tailscale/ipn/ipnlocal/web.go

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// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
//go:build !ios && !android
package ipnlocal
import (
"context"
"errors"
"fmt"
"net/http"
"sync"
"tailscale.com/client/tailscale"
"tailscale.com/client/web"
"tailscale.com/envknob"
)
// webServer holds state for the web interface for managing
// this tailscale instance. The web interface is not used by
// default, but initialized by calling LocalBackend.WebOrInit.
type webServer struct {
ws *web.Server // or nil, initialized lazily
httpServer *http.Server // or nil, initialized lazily
// lc optionally specifies a LocalClient to use to connect
// to the localapi for this tailscaled instance.
// If nil, a default is used.
lc *tailscale.LocalClient
wg sync.WaitGroup
}
// SetWebLocalClient sets the b.web.lc function.
// If lc is provided as nil, b.web.lc is cleared out.
func (b *LocalBackend) SetWebLocalClient(lc *tailscale.LocalClient) {
b.mu.Lock()
defer b.mu.Unlock()
b.web.lc = lc
}
// WebInit initializes the web interface for managing
// this tailscaled instance. If the web interface is
// already running, WebInit is a no-op.
func (b *LocalBackend) WebInit() (err error) {
if !envknob.Bool("TS_DEBUG_WEB_UI") {
return errors.New("web ui flag unset")
}
b.mu.Lock()
defer b.mu.Unlock()
if b.web.ws != nil {
return nil
}
b.logf("WebInit: initializing web ui")
if b.web.ws, err = web.NewServer(web.ServerOpts{
// TODO(sonia): allow passing back dev mode flag
LocalClient: b.web.lc,
Logf: b.logf,
}); err != nil {
return fmt.Errorf("web.NewServer: %w", err)
}
// Start up the server.
b.web.wg.Add(1)
go func() {
defer b.web.wg.Done()
// TODO(sonia/will): only listen on Tailscale IP addresses
addr := ":5252"
b.web.httpServer = &http.Server{
Addr: addr,
Handler: http.HandlerFunc(b.web.ws.ServeHTTP),
}
b.logf("WebInit: serving web ui on %s", addr)
if err := b.web.httpServer.ListenAndServe(); err != nil {
if err != http.ErrServerClosed {
b.logf("[unexpected] WebInit: %v", err)
}
}
}()
b.logf("WebInit: started web ui")
return nil
}
// WebShutdown shuts down any running b.web servers and
// clears out b.web state (besides the b.web.lc field,
// which is left untouched because required for future
// web startups).
// WebShutdown obtains the b.mu lock.
func (b *LocalBackend) WebShutdown() {
b.mu.Lock()
webS := b.web.ws
httpS := b.web.httpServer
b.web.ws = nil
b.web.httpServer = nil
b.mu.Unlock() // release lock before shutdown
if webS != nil {
b.web.ws.Shutdown()
}
if httpS != nil {
if err := b.web.httpServer.Shutdown(context.Background()); err != nil {
b.logf("[unexpected] WebShutdown: %v", err)
}
}
b.web.wg.Wait()
b.logf("WebShutdown: shut down web ui")
}