docs: refine gRPC guide section numbers and add CloseAndRecv & fileStore explanations
This commit is contained in:
@@ -0,0 +1,257 @@
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package modular
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import (
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"context"
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"fmt"
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"io"
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"math/rand"
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"net"
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"sync"
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"time"
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"grpccanary/lib/grpc/modular/protoapi"
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"google.golang.org/grpc"
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"google.golang.org/grpc/codes"
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"google.golang.org/grpc/reflection"
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"google.golang.org/grpc/status"
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)
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type UploadedFile struct {
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FileName string
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Content []byte
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UploadedAt int64
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}
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type AlertSubscriber struct {
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ClientId string
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Channel chan *protoapi.AlertMessage
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}
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var (
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fileStore = make(map[string]*UploadedFile)
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storeMu sync.RWMutex
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subscribers = make(map[string]*AlertSubscriber)
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subMu sync.Mutex
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)
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func publishAlert(alert *protoapi.AlertMessage) {
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subMu.Lock()
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defer subMu.Unlock()
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for _, sub := range subscribers {
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select {
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case sub.Channel <- alert:
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default:
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fmt.Printf("Alert channel blocked for client %s, dropping event\n", sub.ClientId)
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}
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}
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}
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func random(min, max int, src rand.Source) int {
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return rand.New(src).Intn(max-min) + min
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}
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func getString(len int64, src rand.Source) string {
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temp := ""
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startChar := "!"
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var i int64 = 1
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for {
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myRand := random(0, 94, src)
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newChar := string(startChar[0] + byte(myRand))
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temp = temp + newChar
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if i == len {
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break
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}
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i++
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}
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return temp
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}
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// 1. Core Server Implementation
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type CoreServer struct {
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protoapi.UnimplementedCoreServiceServer
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}
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func (CoreServer) GetDate(ctx context.Context, r *protoapi.RequestDateTime) (*protoapi.DateTime, error) {
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currentTime := time.Now()
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return &protoapi.DateTime{
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Value: currentTime.String(),
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}, nil
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}
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func (CoreServer) UpdateSensingData(ctx context.Context, r *protoapi.SensingData) (*protoapi.SensingResponse, error) {
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fmt.Printf("[Modular Core] Received sensing data - Device: %s, Temp: %.2f°C, Humid: %.2f%%\n", r.GetDeviceId(), r.GetTemperature(), r.GetHumidity())
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if r.GetTemperature() > 40.0 {
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fmt.Printf("⚠️ [Modular Core] Critical temperature detected: %.2f°C! Publishing warning...\n", r.GetTemperature())
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publishAlert(&protoapi.AlertMessage{
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AlertId: fmt.Sprintf("alert-%d", time.Now().UnixNano()),
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DeviceId: r.GetDeviceId(),
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Message: fmt.Sprintf("Critical high temperature: %.2f°C (Humidity: %.2f%%)", r.GetTemperature(), r.GetHumidity()),
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Timestamp: time.Now().Unix(),
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})
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}
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return &protoapi.SensingResponse{
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Success: true,
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Message: fmt.Sprintf("Sensing data updated successfully for device %s", r.GetDeviceId()),
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}, nil
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}
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func (CoreServer) GetRandomPass(ctx context.Context, r *protoapi.RequestPass) (*protoapi.RandomPass, error) {
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src := rand.NewSource(r.GetSeed())
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temp := getString(r.GetLength(), src)
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return &protoapi.RandomPass{
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Password: temp,
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}, nil
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}
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// 2. File Transfer Server Implementation
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type FileTransferServer struct {
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protoapi.UnimplementedFileTransferServiceServer
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}
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func (FileTransferServer) UploadFile(stream protoapi.FileTransferService_UploadFileServer) error {
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var totalBytes int64
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var fileName string
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var buffer []byte
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for {
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chunk, err := stream.Recv()
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if err == io.EOF {
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fmt.Printf("[Modular File] File upload completed. Received %d bytes for file '%s'\n", totalBytes, fileName)
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if fileName != "" {
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storeMu.Lock()
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fileStore[fileName] = &UploadedFile{
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FileName: fileName,
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Content: buffer,
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UploadedAt: time.Now().Unix(),
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}
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storeMu.Unlock()
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}
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return stream.SendAndClose(&protoapi.UploadStatus{
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Success: true,
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Message: fmt.Sprintf("File '%s' uploaded successfully.", fileName),
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BytesUploaded: totalBytes,
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})
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}
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if err != nil {
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fmt.Println("[Modular File] File upload error:", err)
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return err
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}
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if fileName == "" {
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fileName = chunk.GetFileName()
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}
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buffer = append(buffer, chunk.GetContent()...)
