sidekiq_stats.go

package main

import (
	"context"
	"encoding/json"
	"fmt"
	"github.com/aws/aws-lambda-go/events"
	"github.com/aws/aws-lambda-go/lambda"
	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/config"
	"github.com/aws/aws-sdk-go-v2/service/cloudwatch"
	"github.com/aws/aws-sdk-go-v2/service/cloudwatch/types"
	"github.com/aws/aws-sdk-go-v2/service/ecs"
	"io"
	"net/http"
	"time"
)

type Stats struct {
	Sidekiq Sidekiq
}

type Sidekiq struct {
	Enqueued float64
}

func HandleRequest(ctx context.Context, event *events.CloudWatchEvent) error {
	if event == nil {
		return fmt.Errorf("received nil event")
	}

	cfg, err := config.LoadDefaultConfig(ctx, config.WithRegion("ap-northeast-1"))
	if err != nil {
		return err
	}

	ecsClient := ecs.NewFromConfig(cfg)

	tasks, err := ecsClient.ListTasks(ctx, &ecs.ListTasksInput{
		Cluster:     aws.String("example-cluster"),
		ServiceName: aws.String("example-service"),
	})
	if err != nil {
		return err
	}

	if len(tasks.TaskArns) == 0 {
		return nil
	}

	desc, err := ecsClient.DescribeTasks(ctx, &ecs.DescribeTasksInput{
		Cluster: aws.String("example-cluster"),
		Tasks:   tasks.TaskArns,
	})
	if err != nil {
		return err
	}

	var host string
	for _, attachment := range desc.Tasks[0].Attachments {
		if *attachment.Type == "ElasticNetworkInterface" {
			for _, detail := range attachment.Details {
				if *detail.Name == "privateIPv4Address" {
					host = *detail.Value
				}
			}
		}
	}

	res, err := http.Get(fmt.Sprintf("http://%s/sidekiq/stats", host))
	if err != nil {
		return err
	}

	body, _ := io.ReadAll(res.Body)

	var stats Stats
	err = json.Unmarshal(body, &stats)
	if err != nil {
		return err
	}

	cwClient := cloudwatch.NewFromConfig(cfg)

	metricData := &cloudwatch.PutMetricDataInput{
		Namespace: aws.String("Sidekiq"),
		MetricData: []types.MetricDatum{
			{
				MetricName: aws.String("Stats"),
				Dimensions: []types.Dimension{
					{
						Name:  aws.String("SidekiqStats"),
						Value: aws.String("Enqueued"),
					},
				},
				Timestamp: aws.Time(time.Now()),
				Value:     aws.Float64(stats.Sidekiq.Enqueued),
				Unit:      types.StandardUnitCount,
			},
		},
	}

	_, err = cwClient.PutMetricData(context.TODO(), metricData)
	if err != nil {
		return err
	}

	return nil
}

func main() {
	lambda.Start(HandleRequest)
}