From a2761a95af2a154702a7fd0b719221cf091ca5a7 Mon Sep 17 00:00:00 2001
From: Roman Dmytrenko <rdmytrenko@gmail.com>
Date: Mon, 30 Sep 2024 23:22:13 +0300
Subject: [PATCH 1/3] Check all errors in tests

---
 .../server/request_buffer_middleware_test.go  |  3 +-
 .../server/response_buffer_middleware_test.go |  3 +-
 internal/server/router_test.go                |  9 ++--
 internal/server/service_test.go               |  9 ++--
 internal/server/target_test.go                | 43 ++++++++++++-------
 internal/server/testing.go                    | 43 +++++++++----------
 6 files changed, 65 insertions(+), 45 deletions(-)

diff --git a/internal/server/request_buffer_middleware_test.go b/internal/server/request_buffer_middleware_test.go
index 07c2bde..f51b726 100644
--- a/internal/server/request_buffer_middleware_test.go
+++ b/internal/server/request_buffer_middleware_test.go
@@ -12,7 +12,8 @@ import (
 func TestRequestBufferMiddleware(t *testing.T) {
 	sendRequest := func(requestBody, responseBody string) *httptest.ResponseRecorder {
 		middleware := WithRequestBufferMiddleware(4, 8, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			w.Write([]byte(responseBody))
+			_, err := w.Write([]byte(responseBody))
+			assert.NoError(t, err)
 		}))
 
 		req := httptest.NewRequest("POST", "http://app.example.com/somepath", strings.NewReader(requestBody))
diff --git a/internal/server/response_buffer_middleware_test.go b/internal/server/response_buffer_middleware_test.go
index 179e5e2..de415fb 100644
--- a/internal/server/response_buffer_middleware_test.go
+++ b/internal/server/response_buffer_middleware_test.go
@@ -12,7 +12,8 @@ import (
 func TestResponseBufferMiddleware(t *testing.T) {
 	sendRequest := func(requestBody, responseBody string) *httptest.ResponseRecorder {
 		middleware := WithResponseBufferMiddleware(4, 8, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			w.Write([]byte(responseBody))
+			_, err := w.Write([]byte(responseBody))
+			assert.NoError(t, err)
 		}))
 
 		req := httptest.NewRequest("POST", "http://app.example.com/somepath", strings.NewReader(requestBody))
diff --git a/internal/server/router_test.go b/internal/server/router_test.go
index 00b3dff..2450f46 100644
--- a/internal/server/router_test.go
+++ b/internal/server/router_test.go
@@ -203,7 +203,8 @@ func TestRouter_UpdatingPauseStateIndependentlyOfDeployments(t *testing.T) {
 	_, target := testBackend(t, "first", http.StatusOK)
 
 	require.NoError(t, router.SetServiceTarget("service1", []string{"dummy.example.com"}, target, defaultServiceOptions, defaultTargetOptions, DefaultDeployTimeout, DefaultDrainTimeout))
-	router.PauseService("service1", time.Second, time.Millisecond*10)
+	err := router.PauseService("service1", time.Second, time.Millisecond*10)
+	require.NoError(t, err)
 
 	statusCode, _ := sendRequest(router, httptest.NewRequest(http.MethodPost, "http://dummy.example.com", strings.NewReader("Something longer than 10")))
 	assert.Equal(t, http.StatusGatewayTimeout, statusCode)
@@ -213,7 +214,8 @@ func TestRouter_UpdatingPauseStateIndependentlyOfDeployments(t *testing.T) {
 	statusCode, _ = sendRequest(router, httptest.NewRequest(http.MethodPost, "http://dummy.example.com", strings.NewReader("Something longer than 10")))
 	assert.Equal(t, http.StatusGatewayTimeout, statusCode)
 
