Add packet capture to debug bundle and CLI

client/wasm/cmd/main.go

@@ -5,6 +5,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"sync"
 	"syscall/js"
 	"time"
 
@@ -14,6 +15,7 @@ import (
 	netbird "github.com/netbirdio/netbird/client/embed"
 	sshdetection "github.com/netbirdio/netbird/client/ssh/detection"
 	nbstatus "github.com/netbirdio/netbird/client/status"
+	wasmcapture "github.com/netbirdio/netbird/client/wasm/internal/capture"
 	"github.com/netbirdio/netbird/client/wasm/internal/http"
 	"github.com/netbirdio/netbird/client/wasm/internal/rdp"
 	"github.com/netbirdio/netbird/client/wasm/internal/ssh"
@@ -459,6 +461,95 @@ func createSetLogLevelMethod(client *netbird.Client) js.Func {
 	})
 }
 
+// createStartCaptureMethod creates the programmable packet capture method.
+// Returns a JS interface with onpacket callback and stop() method.
+//
+// Usage from JavaScript:
+//
+//	const cap = await client.startCapture({ filter: "tcp port 443", verbose: true })
+//	cap.onpacket = (line) => console.log(line)
+//	const stats = cap.stop()
+func createStartCaptureMethod(client *netbird.Client) js.Func {
+	return js.FuncOf(func(_ js.Value, args []js.Value) any {
+		var opts js.Value
+		if len(args) > 0 {
+			opts = args[0]
+		}
+
+		return createPromise(func(resolve, reject js.Value) {
+			iface, err := wasmcapture.Start(client, opts)
+			if err != nil {
+				reject.Invoke(js.ValueOf(fmt.Sprintf("start capture: %v", err)))
+				return
+			}
+			resolve.Invoke(iface)
+		})
+	})
+}
+
+// captureMethods returns capture() and stopCapture() that share state for
+// the console-log shortcut. capture() logs packets to the browser console
+// and stopCapture() ends it, like Ctrl+C on the CLI.
+//
+// Usage from browser devtools console:
+//
+//	await client.capture()              // capture all packets
+//	await client.capture("tcp")         // capture with filter
+//	await client.capture({filter: "host 10.0.0.1", verbose: true})
+//	client.stopCapture()                // stop and print stats
+func captureMethods(client *netbird.Client) (startFn, stopFn js.Func) {
+	var mu sync.Mutex
+	var active *wasmcapture.Handle
+
+	startFn = js.FuncOf(func(_ js.Value, args []js.Value) any {
+		var opts js.Value
+		if len(args) > 0 {
+			opts = args[0]
+		}
+
+		return createPromise(func(resolve, reject js.Value) {
+			mu.Lock()
+			defer mu.Unlock()
+
+			if active != nil {
+				active.Stop()
+				active = nil
+			}
+
+			h, err := wasmcapture.StartConsole(client, opts)
+			if err != nil {
+				reject.Invoke(js.ValueOf(fmt.Sprintf("start capture: %v", err)))
+				return
+			}
+			active = h
+
+			console := js.Global().Get("console")
+			console.Call("log", "[capture] started, call client.stopCapture() to stop")
+			resolve.Invoke(js.Undefined())
+		})
+	})
+
+	stopFn = js.FuncOf(func(_ js.Value, _ []js.Value) any {
+		mu.Lock()
+		defer mu.Unlock()
+
+		if active == nil {
+			js.Global().Get("console").Call("log", "[capture] no active capture")
+			return js.Undefined()
+		}
+
+		stats := active.Stop()
+		active = nil
+
+		console := js.Global().Get("console")
+		console.Call("log", fmt.Sprintf("[capture] stopped: %d packets, %d bytes, %d dropped",
+			stats.Packets, stats.Bytes, stats.Dropped))
+		return js.Undefined()
+	})
+
+	return startFn, stopFn
+}
+
 // createPromise is a helper to create JavaScript promises
 func createPromise(handler func(resolve, reject js.Value)) js.Value {
 	return js.Global().Get("Promise").New(js.FuncOf(func(_ js.Value, promiseArgs []js.Value) any {
@@ -521,6 +612,11 @@ func createClientObject(client *netbird.Client) js.Value {
 	obj["statusDetail"] = createStatusDetailMethod(client)
 	obj["getSyncResponse"] = createGetSyncResponseMethod(client)
 	obj["setLogLevel"] = createSetLogLevelMethod(client)
+	obj["startCapture"] = createStartCaptureMethod(client)
+
+	capStart, capStop := captureMethods(client)
+	obj["capture"] = capStart
+	obj["stopCapture"] = capStop
 
