| 1 | package serve |
| 2 | |
| 3 | import ( |
| 4 | "encoding/json" |
| 5 | "strings" |
| 6 | "sync" |
| 7 | "time" |
| 8 | |
| 9 | "reasonix/internal/agent" |
| 10 | "reasonix/internal/billing" |
| 11 | "reasonix/internal/event" |
| 12 | "reasonix/internal/eventwire" |
| 13 | ) |
| 14 | |
| 15 | type subscription struct { |
| 16 | all bool |
| 17 | } |
| 18 | |
| 19 | const ( |
| 20 | subscriberBufferSize = 128 |
| 21 | subscriberPriorityReserve = 32 |
| 22 | ) |
| 23 | |
| 24 | // Broadcaster is the event.Sink the controllers emit to in server mode. It |
| 25 | // marshals each event once and fans it out to every connected SSE subscriber. |
| 26 | // A slow subscriber's buffer is allowed to drop rather than back-pressure the |
| 27 | // agent goroutine — a browser that can't keep up loses intermediate frames, not |
| 28 | // the whole session (it can refetch /history). |
| 29 | type Broadcaster struct { |
| 30 | mu sync.Mutex |
| 31 | subs map[chan []byte]subscription |
| 32 | ledgers map[string]*billing.Ledger |
| 33 | current string |
| 34 | displayCurrency string |
| 35 | modelApplicationChanged func() |
| 36 | } |
| 37 | |
| 38 | // NewBroadcaster returns an empty Broadcaster ready to accept subscribers. |
| 39 | func NewBroadcaster() *Broadcaster { |
| 40 | return &Broadcaster{ |
| 41 | subs: map[chan []byte]subscription{}, |
| 42 | ledgers: map[string]*billing.Ledger{}, |
| 43 | } |
| 44 | } |
| 45 | |
| 46 | // SetDisplayCurrency rebinds the session ledger to a stored valuation. Empty |
| 47 | // keeps automatic mode: a single original currency is selected and mixed |
| 48 | // currencies remain buckets. |
| 49 | func (b *Broadcaster) SetDisplayCurrency(currency string) { |
| 50 | if b == nil { |
| 51 | return |
| 52 | } |
| 53 | b.mu.Lock() |
| 54 | b.displayCurrency = billing.NormalizeCurrency(currency) |
| 55 | b.mu.Unlock() |
| 56 | } |
| 57 | |
| 58 | // sessionRouteKey is the one normalization rule for session references the |
| 59 | // broadcaster keys on: final-format identity routes ("session-id:<id>") are not |
| 60 | // filesystem paths and stay verbatim, legacy transcript paths take their |
| 61 | // canonical form. Every emit, ledger and current-session update goes through |
| 62 | // it so an identity route can never be rewritten into a cwd-relative pseudo |
| 63 | // path that no subscriber or registry matches. |
| 64 | func sessionRouteKey(path string) string { |
| 65 | path = strings.TrimSpace(path) |
| 66 | if strings.HasPrefix(path, remoteSessionIDQueryPrefix) { |
| 67 | return path |
| 68 | } |
| 69 | return agent.CanonicalSessionPath(path) |
| 70 | } |
| 71 | |
| 72 | // hiddenFromCurrentOnly reports whether a routed frame is filtered out for |
| 73 | // subscribers that watch only the current session. The filter compares path |
| 74 | // keys; identity routes are not path-keyed and are routed by the client from |
| 75 | // the frame itself, exactly like identity-tagged live frames (which carry no |
| 76 | // path), so they are never dropped here. |
| 77 | func hiddenFromCurrentOnly(sessionPath, current string) bool { |
| 78 | if sessionPath == "" || strings.HasPrefix(sessionPath, remoteSessionIDQueryPrefix) { |
| 79 | return false |
| 80 | } |
| 81 | return sessionPath != current |
| 82 | } |
| 83 | |
| 84 | // SetCurrentSession records the controller shown by current-only subscribers. |
| 85 | // Untagged events remain compatible and are attributed to this session. |
| 86 | func (b *Broadcaster) SetCurrentSession(path string) { |
| 87 | if b == nil { |
| 88 | return |
| 89 | } |
| 90 | path = sessionRouteKey(path) |
| 91 | b.mu.Lock() |
| 92 | b.current = path |
| 93 | b.mu.Unlock() |
| 94 | } |
| 95 | |
| 96 | // CurrentSession reports the session currently selected by Serve. |
| 97 | func (b *Broadcaster) CurrentSession() string { |
| 98 | if b == nil { |
| 99 | return "" |
| 100 | } |
| 101 | b.mu.Lock() |
| 102 | defer b.mu.Unlock() |
| 103 | return b.current |