-	router.ResumeService("service1")
+	err = router.ResumeService("service1")
+	require.NoError(t, err)
 
 	statusCode, _ = sendRequest(router, httptest.NewRequest(http.MethodPost, "http://dummy.example.com", strings.NewReader("Something longer than 10")))
 	assert.Equal(t, http.StatusOK, statusCode)
@@ -369,7 +371,8 @@ func TestRouter_RestoreLastSavedState(t *testing.T) {
 	assert.Equal(t, http.StatusMovedPermanently, statusCode)
 
 	router = NewRouter(statePath)
-	router.RestoreLastSavedState()
+	err := router.RestoreLastSavedState()
+	require.NoError(t, err)
 
 	statusCode, body = sendGETRequest(router, "http://something.example.com")
 	assert.Equal(t, http.StatusOK, statusCode)
diff --git a/internal/server/service_test.go b/internal/server/service_test.go
index 2e10b0f..95c8e23 100644
--- a/internal/server/service_test.go
+++ b/internal/server/service_test.go
@@ -90,15 +90,18 @@ func TestService_ReturnSuccessfulHealthCheckWhilePausedOrStopped(t *testing.T) {
 	assert.Equal(t, http.StatusOK, checkRequest("/up"))
 	assert.Equal(t, http.StatusOK, checkRequest("/other"))
 
-	service.Pause(time.Second, time.Millisecond)
+	err := service.Pause(time.Second, time.Millisecond)
+	assert.NoError(t, err)
 	assert.Equal(t, http.StatusOK, checkRequest("/up"))
 	assert.Equal(t, http.StatusGatewayTimeout, checkRequest("/other"))
 
-	service.Stop(time.Second, DefaultStopMessage)
+	err = service.Stop(time.Second, DefaultStopMessage)
+	assert.NoError(t, err)
 	assert.Equal(t, http.StatusOK, checkRequest("/up"))
 	assert.Equal(t, http.StatusServiceUnavailable, checkRequest("/other"))
 
-	service.Resume()
+	err = service.Resume()
+	assert.NoError(t, err)
 	assert.Equal(t, http.StatusOK, checkRequest("/up"))
 	assert.Equal(t, http.StatusOK, checkRequest("/other"))
 }
diff --git a/internal/server/target_test.go b/internal/server/target_test.go
index c0d4e94..8c350fa 100644
--- a/internal/server/target_test.go
+++ b/internal/server/target_test.go
@@ -19,7 +19,8 @@ import (
 
 func TestTarget_Serve(t *testing.T) {
 	target := testTarget(t, func(w http.ResponseWriter, r *http.Request) {
-		w.Write([]byte("ok"))
+		_, err := w.Write([]byte("ok"))
+		assert.NoError(t, err)
 	})
 
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
@@ -105,11 +106,13 @@ func TestTarget_ServeWebSocket(t *testing.T) {
 
 			go func() {
 				kind, body, err := c.Read(context.Background())
-				require.NoError(t, err)
+				assert.NoError(t, err)
 				assert.Equal(t, websocket.MessageText, kind)
 
-				c.Write(context.Background(), websocket.MessageText, body)
-				defer c.CloseNow()
+				err = c.Write(context.Background(), websocket.MessageText, body)
+				assert.NoError(t, err)
+				err = c.CloseNow()
+				assert.NoError(t, err)
 			}()
 		})
 
@@ -124,9 +127,12 @@ func TestTarget_ServeWebSocket(t *testing.T) {
 
 		c, _, err := websocket.Dial(context.Background(), websocketURL, nil)
 		require.NoError(t, err)
-		defer c.CloseNow()
+		defer func() {
+			assert.NoError(t, c.CloseNow())
+		}()
 
-		c.Write(context.Background(), websocket.MessageText, []byte(body))
+		err = c.Write(context.Background(), websocket.MessageText, []byte(body))
+		require.NoError(t, err)
 
 		return c.Read(context.Background())
 	}
@@ -271,7 +277,8 @@ func TestTarget_IsHealthCheckRequest(t *testing.T) {
 
 func TestTarget_AddedTargetBecomesHealthy(t *testing.T) {
 	target := testTarget(t, func(w http.ResponseWriter, r *http.Request) {
-		w.Write([]byte("ok"))
+		_, err := w.Write([]byte("ok"))
+		assert.NoError(t, err)
 	})
 
 	target.BeginHealthChecks()
@@ -351,25 +358,30 @@ func TestTarget_DrainRequestsThatNeedToBeCancelled(t *testing.T) {
 func TestTarget_DrainHijackedConnectionsImmediately(t *testing.T) {
 	target := testTarget(t, func(w http.ResponseWriter, r *http.Request) {
 		c, err := websocket.Accept(w, r, &websocket.AcceptOptions{})
-		require.NoError(t, err)
-		defer c.CloseNow()
-
+		assert.NoError(t, err)
 		_, _, err = c.Read(context.Background())
-		require.Error(t, err)
+		assert.Error(t, err)
+		err = c.CloseNow()
+		// TODO: this check works strange if set to NoError.
+		// if it runs isolated it works, but if it runs with all, it fails.
+		assert.Error(t, err)
 	})
 
