The pkg/tailscale package provides a Tailscale-network-only HTTP server that is a true drop-in replacement for Go's standard http.Server. This creates HTTP servers that are only accessible via the Tailscale network (tailnet), providing automatic security, TLS certificates, and identity resolution.

Go Documentation: pkg.go.dev/github.com/spechtlabs/tka/pkg/tailscale

Overview

This package provides a clean, modern interface for Tailscale HTTP servers with multiple usage patterns:

• Network Isolation: HTTP server only accessible via Tailscale network
• Automatic TLS: HTTPS certificates handled by Tailscale
• Identity Resolution: Built-in user identity and capability checking
• Funnel Detection: Ability to detect and reject public Funnel traffic
• Drop-in Replacement: True drop-in replacement for http.Server
• Flexible Interface: Multiple usage patterns from simple to advanced

Architecture

Key Design:

1. tailscale.Server embeds http.Server directly - it IS an http.Server
2. tailscale.Server connects to Tailscale network via tsnet
3. tailscale.Server provides standard net.Listener instances from Tailscale
4. No abstraction layers - direct integration with standard Go HTTP patterns

Usage Patterns

The package supports two usage patterns to match different complexity needs:

1. High-Level Usage (All-in-One)

Use the Serve() method for a complete solution:

server := tailscale.NewServer("myapp",
    tailscale.WithPort(443),
    tailscale.WithDebug(true),
)

handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    info, err := server.WhoIs(r.Context(), r.RemoteAddr)
    if err != nil {
        http.Error(w, "Authentication failed", http.StatusUnauthorized)
        return
    }
    fmt.Fprintf(w, "Hello, %s!", info.LoginName)
})

if err := server.Serve(ctx, handler); err != nil {
    log.Fatal(err)
}

Tip

See the Example: High-Level Usage (All-in-One) for more info

2. Low-Level Usage (Maximum Control)

Use Start() + ListenTCP() with standard http.Server for maximum control:

server := tailscale.NewServer("myapp")
if err := server.Start(ctx); err != nil {
    log.Fatal(err)
}

listener, err := server.ListenTCP(":8080")
if err != nil {
    log.Fatal(err)
}

// Use any http.Server - server is just for connection setup
httpServer := &http.Server{
    Handler: myHandler,
    ReadTimeout: 30 * time.Second,
}
go func() {
    if err := httpServer.Serve(listener); !errors.Is(err, http.ErrServerClosed) {
        log.Printf("HTTP server error: %v", err)
    }
}()

// Graceful shutdown
shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
if err := httpServer.Shutdown(shutdownCtx); err != nil {
    log.Printf("HTTP shutdown error: %v", err)
}
if err := server.Stop(shutdownCtx); err != nil {
    log.Printf("Tailscale shutdown error: %v", err)
}

Tip

See the Example: Low-Level Usage (Maximum Control) for more info

Core Types

Server

The main server type that embeds http.Server and adds Tailscale functionality:

type Server struct {
    *http.Server  // Embedded - IS an http.Server

    // Configuration
    debug    bool
    port     int
    hostname string

    // Tailscale components
    ts        *tsnet.Server
    lc        *local.Client
    st        *ipnstate.Status
    serverURL string
    started   bool
}

WhoIsInfo

Identity information extracted from Tailscale WhoIs lookups:

type WhoIsInfo struct {
    LoginName string               // User's login name (e.g., "[email protected]")
    CapMap    tailcfg.PeerCapMap   // Capability grants from ACL
    IsTagged  bool                 // Whether the source is a tagged device
}

WhoIsResolver

Interface for identity resolution:

type WhoIsResolver interface {
    WhoIs(ctx context.Context, remoteAddr string) (*WhoIsInfo, humane.Error)
}

This interface is implemented by the tailscale.Server and can be mocked for testing with the pkg/tailscale/mock package.

API Reference

Constructor

NewServer

func NewServer(hostname string, opts ...Option) *Server

Creates a new Tailscale HTTP server with the specified hostname.

