Startup Trace and Automatic image switching (#8)

* fix: Fixed startup tracing

* feat: Added automatic image switchover

* Updated go version on PR

* Fixed indentation

* fix: cleaned up some error handling

* fix: linter errors

* fix: capitalizations on error messages

* fix: Missed one

.github/workflows/Deploy.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
 
-  deploy:
+  build:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
@@ -28,9 +28,20 @@ jobs:
         context: .
         file: ./Dockerfile
         push: true
-        tags: ${{ secrets.REGISTRY_URL }}/gavinpower747/shortener:latest
+        tags: ${{ secrets.REGISTRY_URL }}/gavinpower747/shortener:${{ github.sha }}
         build-args: |
-          GIT_COMMIT=${{github.sha}}
-          GIT_BRANCH=${{github.ref}}
+          GIT_COMMIT=${{ github.sha }}
+          GIT_BRANCH=${{ github.ref }}
           BUILD_DATE=${{ github.event.repository.updated_at }}
-        
+
+  deploy:
+    runs-on: ubuntu-latest
+    needs: build
+    steps:    
+    - name: 'Deploy new image to app service'
+      uses: azure/webapps-deploy@v2
+      with:
+        app-name: 'shortener'
+        slot-name: 'production'
+        publish_profile: ${{ secrets.AZURE_PUBLISH_PROFILE }}
+        images: ${{ secrets.REGISTRY_URL }}/gavinpower747/shortener:${{ github.sha }}

.github/workflows/PR.yml

@@ -14,7 +14,7 @@ jobs:
     - name: 'Set up Go'
       uses: actions/setup-go@v3
       with:
-        go-version: '1.20'
+        go-version: '1.23'
 
     - name: Verify dependencies
       run: go mod verify

cmd/server/main.go

@@ -26,31 +26,40 @@ func main() {
 	}
 }
 
-func run() (err error) {
+const (
+	ServiceName = "gavs.at"
+)
 
+func run() (err error) {
 	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
 	defer stop()
 
-	otelShutdown, err := observability.SetupOTelSDK(ctx)
+	otelShutdown, err := observability.SetupOTelSDK(ctx, ServiceName)
 	if err != nil {
-		log.Fatalf("Failed to setup otel: %v", err)
-		return
+		log.Printf("Failed to setup otel: %v", err)
+		return err
 	}
 
-	tracer := otel.GetTracerProvider().Tracer("gavs.at/shortener")
+	tracer := otel.GetTracerProvider().Tracer(ServiceName)
 
-	_, span := tracer.Start(ctx, "startup")
-	defer span.End()
+	ctx, span := tracer.Start(ctx, "ApplicationStartup")
 
 	defer func() {
-		err = errors.Join(err, otelShutdown(context.Background()))
+		if span.IsRecording() && err != nil {
+			span.RecordError(err)
+			span.End()
+		}
+
+		err = errors.Join(err, otelShutdown(ctx))
 	}()
 
 	listenAddr := ":80"
 
-	storageAccount, err := storage.NewStorageAccount()
+	storageAccount, err := storage.NewStorageAccount(ctx)
 	if err != nil {
-		log.Fatal(err)
+		log.Println(err)
+
+		return err
 	}
 
 	reqHandlers := handlers.NewHandlers(storageAccount)
@@ -68,27 +77,35 @@ func run() (err error) {
 	}
 
 	srvErr := make(chan error, 1)
+
+	span.End()
+
 	go func() {
 		log.Println("Listening on", listenAddr)
 		srvErr <- srv.ListenAndServe()
 	}()
 
 	select {
 	case err = <-srvErr:
-		return
+		if span.IsRecording() {
+			span.RecordError(err)
+			span.End()
+		}
+
+		return err
 	case <-ctx.Done():
 		stop()
 	}
 
-	err = srv.Shutdown(context.Background())
+	err = srv.Shutdown(ctx)
 
-	return
+	return nil
 }
 
 func configureRouter(reqHandlers *handlers.Handlers) *mux.Router {
 	r := mux.NewRouter()
 
-	r.Use(otelmux.Middleware("gavs.at"))
+	r.Use(otelmux.Middleware(ServiceName))
 	r.Use(middleware.RequestMetrics)
 
 	apiRouter := r.PathPrefix("/api").Subrouter()

internal/handlers/create_redirect.go

@@ -25,7 +25,7 @@ func (h *Handlers) UpsertRedirect(w http.ResponseWriter, r *http.Request) {
 		Entity:  aztables.Entity{PartitionKey: "pk001", RowKey: req.Slug},
 	}
 
