fix: remove context reaper to prevent background tabs from going stale
Some checks failed
CI / Build and Test (push) Failing after 35s
CI / Build and Test (pull_request) Failing after 35s

Background windows stopped updating because the reaper suspended contexts
after ContextSuspendAfter and fully reaped them after ContextTTL. Suspended
contexts had to re-run the page init function from scratch on reconnect,
losing the live-updating experience.

Contexts now live until the browser tab closes (beforeunload beacon) or
the server shuts down. The context map grows indefinitely — no background
reaper.

Removes: startReaper, reapOrphanedContexts, suspend/resume logic,
ContextSuspendAfter/ContextTTL config fields, lastSeenAt/suspended
context fields, and all associated tests.
This commit is contained in:
Ryan Hamamura
2026-02-20 08:48:21 -10:00
parent c0f4782f2b
commit b3c2d3ae32
6 changed files with 1 additions and 274 deletions

View File

@@ -1,8 +1,6 @@
package via
import (
"time"
"github.com/alexedwards/scs/v2"
"github.com/rs/zerolog"
)
@@ -62,16 +60,6 @@ type Options struct {
// the embedded NATS server. Ignored when a custom PubSub is configured.
Streams []StreamConfig
// ContextSuspendAfter is the time a context may be disconnected before
// the reaper suspends it (frees page resources but keeps the context
// shell for seamless re-init on reconnect). Default: 15m.
ContextSuspendAfter time.Duration
// ContextTTL is the maximum time a context may exist without an SSE
// connection before the background reaper fully disposes it.
// Default: 1h. Negative value disables the reaper.
ContextTTL time.Duration
// ActionRateLimit configures the default token-bucket rate limiter for
// action endpoints. Zero values use built-in defaults (10 req/s, burst 20).
// Set Rate to -1 to disable rate limiting entirely.

View File

@@ -42,8 +42,6 @@ type Context struct {
createdAt time.Time
sseConnected atomic.Bool
sseDisconnectedAt atomic.Pointer[time.Time]
lastSeenAt atomic.Pointer[time.Time]
suspended atomic.Bool
}
// View defines the UI rendered by this context.
@@ -444,13 +442,6 @@ func (c *Context) resetPageState() {
c.mu.Unlock()
}
// suspend frees page-scoped resources while keeping the context shell alive
// in the registry for seamless re-init on reconnect.
func (c *Context) suspend() {
c.resetPageState()
c.suspended.Store(true)
}
// Navigate performs an SPA navigation to the given path. It resets page state,
// runs the target page's init function (with middleware), and pushes the new
// view over the existing SSE connection with a view transition animation.

View File

@@ -66,7 +66,6 @@ v.Config(via.Options{
Plugins: []via.Plugin{MyPlugin},
SessionManager: sm,
PubSub: customBackend,
ContextTTL: 60 * time.Second,
ActionRateLimit: via.RateLimitConfig{Rate: 20, Burst: 40},
})
```
@@ -83,7 +82,6 @@ v.Config(via.Options{
| `DatastarContent` | (embedded) | Custom Datastar JS bytes |
| `DatastarPath` | `"/_datastar.js"` | URL path for the Datastar script |
| `PubSub` | embedded NATS | Custom PubSub backend. Replaces the default NATS. See [PubSub and Sessions](pubsub-and-sessions.md) |
| `ContextTTL` | `30s` | Max time a context survives without an SSE connection before cleanup. Negative value disables the reaper |
| `ActionRateLimit` | `10 req/s, burst 20` | Default token-bucket rate limiter for action endpoints. Rate of `-1` disables limiting |
## Static Files

View File

@@ -14,7 +14,7 @@ Browser hits page → new Context created → init function runs → HTML render
action fires → signals injected from browser → handler runs → Sync() → DOM patched
```
The context is disposed when the SSE connection closes (tab close, navigation away, network loss). A background reaper also cleans up contexts that never establish an SSE connection within `ContextTTL` (default 30s).
The context lives until the browser tab closes (detected via a `beforeunload` beacon) or the server shuts down. There is no background reaper — contexts persist across temporary SSE disconnections so backgrounded tabs resume seamlessly.
During [SPA navigation](routing-and-navigation.md#spa-navigation), the context itself survives — only page-level state (signals, actions, fields, intervals, subscriptions) is reset. The SSE connection persists.

