Creates an alarm which is triggered whenever the percentage of requests with a 4xx response code exceeds the specified threshold.

Hierarchy (view full)

Constructors

Properties

alarmActionArns?: string[]
alarmArn: string

ARN of this alarm

alarmName: string

Name of this alarm.

env: ResourceEnvironment

The environment this resource belongs to. For resources that are created and managed by the CDK (generally, those created by creating new class instances like Role, Bucket, etc.), this is always the same as the environment of the stack they belong to; however, for imported resources (those obtained from static methods like fromRoleArn, fromBucketName, etc.), that might be different than the stack they were imported into.

insufficientDataActionArns?: string[]
metric: IMetric

The metric object this alarm was based on

node: Node

The tree node.

okActionArns?: string[]
physicalName: string

Returns a string-encoded token that resolves to the physical name that should be passed to the CloudFormation resource.

This value will resolve to one of the following:

  • a concrete value (e.g. "my-awesome-bucket")
  • undefined, when a name should be generated by CloudFormation
  • a concrete name generated automatically during synthesis, in cross-environment scenarios.
stack: Stack

The stack in which this resource is defined.

Methods

  • Internal

    Called when this resource is referenced across environments (account/region) to order to request that a physical name will be generated for this resource during synthesis, so the resource can be referenced through its absolute name/arn.

    Returns void

  • Trigger this action if the alarm fires

    Typically SnsAction or AutoScalingAction.

    Parameters

    • Rest...actions: IAlarmAction[]

    Returns void

  • Trigger this action if there is insufficient data to evaluate the alarm

    Typically SnsAction or AutoScalingAction.

    Parameters

    • Rest...actions: IAlarmAction[]

    Returns void

  • Trigger this action if the alarm returns from breaching state into ok state

    Typically SnsAction or AutoScalingAction.

    Parameters

    • Rest...actions: IAlarmAction[]

    Returns void

  • Apply the given removal policy to this resource

    The Removal Policy controls what happens to this resource when it stops being managed by CloudFormation, either because you've removed it from the CDK application or because you've made a change that requires the resource to be replaced.

    The resource can be deleted (RemovalPolicy.DESTROY), or left in your AWS account for data recovery and cleanup later (RemovalPolicy.RETAIN).

    Parameters

    • policy: RemovalPolicy

    Returns void

  • Returns string

  • Returns an environment-sensitive token that should be used for the resource's "ARN" attribute (e.g. bucket.bucketArn).

    Normally, this token will resolve to arnAttr, but if the resource is referenced across environments, arnComponents will be used to synthesize a concrete ARN with the resource's physical name. Make sure to reference this.physicalName in arnComponents.

    Parameters

    • arnAttr: string

      The CFN attribute which resolves to the ARN of the resource. Commonly it will be called "Arn" (e.g. resource.attrArn), but sometimes it's the CFN resource's ref.

    • arnComponents: ArnComponents

      The format of the ARN of this resource. You must reference this.physicalName somewhere within the ARN in order for cross-environment references to work.

    Returns string

  • Returns an environment-sensitive token that should be used for the resource's "name" attribute (e.g. bucket.bucketName).

    Normally, this token will resolve to nameAttr, but if the resource is referenced across environments, it will be resolved to this.physicalName, which will be a concrete name.

    Parameters

    • nameAttr: string

      The CFN attribute which resolves to the resource's name. Commonly this is the resource's ref.

    Returns string

  • AlarmRule indicating ALARM state for Alarm.

    Returns string

  • Turn this alarm into a horizontal annotation

    This is useful if you want to represent an Alarm in a non-AlarmWidget. An AlarmWidget can directly show an alarm, but it can only show a single alarm and no other metrics. Instead, you can convert the alarm to a HorizontalAnnotation and add it as an annotation to another graph.

    This might be useful if:

    • You want to show multiple alarms inside a single graph, for example if you have both a "small margin/long period" alarm as well as a "large margin/short period" alarm.

    • You want to show an Alarm line in a graph with multiple metrics in it.

    Returns HorizontalAnnotation

  • Returns a string representation of this construct.

    Returns string

  • Import an existing CloudWatch alarm provided an ARN

    Parameters

    • scope: Construct

      The parent creating construct (usually this).

    • id: string

      The construct's name

    • alarmArn: string

      Alarm ARN (i.e. arn:aws:cloudwatch:::alarm:Foo)

    Returns IAlarm

  • Import an existing CloudWatch alarm provided an Name.

    Parameters

    • scope: Construct

      The parent creating construct (usually this)

    • id: string

      The construct's name

    • alarmName: string

      Alarm Name

    Returns IAlarm

  • Checks if x is a construct.

    Use this method instead of instanceof to properly detect Construct instances, even when the construct library is symlinked.

    Explanation: in JavaScript, multiple copies of the constructs library on disk are seen as independent, completely different libraries. As a consequence, the class Construct in each copy of the constructs library is seen as a different class, and an instance of one class will not test as instanceof the other class. npm install will not create installations like this, but users may manually symlink construct libraries together or use a monorepo tool: in those cases, multiple copies of the constructs library can be accidentally installed, and instanceof will behave unpredictably. It is safest to avoid using instanceof, and using this type-testing method instead.

    Parameters

    • x: any

      Any object

    Returns x is Construct

    true if x is an object created from a class which extends Construct.

  • Returns true if the construct was created by CDK, and false otherwise

    Parameters

    • construct: IConstruct

    Returns boolean

  • Check whether the given construct is a Resource

    Parameters

    • construct: IConstruct

    Returns construct is Resource