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		r, err := target.StartRequest(r)
-		require.NoError(t, err)
+		assert.NoError(t, err)
 		target.SendRequest(w, r)
 	}))
-	defer server.Close()
+
+	t.Cleanup(server.Close)
 
 	websocketURL := strings.Replace(server.URL, "http:", "ws:", 1)
 
 	c, _, err := websocket.Dial(context.Background(), websocketURL, nil)
 	require.NoError(t, err)
-	defer c.CloseNow()
+	defer func() {
+		assert.NoError(t, c.CloseNow())
+	}()
 
 	startedDraining := time.Now()
 	target.Drain(time.Second * 5)
@@ -387,7 +399,8 @@ func TestTarget_EnforceMaxBodySizes(t *testing.T) {
 			HealthCheckConfig:   defaultHealthCheckConfig,
 		}
 		target := testTargetWithOptions(t, targetOptions, func(w http.ResponseWriter, r *http.Request) {
-			w.Write([]byte(responseBody))
+			_, err := w.Write([]byte(responseBody))
+			assert.NoError(t, err)
 		})
 
 		req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(requestBody))
diff --git a/internal/server/testing.go b/internal/server/testing.go
index de5c88b..c09588c 100644
--- a/internal/server/testing.go
+++ b/internal/server/testing.go
@@ -5,10 +5,9 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"net/url"
-	"os"
 	"testing"
 
-	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
@@ -19,7 +18,9 @@ var (
 	defaultTargetOptions     = TargetOptions{HealthCheckConfig: defaultHealthCheckConfig, ResponseTimeout: DefaultTargetTimeout}
 )
 
-func testTarget(t *testing.T, handler http.HandlerFunc) *Target {
+func testTarget(t testing.TB, handler http.HandlerFunc) *Target {
+	t.Helper()
+
 	_, targetURL := testBackendWithHandler(t, handler)
 
 	target, err := NewTarget(targetURL, defaultTargetOptions)
@@ -27,7 +28,9 @@ func testTarget(t *testing.T, handler http.HandlerFunc) *Target {
 	return target
 }
 
-func testTargetWithOptions(t *testing.T, targetOptions TargetOptions, handler http.HandlerFunc) *Target {
+func testTargetWithOptions(t testing.TB, targetOptions TargetOptions, handler http.HandlerFunc) *Target {
+	t.Helper()
+
 	_, targetURL := testBackendWithHandler(t, handler)
 
 	target, err := NewTarget(targetURL, targetOptions)
@@ -35,14 +38,19 @@ func testTargetWithOptions(t *testing.T, targetOptions TargetOptions, handler ht
 	return target
 }
 
-func testBackend(t *testing.T, body string, statusCode int) (*httptest.Server, string) {
+func testBackend(t testing.TB, body string, statusCode int) (*httptest.Server, string) {
+	t.Helper()
+
 	return testBackendWithHandler(t, func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(statusCode)
-		w.Write([]byte(body))
+		_, err := w.Write([]byte(body))
+		assert.NoError(t, err)
 	})
 }
 
-func testBackendWithHandler(t *testing.T, handler http.HandlerFunc) (*httptest.Server, string) {
+func testBackendWithHandler(t testing.TB, handler http.HandlerFunc) (*httptest.Server, string) {
+	t.Helper()
+
 	server := httptest.NewServer(handler)
 	t.Cleanup(server.Close)
 
@@ -52,31 +60,22 @@ func testBackendWithHandler(t *testing.T, handler http.HandlerFunc) (*httptest.S
 	return server, serverURL.Host
 }
 