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totalBytes += int64(len(chunk.GetContent()))
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}
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}
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func (FileTransferServer) ListFiles(ctx context.Context, r *protoapi.EmptyRequest) (*protoapi.FileList, error) {
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storeMu.RLock()
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defer storeMu.RUnlock()
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var files []*protoapi.FileMetadata
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for _, f := range fileStore {
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files = append(files, &protoapi.FileMetadata{
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FileName: f.FileName,
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FileSize: int64(len(f.Content)),
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UploadedAt: f.UploadedAt,
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})
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}
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return &protoapi.FileList{Files: files}, nil
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}
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func (FileTransferServer) DownloadFile(r *protoapi.DownloadRequest, stream protoapi.FileTransferService_DownloadFileServer) error {
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storeMu.RLock()
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f, exists := fileStore[r.GetFileName()]
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storeMu.RUnlock()
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if !exists {
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return status.Errorf(codes.NotFound, "file %s not found", r.GetFileName())
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}
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chunkSize := 1024
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totalBytes := len(f.Content)
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for i := 0; i < totalBytes; i += chunkSize {
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end := i + chunkSize
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if end > totalBytes {
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end = totalBytes
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}
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err := stream.Send(&protoapi.FileChunk{
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FileName: f.FileName,
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Content: f.Content[i:end],
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})
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if err != nil {
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return err
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}
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}
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return nil
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}
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// 3. Alert Server Implementation
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type AlertServer struct {
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protoapi.UnimplementedAlertServiceServer
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}
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func (AlertServer) SubscribeAlerts(r *protoapi.AlertSubscription, stream protoapi.AlertService_SubscribeAlertsServer) error {
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clientId := r.GetClientId()
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ch := make(chan *protoapi.AlertMessage, 10)
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sub := &AlertSubscriber{
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ClientId: clientId,
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Channel: ch,
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}
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subMu.Lock()
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subscribers[clientId] = sub
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subMu.Unlock()
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fmt.Printf("[Modular Alert] Client %s subscribed to alerts on topic '%s'\n", clientId, r.GetTopic())
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for {
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select {
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case alert := <-ch:
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err := stream.Send(alert)
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if err != nil {
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subMu.Lock()
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delete(subscribers, clientId)
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subMu.Unlock()
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fmt.Printf("[Modular Alert] Client %s alert subscription disconnected: %v\n", clientId, err)
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return err
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}
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case <-stream.Context().Done():
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subMu.Lock()
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delete(subscribers, clientId)
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subMu.Unlock()
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fmt.Printf("[Modular Alert] Client %s unsubscribed (context done)\n", clientId)
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return nil
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}
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}
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}
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func ServerRun(addr string) {
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server := grpc.NewServer()
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// Register multiple services on the same gRPC server
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protoapi.RegisterCoreServiceServer(server, CoreServer{})
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protoapi.RegisterFileTransferServiceServer(server, FileTransferServer{})
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protoapi.RegisterAlertServiceServer(server, AlertServer{})
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reflection.Register(server)
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listen, err := net.Listen("tcp", addr)
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if err != nil {
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fmt.Println(err)
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return
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}
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fmt.Printf("[Modular Server] Listening on %s...\n", addr)
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server.Serve(listen)
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}
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