Files
Pierre Tachoire 4147fee4e5 fix(browser): make Lightpanda backend usable end-to-end
Live testing surfaced three issues:

- Lightpanda numbers targets per-browser, and each conn is its own
  browser, so every tab gets the same upstream targetID
  ("FID-0000000001"). Synthesize globally-unique "lp-N" keys for our
  internal map so multi-tenant tab tracking works.
- page.Info() returns valid data once post-open then errors on
  subsequent calls, which made ListTabs silently drop tabs. Cache URL
  and Title at OpenTab time and read from the cache in ListTabs.
- rod.Browser.Close() calls Browser.close which Lightpanda doesn't
  implement; the WS drops cleanly anyway. Swallow the error to quiet
  the noisy log line.

Two Lightpanda upstream bugs are documented in docs/browser-backends.md
and exercised by TestLightpanda_KnownUpstreamGaps:
  1. Accessibility.getFullAXTree returns nodeId as a JSON number
     (CDP spec: string)
  2. Runtime.evaluate rejects go-rod's function-apply wrapper
2026-07-01 10:23:20 +02:00

374 lines
10 KiB
Go

package browser
import (
"context"
"fmt"
"time"
"github.com/go-rod/rod"
"github.com/go-rod/rod/lib/proto"
)
// ListTabs returns open tabs filtered by the caller's tenant context.
func (m *Manager) ListTabs(ctx context.Context) ([]TabInfo, error) {
m.mu.Lock()
defer m.mu.Unlock()
if !m.isRunningLocked() {
return nil, fmt.Errorf("browser not running")
}
tenantID := tenantIDFromCtx(ctx)
// Lightpanda: no server-side enumeration — return what we're tracking.
// Use the cache populated at OpenTab; page.Info() is unreliable upstream
// after the initial call.
if m.backend == BackendLightpanda {
tabs := make([]TabInfo, 0, len(m.pages))
for tid := range m.pages {
if !m.pageVisibleToTenantLocked(tid, tenantID) {
continue
}
if cached, ok := m.pageInfos[tid]; ok {
tabs = append(tabs, cached)
continue
}
tabs = append(tabs, TabInfo{TargetID: tid})
}
return tabs, nil
}
// Use tenant-scoped browser context for page listing
b, err := m.tenantBrowserLocked(tenantID)
if err != nil {
return nil, err
}
pages, err := b.Pages()
if err != nil {
if m.remoteURL != "" {
if reconnErr := m.reconnectLocked(); reconnErr != nil {
return nil, fmt.Errorf("list pages: %w (reconnect also failed: %v)", err, reconnErr)
}
m.logger.Info("auto-reconnected to remote Chrome")
// Re-acquire tenant browser after reconnect (incognito contexts were reset)
b, err = m.tenantBrowserLocked(tenantID)
if err != nil {
return nil, err
}
pages, err = b.Pages()
if err != nil {
return nil, fmt.Errorf("list pages after reconnect: %w", err)
}
} else {
return nil, fmt.Errorf("list pages: %w", err)
}
}
tabs := make([]TabInfo, 0, len(pages))
for _, p := range pages {
info, err := p.Info()
if err != nil || info == nil {
continue
}
tid := string(p.TargetID)
m.pages[tid] = p
if tenantID != "" {
m.pageTenants[tid] = tenantID
}
tabs = append(tabs, TabInfo{
TargetID: tid,
URL: info.URL,
Title: info.Title,
})
}
return tabs, nil
}
// pageVisibleToTenantLocked reports whether a page is accessible to the given tenant.
// Master tenant and empty context see everything; scoped tenants see only their own pages.
// Must be called with mu held.
func (m *Manager) pageVisibleToTenantLocked(targetID, tenantID string) bool {
if tenantID == "" || tenantID == MasterTenantID {
return true
}
owner, ok := m.pageTenants[targetID]
if !ok {
return false // scoped tenant can't see pages with no recorded owner
}
return owner == tenantID
}
// OpenTab opens a new tab with the given URL.
// Pages are created within the tenant's incognito browser context for isolation.
// If the tenant already has maxPages open, the oldest idle page is closed first.