-func testServer(t *testing.T) (*Server, string) {
+func testServer(t testing.TB) (*Server, string) {
+	t.Helper()
+
 	config := &Config{
 		Bind:               "127.0.0.1",
 		HttpPort:           0,
 		HttpsPort:          0,
-		AlternateConfigDir: shortTmpDir(t),
+		AlternateConfigDir: t.TempDir(),
 	}
 	router := NewRouter(config.StatePath())
 	server := NewServer(config, router)
-	server.Start()
-
+	err := server.Start()
+	require.NoError(t, err)
 	t.Cleanup(server.Stop)
 
 	addr := fmt.Sprintf("http://localhost:%d", server.HttpPort())
 
 	return server, addr
 }
-
-func shortTmpDir(t *testing.T) string {
-	path := "/tmp/" + uuid.New().String()
-	os.Mkdir(path, 0755)
-
-	t.Cleanup(func() {
-		os.RemoveAll(path)
-	})
-
-	return path
-}

From 06f0917b4ae2dfd59edd653cec7e7ea97f66e171 Mon Sep 17 00:00:00 2001
From: Roman Dmytrenko <rdmytrenko@gmail.com>
Date: Tue, 1 Oct 2024 14:02:30 +0300
Subject: [PATCH 2/3] Handle errors in main code

---
 internal/cmd/deploy.go              |  1 +
 internal/cmd/rollout_deploy.go      |  1 +
 internal/cmd/run.go                 |  7 ++-
 internal/server/buffer.go           | 20 ++++++---
 internal/server/commands.go         |  5 ++-
 internal/server/pause_controller.go |  6 +--
 internal/server/router.go           | 68 +++++++++++++++++------------
 internal/server/server.go           | 21 +++++++--
 internal/server/service.go          | 16 +++++--
 internal/server/target_test.go      |  3 +-
 10 files changed, 100 insertions(+), 48 deletions(-)

diff --git a/internal/cmd/deploy.go b/internal/cmd/deploy.go
index 82ae5c4..ff8e6a4 100644
--- a/internal/cmd/deploy.go
+++ b/internal/cmd/deploy.go
@@ -54,6 +54,7 @@ func newDeployCommand() *deployCommand {
 
 	deployCommand.cmd.Flags().BoolVar(&deployCommand.args.TargetOptions.ForwardHeaders, "forward-headers", false, "Forward X-Forwarded headers to target (default false if TLS enabled; otherwise true)")
 
+	//nolint:errcheck
 	deployCommand.cmd.MarkFlagRequired("target")
 	deployCommand.cmd.MarkFlagsRequiredTogether("tls-certificate-path", "tls-private-key-path")
 
diff --git a/internal/cmd/rollout_deploy.go b/internal/cmd/rollout_deploy.go
index 54d5021..a68ece0 100644
--- a/internal/cmd/rollout_deploy.go
+++ b/internal/cmd/rollout_deploy.go
@@ -26,6 +26,7 @@ func newRolloutDeployCommand() *rolloutDeployCommand {
 	rolloutDeployCommand.cmd.Flags().DurationVar(&rolloutDeployCommand.args.DeployTimeout, "deploy-timeout", server.DefaultDeployTimeout, "Maximum time to wait for the new target to become healthy")
 	rolloutDeployCommand.cmd.Flags().DurationVar(&rolloutDeployCommand.args.DrainTimeout, "drain-timeout", server.DefaultDrainTimeout, "Maximum time to allow existing connections to drain before removing old target")
 
+	//nolint:errcheck
 	rolloutDeployCommand.cmd.MarkFlagRequired("target")
 
 	return rolloutDeployCommand
diff --git a/internal/cmd/run.go b/internal/cmd/run.go
index 900b76f..a0e3f18 100644
--- a/internal/cmd/run.go
+++ b/internal/cmd/run.go
@@ -35,10 +35,13 @@ func (c *runCommand) run(cmd *cobra.Command, args []string) error {
 	c.setLogger()
 
 	router := server.NewRouter(globalConfig.StatePath())
-	router.RestoreLastSavedState()
+	err := router.RestoreLastSavedState()
+	if err != nil {
+		return err
+	}
 
 	s := server.NewServer(&globalConfig, router)
-	err := s.Start()
+	err = s.Start()
 	if err != nil {
 		return err
 	}
diff --git a/internal/server/buffer.go b/internal/server/buffer.go
index fd05f0e..3713603 100644
--- a/internal/server/buffer.go
+++ b/internal/server/buffer.go
@@ -86,7 +86,10 @@ func (b *Buffer) Write(p []byte) (int, error) {
 }
 
 func (b *Buffer) Read(p []byte) (n int, err error) {
-	b.setReader()
+	err = b.setReader()
+	if err != nil {
+		return 0, err
+	}
 	return b.reader.Read(p)
 }
 
