Merge pull request #23 from hoangnd25/disable-autoscaling

Service: expose scaling & allow default rules to be disabled

.changeset/tame-taxis-enjoy.md

@@ -0,0 +1,6 @@
+---
+"sst": patch
+"@sst/docs": patch
+---
+
+Service: allow default rules to be disabled

packages/sst/src/constructs/Service.ts

@@ -65,6 +65,7 @@ import {
   FargateTaskDefinition,
   FargateServiceProps,
   ICluster,
+  ScalableTaskCount,
 } from "aws-cdk-lib/aws-ecs";
 import { LogGroup, LogRetention, RetentionDays } from "aws-cdk-lib/aws-logs";
 import { Platform } from "aws-cdk-lib/aws-ecr-assets";
@@ -284,7 +285,7 @@ export interface ServiceProps {
      */
     maxContainers?: number;
     /**
-     * Scales in or out to achieve a target cpu utilization.
+     * Scales in or out to achieve a target cpu utilization. Set to `false` to disable.
      * @default 70
      * @example
      * ```js
@@ -296,9 +297,9 @@ export interface ServiceProps {
      * }
      *```
      */
-    cpuUtilization?: number;
+    cpuUtilization?: number | false;
     /**
-     * Scales in or out to achieve a target memory utilization.
+     * Scales in or out to achieve a target memory utilization. Set to `false` to disable.
      * @default 70
      * @example
      * ```js
@@ -310,9 +311,9 @@ export interface ServiceProps {
      * }
      *```
      */
-    memoryUtilization?: number;
+    memoryUtilization?: number | false;
     /**
-     * Scales in or out to achieve a target request count per container.
+     * Scales in or out to achieve a target request count per container. Set to `false` to disable.
      * @default 500
      * @example
      * ```js
@@ -323,7 +324,7 @@ export interface ServiceProps {
      * }
      *```
      */
-    requestsPerContainer?: number;
+    requestsPerContainer?: number | false;
   };
   /**
    * Bind resources for the function
@@ -660,6 +661,7 @@ export class Service extends Construct implements SSTConstruct {
   private service?: FargateService;
   private distribution?: Distribution;
   private alb?: ApplicationLoadBalancer;
+  private scaling?: ScalableTaskCount;
 
   constructor(scope: Construct, id: string, props: ServiceProps) {
     super(scope, id);
@@ -695,7 +697,7 @@ export class Service extends Construct implements SSTConstruct {
     const cluster = this.createCluster(vpc);
     const { container, taskDefinition, service } = this.createService(cluster);
     const { alb, target } = this.createLoadBalancer(vpc, service);
-    this.createAutoScaling(service, target);
+    const scaling = this.createAutoScaling(service, target);
     this.alb = alb;
 
     // Create Distribution
@@ -706,6 +708,7 @@ export class Service extends Construct implements SSTConstruct {
     this.service = service;
     this.container = container;
     this.taskDefinition = taskDefinition;
+    this.scaling = scaling;
     this.bindForService(props?.bind || []);
     this.attachPermissionsForService(props?.permissions || []);
     Object.entries(props?.environment || {}).map(([key, value]) =>
@@ -784,6 +787,7 @@ export class Service extends Construct implements SSTConstruct {
       applicationLoadBalancer: this.alb,
       hostedZone: this.distribution?.cdk.hostedZone,
       certificate: this.distribution?.cdk.certificate,
+      scaling: this.scaling,
     };
   }
 
@@ -1098,20 +1102,26 @@ export class Service extends Construct implements SSTConstruct {
       minCapacity: minContainers ?? 1,
       maxCapacity: maxContainers ?? 1,
     });
-    scaling.scaleOnCpuUtilization("CpuScaling", {
-      targetUtilizationPercent: cpuUtilization ?? 70,
-      scaleOutCooldown: CdkDuration.seconds(300),
-    });
-    scaling.scaleOnMemoryUtilization("MemoryScaling", {
-      targetUtilizationPercent: memoryUtilization ?? 70,
-      scaleOutCooldown: CdkDuration.seconds(300),
-    });
-    if (target) {
+    if (cpuUtilization !== false) {
+      scaling.scaleOnCpuUtilization("CpuScaling", {
+        targetUtilizationPercent: cpuUtilization ?? 70,
+        scaleOutCooldown: CdkDuration.seconds(300),
+      });
+    }
+    if (memoryUtilization !== false) {
+      scaling.scaleOnMemoryUtilization("MemoryScaling", {
+        targetUtilizationPercent: memoryUtilization ?? 70,
+        scaleOutCooldown: CdkDuration.seconds(300),
+      });
+    }
+    if (target && requestsPerContainer !== false) {
       scaling.scaleOnRequestCount("RequestScaling", {
         requestsPerTarget: requestsPerContainer ?? 500,
         targetGroup: target,
       });
     }
+
+    return scaling;
   }
 
