feat(aws-cloudwatch): CompositeAlarm

Author: SeekerWing

packages/@aws-cdk/aws-cloudwatch/README.md

@@ -183,9 +183,9 @@ can be created from existing Alarm resources.
 const alarmRule = AlarmRule.anyOf(
   AlarmRule.allOf(
     AlarmRule.anyOf(
-      AlarmRule.fromAlarm(alarm1, AlarmState.ALARM),
+      alarm1,
       AlarmRule.fromAlarm(alarm2, AlarmState.OK),
-      AlarmRule.fromAlarm(alarm3, AlarmState.ALARM),
+      alarm3,
     ),
     AlarmRule.not(AlarmRule.fromAlarm(alarm4, AlarmState.INSUFFICIENT_DATA)),
   ),

packages/@aws-cdk/aws-cloudwatch/lib/alarm-action.ts

@@ -1,5 +1,5 @@
 import { Construct } from '@aws-cdk/core';
-import { IAlarm } from './alarm';
+import { IAlarm } from './alarm-base';
 
 /**
  * Interface for objects that can be the targets of CloudWatch alarm actions

packages/@aws-cdk/aws-cloudwatch/lib/alarm.ts

@@ -1,5 +1,5 @@
-import { Construct, IResource, Lazy, Resource, Stack, Token } from '@aws-cdk/core';
-import { IAlarmAction } from './alarm-action';
+import { Construct, Lazy, Stack, Token } from '@aws-cdk/core';
+import { AlarmBase, IAlarm } from './alarm-base';
 import { CfnAlarm, CfnAlarmProps } from './cloudwatch.generated';
 import { HorizontalAnnotation } from './graph';
 import { CreateAlarmOptions } from './metric';
@@ -9,37 +9,6 @@ import { dropUndefined } from './private/object';
 import { MetricSet } from './private/rendering';
 import { parseStatistic } from './private/statistic';
 
-/**
- * Interface for Alarm Rule.
- */
-export interface IAlarmRule {
-
-  /**
-   * serialized representation of Alarm Rule to be used when building the Composite Alarm resource.
-   */
-  toAlarmRule(): string;
-
-}
-
-/**
- * Represents a CloudWatch Alarm
- */
-export interface IAlarm extends IAlarmRule, IResource {
-  /**
-   * Alarm ARN (i.e. arn:aws:cloudwatch:<region>:<account-id>:alarm:Foo)
-   *
-   * @attribute
-   */
-  readonly alarmArn: string;
-
-  /**
-   * Name of the alarm
-   *
-   * @attribute
-   */
-  readonly alarmName: string;
-}
-
 /**
  * Properties for Alarms
  */
@@ -51,14 +20,6 @@ export interface AlarmProps extends CreateAlarmOptions {
    * custom Metric objects by instantiating one.
    */
   readonly metric: IMetric;
-
-  /**
-   * AlarmState to build composite alarm expressions.
-   *
-   * @default - ALARM
-   */
-  readonly alarmState?: AlarmState;
-
 }
 
