如何使用 aws cdk 将输入转换添加到 CloudWatch 事件规则的目标？

问题描述 投票：0回答：4

创建云监视事件规则后，我尝试向其添加目标，但无法添加输入转换。以前，添加目标具有允许输入转换的道具，但现在不再有。

codeBuildRule.addTarget(new SnsTopic(props.topic));

aws cdk 页面提供了这个解决方案，但我不太明白它说的是什么

您可以使用 eventRule.addTarget(target[, input]) 使用可选的输入转换器添加其他目标。例如，我们可以添加一个 SNS 主题目标，该目标格式化人类可读的提交消息。

aws-cdk
4个回答
19
投票

您应该指定 

message
属性并使用 
RuleTargetInput
静态方法。其中一些方法可以使用 
EventField.fromPath()
 返回的字符串： 

// From a path
codeBuildRule.addTarget(new SnsTopic(props.topic, {
  message: events.RuleTargetInput.fromEventPath('$.detail')
}));

// Custom object
codeBuildRule.addTarget(new SnsTopic(props.topic, {
  message: RuleTargetInput.fromObject({
    foo: EventField.fromPath('$.detail.bar')
  })
}));
8
投票

我在尝试在 CDK 中实现本教程时遇到了同样的问题：教程：设置 CloudWatch Events 规则以接收管道状态更改的电子邮件通知

我发现这也很有帮助：使用 Amazon CloudWatch Events 检测管道状态的变化并做出反应

注意：我无法使用 Pipeline 的类方法 onStateChange() 让它工作。

我最终写了一条规则：

const topic = new Topic(this, 'topic', {topicName: 'codepipeline-notes-failure',
});

const description = `Generated by the CDK for stack: ${this.stackName}`;
new Rule(this, 'failed', {
  description: description,
  eventPattern: {
    detail: {state: ['FAILED'], pipeline: ['notes']},
    detailType: ['CodePipeline Pipeline Execution State Change'],
    source: ['aws.codepipeline'],
  },
  targets: [
    new SnsTopic(topic, {
      message: RuleTargetInput.fromText(
        `The Pipeline '${EventField.fromPath('$.detail.pipeline')}' has ${EventField.fromPath(
          '$.detail.state',
        )}`,
      ),
    }),
  ],
});

实施后，如果您导航到 Amazon EventBridge -> 规则，然后选择规则，然后选择目标，然后单击查看详细信息，您将看到带有输入转换器和输入模板的目标详细信息。

输入变压器： {"InputPathsMap":{"detail-pipeline":"$.detail.pipeline","detail-state":"$.detail.state"},"InputTemplate":"\" 管道“”有 \""}

1
投票

这适用于 CDK Python。 CodeBuild 到 SNS 通知。

sns_topic = sns.Topic(...)
codebuild_project = codebuild.Project(...)
sns_topic.grant_publish(codebuild_project)
codebuild_project.on_build_failed(
            f'rule-on-failed',
            target=events_targets.SnsTopic(
                sns_topic,
                message=events.RuleTargetInput.from_multiline_text(
                    f"""
                    Name: {events.EventField.from_path('$.detail.project-name')} 
                    State: {events.EventField.from_path('$.detail.build-status')}
                    Build: {events.EventField.from_path('$.detail.build-id')}
                    Account: {events.EventField.from_path('$.account')}
                """
                )
            )
        )

感谢 @pruthvi-raj 对上述答案的评论

0
投票

我遇到了同样的问题，试图找出在哪里定义 

inputPath
和 
inputTemplate
。只有一些 CDK 抽象可用于一个输入字段（基于目标对象的 
message
、
event
或 
input
）。事实证明，抽象已经包含了创建 
inputPath
和 
inputTemplate
所需的一切，这只是文档不足的问题。