   private createDistribution(alb?: ApplicationLoadBalancer) {

packages/sst/test/constructs/Service.test.ts

@@ -50,6 +50,7 @@ test("default", async () => {
   expect(service.cdk?.distribution?.distributionDomainName).toBeDefined();
   expect(service.cdk?.applicationLoadBalancer).toBeDefined();
   expect(service.cdk?.certificate).toBeUndefined();
+  expect(service.cdk?.scaling).toBeDefined();
   countResources(stack, "AWS::EC2::VPC", 1);
   hasResource(stack, "AWS::EC2::VPC", {
     CidrBlock: "10.0.0.0/16",
@@ -386,6 +387,20 @@ test("scaling.cpuUtilization defined", async () => {
     }),
   });
 });
+test("scaling.cpuUtilization false", async () => {
+  const { service, stack } = await createService({
+    scaling: {
+      cpuUtilization: false,
+    },
+  });
+  countResourcesLike(stack, "AWS::ApplicationAutoScaling::ScalingPolicy", 0, {
+    TargetTrackingScalingPolicyConfiguration: objectLike({
+      PredefinedMetricSpecification: {
+        PredefinedMetricType: "ECSServiceAverageCPUUtilization",
+      },
+    }),
+  });
+});
 
 test("scaling.memoryUtilization undefined", async () => {
   const { service, stack } = await createService();
@@ -413,6 +428,20 @@ test("scaling.memoryUtilization defined", async () => {
     }),
   });
 });
+test("scaling.memoryUtilization false", async () => {
+  const { service, stack } = await createService({
+    scaling: {
+      memoryUtilization: false,
+    },
+  });
+  countResourcesLike(stack, "AWS::ApplicationAutoScaling::ScalingPolicy", 0, {
+    TargetTrackingScalingPolicyConfiguration: objectLike({
+      PredefinedMetricSpecification: {
+        PredefinedMetricType: "ECSServiceAverageMemoryUtilization",
+      },
+    }),
+  });
+});
 
 test("scaling.requestsPerContainer undefined", async () => {
   const { service, stack } = await createService();
@@ -440,6 +469,20 @@ test("scaling.requestsPerContainer defined", async () => {
     }),
   });
 });
+test("scaling.requestsPerContainer false", async () => {
+  const { service, stack } = await createService({
+    scaling: {
+      requestsPerContainer: false,
+    },
+  });
+  countResourcesLike(stack, "AWS::ApplicationAutoScaling::ScalingPolicy", 0, {
+    TargetTrackingScalingPolicyConfiguration: objectLike({
+      PredefinedMetricSpecification: objectLike({
+        PredefinedMetricType: "ALBRequestCountPerTarget",
+      }),
+    }),
+  });
+});
 
 test("bind", async () => {
   const { stack } = await createService((stack) => {
@@ -581,6 +624,7 @@ test("cdk.cloudfrontDistribution is false", async () => {
   expect(service.cdk?.fargateService).toBeDefined();
   expect(service.cdk?.taskDefinition).toBeDefined();
   expect(service.cdk?.distribution).toBeUndefined();
+  expect(service.cdk?.scaling).toBeDefined();
 });
 test("cdk.cloudfrontDistribution is props", async () => {
   const { stack, service } = await createService({
@@ -615,6 +659,7 @@ test("cdk.applicationLoadBalancer is false", async () => {
   expect(service.cdk?.taskDefinition).toBeDefined();
   expect(service.cdk?.distribution).toBeUndefined();
   expect(service.cdk?.applicationLoadBalancer).toBeUndefined();
+  expect(service.cdk?.scaling).toBeDefined();
 });
 test("cdk.applicationLoadBalancer is props", async () => {
   const { stack, service } = await createService({

www/docs/constructs/Service.about.md

@@ -328,6 +328,33 @@ new Service(stack, "MyService", {
 
 ### Advanced examples
 
+#### Configuring Custom Scaling
+
+Here's an example of disabling the default scaling rules.
+
+```js
+const service = new Service(stack, "MyService", {
+  scaling: {
+    minContainers: 4,
+    maxContainers: 16,
+    cpuUtilization: false, // disable default rules
+    memoryUtilization: false,
+    requestsPerContainer: false,
+  }
+});
+```
+
+And add a custom rule to start the service at 9am Monday to Friday
+
+```js
+import { Schedule } from "aws-cdk-lib/aws-applicationautoscaling";
+
+service.cdk?.scaling.scaleOnSchedule("StartOnSchedule", {
+  schedule: Schedule.expression(`cron(0 9 ? * MON-FRI *)`),
+  minCapacity: 1,
+});
+```
+
 #### Configuring Fargate Service
 
 Here's an example of configuring the circuit breaker for the Fargate service.

www/generate.mjs

@@ -79,6 +79,7 @@ const CDK_DOCS_MAP = {
   HttpLambdaResponseType: "aws_apigatewayv2_authorizers",
   HttpUserPoolAuthorizer: "aws_apigatewayv2_authorizers",
   WebSocketLambdaAuthorizer: "aws_apigatewayv2_authorizers",
+  ScalableTaskCount: "aws_ecs",
   ServerlessCluster: "aws_rds",
   IServerlessCluster: "aws_rds",
   Role: "aws_iam",