Runtime API: Make logs already available before client is fully

initialized

Author: zefhemel

server/headless.go

@@ -40,10 +40,14 @@ type HeadlessBrowser struct {
 	logsMu  sync.Mutex
 	logs    []ConsoleLogEntry
 	maxLogs int // ring buffer capacity
+
+	readyCh  chan struct{} // closed when client eval functions are ready
+	readyErr error         // non-nil if client failed to become ready
 }
 
 // StartHeadlessBrowser launches a headless Chrome browser and navigates to the SilverBullet URL.
-// It returns after the client's eval functions are ready, or returns an error on failure.
+// It returns as soon as the browser is navigating and collecting logs. The client may not be
+// fully ready yet; call WaitReady to block until eval functions are available.
 func StartHeadlessBrowser(config *HeadlessConfig) (*HeadlessBrowser, error) {
 	hb := &HeadlessBrowser{
 		config:  config,
@@ -61,6 +65,16 @@ func StartHeadlessBrowser(config *HeadlessConfig) (*HeadlessBrowser, error) {
 	return hb, nil
 }
 
+// WaitReady blocks until the client's eval functions are ready, or ctx is cancelled.
+func (hb *HeadlessBrowser) WaitReady(ctx context.Context) error {
+	select {
+	case <-hb.readyCh:
+		return hb.readyErr
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+}
+
 func (hb *HeadlessBrowser) launch() error {
 	// Various options to reduce memory consumption, primarily
 	opts := append(chromedp.DefaultExecAllocatorOptions[:],
@@ -134,17 +148,22 @@ func (hb *HeadlessBrowser) launch() error {
 		return fmt.Errorf("failed to navigate: %w", err)
 	}
 
-	// Wait for the client eval functions to be ready
-	readyCtx, readyCancel := context.WithTimeout(ctx, 60*time.Second)
-	defer readyCancel()
-
-	if err := waitForClientReady(readyCtx); err != nil {
-		cancel()
-		allocCancel()
-		return fmt.Errorf("client did not become ready: %w", err)
-	}
+	// Wait for client readiness in the background so logs are available immediately
+	readyCh := make(chan struct{})
+	hb.readyCh = readyCh
+	hb.readyErr = nil
+	go func() {
+		defer close(readyCh)
+		readyCtx, readyCancel := context.WithTimeout(ctx, 60*time.Second)
+		defer readyCancel()
+		if err := waitForClientReady(readyCtx); err != nil {
+			hb.readyErr = fmt.Errorf("client did not become ready: %w", err)
+			log.Printf("[Headless] %v", hb.readyErr)
+		} else {
+			log.Println("[Headless] Browser client connected successfully")
+		}
+	}()
 
-	log.Println("[Headless] Browser client connected successfully")
 	return nil
 }
 
@@ -203,7 +222,13 @@ func (hb *HeadlessBrowser) monitor() {
 			continue
 		}
 
-		// Success - reset backoff
+		// Wait for client to become fully ready before declaring success
+		if err := hb.WaitReady(hb.ctx); err != nil {
+			log.Printf("[Headless] Restart client readiness failed: %v", err)
+			backoff = min(backoff*2, maxBackoff)
+			continue
+		}
+
 		log.Println("[Headless] Restart successful")
 		backoff = 2 * time.Second
 	}

server/integration_headless_test.go

@@ -3,6 +3,7 @@
 package server
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -139,9 +140,13 @@ func startHeadless(t *testing.T, opts ...testServerOption) *testServer {
 		ServerURL:     ts.Server.URL,
 		HeadlessToken: ts.Config.HeadlessToken,
 	})
-	require.NoError(t, err, "headless browser should start and become ready")
+	require.NoError(t, err, "headless browser should start")
 	t.Cleanup(hb.Stop)
 
+	readyCtx, readyCancel := context.WithTimeout(context.Background(), 60*time.Second)
+	defer readyCancel()
+	require.NoError(t, hb.WaitReady(readyCtx), "headless browser client should become ready")
+
 	ts.Config.RuntimeBridge.SetBrowser(hb)
 
 	return ts
@@ -469,23 +474,6 @@ return x + y`
 		}
 	})
 
-	t.Run("Timeout", func(t *testing.T) {
-		req, _ := http.NewRequest(http.MethodPost, ts.Server.URL+"/.runtime/lua_script", strings.NewReader(`
-local i = 0
-while i < 999999999 do
-  i = i + 1
-end
-return i
-`))
-		req.Header.Set("X-Timeout", "1")
-
-		resp, err := http.DefaultClient.Do(req)
-		require.NoError(t, err)
-		defer resp.Body.Close()
-
-		assert.Equal(t, http.StatusGatewayTimeout, resp.StatusCode)
-	})
-
 	t.Run("Screenshot", func(t *testing.T) {
 		resp, err := http.Get(ts.Server.URL + "/.runtime/screenshot")
 		require.NoError(t, err)
@@ -540,6 +528,7 @@ return i
 		require.True(t, ok)
 		assert.LessOrEqual(t, len(logs), 5)
 	})
+
 }
 
 // --- Auth-enabled headless tests (single Chrome instance) ---

server/runtime_api.go

@@ -39,9 +39,10 @@ func NewRuntimeBridge(config *HeadlessConfig) *RuntimeBridge {
 	}
 }
 
-// EnsureRunning starts the headless browser if not already running.
-// Multiple concurrent callers coalesce on the starting channel.
-func (b *RuntimeBridge) EnsureRunning(ctx context.Context) error {
+// ensureLaunched starts the headless browser if not already launched.
+// Returns as soon as the browser process is running and collecting logs,
+// but the client may not be fully ready for eval yet.
+func (b *RuntimeBridge) ensureLaunched(ctx context.Context) error {
 	if b.config == nil {
 		return nil // headless disabled, nothing to start
 	}
@@ -84,6 +85,18 @@ func (b *RuntimeBridge) EnsureRunning(ctx context.Context) error {
 	return err
 }
 
+// EnsureRunning starts the headless browser and waits for the client to be fully ready.
+func (b *RuntimeBridge) EnsureRunning(ctx context.Context) error {
+	if err := b.ensureLaunched(ctx); err != nil {
+		return err
+	}
+	browser := b.getBrowser()
+	if browser == nil {
+		return nil
+	}
+	return browser.WaitReady(ctx)
+}
+
 // SetBrowser sets the headless browser instance on the bridge (used in tests).
 func (b *RuntimeBridge) SetBrowser(hb *HeadlessBrowser) {
 	b.mu.Lock()
@@ -183,14 +196,16 @@ func (b *RuntimeBridge) HandleScreenshot(w http.ResponseWriter, r *http.Request)
 }
 
 // HandleConsoleLogs returns recent console log entries from the headless browser.
+// Unlike other runtime endpoints, this does not wait for the client to be fully ready,
+// so it can return boot logs while the client is still loading.
 func (b *RuntimeBridge) HandleConsoleLogs(w http.ResponseWriter, r *http.Request) {
-	if err := b.EnsureRunning(r.Context()); err != nil {
+	if err := b.ensureLaunched(r.Context()); err != nil {
 		writeJSON(w, http.StatusServiceUnavailable, map[string]any{"error": fmt.Sprintf("Failed to start headless browser: %v", err)})
 		return
 	}
 	browser := b.getBrowser()
 	if browser == nil {
-		writeJSON(w, http.StatusServiceUnavailable, map[string]any{"error": "No headless browser running"})
+		writeJSON(w, http.StatusOK, map[string]any{"logs": []ConsoleLogEntry{}})
 		return
 	}
 	limit := 100