93
via.go
View File

@@ -58,7 +58,6 @@ type V struct {
datastarPath string
datastarContent []byte
datastarOnce sync.Once
reaperStop chan struct{}
middleware []Middleware
layout func(func() h.H) h.H
}
@@ -139,12 +138,6 @@ func (v *V) Config(cfg Options) {
v.defaultNATS = nil
v.pubsub = cfg.PubSub
}
if cfg.ContextSuspendAfter != 0 {
v.cfg.ContextSuspendAfter = cfg.ContextSuspendAfter
}
if cfg.ContextTTL != 0 {
v.cfg.ContextTTL = cfg.ContextTTL
}
if cfg.Streams != nil {
v.cfg.Streams = cfg.Streams
}
@@ -292,75 +285,6 @@ func (v *V) getCtx(id string) (*Context, error) {
return nil, fmt.Errorf("ctx '%s' not found", id)
}
func (v *V) startReaper() {
ttl := v.cfg.ContextTTL
if ttl < 0 {
return
}
if ttl == 0 {
ttl = time.Hour
}
suspendAfter := v.cfg.ContextSuspendAfter
if suspendAfter == 0 {
suspendAfter = 15 * time.Minute
}
if suspendAfter > ttl {
suspendAfter = ttl
}
interval := suspendAfter / 3
if interval < 5*time.Second {
interval = 5 * time.Second
}
v.reaperStop = make(chan struct{})
go func() {
ticker := time.NewTicker(interval)
defer ticker.Stop()
for {
select {
case <-v.reaperStop:
return
case <-ticker.C:
v.reapOrphanedContexts(suspendAfter, ttl)
}
}
}()
}
func (v *V) reapOrphanedContexts(suspendAfter, ttl time.Duration) {
now := time.Now()
v.contextRegistryMutex.RLock()
var toSuspend, toReap []*Context
for _, c := range v.contextRegistry {
if c.sseConnected.Load() {
continue
}
// Use the most recent liveness signal
lastAlive := c.createdAt
if dc := c.sseDisconnectedAt.Load(); dc != nil && dc.After(lastAlive) {
lastAlive = *dc
}
if seen := c.lastSeenAt.Load(); seen != nil && seen.After(lastAlive) {
lastAlive = *seen
}
silentFor := now.Sub(lastAlive)
if silentFor > ttl {
toReap = append(toReap, c)
} else if silentFor > suspendAfter && !c.suspended.Load() {
toSuspend = append(toSuspend, c)
}
}
v.contextRegistryMutex.RUnlock()
for _, c := range toSuspend {
v.logInfo(c, "suspending context (no SSE connection after %s)", suspendAfter)
c.suspend()
}
for _, c := range toReap {
v.logInfo(c, "reaping orphaned context (no SSE connection after %s)", ttl)
v.cleanupCtx(c)
}
}
// Start starts the Via HTTP server and blocks until a SIGINT or SIGTERM
// signal is received, then performs a graceful shutdown.
func (v *V) Start() {
@@ -389,8 +313,6 @@ func (v *V) Start() {
Handler: handler,
}
v.startReaper()
errCh := make(chan error, 1)
go func() {
errCh <- v.server.ListenAndServe()
@@ -417,9 +339,6 @@ func (v *V) Start() {
// Shutdown gracefully shuts down the server and all contexts.
// Safe for programmatic or test use.
func (v *V) Shutdown() {
if v.reaperStop != nil {
close(v.reaperStop)
}
v.logInfo(nil, "draining all contexts")
v.drainAllContexts()
@@ -667,8 +586,6 @@ func New() *V {
return
}
c.reqCtx = r.Context()
now := time.Now()
c.lastSeenAt.Store(&now)
sse := datastar.NewSSE(w, r, datastar.WithCompression(datastar.WithBrotli(datastar.WithBrotliLevel(5))))
@@ -690,16 +607,6 @@ func New() *V {
c.sseDisconnectedAt.Store(nil)
v.logDebug(c, "SSE connection established")
if c.suspended.Load() {
c.navMu.Lock()
c.suspended.Store(false)
if initFn := v.pageRegistry[c.route]; initFn != nil {
v.logInfo(c, "resuming suspended context")
initFn(c)
}
c.navMu.Unlock()
}
go c.Sync()
keepalive := time.NewTicker(30 * time.Second)