Parameters:

• hostname: The hostname for this server on the tailnet (e.g., "tka")
• opts: Configuration options

Returns: A configured *Server ready to serve HTTP traffic

Example:

server := tailscale.NewServer("myapp",
    tailscale.WithPort(443),
    tailscale.WithDebug(true),
    tailscale.WithStateDir("/var/lib/myapp/ts-state"),
)

Configuration Options

WithPort

func WithPort(port int) Option

Sets the listening port. Default is 443 (HTTPS).

WithDebug

func WithDebug(debug bool) Option

Enables debug logging for Tailscale operations.

WithStateDir

func WithStateDir(dir string) Option

Sets the directory for Tailscale state storage. If empty, uses automatic directory selection.

HTTP Timeout Options

Configure standard HTTP server timeouts:

func WithReadTimeout(timeout time.Duration) Option
func WithReadHeaderTimeout(timeout time.Duration) Option
func WithWriteTimeout(timeout time.Duration) Option
func WithIdleTimeout(timeout time.Duration) Option

Server Methods

Start

func (s *Server) Start(ctx context.Context) humane.Error

Connects to the Tailscale network and prepares the server for accepting connections. This method separates connection setup from serving.

Example:

server := tailscale.NewServer("myapp")
if err := server.Start(ctx); err != nil {
    log.Fatal(err.Display())
}

ListenTCP

func (s *Server) ListenTCP(address string) (net.Listener, humane.Error)

Creates a TCP listener on the Tailscale network. Returns a standard net.Listener that can be used with any http.Server.

Note: The server must be started with Start() before calling this method.

Example:

listener, err := server.ListenTCP(":8080")
if err != nil {
    log.Fatal(err.Display())
}

httpServer := &http.Server{
    Handler: myHandler,
    ReadTimeout: 30 * time.Second,
}
go httpServer.Serve(listener)

Stop

func (s *Server) Stop(ctx context.Context) humane.Error

Gracefully stops the Tailscale server.

Example:

if err := server.Stop(ctx); err != nil {
    log.Printf("Stop error: %v", err)
}

Serve

func (s *Server) Serve(ctx context.Context, handler http.Handler) humane.Error

Starts the server with the provided HTTP handler. This is the high-level method that handles everything automatically.

Parameters:

• ctx: Context for server lifecycle
• handler: HTTP handler to serve requests

Returns: humane.Error if startup or serving fails

Example:

ctx := context.Background()
handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "Hello from tailnet!")
})

if err := server.Serve(ctx, handler); err != nil {
    log.Fatal("Server failed:", err.Display())
}

ListenAndServe

func (s *Server) ListenAndServe() error

Standard library compatible method. Uses s.Handler and background context.

Example:

server.Handler = myHandler
if err := server.ListenAndServe(); err != nil {
    log.Fatal("Server failed:", err)
}

Shutdown

func (s *Server) Shutdown(ctx context.Context) humane.Error

Gracefully shuts down the server.

Example:

shutdownCtx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()

if err := server.Shutdown(shutdownCtx); err != nil {
    log.Printf("Shutdown error: %v", err)
}

WhoIs

func (s *Server) WhoIs(ctx context.Context, remoteAddr string) (*WhoIsInfo, error)

Directly resolves identity for a remote address.

Example:

info, err := server.WhoIs(ctx, "100.64.1.2:12345")
if err != nil {
    return fmt.Errorf("identity lookup failed: %w", err)
}

// Check capabilities
if caps, ok := info.CapMap["example.com/cap/admin"]; ok {
    // User has admin capabilities
}

Utility Functions

IsFunnelRequest

func IsFunnelRequest(r *http.Request) bool

Detects if an HTTP request is coming through Tailscale Funnel (public internet).

Example:

func authMiddleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        if tailscale.IsFunnelRequest(r) {
            http.Error(w, "Access denied: Funnel requests not allowed", http.StatusForbidden)
            return
        }
        next.ServeHTTP(w, r)
    })
}

Tip

See the Example: Authentication Middleware for more info

CtxConnKey

type CtxConnKey struct{}

Context key for retrieving the underlying net.Conn from request context.

