discovery service

api/discovery/internal/server/internal/config.go

@@ -0,0 +1,47 @@
+package serverimp
+
+import (
+	"os"
+	"strings"
+
+	msg "github.com/tech/sendico/pkg/messaging"
+	"github.com/tech/sendico/pkg/server/grpcapp"
+	"go.uber.org/zap"
+	"gopkg.in/yaml.v3"
+)
+
+const defaultMetricsAddress = ":9405"
+
+type config struct {
+	Runtime   *grpcapp.RuntimeConfig `yaml:"runtime"`
+	Messaging *msg.Config            `yaml:"messaging"`
+	Metrics   *metricsConfig         `yaml:"metrics"`
+}
+
+type metricsConfig struct {
+	Address string `yaml:"address"`
+}
+
+func (i *Imp) loadConfig() (*config, error) {
+	data, err := os.ReadFile(i.file)
+	if err != nil {
+		i.logger.Error("Could not read configuration file", zap.String("config_file", i.file), zap.Error(err))
+		return nil, err
+	}
+
+	cfg := &config{}
+	if err := yaml.Unmarshal(data, cfg); err != nil {
+		i.logger.Error("Failed to parse configuration", zap.Error(err))
+		return nil, err
+	}
+
+	if cfg.Runtime == nil {
+		cfg.Runtime = &grpcapp.RuntimeConfig{ShutdownTimeoutSeconds: 15}
+	}
+
+	if cfg.Metrics != nil && strings.TrimSpace(cfg.Metrics.Address) == "" {
+		cfg.Metrics.Address = defaultMetricsAddress
+	}
+
+	return cfg, nil
+}

api/discovery/internal/server/internal/discovery.go

@@ -0,0 +1,58 @@
+package serverimp
+
+import (
+	"github.com/tech/sendico/discovery/internal/appversion"
+	"github.com/tech/sendico/pkg/discovery"
+	"github.com/tech/sendico/pkg/merrors"
+	msg "github.com/tech/sendico/pkg/messaging"
+	msgproducer "github.com/tech/sendico/pkg/messaging/producer"
+	"github.com/tech/sendico/pkg/mservice"
+	"go.uber.org/zap"
+)
+
+func (i *Imp) startDiscovery(cfg *config) error {
+	if cfg == nil || cfg.Messaging == nil || cfg.Messaging.Driver == "" {
+		return merrors.InvalidArgument("discovery service: messaging configuration is required", "messaging")
+	}
+
+	broker, err := msg.CreateMessagingBroker(i.logger.Named("discovery_bus"), cfg.Messaging)
+	if err != nil {
+		return err
+	}
+	i.logger.Info("Discovery messaging broker ready", zap.String("messaging_driver", string(cfg.Messaging.Driver)))
+	producer := msgproducer.NewProducer(i.logger.Named("discovery_producer"), broker)
+
+	registry := discovery.NewRegistry()
+	svc, err := discovery.NewRegistryService(i.logger, broker, producer, registry, string(mservice.Discovery))
+	if err != nil {
+		return err
+	}
+	svc.Start()
+	i.registrySvc = svc
+
+	announce := discovery.Announcement{
+		Service:    "DISCOVERY",
+		InstanceID: discovery.InstanceID(),
+		Operations: []string{"discovery.lookup"},
+		Version:    appversion.Create().Short(),
+	}
+	i.announcer = discovery.NewAnnouncer(i.logger, producer, string(mservice.Discovery), announce)
+	i.announcer.Start()
+
+	i.logger.Info("Discovery registry service started", zap.String("messaging_driver", string(cfg.Messaging.Driver)))
+	return nil
+}
+
+func (i *Imp) stopDiscovery() {
+	if i == nil {
+		return
+	}
+	if i.announcer != nil {
+		i.announcer.Stop()
+		i.announcer = nil
+	}
+	if i.registrySvc != nil {
+		i.registrySvc.Stop()
+		i.registrySvc = nil
+	}
+}

api/discovery/internal/server/internal/metrics.go

@@ -0,0 +1,85 @@
+package serverimp
+
+import (
+	"context"
+	"errors"
+	"net"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"github.com/tech/sendico/pkg/api/routers"
+	"github.com/tech/sendico/pkg/api/routers/health"
+	"go.uber.org/zap"
+)
+
+func (i *Imp) startMetrics(cfg *metricsConfig) {
+	if i == nil {
+		return
+	}
+	address := ""
+	if cfg != nil {
+		address = strings.TrimSpace(cfg.Address)
+	}
+	if address == "" {
+		i.logger.Info("Metrics endpoint disabled")
+		return
+	}
+
+	listener, err := net.Listen("tcp", address)
+	if err != nil {
+		i.logger.Error("Failed to bind metrics listener", zap.String("address", address), zap.Error(err))
+		return
+	}
+
+	router := chi.NewRouter()
+	router.Handle("/metrics", promhttp.Handler())
+
+	var healthRouter routers.Health
+	if hr, err := routers.NewHealthRouter(i.logger.Named("metrics"), router, ""); err != nil {
+		i.logger.Warn("Failed to initialise health router", zap.Error(err))
+	} else {
+		hr.SetStatus(health.SSStarting)
+		healthRouter = hr
+	}
+
+	i.metricsHealth = healthRouter
+	i.metricsSrv = &http.Server{
+		Addr:              address,
+		Handler:           router,
+		ReadHeaderTimeout: 5 * time.Second,
+	}
+
+	if healthRouter != nil {
+		healthRouter.SetStatus(health.SSRunning)
+	}
+
+	go func() {
+		i.logger.Info("Prometheus endpoint listening", zap.String("address", address))
+		if err := i.metricsSrv.Serve(listener); err != nil && !errors.Is(err, http.ErrServerClosed) {
+			i.logger.Error("Prometheus endpoint stopped unexpectedly", zap.Error(err))
+			if healthRouter != nil {
+				healthRouter.SetStatus(health.SSTerminating)
+			}
+		}
+	}()
+}
+
+func (i *Imp) shutdownMetrics(ctx context.Context) {
+	if i.metricsHealth != nil {
+		i.metricsHealth.SetStatus(health.SSTerminating)
+		i.metricsHealth.Finish()
+		i.metricsHealth = nil
+	}
+	if i.metricsSrv == nil {
+		return
+	}
+	if err := i.metricsSrv.Shutdown(ctx); err != nil && !errors.Is(err, http.ErrServerClosed) {
+		i.logger.Warn("Failed to stop metrics server", zap.Error(err))
+	} else {
+		i.logger.Info("Metrics server stopped")
+	}
+	i.metricsSrv = nil
+}