 /**
@@ -124,86 +85,6 @@ export enum TreatMissingData {
   MISSING = 'missing'
 }
 
-/**
- * Enumeration indicates state of Alarm used in building Alarm Rule.
- */
-export enum AlarmState {
-
-  /**
-   * State indicates resource is in ALARM
-   */
-  ALARM = 'ALARM',
-
-  /**
-   * State indicates resource is not in ALARM
-   */
-  OK = 'OK',
-
-  /**
-   * State indicates there is not enough data to determine is resource is in ALARM
-   */
-  INSUFFICIENT_DATA = 'INSUFFICIENT_DATA',
-
-}
-
-/**
- * The base class for Alarm and CompositeAlarm resources.
- */
-export abstract class AlarmBase extends Resource implements IAlarm {
-
-  /**
-   * @attribute
-   */
-  public abstract readonly alarmArn: string;
-  public abstract readonly alarmName: string;
-
-  protected alarmActionArns?: string[];
-  protected insufficientDataActionArns?: string[];
-  protected okActionArns?: string[];
-
-  public abstract toAlarmRule(): string;
-
-  /**
-   * Trigger this action if the alarm fires
-   *
-   * Typically the ARN of an SNS topic or ARN of an AutoScaling policy.
-   */
-  public addAlarmAction(...actions: IAlarmAction[]) {
-    if (this.alarmActionArns === undefined) {
-      this.alarmActionArns = [];
-    }
-
-    this.alarmActionArns.push(...actions.map(a => a.bind(this, this).alarmActionArn));
-  }
-
-  /**
-   * Trigger this action if there is insufficient data to evaluate the alarm
-   *
-   * Typically the ARN of an SNS topic or ARN of an AutoScaling policy.
-   */
-  public addInsufficientDataAction(...actions: IAlarmAction[]) {
-    if (this.insufficientDataActionArns === undefined) {
-      this.insufficientDataActionArns = [];
-    }
-
-    this.insufficientDataActionArns.push(...actions.map(a => a.bind(this, this).alarmActionArn));
-  }
-
-  /**
-   * Trigger this action if the alarm returns from breaching state into ok state
-   *
-   * Typically the ARN of an SNS topic or ARN of an AutoScaling policy.
-   */
-  public addOkAction(...actions: IAlarmAction[]) {
-    if (this.okActionArns === undefined) {
-      this.okActionArns = [];
-    }
-
-    this.okActionArns.push(...actions.map(a => a.bind(this, this).alarmActionArn));
-  }
-
-}
-
 /**
  * An alarm on a CloudWatch metric
  */
@@ -217,13 +98,9 @@ export class Alarm extends AlarmBase {
    * @param alarmArn Alarm ARN (i.e. arn:aws:cloudwatch:<region>:<account-id>:alarm:Foo)
    */
   public static fromAlarmArn(scope: Construct, id: string, alarmArn: string): IAlarm {
-    class Import extends Resource implements IAlarm {
+    class Import extends AlarmBase implements IAlarm {
       public readonly alarmArn = alarmArn;
       public readonly alarmName = Stack.of(scope).parseArn(alarmArn, ':').resourceName!;
-
-      public toAlarmRule(): string {
-        throw new Error('Method not implemented.');
-      }
     }
     return new Import(scope, id);
   }
@@ -252,8 +129,6 @@ export class Alarm extends AlarmBase {
    */
   private readonly annotation: HorizontalAnnotation;
 
-  private readonly alarmState: AlarmState;
-
   constructor(scope: Construct, id: string, props: AlarmProps) {
     super(scope, id, {
       physicalName: props.alarmName,
@@ -314,7 +189,6 @@ export class Alarm extends AlarmBase {
       label: `${this.metric} ${OPERATOR_SYMBOLS[comparisonOperator]} ${props.threshold} for ${datapoints} datapoints within ${describePeriod(props.evaluationPeriods * metricPeriod(props.metric).toSeconds())}`,
       value: props.threshold,
     };
-    this.alarmState = props.alarmState || AlarmState.ALARM;
   }
 
   /**
@@ -337,10 +211,6 @@ export class Alarm extends AlarmBase {
     return this.annotation;
   }
 
-  public toAlarmRule(): string {
-    return `${this.alarmState}(${this.alarmArn})`;
-  }
-
   private renderMetric(metric: IMetric) {
     const self = this;
     return dispatchMetric(metric, {

packages/@aws-cdk/aws-cloudwatch/lib/composite-alarm.ts

@@ -1,111 +1,7 @@
-import { Construct, Lazy, Resource, Stack } from '@aws-cdk/core';
-import { AlarmBase, AlarmState, IAlarm, IAlarmRule } from './alarm';
+import { Construct, Lazy, Stack } from '@aws-cdk/core';
+import { AlarmBase, IAlarm, IAlarmRule } from './alarm-base';
 import { CfnCompositeAlarm } from './cloudwatch.generated';
 