Examples

Example: High-Level Usage (All-in-One)

package main

import (
    "context"
    "fmt"
    "net/http"

    "github.com/spechtlabs/tka/pkg/tshttp"
)

func main() {
    // Create server
    server := tailscale.NewServer("myapp",
        tailscale.WithPort(443),
        tailscale.WithDebug(true),
    )

    // Simple handler
    handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintf(w, "Hello from %s!", r.Host)
    })

    // Start server
    ctx := context.Background()
    if err := server.Serve(ctx, handler); err != nil {
        panic(err.Display())
    }
}

Example: Low-Level Usage (Maximum Control)

package main

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

    "github.com/spechtlabs/tka/pkg/tshttp"
)

func main() {
    // Create server
    server := tailscale.NewServer("myapp")

    // Start with timeout
    ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
    defer cancel()
    if err := server.Start(ctx); err != nil {
        log.Fatal(err.Display())
    }

    // Create HTTP server
    mux := http.NewServeMux()
    mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        info, err := server.WhoIs(r.Context(), r.RemoteAddr)
        if err != nil {
            http.Error(w, "Authentication failed", http.StatusUnauthorized)
            return
        }
        fmt.Printf("Request from %s: %s %s\n", info.LoginName, r.Method, r.URL.Path)
        fmt.Fprintf(w, "Hello %s from Tailscale!", info.LoginName)
    })

    // Listen on Tailscale network
    listener, err := server.ListenTCP(":8080")
    if err != nil {
        log.Fatal(err.Display())
    }

    // Standard HTTP server
    httpServer := &http.Server{Handler: mux}
    go func() {
        if err := httpServer.Serve(listener); !errors.Is(err, http.ErrServerClosed) {
            log.Printf("HTTP server error: %v", err)
        }
    }()

    log.Printf("HTTP server listening on Tailscale network port 8080")

    // Handle shutdown
    stop := make(chan os.Signal, 1)
    signal.Notify(stop, syscall.SIGINT, syscall.SIGTERM)
    <-stop

    shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
    defer cancel()

    if err := httpServer.Shutdown(shutdownCtx); err != nil {
        log.Printf("HTTP shutdown error: %v", err)
    }
    if err := server.Stop(shutdownCtx); err != nil {
        log.Printf("Tailscale shutdown error: %v", err)
    }
}

Example: Authentication Middleware

func authMiddleware(server *tailscale.Server) func(http.Handler) http.Handler {
    return func(next http.Handler) http.Handler {
        return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
            // Reject Funnel requests
            if tailscale.IsFunnelRequest(r) {
                http.Error(w, "Access denied", http.StatusForbidden)
                return
            }

            // Get user identity
            info, err := server.WhoIs(r.Context(), r.RemoteAddr)
            if err != nil {
                http.Error(w, "Authentication failed", http.StatusUnauthorized)
                return
            }

            // Check for required capability
            if _, ok := info.CapMap["example.com/cap/api-access"]; !ok {
                http.Error(w, "Insufficient permissions", http.StatusForbidden)
                return
            }

            // Add user info to context
            ctx := context.WithValue(r.Context(), "user", info.LoginName)
            next.ServeHTTP(w, r.WithContext(ctx))
        })
    }
}

Tip

To see a Gin-Authentication Middleware in action, check out the tka source code on GitHub

Security Considerations

• Tailnet Only: Server is never exposed to internet directly, only via your tailnet
• Device Authentication: All clients must be authenticated members of your tailnet
• Network ACLs: Tailscale ACLs control which devices can reach the server
• Public Traffic: Your server can still receive unauthenticated traffic from the public internet through Tailscale Funnel
  • Public traffic can easily identified by using the IsFunnelRequest() function
  • Applications should reject Funnel requests for sensitive operations

Dependencies

• tailscale.com/tsnet Embedded Tailscale networking
• tailscale.com/client/local Local Tailscale client for WhoIs
• tailscale.com/ipn/ipnstate(Open in new window) Status and state management
• github.com/sierrasoftworks/humane-errors-go(Open in new window) Human-friendly error handling

Related Documentation

• TKA Architecture(Open in new window) - How this fits into TKA
• Security Model(Open in new window) - Security implications
• Production Deployment(Open in new window) - Production usage patterns

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