@@ -95,8 +98,11 @@ func (b *Buffer) Overflowed() bool {
 }
 
 func (b *Buffer) Send(w io.Writer) error {
-	b.setReader()
-	_, err := io.Copy(w, b.reader)
+	err := b.setReader()
+	if err != nil {
+		return err
+	}
+	_, err = io.Copy(w, b.reader)
 	return err
 }
 
@@ -120,15 +126,19 @@ func (b *Buffer) writeToDisk(p []byte) (int, error) {
 	return n, err
 }
 
-func (b *Buffer) setReader() {
+func (b *Buffer) setReader() error {
 	if b.reader == nil {
 		if b.diskBuffer != nil {
-			b.diskBuffer.Seek(0, 0)
+			_, err := b.diskBuffer.Seek(0, 0)
+			if err != nil {
+				return err
+			}
 			b.reader = io.MultiReader(&b.memoryBuffer, b.diskBuffer)
 		} else {
 			b.reader = &b.memoryBuffer
 		}
 	}
+	return nil
 }
 
 func (b *Buffer) createSpill() error {
diff --git a/internal/server/commands.go b/internal/server/commands.go
index 8d34420..8997fea 100644
--- a/internal/server/commands.go
+++ b/internal/server/commands.go
@@ -134,9 +134,10 @@ func (h *CommandHandler) Remove(args RemoveArgs, reply *bool) error {
 }
 
 func (h *CommandHandler) List(args bool, reply *ListResponse) error {
-	reply.Targets = h.router.ListActiveServices()
+	var err error
+	reply.Targets, err = h.router.ListActiveServices()
 
-	return nil
+	return err
 }
 
 func (h *CommandHandler) RolloutDeploy(args RolloutDeployArgs, reply *bool) error {
diff --git a/internal/server/pause_controller.go b/internal/server/pause_controller.go
index 78be849..e36d9af 100644
--- a/internal/server/pause_controller.go
+++ b/internal/server/pause_controller.go
@@ -57,11 +57,11 @@ func (p *PauseController) UnmarshalJSON(data []byte) error {
 
 	switch p.State {
 	case PauseStateRunning:
-		p.Resume()
+		return p.Resume()
 	case PauseStatePaused:
-		p.Pause(p.FailAfter)
+		return p.Pause(p.FailAfter)
 	case PauseStateStopped:
-		p.Stop(p.StopMessage)
+		return p.Stop(p.StopMessage)
 	}
 
 	return nil
diff --git a/internal/server/router.go b/internal/server/router.go
index 9cad182..971452e 100644
--- a/internal/server/router.go
+++ b/internal/server/router.go
@@ -97,7 +97,7 @@ func (r *Router) RestoreLastSavedState() error {
 		return err
 	}
 
-	r.withWriteLock(func() error {
+	err = r.withWriteLock(func() error {
 		r.services = ServiceMap{}
 		for _, service := range services {
 			r.services[service.name] = service
@@ -106,6 +106,9 @@ func (r *Router) RestoreLastSavedState() error {
 		r.hostServices = r.services.HostServices()
 		return nil
 	})
+	if err != nil {
+		return err
+	}
 
 	slog.Info("Restored saved state", "path", r.statePath)
 	return nil
@@ -125,8 +128,6 @@ func (r *Router) SetServiceTarget(name string, hosts []string, targetURL string,
 	options ServiceOptions, targetOptions TargetOptions,
 	deployTimeout time.Duration, drainTimeout time.Duration,
 ) error {
-	defer r.saveStateSnapshot()
-
 	slog.Info("Deploying", "service", name, "hosts", hosts, "target", targetURL, "tls", options.TLSEnabled)
 
 	target, err := NewTarget(targetURL, targetOptions)
@@ -146,12 +147,10 @@ func (r *Router) SetServiceTarget(name string, hosts []string, targetURL string,
 	}
 
