feat: rds-scheduler

src/cron.ts

@@ -0,0 +1,82 @@
+/**
+ * Options to configure a cron expression
+ *
+ * All fields are strings so you can use complex expressions. Absence of
+ * a field implies '*' or '?', whichever one is appropriate.
+ *
+ * @see https://docs.aws.amazon.com/eventbridge/latest/userguide/scheduled-events.html#cron-expressions
+ */
+export interface CronOptions {
+  /**
+     * The minute to run this rule at
+     *
+     * @default - Every minute
+     */
+  readonly minute?: string;
+
+  /**
+     * The hour to run this rule at
+     *
+     * @default - Every hour
+     */
+  readonly hour?: string;
+
+  /**
+     * The day of the month to run this rule at
+     *
+     * @default - Every day of the month
+     */
+  readonly day?: string;
+
+  /**
+     * The month to run this rule at
+     *
+     * @default - Every month
+     */
+  readonly month?: string;
+
+  /**
+     * The year to run this rule at
+     *
+     * @default - Every year
+     */
+  readonly year?: string;
+
+  /**
+     * The day of the week to run this rule at
+     *
+     * @default - Any day of the week
+     */
+  readonly weekDay?: string;
+}
+
+export class Cron {
+  private readonly minute: string;
+  private readonly hour: string;
+  private readonly day: string;
+  private readonly month: string;
+  private readonly weekDay: string;
+  private readonly year: string;
+
+  /**
+     * Create a cron expression
+     */
+  constructor(options: CronOptions) {
+    // TODO - validate that the expression is valid
+    // @see https://docs.aws.amazon.com/scheduler/latest/UserGuide/schedule-types.html?icmpid=docs_console_unmapped#cron-based
+
+    this.minute = options.minute ?? '*';
+    this.hour = options.hour ?? '*';
+    this.day = options.day ?? '*';
+    this.month = options.month ?? '*';
+    this.year = options.year ?? '*';
+    this.weekDay = options.weekDay ?? '?';
+  }
+
+  /**
+     * Return the cron expression
+     */
+  public toString() {
+    return `cron(${this.minute} ${this.hour} ${this.day} ${this.month} ${this.weekDay} ${this.year})`;
+  }
+}

src/index.ts

@@ -1,5 +1,2 @@
-export class Hello {
-  public sayHello() {
-    return 'hello, world!';
-  }
-}
+export * from './rds-scheduler';
+export * from './cron';

src/rds-scheduler.ts

@@ -0,0 +1,145 @@
+import { Stack, TimeZone } from 'aws-cdk-lib';
+import * as iam from 'aws-cdk-lib/aws-iam';
+import * as rds from 'aws-cdk-lib/aws-rds';
+import * as scheduler from 'aws-cdk-lib/aws-scheduler';
+import { Construct } from 'constructs';
+import { Cron } from './cron';
+
+export interface Schedule {
+  /**
+   * The start schedule
+   *
+   * @default - no start schedule. The RDS instance or cluster will not be started automatically.
+   */
+  readonly start?: Cron;
+  /**
+   * The stop schedule
+   *
+   * @default - no stop schedule. The RDS instance or cluster will not be stopped automatically.
+   */
+  readonly stop?: Cron;
+  /**
+   * The timezone for the cron expression
+   *
+   * @default UTC
+   */
+  readonly timezone?: TimeZone;
+}
+
+/**
+ * Properties for the RdsScheduler
+ */
+export interface RdsSchedulerProps {
+  /**
+   * The RDS cluster to start and stop.
+   * If you specify a cluster, you cannot specify an instance.
+   *
+   * @default - no cluster is specified and you must specify an instance
+   */
+  readonly cluster?: rds.IDatabaseCluster;
+  /**
+   * The RDS instance to start and stop.
+   * If you specify an instance, you cannot specify a cluster.
+   *
+   * @default - no instance is specified and you must specify a cluster
+   */
+  readonly instance?: rds.IDatabaseInstance;
+  /**
+   * The schedule for starting and stopping the RDS instance or cluster
+   */
+  readonly schedule: Schedule[];
+}
+
+/**
+ * A scheduler for RDS instances or clusters
+ */
+export class RdsScheduler extends Construct {
+  constructor (scope: Construct, id: string, props: RdsSchedulerProps) {
+    super(scope, id);
+
+    if (props.cluster && props.instance) {
+      throw new Error('You can only specify either a cluster or an instance, not both.');
+    }
+    if (!props.cluster && !props.instance) {
+      throw new Error('You must specify either a cluster or an instance.');
+    }
+    if (props.schedule.length === 0) {
+      throw new Error('You must specify at least one schedule.');
+    }
+    const isCluster = !!props.cluster;
+
+    const identifier = isCluster ? props.cluster!.clusterIdentifier : props.instance!.instanceIdentifier;
+    const schedulerRole = new iam.Role(this, 'SchedulerRole', {
+      assumedBy: new iam.ServicePrincipal('scheduler.amazonaws.com'),
+      inlinePolicies: {
+        SchedulerPolicy: new iam.PolicyDocument({
+          statements: [
+            new iam.PolicyStatement({
+              effect: iam.Effect.ALLOW,
+              actions: isCluster ? ['rds:StartDBCluster', 'rds:StopDBCluster'] : ['rds:StartDBInstance', 'rds:StopDBInstance'],
+              resources: [
+                Stack.of(this).formatArn({
+                  service: 'rds',
+                  resource: isCluster ? 'cluster' : 'db',
+                  resourceName: identifier,
+                }),
+              ],
+            }),
+          ],
+        }),
+      },
+    });
+
+    props.schedule.forEach((schedule, index) => {
+      if (schedule.start) {
+        new scheduler.CfnSchedule(this, `StartSchedule${index}`, {
+          flexibleTimeWindow: {
+            mode: 'OFF',
+          },
+          scheduleExpression: schedule.start.toString(),
+          scheduleExpressionTimezone: schedule.timezone?.timezoneName ?? TimeZone.ETC_UTC.timezoneName,
+          target: {
+            arn: Stack.of(this).formatArn({
+              service: 'scheduler',
+              resource: 'aws-sdk:rds',
+              resourceName: isCluster ? 'startDBCluster' : 'startDBInstance',
+            }),
+            roleArn: schedulerRole.roleArn,
+            input: JSON.stringify({
+              ...(isCluster ? {
+                DBClusterIdentifier: identifier,
+              } : {
+                DBInstanceIdentifier: identifier,
+              }),
+            }),
+          },
+        });
+      }
+
+      if (schedule.stop) {
+        new scheduler.CfnSchedule(this, `StopSchedule${index}`, {
+          flexibleTimeWindow: {
+            mode: 'OFF',
+          },
+          scheduleExpression: schedule.stop.toString(),
+          scheduleExpressionTimezone: schedule.timezone?.timezoneName ?? TimeZone.ETC_UTC.timezoneName,
+          target: {
+            arn: Stack.of(this).formatArn({
+              service: 'scheduler',
+              resource: 'aws-sdk:rds',
+              resourceName: isCluster ? 'stopDBCluster' : 'stopDBInstance',
+            }),
+            roleArn: schedulerRole.roleArn,
+            input: JSON.stringify({
+              ...(isCluster ? {
+                DBClusterIdentifier: identifier,
+              } : {
+                DBInstanceIdentifier: identifier,
+              }),
+            }),
+          },
+        });
+      }
+    });
+  }
+}