Open source rightsizer

Co-authored-by: Marco Ippolito <[email protected]>
Co-authored-by: Marty Dill <[email protected]>

Author: 3 people

.dockerignore

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+.git
+.github
+.buildkite
+Dockerfile
+rightsizer

.github/workflows/go.yml

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+name: Go
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: 1.23
+
+      - name: Build
+        run: go build -v ./...
+
+      - name: Test
+        run: go test -v ./...

.github/workflows/ship-latest.yml

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+name: "Publish latest artifacts"
+
+on:
+  push:
+    branches: [main]
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to DockerHub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USER }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Build and push
+        id: docker_build
+        uses: docker/build-push-action@v6
+        with:
+          push: true
+          platforms: linux/amd64,linux/arm64
+          tags: |
+            nextroll/rightsizer:latest
+
+      - name: Image digest
+        run: echo ${{ steps.docker_build.outputs.digest }}

.github/workflows/ship-version.yml

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+name: "Publish versioned artifacts"
+
+on:
+  release:
+    types: ["published"]
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to DockerHub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USER }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Build and push
+        id: docker_build
+        uses: docker/build-push-action@v6
+        with:
+          push: true
+          platforms: linux/amd64,linux/arm64
+          tags: |
+            nextroll/rightsizer:v3
+            nextroll/rightsizer:v3.0
+            nextroll/rightsizer:v3.0.0
+
+      - name: Image digest
+        run: echo ${{ steps.docker_build.outputs.digest }}

.gitignore

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+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# Just in case I go build
+rightsizer
+rightsizer.report.json
+.rightsizer.json

Dockerfile

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+FROM golang:1.23-alpine AS builder
+COPY . /src/github.com/adroll/rightsizer/
+RUN cd /src/github.com/adroll/rightsizer/ && CGO_ENABLED=0 go build -a -ldflags '-extldflags "-static"' .
+
+FROM alpine
+COPY --from=builder /src/github.com/adroll/rightsizer/rightsizer /usr/bin/
+COPY --from=nextroll/ecs-ship:v2.0.0 /usr/bin/ecs-ship /usr/bin/
+CMD [ "rightsizer" ]

LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2025 AdRoll, Inc. and rightsizer contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# rightsizer
+
+`rightsizer` allows you to compute the appropriate size of your ECS services
+based on the average resource usage in a given period of time. You can use the
+output of the program to update your task definitions and keep your services on
+the perfect size.
+
+## Usage
+
+In order to use `rightsizer` you need to be logged in to your `AWS Cli` using
+[aws config files][aws-config] or a credential manager like our own
+[hologram][hologram]. Then you invoque the `rightsizer` command using your
+target **cluster** and **service**:
+
+```sh
+$ rightsizer some-cluster some-service
+containerDefinitions:
+  some-database:
+    cpu: 1
+    memory: 500
+    memoryReservation: 95
+  some-nginx-thing:
+    cpu: 1
+    memory: 500
+    memoryReservation: 95
+  some-language-api:
+    cpu: 1
+    memory: 500
+    memoryReservation: 95
+```
+
+The program will output the suggested configuration for your service based on
+your actual usage. Then you can use this output to patch your service or patch
+your deploy configuration.
+
+## Getting rightsizer
+
+The best way to get `rightsizer` is from dockerhub:
+
+```sh
+docker pull nextroll/rightsizer
+```
+
+Then you can run the container with the following command:
+
+```sh
+docker run --rm nextroll/rightsizer rightsizer some-cluster some-service
+```
+
+## Building rightsizer
+
+If you want to build `rightsizer` from source you can use the following,
+
+```sh
+go build .
+```
+
+This will generate a binary called `rightsizer` that you can use to run the
+program.
+
+## Testing rightsizer
+
+We use [gomock][gomock] to generate mocks for our custom clients. If you update
+or create a new client, you need to regenerate the mocks. You can do this by
+running:
+
+```sh
+go generate ./...
+```
+
+Then you can run the tests with the following command:
+
+```sh
+go test ./...
+```
+
+[aws-config]: https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-files.html "AWS Config"
+[hologram]: https://github.com/AdRoll/hologram "Hologram"
+[gomock]: https://github.com/uber-go/mock "gomock"