| 104 | } |
| 105 | |
| 106 | // ResetSession clears the current session usage ledger for legacy callers. |
| 107 | func (b *Broadcaster) ResetSession() { |
| 108 | b.ResetSessionPath("") |
| 109 | } |
| 110 | |
| 111 | // ResetSessionPath clears one session ledger without affecting detached |
| 112 | // sessions. Empty selects the current session. |
| 113 | func (b *Broadcaster) ResetSessionPath(path string) { |
| 114 | if b == nil { |
| 115 | return |
| 116 | } |
| 117 | b.mu.Lock() |
| 118 | if path == "" { |
| 119 | path = b.current |
| 120 | } else { |
| 121 | path = sessionRouteKey(path) |
| 122 | } |
| 123 | delete(b.ledgers, path) |
| 124 | b.mu.Unlock() |
| 125 | } |
| 126 | |
| 127 | // SessionCostQuote returns the current aggregate quote without repricing. |
| 128 | func (b *Broadcaster) SessionCostQuote() billing.CostQuote { |
| 129 | return b.SessionCostQuoteFor("") |
| 130 | } |
| 131 | |
| 132 | // SessionCostQuoteFor returns one session's aggregate quote. Empty selects |
| 133 | // the current session so existing single-session callers keep their contract. |
| 134 | func (b *Broadcaster) SessionCostQuoteFor(path string) billing.CostQuote { |
| 135 | if b == nil { |
| 136 | return billing.AggregateQuotes(nil, "") |
| 137 | } |
| 138 | b.mu.Lock() |
| 139 | defer b.mu.Unlock() |
| 140 | return b.ledgerLocked(path).Total(b.displayCurrency) |
| 141 | } |
| 142 | |
| 143 | func (b *Broadcaster) ledgerLocked(path string) *billing.Ledger { |
| 144 | if path == "" { |
| 145 | path = b.current |
| 146 | } else { |
| 147 | path = sessionRouteKey(path) |
| 148 | } |
| 149 | ledger := b.ledgers[path] |
| 150 | if ledger == nil { |
| 151 | ledger = billing.NewLedger() |
| 152 | b.ledgers[path] = ledger |
| 153 | } |
| 154 | return ledger |
| 155 | } |
| 156 | |
| 157 | // Emit marshals the event to JSON and delivers it to every subscriber. Drops to |
| 158 | // a subscriber whose buffer is full rather than blocking. A marshal failure is |
| 159 | // dropped silently — one bad event shouldn't stall the stream. |
| 160 | func (b *Broadcaster) Emit(e event.Event) { |
| 161 | if e.SessionPath != "" { |
| 162 | e.SessionPath = sessionRouteKey(e.SessionPath) |
| 163 | } |
| 164 | wired := eventwire.ToWire(e) |
| 165 | b.mu.Lock() |
| 166 | observedCurrent := b.current |
| 167 | b.mu.Unlock() |
| 168 | wired.SessionCurrent = e.SessionPath != "" && e.SessionPath == observedCurrent |
| 169 | data, err := json.Marshal(wired) |
| 170 | if err != nil { |
| 171 | return |
| 172 | } |
| 173 | b.mu.Lock() |
| 174 | defer b.mu.Unlock() |
| 175 | if b.current != observedCurrent { |
| 176 | wired.SessionCurrent = e.SessionPath != "" && e.SessionPath == b.current |
| 177 | data, err = json.Marshal(wired) |
| 178 | if err != nil { |
| 179 | return |
| 180 | } |
| 181 | } |
| 182 | if e.Kind == event.Usage && e.Usage != nil && e.CostQuote != nil { |
| 183 | b.ledgerLocked(e.SessionPath).Add(*e.CostQuote, billing.UsageTokens{ |
| 184 | PromptTokens: e.Usage.PromptTokens, CompletionTokens: e.Usage.CompletionTokens, |
| 185 | CacheHitTokens: e.Usage.CacheHitTokens, CacheMissTokens: e.Usage.CacheMissTokens, |
| 186 | CacheWriteTokens: e.Usage.CacheWriteTokens, CacheWriteBilledTokens: e.Usage.CacheWriteBilledTokens, |
| 187 | Estimated: e.Usage.Estimated, |
| 188 | }, time.Now().UTC()) |
| 189 | } |
| 190 | for ch, sub := range b.subs { |
| 191 | if !sub.all && hiddenFromCurrentOnly(e.SessionPath, b.current) { |
| 192 | continue |
| 193 | } |
| 194 | enqueueSubscriberFrame(ch, data, e.Kind) |
| 195 | } |
| 196 | } |
| 197 | |
| 198 | // EmitTo delivers an event only to the supplied subscriber. It is used for |
| 199 | // connection-local recovery frames, such as replaying a prompt to a browser |
| 200 | // that attached after the original event was emitted. Normal runtime events |
| 201 | // should continue to use Emit so every subscriber receives them. |
| 202 | func (b *Broadcaster) EmitTo(target <-chan []byte, e event.Event) { |