//
// Lightpanda: each tab gets its own dedicated CDP connection (lightpanda
// requires 1 conn per tab, and each connection is its own browser, so tenant
// isolation is automatic).
func (m *Manager) OpenTab(ctx context.Context, url string) (*TabInfo, error) {
scope := scopeFromCtx(ctx)
cookies, err := m.cookiesForURL(ctx, scope, url)
if err != nil {
return nil, fmt.Errorf("load browser cookies: %w", err)
}
m.mu.Lock()
defer m.mu.Unlock()
tenantID := scope.Key()
// Enforce max pages per tenant
if m.maxPages > 0 {
m.evictOldestIfOverLimitLocked(tenantID)
}
if m.backend == BackendLightpanda {
return m.openTabLightpandaLocked(ctx, tenantID, url)
}
b, err := m.tenantBrowserLocked(tenantID)
if err != nil {
return nil, err
}
initialURL := url
if len(cookies) > 0 {
initialURL = "about:blank"
}
page, err := b.Page(proto.TargetCreateTarget{URL: initialURL})
if err != nil {
return nil, fmt.Errorf("open tab: %w", err)
}
if len(cookies) > 0 {
if err := page.SetCookies(cookies); err != nil {
_ = page.Close()
return nil, fmt.Errorf("set browser cookies: %w", err)
}
if err := page.Navigate(url); err != nil {
_ = page.Close()
return nil, fmt.Errorf("navigate after setting cookies: %w", err)
}
}
// Watchdog: close page on ctx cancel to unblock WaitStable CDP call.
stopWatchdog := watchPageClose(ctx, page)
if err := page.WaitStable(300 * time.Millisecond); err != nil {
stopWatchdog()
if ctx.Err() != nil {
return nil, ctx.Err()
}
return nil, fmt.Errorf("wait stable: %w", err)
}
stopWatchdog()
info, _ := page.Info()
tid := string(page.TargetID)
m.pages[tid] = page
m.touchPageLocked(tid)
if tenantID != "" {
m.pageTenants[tid] = tenantID
}
// Set up console listener
m.setupConsoleListener(page, tid)
tab := &TabInfo{TargetID: tid, URL: url}
if info != nil {
tab.URL = info.URL
tab.Title = info.Title
}
return tab, nil
}
// openTabLightpandaLocked mints a fresh CDP connection, creates a browser
// context (required per-conn on lightpanda), creates a target, and attaches
// the resulting rod.Page. Must be called with mu held.
func (m *Manager) openTabLightpandaLocked(ctx context.Context, tenantID, targetURL string) (*TabInfo, error) {
conn := rod.New().Context(ctx).ControlURL(m.cdpURL)
if err := conn.Connect(); err != nil {
return nil, fmt.Errorf("lightpanda: connect: %w", err)
}
// Lightpanda requires Target.createBrowserContext per connection.
bc, err := proto.TargetCreateBrowserContext{}.Call(conn)
if err != nil {
_ = conn.Close()
return nil, fmt.Errorf("lightpanda: create browser context: %w", err)
}
tgt, err := proto.TargetCreateTarget{
URL: targetURL,
BrowserContextID: bc.BrowserContextID,
}.Call(conn)
if err != nil {
_ = conn.Close()
return nil, fmt.Errorf("lightpanda: create target: %w", err)
}
page, err := conn.PageFromTarget(tgt.TargetID)
if err != nil {
_ = conn.Close()
return nil, fmt.Errorf("lightpanda: page from target: %w", err)
}
// Best-effort stability wait — lightpanda may not fire every lifecycle event.
stopWatchdog := watchPageClose(ctx, page)
_ = page.WaitStable(300 * time.Millisecond)
stopWatchdog()
info, _ := page.Info()
// Lightpanda numbers targets per-browser, and each conn is its own browser,
// so every conn's first target is "FID-0000000001". Synthesize a globally
// unique key for our maps; the upstream targetID is only needed inside this
// function (for createTarget / PageFromTarget).
m.nextLpTabSeq++
tid := fmt.Sprintf("lp-%d", m.nextLpTabSeq)
m.pages[tid] = page
m.pageConns[tid] = conn
m.touchPageLocked(tid)
if tenantID != "" {
m.pageTenants[tid] = tenantID
}
m.setupConsoleListener(page, tid)
tab := TabInfo{TargetID: tid, URL: targetURL}
if info != nil {
tab.URL = info.URL
tab.Title = info.Title
}
// Cache for ListTabs — page.Info() is unreliable on Lightpanda after the
// initial post-open call.
m.pageInfos[tid] = tab
tabCopy := tab
return &tabCopy, nil
}
// evictOldestIfOverLimitLocked closes the oldest idle page for a tenant if at or over maxPages.