这个抽象非常简洁，因为当您在 CDK 目标对象中指定 

inputPath
（或 
inputTemplate
、
message
，...）时，它会自动为您创建 
input
和 
event
。对于您使用的每个唯一的 
EventField.fromPath()
，它会为您创建一个 
inputPath
键值对，并在 
inputTemplate
中使用该键。

对于我自己来说，我通过模仿代码中的输入变压器使其变得更清楚：

import * as events from 'aws-cdk-lib/aws-events'
import * as targets from 'aws-cdk-lib/aws-events-targets'
...

const eventInputMapping = {
  account: events.EventField.account,
  region: events.EventField.region,
  alarmName: events.EventField.fromPath('$.detail.alarmName'),
  description: events.EventField.fromPath('$.detail.configuration.description'),
  startTime: events.EventField.fromPath('$.detail.state.timestamp'),
  state: events.EventField.fromPath('$.detail.state.value'),
  metric: events.EventField.fromPath('$.detail.configuration.metrics[0].metricStat.metric.name'),
  clusterName: events.EventField.fromPath('$.detail.configuration.metrics[0].metricStat.metric.dimensions.ClusterName'),
  serviceName: events.EventField.fromPath('$.detail.configuration.metrics[0].metricStat.metric.dimensions.ServiceName'),
}

const eventInputTemplate = {
  title: `Service ${eventInputMapping.serviceName} went into ${eventInputMapping.state} state for ${eventInputMapping.metric} ${eventInputMapping.description}.`,
  text: `The ECS scaling alarm ${eventInputMapping.alarmName} got triggered at ${eventInputMapping.startTime}` +
  ` This impacts the scaling of ECS service ${eventInputMapping.serviceName} in ECS cluster ${eventInputMapping.clusterName}. `,
  source_type_name: 'amazon ecs',
  tags: [
    `account-id:${eventInputMapping.account}`,
    `region:${eventInputMapping.region}`,
    `servicename:${eventInputMapping.serviceName}`,
    `clustername:${eventInputMapping.clusterName}`,
  ],
}

new events.Rule(this, 'DefaultEcsMetricsScalingAlarms', {
  ...
  targets: [new targets.ApiDestination(eventsDestination, {
    event: events.RuleTargetInput.fromObject(eventInputTemplate)
  }),
  ],
})

这将导致以下结果 

inputPath
:

{
  "account": "$.account",
  "detail-alarmName": "$.detail.alarmName",
  "detail-configuration-description": "$.detail.configuration.description",
  "detail-configuration-metrics-0--metricStat-metric-dimensions-ClusterName": "$.detail.configuration.metrics[0].metricStat.metric.dimensions.ClusterName",
  "detail-configuration-metrics-0--metricStat-metric-dimensions-ServiceName": "$.detail.configuration.metrics[0].metricStat.metric.dimensions.ServiceName",
  "detail-configuration-metrics-0--metricStat-metric-name": "$.detail.configuration.metrics[0].metricStat.metric.name",
  "detail-state-timestamp": "$.detail.state.timestamp",
  "detail-state-value": "$.detail.state.value",
  "region": "$.region"
}

和

inputTemplate

{
    "title": "Service <detail-configuration-metrics-0--metricStat-metric-dimensions-ServiceName> went into <detail-state-value> state for <detail-configuration-metrics-0--metricStat-metric-name> <detail-configuration-description>.",
    "text": "The ECS scaling alarm <detail-alarmName> got triggered at <detail-state-timestamp> This impacts the scaling of ECS service <detail-configuration-metrics-0--metricStat-metric-dimensions-ServiceName> in ECS cluster <detail-configuration-metrics-0--metricStat-metric-dimensions-ClusterName>. ",
    "source_type_name": "amazon ecs",
    "tags": [
        "account-id:<account>",
        "region:<region>",
        "service:<detail-configuration-metrics-0--metricStat-metric-dimensions-ServiceName>",
        "cluster:<detail-configuration-metrics-0--metricStat-metric-dimensions-ClusterName>"
    ]
}
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