Organize backend into product executable and shared Go modules

backend/product/app/server/internal/server.go

@@ -0,0 +1,177 @@
+package server
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"os"
+	"time"
+
+	ac "git.sendico.io/tech/sxchnge/product/app/api"
+	sharedruntime "git.sendico.io/tech/sxchnge/product/app/runtime"
+	"git.sendico.io/tech/sxchnge/shared/database"
+	mduration "git.sendico.io/tech/sxchnge/shared/duration"
+	"git.sendico.io/tech/sxchnge/shared/errors"
+	"git.sendico.io/tech/sxchnge/shared/logging"
+	"git.sendico.io/tech/sxchnge/shared/service"
+	"github.com/go-chi/chi/v5"
+	"go.uber.org/zap"
+	"gopkg.in/yaml.v3"
+)
+
+type httpServerConf struct {
+	ListenAddress     string `yaml:"listen_address"`
+	ReadHeaderTimeout int    `yaml:"read_header_timeout"`
+	ShutdownTimeout   int    `yaml:"shutdown_timeout"`
+}
+
+// Config represents the server configuration
+type Config struct {
+	API        ac.ConfigProvider
+	DB         *db.Config      `yaml:"database"`
+	HTTPServer *httpServerConf `yaml:"http_server"`
+}
+
+// Instance represents an instance of the server
+type Imp struct {
+	lifecycleCtx    context.Context
+	lifecycleCancel context.CancelFunc
+	logger          mlogger.Logger
+	api             mservice.MicroService
+	config          *Config
+	db              db.Factory
+	httpServer      *http.Server
+	runtime         ac.RuntimeConfig
+	debug           bool
+	file            string
+}
+
+// Shutdown stops the server
+func (i *Imp) Shutdown() {
+	if i.lifecycleCancel != nil {
+		i.lifecycleCancel()
+	}
+	if i.httpServer == nil {
+		return
+	}
+
+	// Shutdown HTTP server
+	ctx, cancel := context.WithTimeout(context.Background(), mduration.Param2Duration(i.config.HTTPServer.ShutdownTimeout, time.Second))
+	i.logger.Info("Shutting HTTP server down...")
+	if err := i.httpServer.Shutdown(ctx); err != nil {
+		if !errors.Is(err, http.ErrServerClosed) {
+			i.logger.Warn("Failed to shutdown HTTP server gracefully", zap.Error(err))
+			cancel()
+			os.Exit(1)
+		}
+	}
+	cancel()
+}
+
+func (i *Imp) Run() error {
+	err := i.httpServer.ListenAndServe()
+	if errors.Is(err, http.ErrServerClosed) {
+		err = nil
+	}
+	i.logger.Info("HTTP Server stopped")
+
+	if err := i.api.Finish(context.Background()); err != nil {
+		i.logger.Warn("Error when finishing service", zap.Error(err))
+	}
+
+	i.db.CloseConnection()
+
+	if err != nil {
+		return merrors.OpaqueWrap(merrors.ErrInternal, err, "HTTP server stopped unexpectedly")
+	}
+	return nil
+}
+
+// Start starts the server
+func (i *Imp) Start() error {
+	if i.lifecycleCancel != nil {
+		defer i.lifecycleCancel()
+	}
+	i.logger.Info("Starting...", zap.String("config_file", i.file), zap.Bool("debug_mode", i.debug))
+	// Load configuration file
+	data, err := os.ReadFile(i.file)
+	if err != nil {
+		i.logger.Error("Could not load configuration", zap.Error(err), zap.String("config_file", i.file))
+		return err
+	}
+
+	if err = i.decodeConfig(data); err != nil {
+		i.logger.Error("Failed to parse configuration", zap.Error(err))
+		return err
+	}
+
+	if i.db, err = db.NewConnection(i.logger, i.config.DB); err != nil {
+		i.logger.Error("Could not open database connection", zap.Error(err))
+		return err
+	}
+
+	rootRouter := chi.NewRouter()
+	apiRouter := chi.NewRouter()
+	if i.api, err = sharedruntime.CreateAPI(i.lifecycleCtx, i.logger, i.config.API.SharedConfig(), i.config.API, i.db, rootRouter, apiRouter, i.debug, i.runtime); err != nil {
+		i.db.CloseConnection()
+		return err
+	}
+	rootRouter.Mount("/", apiRouter)
+
+	// Startup the HTTP Server in a way that we can gracefully shut it down again
+	i.httpServer = &http.Server{
+		Addr:              i.config.HTTPServer.ListenAddress,
+		Handler:           rootRouter,
+		ReadHeaderTimeout: mduration.Param2Duration(i.config.HTTPServer.ReadHeaderTimeout, time.Second),
+	}
+
+	return i.Run()
+}
+
+func (i *Imp) decodeConfig(data []byte) error {
+	var raw struct {
+		API        yaml.Node       `yaml:"api"`
+		DB         *db.Config      `yaml:"database"`
+		HTTPServer *httpServerConf `yaml:"http_server"`
+	}
+	if err := yaml.Unmarshal(data, &raw); err != nil {
+		return err
+	}
+
+	apiConfig := i.runtime.NewConfig()
+	if apiConfig == nil {
+		return merrors.Internal("runtime config factory returned nil api config")
+	}
+	if raw.API.Kind == 0 {
+		return merrors.InvalidArgument("api configuration is required", "api")
+	}
+	if err := raw.API.Decode(apiConfig); err != nil {
+		return err
+	}
+
+	if raw.DB == nil || raw.HTTPServer == nil || apiConfig.SharedConfig() == nil || apiConfig.SharedConfig().Mw == nil {
+		return merrors.InvalidArgument("database, http_server and api.middleware configuration are required")
+	}
+	if raw.HTTPServer.ListenAddress == "" || raw.HTTPServer.ReadHeaderTimeout <= 0 || raw.HTTPServer.ShutdownTimeout <= 0 {
+		return merrors.InvalidArgument("HTTP address and positive timeouts are required")
+	}
+	i.config = &Config{
+		API:        apiConfig,
+		DB:         raw.DB,
+		HTTPServer: raw.HTTPServer,
+	}
+	return nil
+}
+
+func Create(logger mlogger.Logger, file string, debug bool, runtime ac.RuntimeConfig) (*Imp, error) {
+	lifecycleCtx, lifecycleCancel := context.WithCancel(context.Background())
+	srv := &Imp{
+		lifecycleCtx:    lifecycleCtx,
+		lifecycleCancel: lifecycleCancel,
+		logger:          logger,
+		debug:           debug,
+		file:            file,
+		runtime:         runtime,
+	}
+	return srv, nil
+}