clients/cloudwatch.go

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+package clients
+
+//go:generate mockgen -destination=mocks/cloudwatch.go . CloudwatchClient
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/service/cloudwatch"
+	cloudwatchTypes "github.com/aws/aws-sdk-go-v2/service/cloudwatch/types"
+)
+
+type CloudwatchClient interface {
+	// GetAverage returns the average value of a metric over a period of time
+	GetAverage(ctx context.Context, input *GetAverageInput) (*float64, error)
+}
+
+// GetAverageInput is the input for the GetAverage function
+type GetAverageInput struct {
+	// MetricName is the name of the metric to get the average value of
+	MetricName string
+	// ClusterName is the name of the cluster to get the average value of
+	ClusterName string
+	// ServiceName is the name of the service to get the average value of
+	ServiceName string
+	// TimeFrame is the period of time to get the average value over
+	TimeFrame time.Duration
+}
+
+type cloudWatchClient struct {
+	client *cloudwatch.Client
+}
+
+// NewCloudWatchClient returns a new CloudWatchClient
+func NewCloudWatchClient(client *cloudwatch.Client) CloudwatchClient {
+	return &cloudWatchClient{client: client}
+}
+
+func (c *cloudWatchClient) GetAverage(ctx context.Context, input *GetAverageInput) (*float64, error) {
+	now := time.Now()
+	period := int32(input.TimeFrame.Seconds())
+	startTime := now.Add(-input.TimeFrame)
+	getMetricsInput := &cloudwatch.GetMetricStatisticsInput{
+		MetricName: &input.MetricName,
+		Dimensions: []cloudwatchTypes.Dimension{
+			{
+				Name:  aws.String("ClusterName"),
+				Value: &input.ClusterName,
+			},
+			{
+				Name:  aws.String("ServiceName"),
+				Value: &input.ServiceName,
+			},
+		},
+		StartTime: &startTime,
+		EndTime:   &now,
+		Namespace: aws.String("AWS/ECS"),
+		Period:    &period,
+		Statistics: []cloudwatchTypes.Statistic{
+			cloudwatchTypes.StatisticAverage,
+		},
+	}
+	metricsResponse, err := c.client.GetMetricStatistics(ctx, getMetricsInput)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get metrics: %w", err)
+	}
+	if len(metricsResponse.Datapoints) != 1 {
+		return nil, fmt.Errorf("failed to get %s data points from CloudWatch", input.MetricName)
+	}
+	return metricsResponse.Datapoints[0].Average, nil
+}

clients/ecs.go

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+package clients
+
+//go:generate mockgen -destination=mocks/ecs.go . ECSClient
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/aws/aws-sdk-go-v2/service/ecs"
+	ecsTypes "github.com/aws/aws-sdk-go-v2/service/ecs/types"
+)
+
+type ECSClient interface {
+	// GetService returns the service with the given name in the given cluster
+	GetService(ctx context.Context, input *GetServiceInput) (*ecsTypes.Service, error)
+	// GetTaskDefinition returns the task definition with the given name
+	GetTaskDefinition(ctx context.Context, input *GetTaskDefinitionInput) (*ecsTypes.TaskDefinition, error)
+}
+
+// GetServiceInput is the input for GetService
+type GetServiceInput struct {
+	// Cluster is the name of the ECS cluster
+	Cluster string
+	// Service is the name of the ECS service
+	Service string
+}
+
+type GetTaskDefinitionInput struct {
+	// TaskDefinition is the name of the ECS task definition
+	TaskDefinition string
+}
+
+type ecsClient struct {
+	client *ecs.Client
+}
+
+func NewECSClient(client *ecs.Client) ECSClient {
+	return &ecsClient{client: client}
+}
+
+func (c *ecsClient) GetService(ctx context.Context, input *GetServiceInput) (*ecsTypes.Service, error) {
+	output, err := c.client.DescribeServices(ctx, &ecs.DescribeServicesInput{
+		Cluster:  &input.Cluster,
+		Services: []string{input.Service},
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to describe service: %w", err)
+	}
+	if len(output.Services) == 0 {
+		return nil, errors.New("service not found")
+	}
+	return &output.Services[0], nil
+}
+
+func (c *ecsClient) GetTaskDefinition(ctx context.Context, input *GetTaskDefinitionInput) (*ecsTypes.TaskDefinition, error) {
+	output, err := c.client.DescribeTaskDefinition(ctx, &ecs.DescribeTaskDefinitionInput{
+		TaskDefinition: &input.TaskDefinition,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to describe task definition: %w", err)
+	}
+	return output.TaskDefinition, nil
+}