refactor server code for better testing

server/internal/adapter.go

@@ -60,6 +60,7 @@ func getTask(wrk *worker.Worker) http.HandlerFunc {
 			http.Error(writer, "encoding", http.StatusInternalServerError)
 			return
 		}
+		writer.Header().Set("X-Correlation-Id", requestID)
 		writer.Header().Set("Content-Type", "application/json")
 		writer.Header().Set("Content-Length", strconv.Itoa(len(data)))
 		writer.Header().Set("Content-Version", strconv.Itoa(len(info.Attempts)))

server/server.go

@@ -8,10 +8,11 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
-	"sync"
 	"time"
 
 	"gopkg.in/yaml.v2"
+
+	"nano-run/worker"
 )
 
 type Config struct {
@@ -74,58 +75,62 @@ func (cfg Config) SaveFile(file string) error {
 	return ioutil.WriteFile(file, data, 0600)
 }
 
-func (cfg Config) Run(global context.Context) error {
+func (cfg Config) Create(global context.Context) (*Server, error) {
 	units, err := Units(cfg.ConfigDirectory)
 	if err != nil {
-		return err
+		return nil, err
 	}
 	workers, err := Workers(cfg.WorkingDirectory, units)
 	if err != nil {
-		return err
+		return nil, err
 	}
-	defer func() {
+	ctx, cancel := context.WithCancel(global)
-		for _, wrk := range workers {
+	srv := &Server{
-			wrk.Close()
+		Handler: Handler(units, workers),
-		}
+		workers: workers,
-	}()
+		units:   units,
-	handler := Handler(units, workers)
+		done:    make(chan struct{}),
+		cancel:  cancel,
+	}
+	go srv.run(ctx)
+	return srv, nil
+}
+
+func (cfg Config) Run(global context.Context) error {
 
 	ctx, cancel := context.WithCancel(global)
+	defer cancel()
+
+	srv, err := cfg.Create(global)
+	if err != nil {
+		return err
+	}
+	defer srv.Close()
 
 	server := http.Server{
 		Addr:    cfg.Bind,
-		Handler: handler,
+		Handler: srv,
 	}
 
-	var wg sync.WaitGroup
+	done := make(chan struct{})
 
-	wg.Add(1)
 	go func() {
-		defer wg.Done()
 		defer cancel()
 		<-ctx.Done()
 		t, c := context.WithTimeout(context.Background(), cfg.GracefulShutdown)
 		_ = server.Shutdown(t)
 		c()
+		close(done)
 	}()
 
-	wg.Add(1)
-	go func() {
-		defer wg.Done()
-		defer cancel()
-		err := Run(ctx, workers)
-		if err != nil {
-			log.Println("workers stopped:", err)
-		}
-	}()
 	if cfg.TLS.Enable {
 		err = server.ListenAndServeTLS(cfg.TLS.Cert, cfg.TLS.Key)
 	} else {
 		err = server.ListenAndServe()
 	}
 	cancel()
-	wg.Wait()
+	<-done
-	return err
+	return ctx.Err()
 }
 
 func limitRequest(maxSize int64, handler http.Handler) http.Handler {
@@ -142,3 +147,33 @@ func limitRequest(maxSize int64, handler http.Handler) http.Handler {
 		handler.ServeHTTP(writer, request)
 	})
 }
+
+type Server struct {
+	http.Handler
+	workers []*worker.Worker
+	units   []Unit
+	cancel  func()
+	done    chan struct{}
+	err     error
+}
+
+func (srv *Server) Close() {
+	for _, wrk := range srv.workers {
+		wrk.Close()
+	}
+	srv.cancel()
+	<-srv.done
+}
+
+func (srv *Server) Err() error {
+	return srv.err
+}
+
+func (srv *Server) run(ctx context.Context) {
+	err := Run(ctx, srv.workers)
+	if err != nil {
+		log.Println("workers stopped:", err)
+	}
+	srv.err = err
+	close(srv.done)
+}