| 203 | if e.SessionPath != "" { |
| 204 | e.SessionPath = sessionRouteKey(e.SessionPath) |
| 205 | } |
| 206 | wired := eventwire.ToWire(e) |
| 207 | b.mu.Lock() |
| 208 | observedCurrent := b.current |
| 209 | b.mu.Unlock() |
| 210 | wired.SessionCurrent = e.SessionPath != "" && e.SessionPath == observedCurrent |
| 211 | data, err := json.Marshal(wired) |
| 212 | if err != nil { |
| 213 | return |
| 214 | } |
| 215 | b.mu.Lock() |
| 216 | defer b.mu.Unlock() |
| 217 | if b.current != observedCurrent { |
| 218 | wired.SessionCurrent = e.SessionPath != "" && e.SessionPath == b.current |
| 219 | data, err = json.Marshal(wired) |
| 220 | if err != nil { |
| 221 | return |
| 222 | } |
| 223 | } |
| 224 | for ch, sub := range b.subs { |
| 225 | if (<-chan []byte)(ch) != target { |
| 226 | continue |
| 227 | } |
| 228 | if !sub.all && hiddenFromCurrentOnly(e.SessionPath, b.current) { |
| 229 | return |
| 230 | } |
| 231 | enqueueSubscriberFrame(ch, data, e.Kind) |
| 232 | return |
| 233 | } |
| 234 | } |
| 235 | |
| 236 | // eventIsPriority keeps lifecycle and terminal frames out of the high-volume |
| 237 | // delta budget. Slow subscribers may recover text/history over HTTP, but they |
| 238 | // must still learn that a turn, prompt, or foreground-session transition ended. |
| 239 | func eventIsPriority(kind event.Kind) bool { |
| 240 | switch kind { |
| 241 | case event.Reasoning, event.Text, event.ToolProgress, event.StreamAttempt: |
| 242 | return false |
| 243 | default: |
| 244 | return true |
| 245 | } |
| 246 | } |
| 247 | |
| 248 | // eventMustReachSubscriber identifies lifecycle truth that cannot be recovered |
| 249 | // by refetching history. The reserved queue budget protects these frames from |
| 250 | // deltas; if other priority traffic also exhausts that budget, the newest |
| 251 | // terminal/routing frame evicts a recoverable queued frame instead of vanishing. |
| 252 | func eventMustReachSubscriber(kind event.Kind, data []byte) bool { |
| 253 | switch kind { |
| 254 | case event.TurnDone, event.SessionChanged: |
| 255 | return true |
| 256 | case event.Notice: |
| 257 | return wireFrameMustReachSubscriber(data) |
| 258 | default: |
| 259 | return false |
| 260 | } |
| 261 | } |
| 262 | |
| 263 | func enqueueSubscriberFrame(ch chan []byte, data []byte, kind event.Kind) { |
| 264 | priority := eventIsPriority(kind) |
| 265 | if !priority && len(ch) >= cap(ch)-subscriberPriorityReserve { |
| 266 | return |
| 267 | } |
| 268 | select { |
| 269 | case ch <- data: |
| 270 | return |
| 271 | default: |
| 272 | // A slow subscriber exhausted even the priority reserve. Ordinary |
| 273 | // priority events remain lossy, but lifecycle truth gets one slot by |
| 274 | // evicting an older frame while Broadcaster.mu serializes producers. |
| 275 | if !eventMustReachSubscriber(kind, data) || !evictRecoverableSubscriberFrame(ch) { |
| 276 | return |
| 277 | } |
| 278 | } |
| 279 | // Broadcaster.mu excludes every producer, and eviction leaves at least one |
| 280 | // slot. A concurrent consumer can only create more capacity, so this send is |
| 281 | // bounded while guaranteeing the terminal frame is retained. |
| 282 | ch <- data |
| 283 | } |
| 284 | |
| 285 | func evictRecoverableSubscriberFrame(ch chan []byte) bool { |
| 286 | queued := len(ch) |
| 287 | if queued < cap(ch) { |
| 288 | return true |
| 289 | } |
| 290 | frames := make([][]byte, 0, queued) |
| 291 | drain: |
| 292 | for range queued { |
| 293 | select { |
| 294 | case frame := <-ch: |
| 295 | frames = append(frames, frame) |
| 296 | default: |
| 297 | break drain |
| 298 | } |
| 299 | } |
| 300 | if len(frames) == 0 { |
| 301 | return true |
| 302 | } |
| 303 | evict := -1 |
| 304 | for i, frame := range frames { |
| 305 | if !wireFrameMustReachSubscriber(frame) { |
| 306 | evict = i |
| 307 | break |
| 308 | } |
| 309 | } |
| 310 | if evict < 0 { |