api/discovery/internal/server/internal/serverimp.go

@@ -0,0 +1,109 @@
+package serverimp
+
+import (
+	"context"
+	"strings"
+	"time"
+
+	"github.com/tech/sendico/pkg/mlogger"
+	"go.uber.org/zap"
+)
+
+func Create(logger mlogger.Logger, file string, debug bool) (*Imp, error) {
+	return &Imp{
+		logger: logger.Named("server"),
+		file:   file,
+		debug:  debug,
+	}, nil
+}
+
+func (i *Imp) Start() error {
+	i.initStopChannels()
+	defer i.closeDone()
+
+	i.logger.Info("Starting discovery service", zap.String("config_file", i.file), zap.Bool("debug", i.debug))
+
+	cfg, err := i.loadConfig()
+	if err != nil {
+		return err
+	}
+	i.config = cfg
+
+	messagingDriver := "none"
+	if cfg.Messaging != nil {
+		messagingDriver = string(cfg.Messaging.Driver)
+	}
+	metricsAddress := ""
+	if cfg.Metrics != nil {
+		metricsAddress = strings.TrimSpace(cfg.Metrics.Address)
+	}
+	if metricsAddress == "" {
+		metricsAddress = "disabled"
+	}
+	i.logger.Info("Discovery config loaded", zap.String("messaging_driver", messagingDriver), zap.String("metrics_address", metricsAddress))
+
+	i.startMetrics(cfg.Metrics)
+
+	if err := i.startDiscovery(cfg); err != nil {
+		i.stopDiscovery()
+		ctx, cancel := context.WithTimeout(context.Background(), i.shutdownTimeout())
+		i.shutdownMetrics(ctx)
+		cancel()
+		return err
+	}
+
+	i.logger.Info("Discovery service ready", zap.String("messaging_driver", messagingDriver))
+
+	<-i.stopCh
+	i.logger.Info("Discovery service stop signal received")
+	return nil
+}
+
+func (i *Imp) Shutdown() {
+	timeout := i.shutdownTimeout()
+	i.logger.Info("Stopping discovery service", zap.Duration("timeout", timeout))
+
+	i.stopDiscovery()
+	i.signalStop()
+
+	if i.doneCh != nil {
+		<-i.doneCh
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	i.shutdownMetrics(ctx)
+	cancel()
+
+	i.logger.Info("Discovery service stopped")
+}
+
+func (i *Imp) initStopChannels() {
+	if i.stopCh == nil {
+		i.stopCh = make(chan struct{})
+	}
+	if i.doneCh == nil {
+		i.doneCh = make(chan struct{})
+	}
+}
+
+func (i *Imp) signalStop() {
+	i.stopOnce.Do(func() {
+		if i.stopCh != nil {
+			close(i.stopCh)
+		}
+	})
+}
+
+func (i *Imp) closeDone() {
+	i.doneOnce.Do(func() {
+		if i.doneCh != nil {
+			close(i.doneCh)
+		}
+	})
+}
+
+func (i *Imp) shutdownTimeout() time.Duration {
+	if i.config != nil && i.config.Runtime != nil {
+		return i.config.Runtime.ShutdownTimeout()
+	}
+	return 15 * time.Second
+}

api/discovery/internal/server/internal/types.go

@@ -0,0 +1,28 @@
+package serverimp
+
+import (
+	"net/http"
+	"sync"
+
+	"github.com/tech/sendico/pkg/api/routers"
+	"github.com/tech/sendico/pkg/discovery"
+	"github.com/tech/sendico/pkg/mlogger"
+)
+
+type Imp struct {
+	logger mlogger.Logger
+	file   string
+	debug  bool
+
+	config      *config
+	registrySvc *discovery.RegistryService
+	announcer   *discovery.Announcer
+
+	metricsSrv    *http.Server
+	metricsHealth routers.Health
+
+	stopOnce sync.Once
+	doneOnce sync.Once
+	stopCh   chan struct{}
+	doneCh   chan struct{}
+}

api/discovery/internal/server/server.go

@@ -0,0 +1,11 @@
+package server
+
+import (
+	serverimp "github.com/tech/sendico/discovery/internal/server/internal"
+	"github.com/tech/sendico/pkg/mlogger"
+	"github.com/tech/sendico/pkg/server"
+)
+
+func Create(logger mlogger.Logger, file string, debug bool) (server.Application, error) {
+	return serverimp.Create(logger, file, debug)
+}