View File

@@ -400,95 +400,6 @@ func TestPage_PanicsOnNoView(t *testing.T) {
})
}
func TestReaperCleansOrphanedContexts(t *testing.T) {
v := New()
c := newContext("orphan-1", "/", v)
c.createdAt = time.Now().Add(-time.Minute) // created 1 min ago
v.registerCtx(c)
_, err := v.getCtx("orphan-1")
assert.NoError(t, err)
v.reapOrphanedContexts(5*time.Second, 10*time.Second)
_, err = v.getCtx("orphan-1")
assert.Error(t, err, "orphaned context should have been reaped")
}
func TestReaperSuspendsContext(t *testing.T) {
v := New()
c := newContext("suspend-1", "/", v)
c.createdAt = time.Now().Add(-30 * time.Minute)
dc := time.Now().Add(-20 * time.Minute)
c.sseDisconnectedAt.Store(&dc)
v.registerCtx(c)
v.reapOrphanedContexts(15*time.Minute, time.Hour)
got, err := v.getCtx("suspend-1")
assert.NoError(t, err, "suspended context should still be in registry")
assert.True(t, got.suspended.Load(), "context should be marked suspended")
}
func TestReaperReapsAfterTTL(t *testing.T) {
v := New()
c := newContext("reap-1", "/", v)
c.createdAt = time.Now().Add(-3 * time.Hour)
dc := time.Now().Add(-2 * time.Hour)
c.sseDisconnectedAt.Store(&dc)
c.suspended.Store(true)
v.registerCtx(c)
v.reapOrphanedContexts(15*time.Minute, time.Hour)
_, err := v.getCtx("reap-1")
assert.Error(t, err, "context past TTL should have been reaped")
}
func TestReaperIgnoresAlreadySuspended(t *testing.T) {
v := New()
c := newContext("already-sus-1", "/", v)
c.createdAt = time.Now().Add(-30 * time.Minute)
dc := time.Now().Add(-20 * time.Minute)
c.sseDisconnectedAt.Store(&dc)
c.suspended.Store(true)
// give it a fresh pageStopChan so we can verify it's not re-closed
c.pageStopChan = make(chan struct{})
v.registerCtx(c)
v.reapOrphanedContexts(15*time.Minute, time.Hour)
got, err := v.getCtx("already-sus-1")
assert.NoError(t, err, "already-suspended context within TTL should survive")
assert.True(t, got.suspended.Load())
// pageStopChan should still be open (not re-suspended)
select {
case <-got.pageStopChan:
t.Fatal("pageStopChan was closed — context was re-suspended")
default:
}
}
func TestReaperIgnoresConnectedContexts(t *testing.T) {
v := New()
c := newContext("connected-1", "/", v)
c.createdAt = time.Now().Add(-time.Minute)
c.sseConnected.Store(true)
v.registerCtx(c)
v.reapOrphanedContexts(5*time.Second, 10*time.Second)
_, err := v.getCtx("connected-1")
assert.NoError(t, err, "connected context should survive reaping")
}
func TestReaperDisabledWithNegativeTTL(t *testing.T) {
v := New()
v.cfg.ContextTTL = -1
v.startReaper()
assert.Nil(t, v.reaperStop, "reaper should not start with negative TTL")
}
func TestCleanupCtxIdempotent(t *testing.T) {
v := New()
c := newContext("idempotent-1", "/", v)
@@ -503,74 +414,6 @@ func TestCleanupCtxIdempotent(t *testing.T) {
assert.Error(t, err, "context should be removed after cleanup")
}
func TestReaperRespectsLastSeenAt(t *testing.T) {
v := New()
c := newContext("seen-1", "/", v)
c.createdAt = time.Now().Add(-30 * time.Minute)
// Disconnected 20 min ago, but client retried (lastSeenAt) 2 min ago
dc := time.Now().Add(-20 * time.Minute)
c.sseDisconnectedAt.Store(&dc)
seen := time.Now().Add(-2 * time.Minute)
c.lastSeenAt.Store(&seen)
v.registerCtx(c)
v.reapOrphanedContexts(15*time.Minute, time.Hour)
_, err := v.getCtx("seen-1")
assert.NoError(t, err, "context with recent lastSeenAt should survive suspend threshold")
assert.False(t, c.suspended.Load(), "context should not be suspended")
}
func TestReaperFallsBackWithoutLastSeenAt(t *testing.T) {
v := New()
c := newContext("noseen-1", "/", v)
c.createdAt = time.Now().Add(-30 * time.Minute)
dc := time.Now().Add(-20 * time.Minute)
c.sseDisconnectedAt.Store(&dc)
// no lastSeenAt set — should fall back to sseDisconnectedAt
v.registerCtx(c)
v.reapOrphanedContexts(15*time.Minute, time.Hour)
got, err := v.getCtx("noseen-1")
assert.NoError(t, err, "context should still be in registry (suspended, not reaped)")
assert.True(t, got.suspended.Load(), "context should be suspended using sseDisconnectedAt fallback")
}
func TestReaperReapsWithStaleLastSeenAt(t *testing.T) {
v := New()
c := newContext("stale-seen-1", "/", v)
c.createdAt = time.Now().Add(-3 * time.Hour)
dc := time.Now().Add(-2 * time.Hour)
c.sseDisconnectedAt.Store(&dc)
// lastSeenAt is also old — beyond TTL
seen := time.Now().Add(-90 * time.Minute)
c.lastSeenAt.Store(&seen)
c.suspended.Store(true)
v.registerCtx(c)
v.reapOrphanedContexts(15*time.Minute, time.Hour)
_, err := v.getCtx("stale-seen-1")
assert.Error(t, err, "context with stale lastSeenAt beyond TTL should be reaped")
}
func TestLastSeenAtUpdatedOnSSEConnect(t *testing.T) {
v := New()
c := newContext("seen-sse-1", "/", v)
v.registerCtx(c)
assert.Nil(t, c.lastSeenAt.Load(), "lastSeenAt should be nil before SSE connect")
// Simulate what the SSE handler does after getCtx
now := time.Now()
c.lastSeenAt.Store(&now)
got := c.lastSeenAt.Load()
assert.NotNil(t, got, "lastSeenAt should be set after SSE connect")
assert.WithinDuration(t, now, *got, time.Second)
}
func TestDevModeRemovePersistedFix(t *testing.T) {
v := New()
v.cfg.DevMode = true