3ybactuk-marketplace-go-service-project/notifier/internal/app/app.go

package app

import (
	"context"
	"fmt"
	"os"

	"route256/notifier/internal/app/controller"
	"route256/notifier/internal/domain/service"
	"route256/notifier/internal/infra/config"
	"route256/notifier/internal/infra/messaging/kafka"

	"github.com/IBM/sarama"
	"github.com/rs/zerolog"
	"github.com/rs/zerolog/log"
)

type App struct {
	config *config.Config

	controller *controller.Controller
}

func NewApp(configPath string) (*App, error) {
	cfg, err := config.LoadConfig(configPath)
	if err != nil {
		return nil, fmt.Errorf("unable to load config: %w", err)
	}

	log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})
	zerolog.SetGlobalLevel(zerolog.InfoLevel)

	if cfg.Service.LogLevel != "" {
		level, logErr := zerolog.ParseLevel(cfg.Service.LogLevel)
		if logErr != nil {
			return nil, fmt.Errorf("unknown log level `%s` provided: %w", cfg.Service.LogLevel, logErr)
		}

		zerolog.SetGlobalLevel(level)
	}

	log.WithLevel(zerolog.GlobalLevel()).Msgf("using logging level=`%s`", zerolog.GlobalLevel().String())

	consumer, err := setupSaramaConsumerGroup([]string{cfg.Kafka.Brokers}, cfg.Kafka.ConsumerGroupID)
	if err != nil {
		return nil, err
	}

	kafkaConsumer, err := kafka.NewStatusConsumer(cfg.Kafka.OrderTopic, consumer)
	if err != nil {
		return nil, fmt.Errorf("NewKafkaStatusConsumer: %w", err)
	}

	notifierService := service.NewNotifierService(kafkaConsumer)
	controller := controller.NewController(notifierService)

	return &App{
		config:     cfg,
		controller: controller,
	}, err
}

func (a *App) Run(ctx context.Context) {
	a.controller.Run(ctx)
}

func (a *App) Shutdown(ctx context.Context) error {
	return a.controller.Stop(ctx)
}

func setupSaramaConsumerGroup(brokers []string, groupID string) (sarama.ConsumerGroup, error) {
	cfg := sarama.NewConfig()
	cfg.Consumer.Group.Rebalance.Strategy = sarama.NewBalanceStrategyRange()
	cfg.Consumer.Offsets.Initial = sarama.OffsetNewest
	cfg.Metadata.AllowAutoTopicCreation = false

	group, err := sarama.NewConsumerGroup(brokers, groupID, cfg)
	if err != nil {
		return nil, fmt.Errorf("sarama.NewConsumerGroup: %w", err)
	}

	return group, nil
}