-	err := h.storage.UpsertEntity(redirect)
+	err := h.storage.UpsertEntity(r.Context(), redirect)
 
 	if err != nil {
 		log.Printf("Error when upserting redirect: %s", err)

internal/handlers/create_redirect_test.go

@@ -23,7 +23,7 @@ func (m *MockStorage) QueryEntity(_ context.Context, _, _ string) ([]byte, error
 	return nil, nil
 }
 
-func (m *MockStorage) UpsertEntity(entity interface{}) error {
+func (m *MockStorage) UpsertEntity(_ context.Context, entity interface{}) error {
 	if m.UpsertEntityFunc == nil {
 		return nil
 	}
@@ -34,7 +34,7 @@ func (m *MockStorage) UpsertEntity(entity interface{}) error {
 func TestHandlers_UpsertRedirect_ValidRequest(t *testing.T) {
 	// Arrange
 	mockStorage := &MockStorage{
-		UpsertEntityFunc: func(entity interface{}) error {
+		UpsertEntityFunc: func(_ interface{}) error {
 			return nil
 		},
 	}
@@ -91,7 +91,7 @@ func TestHandlers_UpsertRedirect_InvalidRequestBody(t *testing.T) {
 func TestHandlers_UpsertRedirect_StorageError(t *testing.T) {
 	// Arrange
 	mockStorage := &MockStorage{
-		UpsertEntityFunc: func(entity interface{}) error {
+		UpsertEntityFunc: func(_ interface{}) error {
 			return errors.New("test error")
 		},
 	}

internal/handlers/redirect_test.go

@@ -24,7 +24,7 @@ type MockStorageAccount struct {
 	mock.Mock
 }
 
-func (m *MockStorageAccount) QueryEntity(ctx context.Context, partitionKey, rowKey string) ([]byte, error) {
+func (m *MockStorageAccount) QueryEntity(_ context.Context, partitionKey, rowKey string) ([]byte, error) {
 	args := m.Called(partitionKey, rowKey)
 
 	if args.Get(0) == nil {
@@ -34,7 +34,7 @@ func (m *MockStorageAccount) QueryEntity(ctx context.Context, partitionKey, rowK
 	return args.Get(0).([]byte), args.Error(1)
 }
 
-func (m *MockStorageAccount) UpsertEntity(entity interface{}) error {
+func (m *MockStorageAccount) UpsertEntity(_ context.Context, entity interface{}) error {
 	args := m.Called(entity)
 
 	return args.Error(0)

internal/storage/storage_account.go

@@ -15,7 +15,7 @@ import (
 
 type Account interface {
 	QueryEntity(ctx context.Context, partitionKey string, rowKey string) ([]byte, error)
-	UpsertEntity(entity interface{}) error
+	UpsertEntity(ctx context.Context, entity interface{}) error
 }
 
 type storageAccount struct {
@@ -53,7 +53,7 @@ func (sa *storageAccount) QueryEntity(ctx context.Context, partitionKey, rowKey
 	return nil, nil
 }
 
-func (sa *storageAccount) UpsertEntity(entity interface{}) error {
+func (sa *storageAccount) UpsertEntity(ctx context.Context, entity interface{}) error {
 	tableClient := sa.serviceClient.NewClient(TableName)
 
 	jsonEntity, err := json.Marshal(entity)
@@ -62,12 +62,12 @@ func (sa *storageAccount) UpsertEntity(entity interface{}) error {
 		return err
 	}
 
-	_, err = tableClient.UpsertEntity(context.Background(), jsonEntity, nil)
+	_, err = tableClient.UpsertEntity(ctx, jsonEntity, nil)
 
 	return err
 }
 
-func NewStorageAccount() (Account, error) {
+func NewStorageAccount(ctx context.Context) (Account, error) {
 	connectionString, found := os.LookupEnv("API_AzureStorageConnectionString")
 
 	if !found {
@@ -91,14 +91,14 @@ func NewStorageAccount() (Account, error) {
 	pager := sa.NewListTablesPager(pagerOptions)
 
 	for pager.More() {
-		resp, pageErr := pager.NextPage(context.Background())
+		resp, pageErr := pager.NextPage(ctx)
 
 		if pageErr != nil {
 			return nil, pageErr
 		}
 
 		if len(resp.Tables) == 0 {
-			_, err = sa.CreateTable(context.Background(), TableName, nil)
+			_, err = sa.CreateTable(ctx, TableName, nil)
 