 	slog.Info("Deployed", "service", name, "hosts", hosts, "target", targetURL)
-	return nil
+	return r.saveStateSnapshot()
 }
 
 func (r *Router) SetRolloutTarget(name string, targetURL string, deployTimeout time.Duration, drainTimeout time.Duration) error {
-	defer r.saveStateSnapshot()
-
 	slog.Info("Deploying for rollout", "service", name, "target", targetURL)
 
 	service := r.serviceForName(name)
@@ -174,34 +173,36 @@ func (r *Router) SetRolloutTarget(name string, targetURL string, deployTimeout t
 	service.SetTarget(TargetSlotRollout, target, drainTimeout)
 
 	slog.Info("Deployed for rollout", "service", name, "target", targetURL)
-	return nil
+	return r.saveStateSnapshot()
 }
 
 func (r *Router) SetRolloutSplit(name string, percent int, allowList []string) error {
-	defer r.saveStateSnapshot()
-
 	service := r.serviceForName(name)
 	if service == nil {
 		return ErrorServiceNotFound
 	}
 
-	return service.SetRolloutSplit(percent, allowList)
+	err := service.SetRolloutSplit(percent, allowList)
+	if err != nil {
+		return err
+	}
+	return r.saveStateSnapshot()
 }
 
 func (r *Router) StopRollout(name string) error {
-	defer r.saveStateSnapshot()
-
 	service := r.serviceForName(name)
 	if service == nil {
 		return ErrorServiceNotFound
 	}
 
-	return service.StopRollout()
+	err := service.StopRollout()
+	if err != nil {
+		return err
+	}
+	return r.saveStateSnapshot()
 }
 
 func (r *Router) RemoveService(name string) error {
-	defer r.saveStateSnapshot()
-
 	err := r.withWriteLock(func() error {
 		service := r.services[name]
 		if service == nil {
@@ -218,46 +219,52 @@ func (r *Router) RemoveService(name string) error {
 		return err
 	}
 
-	return nil
+	return r.saveStateSnapshot()
 }
 
 func (r *Router) PauseService(name string, drainTimeout time.Duration, pauseTimeout time.Duration) error {
-	defer r.saveStateSnapshot()
-
 	service := r.serviceForName(name)
 	if service == nil {
 		return ErrorServiceNotFound
 	}
 
-	return service.Pause(drainTimeout, pauseTimeout)
+	err := service.Pause(drainTimeout, pauseTimeout)
+	if err != nil {
+		return err
+	}
+	return r.saveStateSnapshot()
 }
 
 func (r *Router) StopService(name string, drainTimeout time.Duration, message string) error {
-	defer r.saveStateSnapshot()
-
 	service := r.serviceForName(name)
 	if service == nil {
 		return ErrorServiceNotFound
 	}
 
-	return service.Stop(drainTimeout, message)
+	err := service.Stop(drainTimeout, message)
+	if err != nil {
+		return err
+	}
+	return r.saveStateSnapshot()
 }
 
 func (r *Router) ResumeService(name string) error {
-	defer r.saveStateSnapshot()
-
 	service := r.serviceForName(name)
 	if service == nil {
 		return ErrorServiceNotFound
 	}
 
-	return service.Resume()
+	err := service.Resume()
+	if err != nil {
+		return err
+	}
+	return r.saveStateSnapshot()
 }
 
-func (r *Router) ListActiveServices() ServiceDescriptionMap {
+func (r *Router) ListActiveServices() (ServiceDescriptionMap, error) {
 	result := ServiceDescriptionMap{}
 
-	r.withReadLock(func() error {
+	err := r.withReadLock(func() error {
 		for name, service := range r.services {
 			host := strings.Join(service.hosts, ",")
 			if host == "" {
@@ -275,7 +282,7 @@ func (r *Router) ListActiveServices() ServiceDescriptionMap {
 		return nil
 	})
 
