue":"INSUFFICIENT_DATA","Trigger":{"MetricName":"NetworkIn","Namespace":"AWS/EC2","Statistic":"SUM","Unit":null,"Dimensions":[{"name":"InstanceId","value":"i-af41ec91"}],"Period":60,"EvaluationPeriods":1,"ComparisonOperator":"GreaterThanOrEqualToThreshold","Threshold":0.0}}'
>>> message = json.loads(message_string)
>>> message['AlarmName']
u'my-alarm-name'
我在 AWS 论坛上读过类似的文章,它对我有用。
如果您知道消息不会进行 base64 编码,则可以更改从队列中读取消息的代码,以便它不会尝试解码消息,如下所示: sqs = boto.connect_sqs() queue = sqs.get_queue('myqueue') queue.set_message_class(boto.sqs.message.RawMessage)