 	return js.ValueOf(obj)
 }

client/wasm/internal/capture/capture.go

@@ -0,0 +1,211 @@
+//go:build js
+
+// Package capture bridges the util/capture package to JavaScript via syscall/js.
+package capture
+
+import (
+	"strings"
+	"sync"
+	"syscall/js"
+
+	log "github.com/sirupsen/logrus"
+
+	netbird "github.com/netbirdio/netbird/client/embed"
+	"github.com/netbirdio/netbird/util/capture"
+)
+
+// Handle holds a running capture session and the embedded client reference
+// so it can be stopped later.
+type Handle struct {
+	client  *netbird.Client
+	sess    *capture.Session
+	stopFn  js.Func
+	stopped bool
+}
+
+// Stop ends the capture and returns stats.
+func (h *Handle) Stop() capture.Stats {
+	if h.stopped {
+		return h.sess.Stats()
+	}
+	h.stopped = true
+	h.stopFn.Release()
+
+	if err := h.client.SetCapture(nil); err != nil {
+		log.Debugf("clear capture: %v", err)
+	}
+	h.sess.Stop()
+	return h.sess.Stats()
+}
+
+func statsToJS(s capture.Stats) js.Value {
+	obj := js.Global().Get("Object").Call("create", js.Null())
+	obj.Set("packets", js.ValueOf(s.Packets))
+	obj.Set("bytes", js.ValueOf(s.Bytes))
+	obj.Set("dropped", js.ValueOf(s.Dropped))
+	return obj
+}
+
+// parseOpts extracts filter/verbose/ascii from a JS options value.
+func parseOpts(jsOpts js.Value) (filter string, verbose, ascii bool) {
+	if jsOpts.IsNull() || jsOpts.IsUndefined() {
+		return
+	}
+	if jsOpts.Type() == js.TypeString {
+		filter = jsOpts.String()
+		return
+	}
+	if jsOpts.Type() != js.TypeObject {
+		return
+	}
+	if f := jsOpts.Get("filter"); !f.IsUndefined() && !f.IsNull() {
+		filter = f.String()
+	}
+	if v := jsOpts.Get("verbose"); !v.IsUndefined() {
+		verbose = v.Truthy()
+	}
+	if a := jsOpts.Get("ascii"); !a.IsUndefined() {
+		ascii = a.Truthy()
+	}
+	return
+}
+
+func buildMatcher(filter string) (capture.Matcher, error) {
+	if filter == "" {
+		return nil, nil
+	}
+	return capture.ParseFilter(filter)
+}
+
+// Start creates a capture session and returns a JS interface for streaming text
+// output. The returned object exposes:
+//
+//	onpacket(callback)  - set callback(string) for each text line
+//	stop()              - stop capture and return stats { packets, bytes, dropped }
+//
+// Options: { filter: string, verbose: bool, ascii: bool } or just a filter string.
+func Start(client *netbird.Client, jsOpts js.Value) (js.Value, error) {
+	filter, verbose, ascii := parseOpts(jsOpts)
+
+	matcher, err := buildMatcher(filter)
+	if err != nil {
+		return js.Undefined(), err
+	}
+
+	cb := &jsCallbackWriter{}
+
+	sess, err := capture.NewSession(capture.Options{
+		TextOutput: cb,
+		Matcher:    matcher,
+		Verbose:    verbose,
+		ASCII:      ascii,
+	})
+	if err != nil {
+		return js.Undefined(), err
+	}
+
+	if err := client.SetCapture(sess); err != nil {
+		sess.Stop()
+		return js.Undefined(), err
+	}
+
+	handle := &Handle{client: client, sess: sess}
+
+	iface := js.Global().Get("Object").Call("create", js.Null())
+	handle.stopFn = js.FuncOf(func(_ js.Value, _ []js.Value) any {
+		return statsToJS(handle.Stop())
+	})
+	iface.Set("stop", handle.stopFn)
+	iface.Set("onpacket", js.Undefined())
+	cb.setInterface(iface)
+
+	return iface, nil
+}
+
+// StartConsole starts a capture that logs every packet line to console.log.
+// Returns a Handle so the caller can stop it later.
+func StartConsole(client *netbird.Client, jsOpts js.Value) (*Handle, error) {
+	filter, verbose, ascii := parseOpts(jsOpts)
+
+	matcher, err := buildMatcher(filter)
+	if err != nil {
+		return nil, err
+	}
+
+	cb := &jsCallbackWriter{}
+
+	sess, err := capture.NewSession(capture.Options{
+		TextOutput: cb,
+		Matcher:    matcher,
+		Verbose:    verbose,
+		ASCII:      ascii,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	if err := client.SetCapture(sess); err != nil {
+		sess.Stop()
+		return nil, err
+	}
+
+	handle := &Handle{client: client, sess: sess}
+	handle.stopFn = js.FuncOf(func(_ js.Value, _ []js.Value) any {
+		return statsToJS(handle.Stop())
+	})
+
+	iface := js.Global().Get("Object").Call("create", js.Null())
+	console := js.Global().Get("console")
+	iface.Set("onpacket", console.Get("log").Call("bind", console, js.ValueOf("[capture]")))
+	cb.setInterface(iface)
+
+	return handle, nil
+}
+
+// jsCallbackWriter is an io.Writer that buffers text until a newline, then
+// invokes the JS onpacket callback with each complete line.
+type jsCallbackWriter struct {
+	mu    sync.Mutex
+	iface js.Value
+	buf   strings.Builder
+}
+
+func (w *jsCallbackWriter) setInterface(iface js.Value) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	w.iface = iface
+}
+
+func (w *jsCallbackWriter) Write(p []byte) (int, error) {
+	w.mu.Lock()
+	w.buf.Write(p)
+
+	var lines []string
+	for {
+		str := w.buf.String()
+		idx := strings.IndexByte(str, '\n')
+		if idx < 0 {
+			break
+		}
+		lines = append(lines, str[:idx])
+		w.buf.Reset()
+		if idx+1 < len(str) {
+			w.buf.WriteString(str[idx+1:])
+		}
+	}
+
+	iface := w.iface
+	w.mu.Unlock()
+
+	if iface.IsUndefined() {
+		return len(p), nil
+	}
+	cb := iface.Get("onpacket")
+	if cb.IsUndefined() || cb.IsNull() {
+		return len(p), nil
+	}
+	for _, line := range lines {
+		cb.Invoke(js.ValueOf(line))
+	}
+	return len(p), nil
+}