-	return result
+	return result, err
 }
 
 func (r *Router) GetCertificate(hello *tls.ClientHelloInfo) (*tls.Certificate, error) {
@@ -303,12 +310,15 @@ func (r *Router) GetCertificate(hello *tls.ClientHelloInfo) (*tls.Certificate, e
 
 func (r *Router) saveStateSnapshot() error {
 	services := []*Service{}
-	r.withReadLock(func() error {
+	err := r.withReadLock(func() error {
 		for _, service := range r.services {
 			services = append(services, service)
 		}
 		return nil
 	})
+	if err != nil {
+		return err
+	}
 
 	f, err := os.Create(r.statePath)
 	if err != nil {
diff --git a/internal/server/server.go b/internal/server/server.go
index bcd31f9..c54e42d 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -3,6 +3,7 @@ package server
 import (
 	"context"
 	"crypto/tls"
+	"errors"
 	"fmt"
 	"log/slog"
 	"net"
@@ -58,7 +59,10 @@ func (s *Server) Stop() {
 	defer cancel()
 
 	s.commandHandler.Close()
-	s.httpServer.Shutdown(ctx)
+	err := s.httpServer.Shutdown(ctx)
+	if err != nil {
+		slog.Warn("Server shutdown error exit", "error", err)
+	}
 
 	slog.Info("Server stopped")
 }
@@ -103,8 +107,19 @@ func (s *Server) startHTTPServers() error {
 		},
 	}
 
-	go s.httpServer.Serve(s.httpListener)
-	go s.httpsServer.ServeTLS(s.httpsListener, "", "")
+	go func() {
+		err := s.httpServer.Serve(s.httpListener)
+		if !errors.Is(err, http.ErrServerClosed) {
+			slog.Error("Error while serving http endpoint", "error", err)
+		}
+	}()
+
+	go func() {
+		err := s.httpsServer.ServeTLS(s.httpsListener, "", "")
+		if !errors.Is(err, http.ErrServerClosed) {
+			slog.Error("Error while serving https endpoint", "error", err)
+		}
+	}()
 
 	return nil
 }
diff --git a/internal/server/service.go b/internal/server/service.go
index 1c4203c..6eca888 100644
--- a/internal/server/service.go
+++ b/internal/server/service.go
@@ -235,9 +235,19 @@ func (s *Service) UnmarshalJSON(data []byte) error {
 	s.pauseController = ms.PauseController
 	s.rolloutController = ms.RolloutController
 
-	s.initialize(ms.Hosts, ms.Options)
-	s.restoreSavedTarget(TargetSlotActive, ms.ActiveTarget, ms.TargetOptions)
-	s.restoreSavedTarget(TargetSlotRollout, ms.RolloutTarget, ms.TargetOptions)
+	err = s.initialize(ms.Hosts, ms.Options)
+	if err != nil {
+		return err
+	}
+	err = s.restoreSavedTarget(TargetSlotActive, ms.ActiveTarget, ms.TargetOptions)
+	if err != nil {
+		return err
+	}
+
+	err = s.restoreSavedTarget(TargetSlotRollout, ms.RolloutTarget, ms.TargetOptions)
+	if err != nil {
+		return err
+	}
 
 	return nil
 }
diff --git a/internal/server/target_test.go b/internal/server/target_test.go
index 8c350fa..90993ef 100644
--- a/internal/server/target_test.go
+++ b/internal/server/target_test.go
@@ -45,7 +45,8 @@ func TestTarget_ServeSSE(t *testing.T) {
 
 		target := testTargetWithOptions(t, targetOptions, func(w http.ResponseWriter, r *http.Request) {
 			w.Header().Set("Content-Type", "text/event-stream")
-			w.Write([]byte("data: hello\n\n"))
+			_, err := w.Write([]byte("data: hello\n\n"))
+			assert.NoError(t, err)
 			w.(http.Flusher).Flush()
 
 			// Don't return until the client has finished reading. Fail the test if this takes too long.

From 11046ce62a015fee75093745c72b64110234dd7a Mon Sep 17 00:00:00 2001
From: Roman Dmytrenko <rdmytrenko@gmail.com>
Date: Tue, 1 Oct 2024 14:10:04 +0300
Subject: [PATCH 3/3] Added go lint action to ci

---
 .github/workflows/ci.yml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 779a063..c3640eb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -25,3 +25,8 @@ jobs:
 
     - name: Test
       run: go test -v ./...
+
+    - name: Lint
+      uses: golangci/golangci-lint-action@v6
+      with:
+        version: v1.61