 			if err != nil {
 				return nil, err

pkg/middleware/basic_auth.go

@@ -34,16 +34,16 @@ func BasicAuth(next http.Handler) http.Handler {
 
 		if authHeader == "" {
 			web.NotAuthorized(w, "Missing Authorization Header")
-			span.RecordError(fmt.Errorf("Missing Authorization Header"))
+			span.RecordError(fmt.Errorf("missing authorization header"))
 
 			return
 		}
 
 		headerSections := strings.Split(authHeader, " ")
 
 		if !strings.HasPrefix(authHeader, "Basic ") {
-			web.NotAuthorized(w, fmt.Sprintf("Invalid Authorization Header, %s authentication scheme is not supported", headerSections[0]))
-			span.RecordError(fmt.Errorf("Invalid Authorization Header, %s authentication scheme is not supported", headerSections[0]))
+			web.NotAuthorized(w, fmt.Sprintf("invalid authorization header, %s authentication scheme is not supported", headerSections[0]))
+			span.RecordError(fmt.Errorf("invalid authorization header, %s authentication scheme is not supported", headerSections[0]))
 
 			return
 		}
@@ -52,7 +52,7 @@ func BasicAuth(next http.Handler) http.Handler {
 
 		if err != nil {
 			web.NotAuthorized(w, "Invalid Authorization Header")
-			span.RecordError(fmt.Errorf("Invalid Authorization Header"))
+			span.RecordError(fmt.Errorf("invalid authorization header"))
 
 			return
 		}
@@ -68,7 +68,7 @@ func BasicAuth(next http.Handler) http.Handler {
 
 		if username != expectedUsername || passwordHash != expectedPasswordHash {
 			web.NotAuthorized(w, "Invalid Credentials")
-			span.RecordError(fmt.Errorf("Invalid Credentials"))
+			span.RecordError(fmt.Errorf("invalid credentials"))
 
 			return
 		}

pkg/observability/otel.go

@@ -14,16 +14,16 @@ import (
 	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
 )
 
-func SetupOTelSDK(ctx context.Context) (shutdown func(context.Context) error, err error) {
+func SetupOTelSDK(ctx context.Context, serviceName string) (shutdown func(context.Context) error, err error) {
 	var shutdownFuncs []func(context.Context) error
 
 	shutdown = func(ctx context.Context) error {
-		var err error
 		for _, fn := range shutdownFuncs {
 			if shutErr := fn(ctx); shutErr != nil {
 				err = errors.Join(err, shutErr)
 			}
 		}
+
 		return err
 	}
 
@@ -33,9 +33,9 @@ func SetupOTelSDK(ctx context.Context) (shutdown func(context.Context) error, er
 		}
 	}
 
-	resource := resource.NewWithAttributes(
+	otelService := resource.NewWithAttributes(
 		semconv.SchemaURL,
-		semconv.ServiceNameKey.String("gavs.at"),
+		semconv.ServiceNameKey.String(serviceName),
 		semconv.ServiceVersionKey.String(os.Getenv("GIT_COMMIT")),
 		attribute.String("build.commit", os.Getenv("GIT_COMMIT")),
 		attribute.String("build.branch", os.Getenv("GIT_BRANCH")),
@@ -45,10 +45,10 @@ func SetupOTelSDK(ctx context.Context) (shutdown func(context.Context) error, er
 
 	otel.SetTextMapPropagator(newPropagator())
 
-	tracerProvider, err := newTraceProvider(ctx, resource)
+	tracerProvider, err := newTraceProvider(ctx, otelService)
 	if err != nil {
 		handleErr(err)
-		return
+		return shutdown, err
 	}
 
 	shutdownFuncs = append(shutdownFuncs, tracerProvider.Shutdown)
@@ -64,7 +64,7 @@ func newPropagator() propagation.TextMapPropagator {
 	)
 }
 
-func newTraceProvider(ctx context.Context, resource *resource.Resource) (*trace.TracerProvider, error) {
+func newTraceProvider(ctx context.Context, service *resource.Resource) (*trace.TracerProvider, error) {
 	exporter, err := otlptracehttp.New(ctx)
 
 	if err != nil {
@@ -73,7 +73,8 @@ func newTraceProvider(ctx context.Context, resource *resource.Resource) (*trace.
 
 	tp := trace.NewTracerProvider(
 		trace.WithBatcher(exporter),
-		trace.WithResource(resource),
+		trace.WithResource(service),
 	)
+
 	return tp, nil
 }