natstonotify/main.go

package main

import (
	"context"
	"encoding/json"
	"fmt"
	"log"
	"log/slog"
	"os"
	"os/signal"

	"git.t-juice.club/torjus/natstonotify/bus"
	"git.t-juice.club/torjus/natstonotify/server"
	"github.com/nats-io/nats.go"
	"github.com/nats-io/nkeys"
	"github.com/urfave/cli/v3"
)

const Version = "v0.1.0"

func connectNats() (*nats.Conn, error) {
	natsURL, ok := os.LookupEnv("NATS_URL")
	if !ok {
		return nil, fmt.Errorf("NATS_URL not set")
	}
	nkey, ok := os.LookupEnv("NATS_NKEY")
	if !ok {
		return nil, fmt.Errorf("NATS_NKEY not set")
	}

	kp, err := nkeys.FromSeed([]byte(nkey))
	if err != nil {
		return nil, err
	}

	pub, err := kp.PublicKey()
	if err != nil {
		return nil, err
	}

	opt := nats.Nkey(pub, kp.Sign)

	nc, err := nats.Connect(natsURL, opt)
	if err != nil {
		return nil, err
	}
	return nc, nil
}

func main() {
	// Setup logging
	logger := slog.New(slog.NewJSONHandler(os.Stderr, &slog.HandlerOptions{
		Level: slog.LevelDebug,
	}))

	slog.SetDefault(logger)

	cmd := &cli.Command{
		EnableShellCompletion: true,
		Usage:                 "NATS-powered notification service",
		Commands: []*cli.Command{
			{
				Name:                  "server",
				Usage:                 "Start the server",
				EnableShellCompletion: true,
				Action: func(ctx context.Context, cmd *cli.Command) error {
					b, err := bus.NewNotifyBus()
					if err != nil {
						fmt.Println("Error creating notification bus: ", err)
						return cli.Exit(err, 1)
					}

					info, err := b.ServerInfo()
					if err != nil {
						return cli.Exit(err, 1)
					}

					logger.Info("Connected to notification bus", "bus_name", info.Name, "bus_version", info.Version)

					defer b.Close()

					nc, err := connectNats()
					if err != nil {
						logger.Error("Error connecting to NATS", "error", err)
						return cli.Exit(err, 1)
					}
					srv, err := server.New(nc, b)
					if err != nil {
						return cli.Exit(err, 1)
					}

					go func() {
						<-ctx.Done()
						srv.Close()
					}()

					slog.Info("Server started", "version", Version)
					if err := srv.Start(); err != nil {
						slog.Info("Server exited with error", "error", err)
						return cli.Exit(err, 2)
					}

					slog.Info("Server stopped")

					return nil
				},
			},
			{
				Name:                  "notify",
				Aliases:               []string{"n"},
				Usage:                 "Send a notification",
				ArgsUsage:             "SUMMARY [BODY]",
				EnableShellCompletion: true,
				Flags: []cli.Flag{
					&cli.BoolFlag{
						Name:  "local",
						Usage: "Send a local notification",
					},
				},
				Action: func(ctx context.Context, cmd *cli.Command) error {
					if cmd.NArg() < 1 {
						return cli.Exit("notify requires exactly one argument", 1)
					}
					summary := cmd.Args().Get(0)
					body := cmd.Args().Get(1)

					bn := bus.BusNotification{
						Summary: summary,
						Body:    body,
					}

					local := cmd.Bool("local")
					if local {
						b, err := bus.NewNotifyBus()
						if err != nil {
							fmt.Println("Error creating notification bus: ", err)
							return cli.Exit(err, 1)
						}
						defer b.Close()

						_, err = b.Notify(bn)
						if err != nil {
							fmt.Println("Sending message: ", err)
							return cli.Exit(err, 1)
						}
					} else {
						nc, err := connectNats()
						if err != nil {
							fmt.Printf("Error connecting to NATS: %s\n", err)
							return cli.Exit(err, 1)
						}
						defer nc.Drain() //nolint: errcheck

						data, err := json.Marshal(bn)
						if err != nil {
							return cli.Exit(err, 1)
						}

						if err := nc.PublishMsg(&nats.Msg{
							Subject: server.DefaultSubject,
							Data:    data,
						}); err != nil {
							fmt.Printf("Error sending message: %s\n", err)
						}
						nc.Flush()
						fmt.Printf("Published message to %s: %s", server.DefaultSubject, data)
					}
					return nil
				},
			},
		},
	}

	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
	defer cancel()

	if err := cmd.Run(ctx, os.Args); err != nil {
		log.Fatal(err)
	}
}