[client] Add embeddable library

client/embed/doc.go

@@ -0,0 +1,172 @@
+package embed
+
+// Package embed provides a way to embed the NetBird client directly
+// into Go programs without requiring a separate NetBird client installation.
+//
+//
+// Basic Usage:
+//
+//	client, err := embed.New(embed.Options{
+//	    DeviceName:    "my-service",
+//	    SetupKey:      os.Getenv("NB_SETUP_KEY"),
+//	    ManagementURL: os.Getenv("NB_MANAGEMENT_URL"),
+//	})
+//	if err != nil {
+//	    log.Fatal(err)
+//	}
+//
+//	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+//	defer cancel()
+//	if err := client.Start(ctx); err != nil {
+//	    log.Fatal(err)
+//	}
+//
+// Complete HTTP Server Example:
+//
+//	package main
+//
+//	import (
+//	    "context"
+//	    "fmt"
+//	    "log"
+//	    "net/http"
+//	    "os"
+//	    "os/signal"
+//	    "syscall"
+//	    "time"
+//
+//	    netbird "github.com/netbirdio/netbird/client/embed"
+//	)
+//
+//	func main() {
+//	    // Create client with setup key and device name
+//	    client, err := netbird.New(netbird.Options{
+//	        DeviceName:    "http-server",
+//	        SetupKey:      os.Getenv("NB_SETUP_KEY"),
+//	        ManagementURL: os.Getenv("NB_MANAGEMENT_URL"),
+//	        LogOutput:     io.Discard,
+//	    })
+//	    if err != nil {
+//	        log.Fatal(err)
+//	    }
+//
+//	    // Start with timeout
+//	    ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+//	    defer cancel()
+//	    if err := client.Start(ctx); err != nil {
+//	        log.Fatal(err)
+//	    }
+//
+//	    // Create HTTP server
+//	    mux := http.NewServeMux()
+//	    mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+//	        fmt.Printf("Request from %s: %s %s\n", r.RemoteAddr, r.Method, r.URL.Path)
+//	        fmt.Fprintf(w, "Hello from netbird!")
+//	    })
+//
+//	    // Listen on netbird network
+//	    l, err := client.ListenTCP(":8080")
+//	    if err != nil {
+//	        log.Fatal(err)
+//	    }
+//
+//	    server := &http.Server{Handler: mux}
+//	    go func() {
+//	        if err := server.Serve(l); !errors.Is(err, http.ErrServerClosed) {
+//	            log.Printf("HTTP server error: %v", err)
+//	        }
+//	    }()
+//
+//	    log.Printf("HTTP server listening on netbird 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 := server.Shutdown(shutdownCtx); err != nil {
+//	        log.Printf("HTTP shutdown error: %v", err)
+//	    }
+//	    if err := client.Stop(shutdownCtx); err != nil {
+//	        log.Printf("Netbird shutdown error: %v", err)
+//	    }
+//	}
+//
+// Complete HTTP Client Example:
+//
+//	package main
+//
+//	import (
+//	    "context"
+//	    "fmt"
+//	    "io"
+//	    "log"
+//	    "os"
+//	    "time"
+//
+//	    netbird "github.com/netbirdio/netbird/client/embed"
+//	)
+//
+//	func main() {
+//	    // Create client with setup key and device name
+//	    client, err := netbird.New(netbird.Options{
+//	        DeviceName:    "http-client",
+//	        SetupKey:      os.Getenv("NB_SETUP_KEY"),
+//	        ManagementURL: os.Getenv("NB_MANAGEMENT_URL"),
+//	        LogOutput:     io.Discard,
+//	    })
+//	    if err != nil {
+//	        log.Fatal(err)
+//	    }
+//
+//	    // Start with timeout
+//	    ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+//	    defer cancel()
+//
+//	    if err := client.Start(ctx); err != nil {
+//	        log.Fatal(err)
+//	    }
+//
+//	    // Create HTTP client that uses netbird network
+//	    httpClient, err := client.NewHTTPClient()
+//	    if err != nil {
+//	        log.Fatal(err)
+//	    }
+//	    httpClient.Timeout = 10 * time.Second
+//
+//	    // Make request to server in netbird network
+//	    target := os.Getenv("NB_TARGET")
+//	    resp, err := httpClient.Get(target)
+//	    if err != nil {
+//	        log.Fatal(err)
+//	    }
+//	    defer resp.Body.Close()
+//
+//	    // Read and print response
+//	    body, err := io.ReadAll(resp.Body)
+//	    if err != nil {
+//	        log.Fatal(err)
+//	    }
+//
+//	    fmt.Printf("Response from server: %s\n", string(body))
+//
+//	    // Clean shutdown
+//	    shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+//	    defer cancel()
+//
+//	    if err := client.Stop(shutdownCtx); err != nil {
+//	        log.Printf("Netbird shutdown error: %v", err)
+//	    }
+//	}
+//
+// The package provides several methods for network operations:
+//   - Dial: Creates outbound connections
+//   - ListenTCP: Creates TCP listeners
+//   - ListenUDP: Creates UDP listeners
+//
+// By default, the embed package uses userspace networking mode, which doesn't
+// require root/admin privileges. For production deployments, consider setting
+// appropriate config and state paths for persistence.