| 311 | // A bounded queue cannot retain an unbounded run of terminal frames. |
| 312 | // Prefer the latest lifecycle truth over an older one in that degenerate |
| 313 | // case; normal saturation always finds a recoverable delta/status frame. |
| 314 | evict = 0 |
| 315 | } |
| 316 | for i, frame := range frames { |
| 317 | if i != evict { |
| 318 | ch <- frame |
| 319 | } |
| 320 | } |
| 321 | return true |
| 322 | } |
| 323 | |
| 324 | func wireFrameMustReachSubscriber(data []byte) bool { |
| 325 | return eventwire.FrameMustReachMirror(data) |
| 326 | } |
| 327 | |
| 328 | // EmitWire publishes an externally authored wire frame (same JSON contract as |
| 329 | // locally emitted events) to every subscriber. The local-takeover mirror uses |
| 330 | // it: a desktop writer that owns the session file pushes its frames through |
| 331 | // Serve so the remote tab keeps rendering the conversation live without any |
| 332 | // change to its own pipeline. |
| 333 | func (b *Broadcaster) EmitWire(wired eventwire.Event) { |
| 334 | if wired.SessionPath != "" { |
| 335 | wired.SessionPath = sessionRouteKey(wired.SessionPath) |
| 336 | } |
| 337 | b.mu.Lock() |
| 338 | observedCurrent := b.current |
| 339 | b.mu.Unlock() |
| 340 | wired.SessionCurrent = wired.SessionPath != "" && wired.SessionPath == observedCurrent |
| 341 | data, err := json.Marshal(wired) |
| 342 | if err != nil { |
| 343 | return |
| 344 | } |
| 345 | b.mu.Lock() |
| 346 | defer b.mu.Unlock() |
| 347 | if b.current != observedCurrent { |
| 348 | wired.SessionCurrent = wired.SessionPath != "" && wired.SessionPath == b.current |
| 349 | data, err = json.Marshal(wired) |
| 350 | if err != nil { |
| 351 | return |
| 352 | } |
| 353 | } |
| 354 | for ch := range b.subs { |
| 355 | enqueueSubscriberWireFrame(ch, data, wired.Kind) |
| 356 | } |
| 357 | } |
| 358 | |
| 359 | // wireKindIsPriority mirrors eventIsPriority for externally supplied frames, |
| 360 | // which arrive as wire kind strings rather than typed event.Kind values. |
| 361 | func wireKindIsPriority(kind string) bool { |
| 362 | return !eventwire.WireKindIsRecoverable(kind) |
| 363 | } |
| 364 | |
| 365 | func enqueueSubscriberWireFrame(ch chan []byte, data []byte, kind string) { |
| 366 | priority := wireKindIsPriority(kind) |
| 367 | if !priority && len(ch) >= cap(ch)-subscriberPriorityReserve { |
| 368 | return |
| 369 | } |
| 370 | select { |
| 371 | case ch <- data: |
| 372 | return |
| 373 | default: |
| 374 | if !wireFrameMustReachSubscriber(data) || !evictRecoverableSubscriberFrame(ch) { |
| 375 | return |
| 376 | } |
| 377 | } |
| 378 | ch <- data |
| 379 | } |
| 380 | |
| 381 | // Subscribe registers a new SSE client and returns its channel plus an |
| 382 | // unsubscribe func the handler must call (defer) when the client disconnects. |
| 383 | func (b *Broadcaster) Subscribe() (<-chan []byte, func()) { |
| 384 | return b.subscribe(false) |
| 385 | } |
| 386 | |
| 387 | // SubscribeAll receives tagged frames from current and detached sessions. |
| 388 | // Desktop uses it to maintain per-session runtime state; browser clients keep |
| 389 | // using Subscribe and see only the selected session. |
| 390 | func (b *Broadcaster) SubscribeAll() (<-chan []byte, func()) { |
| 391 | return b.subscribe(true) |
| 392 | } |
| 393 | |
| 394 | func (b *Broadcaster) subscribe(all bool) (<-chan []byte, func()) { |
| 395 | ch := make(chan []byte, subscriberBufferSize) |
| 396 | b.mu.Lock() |
| 397 | b.subs[ch] = subscription{all: all} |
| 398 | b.mu.Unlock() |
| 399 | return ch, func() { |
| 400 | b.mu.Lock() |
| 401 | if _, ok := b.subs[ch]; ok { |
| 402 | delete(b.subs, ch) |
| 403 | close(ch) |
| 404 | } |
| 405 | b.mu.Unlock() |
| 406 | } |
| 407 | } |
| 408 | |
| 409 | // Subscribers reports the current connection count (for diagnostics/tests). |
| 410 | func (b *Broadcaster) Subscribers() int { |
| 411 | b.mu.Lock() |
| 412 | defer b.mu.Unlock() |
| 413 | return len(b.subs) |
| 414 | } |
| 415 |