// Must be called with mu held.
func (m *Manager) evictOldestIfOverLimitLocked(tenantID string) {
isMaster := tenantID == "" || tenantID == MasterTenantID
// Collect targetIDs belonging to this tenant
var owned []string
for tid := range m.pages {
if isMaster {
// Master tenant owns pages not in pageTenants
if _, hasOwner := m.pageTenants[tid]; !hasOwner {
owned = append(owned, tid)
}
} else {
if m.pageTenants[tid] == tenantID {
owned = append(owned, tid)
}
}
}
if len(owned) < m.maxPages {
return
}
// Find the oldest page by lastUsed
var oldestID string
var oldestTime time.Time
for _, tid := range owned {
lu, ok := m.pageLastUsed[tid]
if !ok {
oldestID = tid
break
}
if oldestID == "" || lu.Before(oldestTime) {
oldestID = tid
oldestTime = lu
}
}
if oldestID == "" {
return
}
m.closeManagedPageLocked(oldestID)
m.logger.Info("evicted oldest page (max pages reached)", "targetId", oldestID, "tenant", tenantID)
}
// closeManagedPageLocked closes a page and removes all associated tracking.
// On Lightpanda, closing the dedicated CDP connection tears down the browser
// server-side (no page.Close() needed). Must be called with mu held.
func (m *Manager) closeManagedPageLocked(targetID string) {
if conn, ok := m.pageConns[targetID]; ok {
// Lightpanda: rod.Browser.Close() calls Browser.close which Lightpanda
// rejects with UnknownMethod; the WS drops anyway and Lightpanda
// auto-cleans the browser. Swallow the error.
_ = conn.Close()
delete(m.pageConns, targetID)
} else if page, ok := m.pages[targetID]; ok {
_ = page.Close()
}
delete(m.pages, targetID)
delete(m.pageInfos, targetID)
delete(m.console, targetID)
delete(m.pageTenants, targetID)
delete(m.pageLastUsed, targetID)
m.refs.Remove(targetID)
}
// FocusTab activates a tab.
func (m *Manager) FocusTab(ctx context.Context, targetID string) error {
tenantID := tenantIDFromCtx(ctx)
m.mu.Lock()
defer m.mu.Unlock()
page, err := m.getPageForTenant(targetID, tenantID)
if err != nil {
return err
}
_, err = page.Activate()
return err
}
// CloseTab closes a tab.
func (m *Manager) CloseTab(ctx context.Context, targetID string) error {
tenantID := tenantIDFromCtx(ctx)
m.mu.Lock()
defer m.mu.Unlock()
// Tenant ownership check — same semantics as getPageForTenant but without
// the upstream refresh, so it works uniformly for both backends.
if tenantID != "" && tenantID != MasterTenantID {
if owner, ok := m.pageTenants[targetID]; ok && owner != tenantID {
return fmt.Errorf("tab not found: %s", targetID)
}
}
if _, ok := m.pages[targetID]; !ok {
return fmt.Errorf("tab not found: %s", targetID)
}
m.closeManagedPageLocked(targetID)
return nil
}
// ConsoleMessages returns captured console messages for a tab.
func (m *Manager) ConsoleMessages(ctx context.Context, targetID string) []ConsoleMessage {
tenantID := tenantIDFromCtx(ctx)
m.mu.Lock()
defer m.mu.Unlock()
// Validate tenant ownership
if tenantID != "" && tenantID != MasterTenantID {
if owner, ok := m.pageTenants[targetID]; ok && owner != tenantID {
return []ConsoleMessage{}
}
}
msgs := m.console[targetID]
if msgs == nil {
return []ConsoleMessage{}
}
// Return copy and clear
result := make([]ConsoleMessage, len(msgs))
copy(result, msgs)
m.console[targetID] = nil
return result
}