-/**
- * Enumeration of supported Composite Alarms operators.
- */
-enum Operator {
-
-  AND = 'AND',
-  OR = 'OR',
-  NOT = 'NOT',
-
-}
-
-/**
- * Class with static functions to build AlarmRule for Composite Alarms.
- */
-export class AlarmRule {
-
-  /**
-   * function to join all provided AlarmRules with AND operator.
-   *
-   * @param operands IAlarmRules to be joined with AND operator.
-   */
-  public static allOf(...operands: IAlarmRule[]): IAlarmRule {
-    return this.concat(Operator.AND, ...operands);
-  }
-
-  /**
-   * function to join all provided AlarmRules with OR operator.
-   *
-   * @param operands IAlarmRules to be joined with OR operator.
-   */
-  public static anyOf(...operands: IAlarmRule[]): IAlarmRule {
-    return this.concat(Operator.OR, ...operands);
-  }
-
-  /**
-   * function to wrap provided AlarmRule in NOT operator.
-   *
-   * @param operand IAlarmRule to be wrapped in NOT operator.
-   */
-  public static not(operand: IAlarmRule): IAlarmRule {
-    // tslint:disable-next-line:new-parens
-    return new class implements IAlarmRule {
-      public toAlarmRule(): string {
-        return `(NOT ${operand.toAlarmRule()})`;
-      }
-    };
-  }
-
-  /**
-   * function to build TRUE/FALSE intent for Rule Expression.
-   *
-   * @param value boolean value to be used in rule expression.
-   */
-  public static fromBoolean(value: boolean): IAlarmRule {
-    // tslint:disable-next-line:new-parens
-    return new class implements IAlarmRule {
-      public toAlarmRule(): string {
-        return `${String(value).toUpperCase()}`;
-      }
-    };
-  }
-
-  /**
-   * function to build Rule Expression for given IAlarm and AlarmState.
-   *
-   * @param alarm IAlarm to be used in Rule Expression.
-   * @param alarmState AlarmState to be used in Rule Expression.
-   */
-  public static fromAlarm(alarm: IAlarm, alarmState: AlarmState): IAlarmRule {
-    // tslint:disable-next-line:new-parens
-    return new class implements IAlarmRule {
-      public toAlarmRule(): string {
-        return `${alarmState}(${alarm.alarmArn})`;
-      }
-    };
-  }
-
-  /**
-   * function to build Rule Expression for given Alarm Rule string.
-   *
-   * @param alarmRule string to be used in Rule Expression.
-   */
-  public static fromString(alarmRule: string): IAlarmRule {
-    // tslint:disable-next-line:new-parens
-    return new class implements IAlarmRule {
-      public toAlarmRule(): string {
-        return alarmRule;
-      }
-    };
-  }
-
-  private static concat(operator: Operator, ...operands: IAlarmRule[]): IAlarmRule {
-    // tslint:disable-next-line:new-parens
-    return new class implements IAlarmRule {
-      public toAlarmRule(): string {
-        return operands
-          .map(operand => `(${operand.toAlarmRule()})`)
-          .join(` ${operator} `);
-      }
-    };
-  }
-
-}
-
 /**
  * Properties for creating a Composite Alarm
  */
@@ -169,13 +65,9 @@ export class CompositeAlarm extends AlarmBase {
    * @param compositeAlarmArn Composite Alarm ARN (i.e. arn:aws:cloudwatch:<region>:<account-id>:alarm/CompositeAlarmName)
    */
   public static fromCompositeAlarmArn(scope: Construct, id: string, compositeAlarmArn: string): IAlarm {
-    class Import extends Resource implements IAlarm {
+    class Import extends AlarmBase implements IAlarm {
       public readonly alarmArn = compositeAlarmArn;
       public readonly alarmName = Stack.of(scope).parseArn(compositeAlarmArn).resourceName!;
-
-      public toAlarmRule(): string {
-        throw new Error('Method not implemented.');
-      }
     }
     return new Import(scope, id);
   }
@@ -201,11 +93,11 @@ export class CompositeAlarm extends AlarmBase {
       physicalName: props.compositeAlarmName ?? Lazy.stringValue({ produce: () => this.generateUniqueId() }),
     });
 
-    if (props.alarmRule.toAlarmRule().length > 10240) {
+    if (props.alarmRule.renderAlarmRule().length > 10240) {
       throw new Error('Alarm Rule expression cannot be greater than 10240 characters, please reduce the conditions in the Alarm Rule');
     }
 
-    this.alarmRule = props.alarmRule.toAlarmRule();
+    this.alarmRule = props.alarmRule.renderAlarmRule();
 
     const alarm = new CfnCompositeAlarm(this, 'Resource', {
       alarmName: this.physicalName,
@@ -226,10 +118,6 @@ export class CompositeAlarm extends AlarmBase {
 
   }
 
-  public toAlarmRule(): string {
-    return this.alarmRule;
-  }
-
   private generateUniqueId(): string {
     const name = this.node.uniqueId;
     if (name.length > 240) {

packages/@aws-cdk/aws-cloudwatch/lib/graph.ts

@@ -1,5 +1,5 @@
 import * as cdk from '@aws-cdk/core';
-import { IAlarm } from './alarm';
+import { IAlarm } from './alarm-base';
 import { IMetric } from './metric-types';
 import { allMetricsGraphJson } from './private/rendering';
 import { ConcreteWidget } from './widget';

packages/@aws-cdk/aws-cloudwatch/lib/index.ts

@@ -1,5 +1,7 @@
 export * from './alarm';
 export * from './alarm-action';
+export * from './alarm-base';
+export * from './alarm-rule';
 export * from './composite-alarm';
 export * from './dashboard';
 export * from './graph';