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The mux package provides utilities for serving multiple protocol servers (HTTP and gRPC) on different ports with graceful shutdown capabilities.

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Overview

The multiplexer allows you to start TCP listeners and serve registered protocol servers, handling graceful shutdown when the context is cancelled. It uses the oklog/run package to manage multiple server lifecycles concurrently.

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Key Features

  • Multi-protocol support: Serve HTTP and gRPC servers simultaneously
  • Graceful shutdown: Coordinated shutdown with configurable grace period
  • Concurrent execution: Run multiple servers using run groups
  • Error handling: Proper error propagation and logging

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API Reference

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Serve

func Serve(ctx context.Context, opts ...Option) error
Starts TCP listeners and serves the registered protocol servers of the given serve targets. Blocks until the servers exit. Context can be cancelled to perform graceful shutdown. Parameters:
  • ctx: Context for controlling server lifecycle and graceful shutdown
  • opts: Variable number of Option functions for configuration
Returns:
  • Error if server startup or shutdown fails
Location: /home/daytona/workspace/source/server/mux/mux.go:21

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Options

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WithHTTPTarget

func WithHTTPTarget(addr string, srv *http.Server) Option
Registers an HTTP server to be served on the specified address. Parameters:
  • addr: TCP address to listen on (e.g., :8080 or localhost:8080)
  • srv: Configured *http.Server instance
Location: /home/daytona/workspace/source/server/mux/option.go:13

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WithGRPCTarget

func WithGRPCTarget(addr string, srv *grpc.Server) Option
Registers a gRPC server to be served on the specified address. Parameters:
  • addr: TCP address to listen on (e.g., :9090 or localhost:9090)
  • srv: Configured *grpc.Server instance
Location: /home/daytona/workspace/source/server/mux/option.go:21

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WithGracePeriod

func WithGracePeriod(d time.Duration) Option
Sets the wait duration for graceful shutdown. Default is 10 seconds. Parameters:
  • d: Duration to wait for graceful shutdown (values less than or equal to 0 use default)
Location: /home/daytona/workspace/source/server/mux/option.go:32

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Usage Examples

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Basic HTTP Server

package main

import (
    "context"
    "log"
    "net/http"
    "os"
    "os/signal"
    "syscall"

    "github.com/yourusername/salt/server/mux"
)

func main() {
    // Create HTTP server
    httpServer := &http.Server{
        Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
            w.Write([]byte("Hello, World!"))
        }),
    }

    // Setup context with cancellation
    ctx, cancel := signal.NotifyContext(context.Background(), 
        os.Interrupt, syscall.SIGTERM)
    defer cancel()

    // Serve with mux
    if err := mux.Serve(ctx, 
        mux.WithHTTPTarget(":8080", httpServer),
    ); err != nil {
        log.Fatal(err)
    }
}

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Multi-Protocol Server

package main

import (
    "context"
    "log"
    "net/http"
    "os"
    "os/signal"
    "syscall"
    "time"

    "github.com/yourusername/salt/server/mux"
    "google.golang.org/grpc"
)

func main() {
    // Create HTTP server
    httpServer := &http.Server{
        Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
            w.Write([]byte("HTTP endpoint"))
        }),
    }

    // Create gRPC server
    grpcServer := grpc.NewServer()
    // Register your gRPC services here...

    // Setup context with cancellation
    ctx, cancel := signal.NotifyContext(context.Background(), 
        os.Interrupt, syscall.SIGTERM)
    defer cancel()

    // Serve both protocols with custom grace period
    if err := mux.Serve(ctx,
        mux.WithHTTPTarget(":8080", httpServer),
        mux.WithGRPCTarget(":9090", grpcServer),
        mux.WithGracePeriod(30*time.Second),
    ); err != nil {
        log.Fatal(err)
    }
}

​
Multiple HTTP Servers

package main

import (
    "context"
    "log"
    "net/http"
    "os"
    "os/signal"
    "syscall"

    "github.com/yourusername/salt/server/mux"
)

func main() {
    // Public API server
    publicServer := &http.Server{
        Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
            w.Write([]byte("Public API"))
        }),
    }

    // Admin API server
    adminServer := &http.Server{
        Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
            w.Write([]byte("Admin API"))
        }),
    }

    // Setup context
    ctx, cancel := signal.NotifyContext(context.Background(), 
        os.Interrupt, syscall.SIGTERM)
    defer cancel()

    // Serve on different ports
    if err := mux.Serve(ctx,
        mux.WithHTTPTarget(":8080", publicServer),
        mux.WithHTTPTarget(":8081", adminServer),
    ); err != nil {
        log.Fatal(err)
    }
}

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Graceful Shutdown

The multiplexer handles graceful shutdown automatically when the context is cancelled:
  1. Signal Detection: Context cancellation triggers shutdown sequence
  2. Grace Period: Servers are given time to complete in-flight requests
  3. Forced Shutdown: After grace period expires, servers are forcefully stopped
  4. Error Logging: Shutdown errors are logged for debugging
ctx, cancel := signal.NotifyContext(context.Background(), 
    os.Interrupt, syscall.SIGTERM)
defer cancel()

// Custom grace period of 30 seconds
err := mux.Serve(ctx,
    mux.WithHTTPTarget(":8080", httpServer),
    mux.WithGracePeriod(30*time.Second),
)

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Implementation Details

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Default Configuration

  • Grace Period: 10 seconds (defaultGracePeriod)
  • Error Handling: Errors are logged with [ERROR] prefix
  • Minimum Targets: At least one serve target must be configured

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Server Lifecycle

The multiplexer uses oklog/run to manage server lifecycles:
  1. Startup: TCP listeners are created for each target
  2. Execution: Each server runs in its own goroutine
  3. Monitoring: Context cancellation is monitored
  4. Shutdown: All servers shut down gracefully when triggered
Location: /home/daytona/workspace/source/server/mux/mux.go:41-73

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Error Handling

The package handles several error conditions:
  • No targets configured: Returns error if no serve targets are provided
  • Listen failures: Returns error if TCP listener cannot be created
  • Serve errors: Logged but don’t necessarily stop other servers
  • Shutdown errors: Logged when graceful shutdown fails
if err := mux.Serve(ctx, opts...); err != nil {
    log.Printf("Server error: %v", err)
    // Handle error appropriately
}

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Best Practices

  1. Always use signal context: Handle OS signals for clean shutdown
  2. Configure appropriate grace period: Consider your request timeouts
  3. Test shutdown behavior: Ensure in-flight requests complete properly
  4. Monitor logs: Check for shutdown errors in production
  5. Set reasonable timeouts: Configure read/write timeouts on HTTP servers

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See Also

  • SPA Server - Single-page application server utilities